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Chat with Java and Servlets

(warning)

Warning

As the Programmable Chat API is set to sunset in 2022, we will no longer maintain these chat tutorials.

Please see our Conversations API QuickStart to start building robust virtual spaces for conversation.

(error)

Danger

Programmable Chat has been deprecated and is no longer supported. Instead, we'll be focusing on the next generation of chat: Twilio Conversations. Find out more about the EOL process here.

If you're starting a new project, please visit the Conversations Docs to begin. If you've already built on Programmable Chat, please visit our Migration Guide to learn about how to switch.

Ready to implement a chat application using Twilio Programmable Chat Client?

This application allows users to exchange messages through different channels, using the Twilio Programmable Chat API. In this example, we'll show how to use this API capabilities to manage channels and their usages.

Properati built a web and mobile messaging app to help real estate buyers and sellers connect in real time. Learn more here.

For your convenience, we consolidated the source code for this tutorial in a single GitHub repository. Feel free to clone it and tweak it as required.

Generate the Token

In order to create a Twilio Programmable Chat client, you will need an access token. This token holds information about your Twilio Account and Chat API keys.

We generate this token by creating a new AccessToken and providing it with a ChatGrant. With the AccessToken at hand, we can use its method ToJWT() to return its string representation.

Generate an Access Token

src/main/java/com/twilio/chat/TwilioTokenCreator.java

1package com.twilio.chat;
2
3import javax.inject.Inject;
4
5import com.twilio.jwt.accesstoken.AccessToken;
6import com.twilio.jwt.accesstoken.ChatGrant;
7
8public class TwilioTokenCreator {
9
10  private final AppConfig appConfig;
11
12  @Inject
13  public TwilioTokenCreator(AppConfig appConfig) {
14    this.appConfig = appConfig;
15    if (appConfig.isIncomplete()) {
16      throw new IncompleteConfigException(appConfig);
17    }
18  }
19
20  String generateToken(String identity) {
21    ChatGrant grant = new ChatGrant();
22    grant.setServiceSid(appConfig.getTwilioChatServiceSID());
23
24    AccessToken token = new AccessToken.Builder(
25      appConfig.getTwilioAccountSID(),
26      appConfig.getTwilioAPIKey(),
27      appConfig.getTwilioAPISecret()
28    ).identity(identity).grant(grant).build();
29
30    return token.toJwt();
31  }
32}

We can generate a token, now we need a way for the chat app to get it.

Token Generation Controller

On our controller we expose the endpoint responsible for providing a valid token. Using this parameter:

identity: identifies the user itself.

It uses tokenGenerator.Generate method to get hold of a new token and return it in a JSON format to be used for our client.

Token Generation Controller

src/main/java/com/twilio/chat/TokenServlet.java

1package com.twilio.chat;
2
3import java.io.BufferedWriter;
4import java.io.IOException;
5import java.util.HashMap;
6import java.util.Map;
7
8import javax.inject.Inject;
9import javax.servlet.http.HttpServlet;
10import javax.servlet.http.HttpServletRequest;
11import javax.servlet.http.HttpServletResponse;
12
13import com.google.gson.Gson;
14import com.google.inject.Singleton;
15
16@Singleton
17public class TokenServlet extends HttpServlet {
18
19  private final TwilioTokenCreator tokenCreator;
20
21  @Inject
22  public TokenServlet(TwilioTokenCreator tokenCreator) {
23    this.tokenCreator = tokenCreator;
24  }
25
26  @Override
27  public void doPost(HttpServletRequest request, HttpServletResponse response) {
28    String identity = request.getParameter("identity");
29
30    if (identity != null) {
31
32      String generatedToken = tokenCreator.generateToken(identity);
33
34      Map<String, String> json = new HashMap<>();
35      json.put("identity", identity);
36      json.put("token", generatedToken);
37      renderJson(response, json);
38    }
39
40  }
41
42  private void renderJson(HttpServletResponse response, Map<String, String> json) {
43    Gson gson = new Gson();
44    response.setContentType("application/json");
45    try (BufferedWriter responseWriter = new BufferedWriter(response.getWriter())) {
46      responseWriter.write(gson.toJson(json));
47      responseWriter.flush();
48    } catch (IOException e) {
49      e.printStackTrace();
50    }
51  }
52}
53

Now that we have a route that generates JWT tokens on demand, let's use this route to initialize our Twilio Chat Client.

Initialize the Programmable Chat Client

On our client, we fetch a new Token using a POST request to our endpoint.

With the token, we can create a new Twilio.AccessManager, and initialize our Twilio.Chat.Client.

Initialize the Chat Client

src/main/webapp/js/twiliochat.js

1var twiliochat = (function() {
2  var tc = {};
3
4  var GENERAL_CHANNEL_UNIQUE_NAME = 'general';
5  var GENERAL_CHANNEL_NAME = 'General Channel';
6  var MESSAGES_HISTORY_LIMIT = 50;
7
8  var $channelList;
9  var $inputText;
10  var $usernameInput;
11  var $statusRow;
12  var $connectPanel;
13  var $newChannelInputRow;
14  var $newChannelInput;
15  var $typingRow;
16  var $typingPlaceholder;
17
18  $(document).ready(function() {
19    tc.$messageList = $('#message-list');
20    $channelList = $('#channel-list');
21    $inputText = $('#input-text');
22    $usernameInput = $('#username-input');
23    $statusRow = $('#status-row');
24    $connectPanel = $('#connect-panel');
25    $newChannelInputRow = $('#new-channel-input-row');
26    $newChannelInput = $('#new-channel-input');
27    $typingRow = $('#typing-row');
28    $typingPlaceholder = $('#typing-placeholder');
29    $usernameInput.focus();
30    $usernameInput.on('keypress', handleUsernameInputKeypress);
31    $inputText.on('keypress', handleInputTextKeypress);
32    $newChannelInput.on('keypress', tc.handleNewChannelInputKeypress);
33    $('#connect-image').on('click', connectClientWithUsername);
34    $('#add-channel-image').on('click', showAddChannelInput);
35    $('#leave-span').on('click', disconnectClient);
36    $('#delete-channel-span').on('click', deleteCurrentChannel);
37  });
38
39  function handleUsernameInputKeypress(event) {
40    if (event.keyCode === 13){
41      connectClientWithUsername();
42    }
43  }
44
45  function handleInputTextKeypress(event) {
46    if (event.keyCode === 13) {
47      tc.currentChannel.sendMessage($(this).val());
48      event.preventDefault();
49      $(this).val('');
50    }
51    else {
52      notifyTyping();
53    }
54  }
55
56  var notifyTyping = $.throttle(function() {
57    tc.currentChannel.typing();
58  }, 1000);
59
60  tc.handleNewChannelInputKeypress = function(event) {
61    if (event.keyCode === 13) {
62      tc.messagingClient.createChannel({
63        friendlyName: $newChannelInput.val()
64      }).then(hideAddChannelInput);
65      $(this).val('');
66      event.preventDefault();
67    }
68  };
69
70  function connectClientWithUsername() {
71    var usernameText = $usernameInput.val();
72    $usernameInput.val('');
73    if (usernameText == '') {
74      alert('Username cannot be empty');
75      return;
76    }
77    tc.username = usernameText;
78    fetchAccessToken(tc.username, connectMessagingClient);
79  }
80
81  function fetchAccessToken(username, handler) {
82    $.post('/twiliochat-servlets/token', {identity: username}, null, 'json')
83      .done(function(response) {
84        console.log('Successfully finished fetch of the Access Token.');
85        handler(response.token);
86      })
87      .fail(function(error) {
88        console.log('Failed to fetch the Access Token with error: ' + error);
89      });
90  }
91
92  function connectMessagingClient(token) {
93    // Initialize the Chat messaging client
94    tc.accessManager = new Twilio.AccessManager(token);
95    Twilio.Chat.Client.create(token).then(function(client) {
96      tc.messagingClient = client;
97      updateConnectedUI();
98      tc.loadChannelList(tc.joinGeneralChannel);
99      tc.messagingClient.on('channelAdded', $.throttle(tc.loadChannelList));
100      tc.messagingClient.on('channelRemoved', $.throttle(tc.loadChannelList));
101      tc.messagingClient.on('tokenExpired', refreshToken);
102    });
103  }
104
105  function refreshToken() {
106    fetchAccessToken(tc.username, setNewToken);
107  }
108
109  function setNewToken(tokenResponse) {
110    tc.accessManager.updateToken(tokenResponse.token);
111  }
112
113  function updateConnectedUI() {
114    $('#username-span').text(tc.username);
115    $statusRow.addClass('connected').removeClass('disconnected');
116    tc.$messageList.addClass('connected').removeClass('disconnected');
117    $connectPanel.addClass('connected').removeClass('disconnected');
118    $inputText.addClass('with-shadow');
119    $typingRow.addClass('connected').removeClass('disconnected');
120  }
121
122  tc.loadChannelList = function(handler) {
123    if (tc.messagingClient === undefined) {
124      console.log('Client is not initialized');
125      return;
126    }
127
128    tc.messagingClient.getPublicChannelDescriptors().then(function(channels) {
129      tc.channelArray = tc.sortChannelsByName(channels.items);
130      $channelList.text('');
131      tc.channelArray.forEach(addChannel);
132      if (typeof handler === 'function') {
133        handler();
134      }
135    });
136  };
137
138  tc.joinGeneralChannel = function() {
139    console.log('Attempting to join "general" chat channel...');
140    if (!tc.generalChannel) {
141      // If it doesn't exist, let's create it
142      tc.messagingClient.createChannel({
143        uniqueName: GENERAL_CHANNEL_UNIQUE_NAME,
144        friendlyName: GENERAL_CHANNEL_NAME
145      }).then(function(channel) {
146        console.log('Created general channel');
147        tc.generalChannel = channel;
148        tc.loadChannelList(tc.joinGeneralChannel);
149      });
150    }
151    else {
152      console.log('Found general channel:');
153      setupChannel(tc.generalChannel);
154    }
155  };
156
157  function initChannel(channel) {
158    console.log('Initialized channel ' + channel.friendlyName);
159    return tc.messagingClient.getChannelBySid(channel.sid);
160  }
161
162  function joinChannel(_channel) {
163    return _channel.join()
164      .then(function(joinedChannel) {
165        console.log('Joined channel ' + joinedChannel.friendlyName);
166        updateChannelUI(_channel);
167        tc.currentChannel = _channel;
168        tc.loadMessages();
169        return joinedChannel;
170      });
171  }
172
173  function initChannelEvents() {
174    console.log(tc.currentChannel.friendlyName + ' ready.');
175    tc.currentChannel.on('messageAdded', tc.addMessageToList);
176    tc.currentChannel.on('typingStarted', showTypingStarted);
177    tc.currentChannel.on('typingEnded', hideTypingStarted);
178    tc.currentChannel.on('memberJoined', notifyMemberJoined);
179    tc.currentChannel.on('memberLeft', notifyMemberLeft);
180    $inputText.prop('disabled', false).focus();
181  }
182
183  function setupChannel(channel) {
184    return leaveCurrentChannel()
185      .then(function() {
186        return initChannel(channel);
187      })
188      .then(function(_channel) {
189        return joinChannel(_channel);
190      })
191      .then(initChannelEvents);
192  }
193
194  tc.loadMessages = function() {
195    tc.currentChannel.getMessages(MESSAGES_HISTORY_LIMIT)
196      .then(function(messages) {
197        messages.items.forEach(tc.addMessageToList);
198    });
199  };
200
201  function leaveCurrentChannel() {
202    if (tc.currentChannel) {
203      return tc.currentChannel.leave().then(function(leftChannel) {
204        console.log('left ' + leftChannel.friendlyName);
205        leftChannel.removeListener('messageAdded', tc.addMessageToList);
206        leftChannel.removeListener('typingStarted', showTypingStarted);
207        leftChannel.removeListener('typingEnded', hideTypingStarted);
208        leftChannel.removeListener('memberJoined', notifyMemberJoined);
209        leftChannel.removeListener('memberLeft', notifyMemberLeft);
210      });
211    } else {
212      return Promise.resolve();
213    }
214  }
215
216  tc.addMessageToList = function(message) {
217    var rowDiv = $('<div>').addClass('row no-margin');
218    rowDiv.loadTemplate($('#message-template'), {
219      username: message.author,
220      date: dateFormatter.getTodayDate(message.dateCreated),
221      body: message.body
222    });
223    if (message.author === tc.username) {
224      rowDiv.addClass('own-message');
225    }
226
227    tc.$messageList.append(rowDiv);
228    scrollToMessageListBottom();
229  };
230
231  function notifyMemberJoined(member) {
232    notify(member.identity + ' joined the channel')
233  }
234
235  function notifyMemberLeft(member) {
236    notify(member.identity + ' left the channel');
237  }
238
239  function notify(message) {
240    var row = $('<div>').addClass('col-md-12');
241    row.loadTemplate('#member-notification-template', {
242      status: message
243    });
244    tc.$messageList.append(row);
245    scrollToMessageListBottom();
246  }
247
248  function showTypingStarted(member) {
249    $typingPlaceholder.text(member.identity + ' is typing...');
250  }
251
252  function hideTypingStarted(member) {
253    $typingPlaceholder.text('');
254  }
255
256  function scrollToMessageListBottom() {
257    tc.$messageList.scrollTop(tc.$messageList[0].scrollHeight);
258  }
259
260  function updateChannelUI(selectedChannel) {
261    var channelElements = $('.channel-element').toArray();
262    var channelElement = channelElements.filter(function(element) {
263      return $(element).data().sid === selectedChannel.sid;
264    });
265    channelElement = $(channelElement);
266    if (tc.currentChannelContainer === undefined && selectedChannel.uniqueName === GENERAL_CHANNEL_UNIQUE_NAME) {
267      tc.currentChannelContainer = channelElement;
268    }
269    tc.currentChannelContainer.removeClass('selected-channel').addClass('unselected-channel');
270    channelElement.removeClass('unselected-channel').addClass('selected-channel');
271    tc.currentChannelContainer = channelElement;
272  }
273
274  function showAddChannelInput() {
275    if (tc.messagingClient) {
276      $newChannelInputRow.addClass('showing').removeClass('not-showing');
277      $channelList.addClass('showing').removeClass('not-showing');
278      $newChannelInput.focus();
279    }
280  }
281
282  function hideAddChannelInput() {
283    $newChannelInputRow.addClass('not-showing').removeClass('showing');
284    $channelList.addClass('not-showing').removeClass('showing');
285    $newChannelInput.val('');
286  }
287
288  function addChannel(channel) {
289    if (channel.uniqueName === GENERAL_CHANNEL_UNIQUE_NAME) {
290      tc.generalChannel = channel;
291    }
292    var rowDiv = $('<div>').addClass('row channel-row');
293    rowDiv.loadTemplate('#channel-template', {
294      channelName: channel.friendlyName
295    });
296
297    var channelP = rowDiv.children().children().first();
298
299    rowDiv.on('click', selectChannel);
300    channelP.data('sid', channel.sid);
301    if (tc.currentChannel && channel.sid === tc.currentChannel.sid) {
302      tc.currentChannelContainer = channelP;
303      channelP.addClass('selected-channel');
304    }
305    else {
306      channelP.addClass('unselected-channel')
307    }
308
309    $channelList.append(rowDiv);
310  }
311
312  function deleteCurrentChannel() {
313    if (!tc.currentChannel) {
314      return;
315    }
316    if (tc.currentChannel.sid === tc.generalChannel.sid) {
317      alert('You cannot delete the general channel');
318      return;
319    }
320    tc.currentChannel.delete().then(function(channel) {
321      console.log('channel: '+ channel.friendlyName + ' deleted');
322      setupChannel(tc.generalChannel);
323    });
324  }
325
326  function selectChannel(event) {
327    var target = $(event.target);
328    var channelSid = target.data().sid;
329    var selectedChannel = tc.channelArray.filter(function(channel) {
330      return channel.sid === channelSid;
331    })[0];
332    if (selectedChannel === tc.currentChannel) {
333      return;
334    }
335    setupChannel(selectedChannel);
336  };
337
338  function disconnectClient() {
339    leaveCurrentChannel();
340    $channelList.text('');
341    tc.$messageList.text('');
342    channels = undefined;
343    $statusRow.addClass('disconnected').removeClass('connected');
344    tc.$messageList.addClass('disconnected').removeClass('connected');
345    $connectPanel.addClass('disconnected').removeClass('connected');
346    $inputText.removeClass('with-shadow');
347    $typingRow.addClass('disconnected').removeClass('connected');
348  }
349
350  tc.sortChannelsByName = function(channels) {
351    return channels.sort(function(a, b) {
352      if (a.friendlyName === GENERAL_CHANNEL_NAME) {
353        return -1;
354      }
355      if (b.friendlyName === GENERAL_CHANNEL_NAME) {
356        return 1;
357      }
358      return a.friendlyName.localeCompare(b.friendlyName);
359    });
360  };
361
362  return tc;
363})();
364

Now that we've initialized our Chat Client, let's see how we can get a list of channels.

Get the Channel List

After initializing the client, we can call its method getPublicChannelDescriptors to retrieve all visible channels. The method returns a promise which we use to show the list of channels retrieved on the UI.

Get the Channel List

src/main/webapp/js/twiliochat.js

1var twiliochat = (function() {
2  var tc = {};
3
4  var GENERAL_CHANNEL_UNIQUE_NAME = 'general';
5  var GENERAL_CHANNEL_NAME = 'General Channel';
6  var MESSAGES_HISTORY_LIMIT = 50;
7
8  var $channelList;
9  var $inputText;
10  var $usernameInput;
11  var $statusRow;
12  var $connectPanel;
13  var $newChannelInputRow;
14  var $newChannelInput;
15  var $typingRow;
16  var $typingPlaceholder;
17
18  $(document).ready(function() {
19    tc.$messageList = $('#message-list');
20    $channelList = $('#channel-list');
21    $inputText = $('#input-text');
22    $usernameInput = $('#username-input');
23    $statusRow = $('#status-row');
24    $connectPanel = $('#connect-panel');
25    $newChannelInputRow = $('#new-channel-input-row');
26    $newChannelInput = $('#new-channel-input');
27    $typingRow = $('#typing-row');
28    $typingPlaceholder = $('#typing-placeholder');
29    $usernameInput.focus();
30    $usernameInput.on('keypress', handleUsernameInputKeypress);
31    $inputText.on('keypress', handleInputTextKeypress);
32    $newChannelInput.on('keypress', tc.handleNewChannelInputKeypress);
33    $('#connect-image').on('click', connectClientWithUsername);
34    $('#add-channel-image').on('click', showAddChannelInput);
35    $('#leave-span').on('click', disconnectClient);
36    $('#delete-channel-span').on('click', deleteCurrentChannel);
37  });
38
39  function handleUsernameInputKeypress(event) {
40    if (event.keyCode === 13){
41      connectClientWithUsername();
42    }
43  }
44
45  function handleInputTextKeypress(event) {
46    if (event.keyCode === 13) {
47      tc.currentChannel.sendMessage($(this).val());
48      event.preventDefault();
49      $(this).val('');
50    }
51    else {
52      notifyTyping();
53    }
54  }
55
56  var notifyTyping = $.throttle(function() {
57    tc.currentChannel.typing();
58  }, 1000);
59
60  tc.handleNewChannelInputKeypress = function(event) {
61    if (event.keyCode === 13) {
62      tc.messagingClient.createChannel({
63        friendlyName: $newChannelInput.val()
64      }).then(hideAddChannelInput);
65      $(this).val('');
66      event.preventDefault();
67    }
68  };
69
70  function connectClientWithUsername() {
71    var usernameText = $usernameInput.val();
72    $usernameInput.val('');
73    if (usernameText == '') {
74      alert('Username cannot be empty');
75      return;
76    }
77    tc.username = usernameText;
78    fetchAccessToken(tc.username, connectMessagingClient);
79  }
80
81  function fetchAccessToken(username, handler) {
82    $.post('/twiliochat-servlets/token', {identity: username}, null, 'json')
83      .done(function(response) {
84        console.log('Successfully finished fetch of the Access Token.');
85        handler(response.token);
86      })
87      .fail(function(error) {
88        console.log('Failed to fetch the Access Token with error: ' + error);
89      });
90  }
91
92  function connectMessagingClient(token) {
93    // Initialize the Chat messaging client
94    tc.accessManager = new Twilio.AccessManager(token);
95    Twilio.Chat.Client.create(token).then(function(client) {
96      tc.messagingClient = client;
97      updateConnectedUI();
98      tc.loadChannelList(tc.joinGeneralChannel);
99      tc.messagingClient.on('channelAdded', $.throttle(tc.loadChannelList));
100      tc.messagingClient.on('channelRemoved', $.throttle(tc.loadChannelList));
101      tc.messagingClient.on('tokenExpired', refreshToken);
102    });
103  }
104
105  function refreshToken() {
106    fetchAccessToken(tc.username, setNewToken);
107  }
108
109  function setNewToken(tokenResponse) {
110    tc.accessManager.updateToken(tokenResponse.token);
111  }
112
113  function updateConnectedUI() {
114    $('#username-span').text(tc.username);
115    $statusRow.addClass('connected').removeClass('disconnected');
116    tc.$messageList.addClass('connected').removeClass('disconnected');
117    $connectPanel.addClass('connected').removeClass('disconnected');
118    $inputText.addClass('with-shadow');
119    $typingRow.addClass('connected').removeClass('disconnected');
120  }
121
122  tc.loadChannelList = function(handler) {
123    if (tc.messagingClient === undefined) {
124      console.log('Client is not initialized');
125      return;
126    }
127
128    tc.messagingClient.getPublicChannelDescriptors().then(function(channels) {
129      tc.channelArray = tc.sortChannelsByName(channels.items);
130      $channelList.text('');
131      tc.channelArray.forEach(addChannel);
132      if (typeof handler === 'function') {
133        handler();
134      }
135    });
136  };
137
138  tc.joinGeneralChannel = function() {
139    console.log('Attempting to join "general" chat channel...');
140    if (!tc.generalChannel) {
141      // If it doesn't exist, let's create it
142      tc.messagingClient.createChannel({
143        uniqueName: GENERAL_CHANNEL_UNIQUE_NAME,
144        friendlyName: GENERAL_CHANNEL_NAME
145      }).then(function(channel) {
146        console.log('Created general channel');
147        tc.generalChannel = channel;
148        tc.loadChannelList(tc.joinGeneralChannel);
149      });
150    }
151    else {
152      console.log('Found general channel:');
153      setupChannel(tc.generalChannel);
154    }
155  };
156
157  function initChannel(channel) {
158    console.log('Initialized channel ' + channel.friendlyName);
159    return tc.messagingClient.getChannelBySid(channel.sid);
160  }
161
162  function joinChannel(_channel) {
163    return _channel.join()
164      .then(function(joinedChannel) {
165        console.log('Joined channel ' + joinedChannel.friendlyName);
166        updateChannelUI(_channel);
167        tc.currentChannel = _channel;
168        tc.loadMessages();
169        return joinedChannel;
170      });
171  }
172
173  function initChannelEvents() {
174    console.log(tc.currentChannel.friendlyName + ' ready.');
175    tc.currentChannel.on('messageAdded', tc.addMessageToList);
176    tc.currentChannel.on('typingStarted', showTypingStarted);
177    tc.currentChannel.on('typingEnded', hideTypingStarted);
178    tc.currentChannel.on('memberJoined', notifyMemberJoined);
179    tc.currentChannel.on('memberLeft', notifyMemberLeft);
180    $inputText.prop('disabled', false).focus();
181  }
182
183  function setupChannel(channel) {
184    return leaveCurrentChannel()
185      .then(function() {
186        return initChannel(channel);
187      })
188      .then(function(_channel) {
189        return joinChannel(_channel);
190      })
191      .then(initChannelEvents);
192  }
193
194  tc.loadMessages = function() {
195    tc.currentChannel.getMessages(MESSAGES_HISTORY_LIMIT)
196      .then(function(messages) {
197        messages.items.forEach(tc.addMessageToList);
198    });
199  };
200
201  function leaveCurrentChannel() {
202    if (tc.currentChannel) {
203      return tc.currentChannel.leave().then(function(leftChannel) {
204        console.log('left ' + leftChannel.friendlyName);
205        leftChannel.removeListener('messageAdded', tc.addMessageToList);
206        leftChannel.removeListener('typingStarted', showTypingStarted);
207        leftChannel.removeListener('typingEnded', hideTypingStarted);
208        leftChannel.removeListener('memberJoined', notifyMemberJoined);
209        leftChannel.removeListener('memberLeft', notifyMemberLeft);
210      });
211    } else {
212      return Promise.resolve();
213    }
214  }
215
216  tc.addMessageToList = function(message) {
217    var rowDiv = $('<div>').addClass('row no-margin');
218    rowDiv.loadTemplate($('#message-template'), {
219      username: message.author,
220      date: dateFormatter.getTodayDate(message.dateCreated),
221      body: message.body
222    });
223    if (message.author === tc.username) {
224      rowDiv.addClass('own-message');
225    }
226
227    tc.$messageList.append(rowDiv);
228    scrollToMessageListBottom();
229  };
230
231  function notifyMemberJoined(member) {
232    notify(member.identity + ' joined the channel')
233  }
234
235  function notifyMemberLeft(member) {
236    notify(member.identity + ' left the channel');
237  }
238
239  function notify(message) {
240    var row = $('<div>').addClass('col-md-12');
241    row.loadTemplate('#member-notification-template', {
242      status: message
243    });
244    tc.$messageList.append(row);
245    scrollToMessageListBottom();
246  }
247
248  function showTypingStarted(member) {
249    $typingPlaceholder.text(member.identity + ' is typing...');
250  }
251
252  function hideTypingStarted(member) {
253    $typingPlaceholder.text('');
254  }
255
256  function scrollToMessageListBottom() {
257    tc.$messageList.scrollTop(tc.$messageList[0].scrollHeight);
258  }
259
260  function updateChannelUI(selectedChannel) {
261    var channelElements = $('.channel-element').toArray();
262    var channelElement = channelElements.filter(function(element) {
263      return $(element).data().sid === selectedChannel.sid;
264    });
265    channelElement = $(channelElement);
266    if (tc.currentChannelContainer === undefined && selectedChannel.uniqueName === GENERAL_CHANNEL_UNIQUE_NAME) {
267      tc.currentChannelContainer = channelElement;
268    }
269    tc.currentChannelContainer.removeClass('selected-channel').addClass('unselected-channel');
270    channelElement.removeClass('unselected-channel').addClass('selected-channel');
271    tc.currentChannelContainer = channelElement;
272  }
273
274  function showAddChannelInput() {
275    if (tc.messagingClient) {
276      $newChannelInputRow.addClass('showing').removeClass('not-showing');
277      $channelList.addClass('showing').removeClass('not-showing');
278      $newChannelInput.focus();
279    }
280  }
281
282  function hideAddChannelInput() {
283    $newChannelInputRow.addClass('not-showing').removeClass('showing');
284    $channelList.addClass('not-showing').removeClass('showing');
285    $newChannelInput.val('');
286  }
287
288  function addChannel(channel) {
289    if (channel.uniqueName === GENERAL_CHANNEL_UNIQUE_NAME) {
290      tc.generalChannel = channel;
291    }
292    var rowDiv = $('<div>').addClass('row channel-row');
293    rowDiv.loadTemplate('#channel-template', {
294      channelName: channel.friendlyName
295    });
296
297    var channelP = rowDiv.children().children().first();
298
299    rowDiv.on('click', selectChannel);
300    channelP.data('sid', channel.sid);
301    if (tc.currentChannel && channel.sid === tc.currentChannel.sid) {
302      tc.currentChannelContainer = channelP;
303      channelP.addClass('selected-channel');
304    }
305    else {
306      channelP.addClass('unselected-channel')
307    }
308
309    $channelList.append(rowDiv);
310  }
311
312  function deleteCurrentChannel() {
313    if (!tc.currentChannel) {
314      return;
315    }
316    if (tc.currentChannel.sid === tc.generalChannel.sid) {
317      alert('You cannot delete the general channel');
318      return;
319    }
320    tc.currentChannel.delete().then(function(channel) {
321      console.log('channel: '+ channel.friendlyName + ' deleted');
322      setupChannel(tc.generalChannel);
323    });
324  }
325
326  function selectChannel(event) {
327    var target = $(event.target);
328    var channelSid = target.data().sid;
329    var selectedChannel = tc.channelArray.filter(function(channel) {
330      return channel.sid === channelSid;
331    })[0];
332    if (selectedChannel === tc.currentChannel) {
333      return;
334    }
335    setupChannel(selectedChannel);
336  };
337
338  function disconnectClient() {
339    leaveCurrentChannel();
340    $channelList.text('');
341    tc.$messageList.text('');
342    channels = undefined;
343    $statusRow.addClass('disconnected').removeClass('connected');
344    tc.$messageList.addClass('disconnected').removeClass('connected');
345    $connectPanel.addClass('disconnected').removeClass('connected');
346    $inputText.removeClass('with-shadow');
347    $typingRow.addClass('disconnected').removeClass('connected');
348  }
349
350  tc.sortChannelsByName = function(channels) {
351    return channels.sort(function(a, b) {
352      if (a.friendlyName === GENERAL_CHANNEL_NAME) {
353        return -1;
354      }
355      if (b.friendlyName === GENERAL_CHANNEL_NAME) {
356        return 1;
357      }
358      return a.friendlyName.localeCompare(b.friendlyName);
359    });
360  };
361
362  return tc;
363})();
364

Next, we need a default channel.

Join the General Channel

This application will try to join a channel called "General Channel" when it starts. If the channel doesn't exist, we'll create one with that name. The scope of this example application will show you how to work only with public channels, but the Programmable Chat client allows you to create private channels and handles invitations.

Notice we set a unique name for the general channel as we don't want to create a new general channel every time we start the application.

Join the General Channel

src/main/webapp/js/twiliochat.js

1var twiliochat = (function() {
2  var tc = {};
3
4  var GENERAL_CHANNEL_UNIQUE_NAME = 'general';
5  var GENERAL_CHANNEL_NAME = 'General Channel';
6  var MESSAGES_HISTORY_LIMIT = 50;
7
8  var $channelList;
9  var $inputText;
10  var $usernameInput;
11  var $statusRow;
12  var $connectPanel;
13  var $newChannelInputRow;
14  var $newChannelInput;
15  var $typingRow;
16  var $typingPlaceholder;
17
18  $(document).ready(function() {
19    tc.$messageList = $('#message-list');
20    $channelList = $('#channel-list');
21    $inputText = $('#input-text');
22    $usernameInput = $('#username-input');
23    $statusRow = $('#status-row');
24    $connectPanel = $('#connect-panel');
25    $newChannelInputRow = $('#new-channel-input-row');
26    $newChannelInput = $('#new-channel-input');
27    $typingRow = $('#typing-row');
28    $typingPlaceholder = $('#typing-placeholder');
29    $usernameInput.focus();
30    $usernameInput.on('keypress', handleUsernameInputKeypress);
31    $inputText.on('keypress', handleInputTextKeypress);
32    $newChannelInput.on('keypress', tc.handleNewChannelInputKeypress);
33    $('#connect-image').on('click', connectClientWithUsername);
34    $('#add-channel-image').on('click', showAddChannelInput);
35    $('#leave-span').on('click', disconnectClient);
36    $('#delete-channel-span').on('click', deleteCurrentChannel);
37  });
38
39  function handleUsernameInputKeypress(event) {
40    if (event.keyCode === 13){
41      connectClientWithUsername();
42    }
43  }
44
45  function handleInputTextKeypress(event) {
46    if (event.keyCode === 13) {
47      tc.currentChannel.sendMessage($(this).val());
48      event.preventDefault();
49      $(this).val('');
50    }
51    else {
52      notifyTyping();
53    }
54  }
55
56  var notifyTyping = $.throttle(function() {
57    tc.currentChannel.typing();
58  }, 1000);
59
60  tc.handleNewChannelInputKeypress = function(event) {
61    if (event.keyCode === 13) {
62      tc.messagingClient.createChannel({
63        friendlyName: $newChannelInput.val()
64      }).then(hideAddChannelInput);
65      $(this).val('');
66      event.preventDefault();
67    }
68  };
69
70  function connectClientWithUsername() {
71    var usernameText = $usernameInput.val();
72    $usernameInput.val('');
73    if (usernameText == '') {
74      alert('Username cannot be empty');
75      return;
76    }
77    tc.username = usernameText;
78    fetchAccessToken(tc.username, connectMessagingClient);
79  }
80
81  function fetchAccessToken(username, handler) {
82    $.post('/twiliochat-servlets/token', {identity: username}, null, 'json')
83      .done(function(response) {
84        console.log('Successfully finished fetch of the Access Token.');
85        handler(response.token);
86      })
87      .fail(function(error) {
88        console.log('Failed to fetch the Access Token with error: ' + error);
89      });
90  }
91
92  function connectMessagingClient(token) {
93    // Initialize the Chat messaging client
94    tc.accessManager = new Twilio.AccessManager(token);
95    Twilio.Chat.Client.create(token).then(function(client) {
96      tc.messagingClient = client;
97      updateConnectedUI();
98      tc.loadChannelList(tc.joinGeneralChannel);
99      tc.messagingClient.on('channelAdded', $.throttle(tc.loadChannelList));
100      tc.messagingClient.on('channelRemoved', $.throttle(tc.loadChannelList));
101      tc.messagingClient.on('tokenExpired', refreshToken);
102    });
103  }
104
105  function refreshToken() {
106    fetchAccessToken(tc.username, setNewToken);
107  }
108
109  function setNewToken(tokenResponse) {
110    tc.accessManager.updateToken(tokenResponse.token);
111  }
112
113  function updateConnectedUI() {
114    $('#username-span').text(tc.username);
115    $statusRow.addClass('connected').removeClass('disconnected');
116    tc.$messageList.addClass('connected').removeClass('disconnected');
117    $connectPanel.addClass('connected').removeClass('disconnected');
118    $inputText.addClass('with-shadow');
119    $typingRow.addClass('connected').removeClass('disconnected');
120  }
121
122  tc.loadChannelList = function(handler) {
123    if (tc.messagingClient === undefined) {
124      console.log('Client is not initialized');
125      return;
126    }
127
128    tc.messagingClient.getPublicChannelDescriptors().then(function(channels) {
129      tc.channelArray = tc.sortChannelsByName(channels.items);
130      $channelList.text('');
131      tc.channelArray.forEach(addChannel);
132      if (typeof handler === 'function') {
133        handler();
134      }
135    });
136  };
137
138  tc.joinGeneralChannel = function() {
139    console.log('Attempting to join "general" chat channel...');
140    if (!tc.generalChannel) {
141      // If it doesn't exist, let's create it
142      tc.messagingClient.createChannel({
143        uniqueName: GENERAL_CHANNEL_UNIQUE_NAME,
144        friendlyName: GENERAL_CHANNEL_NAME
145      }).then(function(channel) {
146        console.log('Created general channel');
147        tc.generalChannel = channel;
148        tc.loadChannelList(tc.joinGeneralChannel);
149      });
150    }
151    else {
152      console.log('Found general channel:');
153      setupChannel(tc.generalChannel);
154    }
155  };
156
157  function initChannel(channel) {
158    console.log('Initialized channel ' + channel.friendlyName);
159    return tc.messagingClient.getChannelBySid(channel.sid);
160  }
161
162  function joinChannel(_channel) {
163    return _channel.join()
164      .then(function(joinedChannel) {
165        console.log('Joined channel ' + joinedChannel.friendlyName);
166        updateChannelUI(_channel);
167        tc.currentChannel = _channel;
168        tc.loadMessages();
169        return joinedChannel;
170      });
171  }
172
173  function initChannelEvents() {
174    console.log(tc.currentChannel.friendlyName + ' ready.');
175    tc.currentChannel.on('messageAdded', tc.addMessageToList);
176    tc.currentChannel.on('typingStarted', showTypingStarted);
177    tc.currentChannel.on('typingEnded', hideTypingStarted);
178    tc.currentChannel.on('memberJoined', notifyMemberJoined);
179    tc.currentChannel.on('memberLeft', notifyMemberLeft);
180    $inputText.prop('disabled', false).focus();
181  }
182
183  function setupChannel(channel) {
184    return leaveCurrentChannel()
185      .then(function() {
186        return initChannel(channel);
187      })
188      .then(function(_channel) {
189        return joinChannel(_channel);
190      })
191      .then(initChannelEvents);
192  }
193
194  tc.loadMessages = function() {
195    tc.currentChannel.getMessages(MESSAGES_HISTORY_LIMIT)
196      .then(function(messages) {
197        messages.items.forEach(tc.addMessageToList);
198    });
199  };
200
201  function leaveCurrentChannel() {
202    if (tc.currentChannel) {
203      return tc.currentChannel.leave().then(function(leftChannel) {
204        console.log('left ' + leftChannel.friendlyName);
205        leftChannel.removeListener('messageAdded', tc.addMessageToList);
206        leftChannel.removeListener('typingStarted', showTypingStarted);
207        leftChannel.removeListener('typingEnded', hideTypingStarted);
208        leftChannel.removeListener('memberJoined', notifyMemberJoined);
209        leftChannel.removeListener('memberLeft', notifyMemberLeft);
210      });
211    } else {
212      return Promise.resolve();
213    }
214  }
215
216  tc.addMessageToList = function(message) {
217    var rowDiv = $('<div>').addClass('row no-margin');
218    rowDiv.loadTemplate($('#message-template'), {
219      username: message.author,
220      date: dateFormatter.getTodayDate(message.dateCreated),
221      body: message.body
222    });
223    if (message.author === tc.username) {
224      rowDiv.addClass('own-message');
225    }
226
227    tc.$messageList.append(rowDiv);
228    scrollToMessageListBottom();
229  };
230
231  function notifyMemberJoined(member) {
232    notify(member.identity + ' joined the channel')
233  }
234
235  function notifyMemberLeft(member) {
236    notify(member.identity + ' left the channel');
237  }
238
239  function notify(message) {
240    var row = $('<div>').addClass('col-md-12');
241    row.loadTemplate('#member-notification-template', {
242      status: message
243    });
244    tc.$messageList.append(row);
245    scrollToMessageListBottom();
246  }
247
248  function showTypingStarted(member) {
249    $typingPlaceholder.text(member.identity + ' is typing...');
250  }
251
252  function hideTypingStarted(member) {
253    $typingPlaceholder.text('');
254  }
255
256  function scrollToMessageListBottom() {
257    tc.$messageList.scrollTop(tc.$messageList[0].scrollHeight);
258  }
259
260  function updateChannelUI(selectedChannel) {
261    var channelElements = $('.channel-element').toArray();
262    var channelElement = channelElements.filter(function(element) {
263      return $(element).data().sid === selectedChannel.sid;
264    });
265    channelElement = $(channelElement);
266    if (tc.currentChannelContainer === undefined && selectedChannel.uniqueName === GENERAL_CHANNEL_UNIQUE_NAME) {
267      tc.currentChannelContainer = channelElement;
268    }
269    tc.currentChannelContainer.removeClass('selected-channel').addClass('unselected-channel');
270    channelElement.removeClass('unselected-channel').addClass('selected-channel');
271    tc.currentChannelContainer = channelElement;
272  }
273
274  function showAddChannelInput() {
275    if (tc.messagingClient) {
276      $newChannelInputRow.addClass('showing').removeClass('not-showing');
277      $channelList.addClass('showing').removeClass('not-showing');
278      $newChannelInput.focus();
279    }
280  }
281
282  function hideAddChannelInput() {
283    $newChannelInputRow.addClass('not-showing').removeClass('showing');
284    $channelList.addClass('not-showing').removeClass('showing');
285    $newChannelInput.val('');
286  }
287
288  function addChannel(channel) {
289    if (channel.uniqueName === GENERAL_CHANNEL_UNIQUE_NAME) {
290      tc.generalChannel = channel;
291    }
292    var rowDiv = $('<div>').addClass('row channel-row');
293    rowDiv.loadTemplate('#channel-template', {
294      channelName: channel.friendlyName
295    });
296
297    var channelP = rowDiv.children().children().first();
298
299    rowDiv.on('click', selectChannel);
300    channelP.data('sid', channel.sid);
301    if (tc.currentChannel && channel.sid === tc.currentChannel.sid) {
302      tc.currentChannelContainer = channelP;
303      channelP.addClass('selected-channel');
304    }
305    else {
306      channelP.addClass('unselected-channel')
307    }
308
309    $channelList.append(rowDiv);
310  }
311
312  function deleteCurrentChannel() {
313    if (!tc.currentChannel) {
314      return;
315    }
316    if (tc.currentChannel.sid === tc.generalChannel.sid) {
317      alert('You cannot delete the general channel');
318      return;
319    }
320    tc.currentChannel.delete().then(function(channel) {
321      console.log('channel: '+ channel.friendlyName + ' deleted');
322      setupChannel(tc.generalChannel);
323    });
324  }
325
326  function selectChannel(event) {
327    var target = $(event.target);
328    var channelSid = target.data().sid;
329    var selectedChannel = tc.channelArray.filter(function(channel) {
330      return channel.sid === channelSid;
331    })[0];
332    if (selectedChannel === tc.currentChannel) {
333      return;
334    }
335    setupChannel(selectedChannel);
336  };
337
338  function disconnectClient() {
339    leaveCurrentChannel();
340    $channelList.text('');
341    tc.$messageList.text('');
342    channels = undefined;
343    $statusRow.addClass('disconnected').removeClass('connected');
344    tc.$messageList.addClass('disconnected').removeClass('connected');
345    $connectPanel.addClass('disconnected').removeClass('connected');
346    $inputText.removeClass('with-shadow');
347    $typingRow.addClass('disconnected').removeClass('connected');
348  }
349
350  tc.sortChannelsByName = function(channels) {
351    return channels.sort(function(a, b) {
352      if (a.friendlyName === GENERAL_CHANNEL_NAME) {
353        return -1;
354      }
355      if (b.friendlyName === GENERAL_CHANNEL_NAME) {
356        return 1;
357      }
358      return a.friendlyName.localeCompare(b.friendlyName);
359    });
360  };
361
362  return tc;
363})();
364

Now let's listen for some channel events.

Listen to Channel Events

Next we listen for channel events. In our case, we're setting listeners to the following events:

messageAdded: When another member sends a message to the channel you are connected to.
typingStarted: When another member is typing a message on the channel that you are connected to.
typingEnded: When another member stops typing a message on the channel that you are connected to.
memberJoined: When another member joins the channel that you are connected to.
memberLeft: When another member leaves the channel that you are connected to.

We register a different function to handle each particular event.

Listen to Channel Events

src/main/webapp/js/twiliochat.js

1var twiliochat = (function() {
2  var tc = {};
3
4  var GENERAL_CHANNEL_UNIQUE_NAME = 'general';
5  var GENERAL_CHANNEL_NAME = 'General Channel';
6  var MESSAGES_HISTORY_LIMIT = 50;
7
8  var $channelList;
9  var $inputText;
10  var $usernameInput;
11  var $statusRow;
12  var $connectPanel;
13  var $newChannelInputRow;
14  var $newChannelInput;
15  var $typingRow;
16  var $typingPlaceholder;
17
18  $(document).ready(function() {
19    tc.$messageList = $('#message-list');
20    $channelList = $('#channel-list');
21    $inputText = $('#input-text');
22    $usernameInput = $('#username-input');
23    $statusRow = $('#status-row');
24    $connectPanel = $('#connect-panel');
25    $newChannelInputRow = $('#new-channel-input-row');
26    $newChannelInput = $('#new-channel-input');
27    $typingRow = $('#typing-row');
28    $typingPlaceholder = $('#typing-placeholder');
29    $usernameInput.focus();
30    $usernameInput.on('keypress', handleUsernameInputKeypress);
31    $inputText.on('keypress', handleInputTextKeypress);
32    $newChannelInput.on('keypress', tc.handleNewChannelInputKeypress);
33    $('#connect-image').on('click', connectClientWithUsername);
34    $('#add-channel-image').on('click', showAddChannelInput);
35    $('#leave-span').on('click', disconnectClient);
36    $('#delete-channel-span').on('click', deleteCurrentChannel);
37  });
38
39  function handleUsernameInputKeypress(event) {
40    if (event.keyCode === 13){
41      connectClientWithUsername();
42    }
43  }
44
45  function handleInputTextKeypress(event) {
46    if (event.keyCode === 13) {
47      tc.currentChannel.sendMessage($(this).val());
48      event.preventDefault();
49      $(this).val('');
50    }
51    else {
52      notifyTyping();
53    }
54  }
55
56  var notifyTyping = $.throttle(function() {
57    tc.currentChannel.typing();
58  }, 1000);
59
60  tc.handleNewChannelInputKeypress = function(event) {
61    if (event.keyCode === 13) {
62      tc.messagingClient.createChannel({
63        friendlyName: $newChannelInput.val()
64      }).then(hideAddChannelInput);
65      $(this).val('');
66      event.preventDefault();
67    }
68  };
69
70  function connectClientWithUsername() {
71    var usernameText = $usernameInput.val();
72    $usernameInput.val('');
73    if (usernameText == '') {
74      alert('Username cannot be empty');
75      return;
76    }
77    tc.username = usernameText;
78    fetchAccessToken(tc.username, connectMessagingClient);
79  }
80
81  function fetchAccessToken(username, handler) {
82    $.post('/twiliochat-servlets/token', {identity: username}, null, 'json')
83      .done(function(response) {
84        console.log('Successfully finished fetch of the Access Token.');
85        handler(response.token);
86      })
87      .fail(function(error) {
88        console.log('Failed to fetch the Access Token with error: ' + error);
89      });
90  }
91
92  function connectMessagingClient(token) {
93    // Initialize the Chat messaging client
94    tc.accessManager = new Twilio.AccessManager(token);
95    Twilio.Chat.Client.create(token).then(function(client) {
96      tc.messagingClient = client;
97      updateConnectedUI();
98      tc.loadChannelList(tc.joinGeneralChannel);
99      tc.messagingClient.on('channelAdded', $.throttle(tc.loadChannelList));
100      tc.messagingClient.on('channelRemoved', $.throttle(tc.loadChannelList));
101      tc.messagingClient.on('tokenExpired', refreshToken);
102    });
103  }
104
105  function refreshToken() {
106    fetchAccessToken(tc.username, setNewToken);
107  }
108
109  function setNewToken(tokenResponse) {
110    tc.accessManager.updateToken(tokenResponse.token);
111  }
112
113  function updateConnectedUI() {
114    $('#username-span').text(tc.username);
115    $statusRow.addClass('connected').removeClass('disconnected');
116    tc.$messageList.addClass('connected').removeClass('disconnected');
117    $connectPanel.addClass('connected').removeClass('disconnected');
118    $inputText.addClass('with-shadow');
119    $typingRow.addClass('connected').removeClass('disconnected');
120  }
121
122  tc.loadChannelList = function(handler) {
123    if (tc.messagingClient === undefined) {
124      console.log('Client is not initialized');
125      return;
126    }
127
128    tc.messagingClient.getPublicChannelDescriptors().then(function(channels) {
129      tc.channelArray = tc.sortChannelsByName(channels.items);
130      $channelList.text('');
131      tc.channelArray.forEach(addChannel);
132      if (typeof handler === 'function') {
133        handler();
134      }
135    });
136  };
137
138  tc.joinGeneralChannel = function() {
139    console.log('Attempting to join "general" chat channel...');
140    if (!tc.generalChannel) {
141      // If it doesn't exist, let's create it
142      tc.messagingClient.createChannel({
143        uniqueName: GENERAL_CHANNEL_UNIQUE_NAME,
144        friendlyName: GENERAL_CHANNEL_NAME
145      }).then(function(channel) {
146        console.log('Created general channel');
147        tc.generalChannel = channel;
148        tc.loadChannelList(tc.joinGeneralChannel);
149      });
150    }
151    else {
152      console.log('Found general channel:');
153      setupChannel(tc.generalChannel);
154    }
155  };
156
157  function initChannel(channel) {
158    console.log('Initialized channel ' + channel.friendlyName);
159    return tc.messagingClient.getChannelBySid(channel.sid);
160  }
161
162  function joinChannel(_channel) {
163    return _channel.join()
164      .then(function(joinedChannel) {
165        console.log('Joined channel ' + joinedChannel.friendlyName);
166        updateChannelUI(_channel);
167        tc.currentChannel = _channel;
168        tc.loadMessages();
169        return joinedChannel;
170      });
171  }
172
173  function initChannelEvents() {
174    console.log(tc.currentChannel.friendlyName + ' ready.');
175    tc.currentChannel.on('messageAdded', tc.addMessageToList);
176    tc.currentChannel.on('typingStarted', showTypingStarted);
177    tc.currentChannel.on('typingEnded', hideTypingStarted);
178    tc.currentChannel.on('memberJoined', notifyMemberJoined);
179    tc.currentChannel.on('memberLeft', notifyMemberLeft);
180    $inputText.prop('disabled', false).focus();
181  }
182
183  function setupChannel(channel) {
184    return leaveCurrentChannel()
185      .then(function() {
186        return initChannel(channel);
187      })
188      .then(function(_channel) {
189        return joinChannel(_channel);
190      })
191      .then(initChannelEvents);
192  }
193
194  tc.loadMessages = function() {
195    tc.currentChannel.getMessages(MESSAGES_HISTORY_LIMIT)
196      .then(function(messages) {
197        messages.items.forEach(tc.addMessageToList);
198    });
199  };
200
201  function leaveCurrentChannel() {
202    if (tc.currentChannel) {
203      return tc.currentChannel.leave().then(function(leftChannel) {
204        console.log('left ' + leftChannel.friendlyName);
205        leftChannel.removeListener('messageAdded', tc.addMessageToList);
206        leftChannel.removeListener('typingStarted', showTypingStarted);
207        leftChannel.removeListener('typingEnded', hideTypingStarted);
208        leftChannel.removeListener('memberJoined', notifyMemberJoined);
209        leftChannel.removeListener('memberLeft', notifyMemberLeft);
210      });
211    } else {
212      return Promise.resolve();
213    }
214  }
215
216  tc.addMessageToList = function(message) {
217    var rowDiv = $('<div>').addClass('row no-margin');
218    rowDiv.loadTemplate($('#message-template'), {
219      username: message.author,
220      date: dateFormatter.getTodayDate(message.dateCreated),
221      body: message.body
222    });
223    if (message.author === tc.username) {
224      rowDiv.addClass('own-message');
225    }
226
227    tc.$messageList.append(rowDiv);
228    scrollToMessageListBottom();
229  };
230
231  function notifyMemberJoined(member) {
232    notify(member.identity + ' joined the channel')
233  }
234
235  function notifyMemberLeft(member) {
236    notify(member.identity + ' left the channel');
237  }
238
239  function notify(message) {
240    var row = $('<div>').addClass('col-md-12');
241    row.loadTemplate('#member-notification-template', {
242      status: message
243    });
244    tc.$messageList.append(row);
245    scrollToMessageListBottom();
246  }
247
248  function showTypingStarted(member) {
249    $typingPlaceholder.text(member.identity + ' is typing...');
250  }
251
252  function hideTypingStarted(member) {
253    $typingPlaceholder.text('');
254  }
255
256  function scrollToMessageListBottom() {
257    tc.$messageList.scrollTop(tc.$messageList[0].scrollHeight);
258  }
259
260  function updateChannelUI(selectedChannel) {
261    var channelElements = $('.channel-element').toArray();
262    var channelElement = channelElements.filter(function(element) {
263      return $(element).data().sid === selectedChannel.sid;
264    });
265    channelElement = $(channelElement);
266    if (tc.currentChannelContainer === undefined && selectedChannel.uniqueName === GENERAL_CHANNEL_UNIQUE_NAME) {
267      tc.currentChannelContainer = channelElement;
268    }
269    tc.currentChannelContainer.removeClass('selected-channel').addClass('unselected-channel');
270    channelElement.removeClass('unselected-channel').addClass('selected-channel');
271    tc.currentChannelContainer = channelElement;
272  }
273
274  function showAddChannelInput() {
275    if (tc.messagingClient) {
276      $newChannelInputRow.addClass('showing').removeClass('not-showing');
277      $channelList.addClass('showing').removeClass('not-showing');
278      $newChannelInput.focus();
279    }
280  }
281
282  function hideAddChannelInput() {
283    $newChannelInputRow.addClass('not-showing').removeClass('showing');
284    $channelList.addClass('not-showing').removeClass('showing');
285    $newChannelInput.val('');
286  }
287
288  function addChannel(channel) {
289    if (channel.uniqueName === GENERAL_CHANNEL_UNIQUE_NAME) {
290      tc.generalChannel = channel;
291    }
292    var rowDiv = $('<div>').addClass('row channel-row');
293    rowDiv.loadTemplate('#channel-template', {
294      channelName: channel.friendlyName
295    });
296
297    var channelP = rowDiv.children().children().first();
298
299    rowDiv.on('click', selectChannel);
300    channelP.data('sid', channel.sid);
301    if (tc.currentChannel && channel.sid === tc.currentChannel.sid) {
302      tc.currentChannelContainer = channelP;
303      channelP.addClass('selected-channel');
304    }
305    else {
306      channelP.addClass('unselected-channel')
307    }
308
309    $channelList.append(rowDiv);
310  }
311
312  function deleteCurrentChannel() {
313    if (!tc.currentChannel) {
314      return;
315    }
316    if (tc.currentChannel.sid === tc.generalChannel.sid) {
317      alert('You cannot delete the general channel');
318      return;
319    }
320    tc.currentChannel.delete().then(function(channel) {
321      console.log('channel: '+ channel.friendlyName + ' deleted');
322      setupChannel(tc.generalChannel);
323    });
324  }
325
326  function selectChannel(event) {
327    var target = $(event.target);
328    var channelSid = target.data().sid;
329    var selectedChannel = tc.channelArray.filter(function(channel) {
330      return channel.sid === channelSid;
331    })[0];
332    if (selectedChannel === tc.currentChannel) {
333      return;
334    }
335    setupChannel(selectedChannel);
336  };
337
338  function disconnectClient() {
339    leaveCurrentChannel();
340    $channelList.text('');
341    tc.$messageList.text('');
342    channels = undefined;
343    $statusRow.addClass('disconnected').removeClass('connected');
344    tc.$messageList.addClass('disconnected').removeClass('connected');
345    $connectPanel.addClass('disconnected').removeClass('connected');
346    $inputText.removeClass('with-shadow');
347    $typingRow.addClass('disconnected').removeClass('connected');
348  }
349
350  tc.sortChannelsByName = function(channels) {
351    return channels.sort(function(a, b) {
352      if (a.friendlyName === GENERAL_CHANNEL_NAME) {
353        return -1;
354      }
355      if (b.friendlyName === GENERAL_CHANNEL_NAME) {
356        return 1;
357      }
358      return a.friendlyName.localeCompare(b.friendlyName);
359    });
360  };
361
362  return tc;
363})();
364

The client emits events as well. Let's see how we can listen to those events as well.

Listen to Client Events

Just like with channels, we can register handlers for events on the Client:

channelAdded: When a channel becomes visible to the Client.
channelRemoved: When a channel is no longer visible to the Client.
tokenExpired: When the supplied token expires.

Listen to Client Events

src/main/webapp/js/twiliochat.js

1var twiliochat = (function() {
2  var tc = {};
3
4  var GENERAL_CHANNEL_UNIQUE_NAME = 'general';
5  var GENERAL_CHANNEL_NAME = 'General Channel';
6  var MESSAGES_HISTORY_LIMIT = 50;
7
8  var $channelList;
9  var $inputText;
10  var $usernameInput;
11  var $statusRow;
12  var $connectPanel;
13  var $newChannelInputRow;
14  var $newChannelInput;
15  var $typingRow;
16  var $typingPlaceholder;
17
18  $(document).ready(function() {
19    tc.$messageList = $('#message-list');
20    $channelList = $('#channel-list');
21    $inputText = $('#input-text');
22    $usernameInput = $('#username-input');
23    $statusRow = $('#status-row');
24    $connectPanel = $('#connect-panel');
25    $newChannelInputRow = $('#new-channel-input-row');
26    $newChannelInput = $('#new-channel-input');
27    $typingRow = $('#typing-row');
28    $typingPlaceholder = $('#typing-placeholder');
29    $usernameInput.focus();
30    $usernameInput.on('keypress', handleUsernameInputKeypress);
31    $inputText.on('keypress', handleInputTextKeypress);
32    $newChannelInput.on('keypress', tc.handleNewChannelInputKeypress);
33    $('#connect-image').on('click', connectClientWithUsername);
34    $('#add-channel-image').on('click', showAddChannelInput);
35    $('#leave-span').on('click', disconnectClient);
36    $('#delete-channel-span').on('click', deleteCurrentChannel);
37  });
38
39  function handleUsernameInputKeypress(event) {
40    if (event.keyCode === 13){
41      connectClientWithUsername();
42    }
43  }
44
45  function handleInputTextKeypress(event) {
46    if (event.keyCode === 13) {
47      tc.currentChannel.sendMessage($(this).val());
48      event.preventDefault();
49      $(this).val('');
50    }
51    else {
52      notifyTyping();
53    }
54  }
55
56  var notifyTyping = $.throttle(function() {
57    tc.currentChannel.typing();
58  }, 1000);
59
60  tc.handleNewChannelInputKeypress = function(event) {
61    if (event.keyCode === 13) {
62      tc.messagingClient.createChannel({
63        friendlyName: $newChannelInput.val()
64      }).then(hideAddChannelInput);
65      $(this).val('');
66      event.preventDefault();
67    }
68  };
69
70  function connectClientWithUsername() {
71    var usernameText = $usernameInput.val();
72    $usernameInput.val('');
73    if (usernameText == '') {
74      alert('Username cannot be empty');
75      return;
76    }
77    tc.username = usernameText;
78    fetchAccessToken(tc.username, connectMessagingClient);
79  }
80
81  function fetchAccessToken(username, handler) {
82    $.post('/twiliochat-servlets/token', {identity: username}, null, 'json')
83      .done(function(response) {
84        console.log('Successfully finished fetch of the Access Token.');
85        handler(response.token);
86      })
87      .fail(function(error) {
88        console.log('Failed to fetch the Access Token with error: ' + error);
89      });
90  }
91
92  function connectMessagingClient(token) {
93    // Initialize the Chat messaging client
94    tc.accessManager = new Twilio.AccessManager(token);
95    Twilio.Chat.Client.create(token).then(function(client) {
96      tc.messagingClient = client;
97      updateConnectedUI();
98      tc.loadChannelList(tc.joinGeneralChannel);
99      tc.messagingClient.on('channelAdded', $.throttle(tc.loadChannelList));
100      tc.messagingClient.on('channelRemoved', $.throttle(tc.loadChannelList));
101      tc.messagingClient.on('tokenExpired', refreshToken);
102    });
103  }
104
105  function refreshToken() {
106    fetchAccessToken(tc.username, setNewToken);
107  }
108
109  function setNewToken(tokenResponse) {
110    tc.accessManager.updateToken(tokenResponse.token);
111  }
112
113  function updateConnectedUI() {
114    $('#username-span').text(tc.username);
115    $statusRow.addClass('connected').removeClass('disconnected');
116    tc.$messageList.addClass('connected').removeClass('disconnected');
117    $connectPanel.addClass('connected').removeClass('disconnected');
118    $inputText.addClass('with-shadow');
119    $typingRow.addClass('connected').removeClass('disconnected');
120  }
121
122  tc.loadChannelList = function(handler) {
123    if (tc.messagingClient === undefined) {
124      console.log('Client is not initialized');
125      return;
126    }
127
128    tc.messagingClient.getPublicChannelDescriptors().then(function(channels) {
129      tc.channelArray = tc.sortChannelsByName(channels.items);
130      $channelList.text('');
131      tc.channelArray.forEach(addChannel);
132      if (typeof handler === 'function') {
133        handler();
134      }
135    });
136  };
137
138  tc.joinGeneralChannel = function() {
139    console.log('Attempting to join "general" chat channel...');
140    if (!tc.generalChannel) {
141      // If it doesn't exist, let's create it
142      tc.messagingClient.createChannel({
143        uniqueName: GENERAL_CHANNEL_UNIQUE_NAME,
144        friendlyName: GENERAL_CHANNEL_NAME
145      }).then(function(channel) {
146        console.log('Created general channel');
147        tc.generalChannel = channel;
148        tc.loadChannelList(tc.joinGeneralChannel);
149      });
150    }
151    else {
152      console.log('Found general channel:');
153      setupChannel(tc.generalChannel);
154    }
155  };
156
157  function initChannel(channel) {
158    console.log('Initialized channel ' + channel.friendlyName);
159    return tc.messagingClient.getChannelBySid(channel.sid);
160  }
161
162  function joinChannel(_channel) {
163    return _channel.join()
164      .then(function(joinedChannel) {
165        console.log('Joined channel ' + joinedChannel.friendlyName);
166        updateChannelUI(_channel);
167        tc.currentChannel = _channel;
168        tc.loadMessages();
169        return joinedChannel;
170      });
171  }
172
173  function initChannelEvents() {
174    console.log(tc.currentChannel.friendlyName + ' ready.');
175    tc.currentChannel.on('messageAdded', tc.addMessageToList);
176    tc.currentChannel.on('typingStarted', showTypingStarted);
177    tc.currentChannel.on('typingEnded', hideTypingStarted);
178    tc.currentChannel.on('memberJoined', notifyMemberJoined);
179    tc.currentChannel.on('memberLeft', notifyMemberLeft);
180    $inputText.prop('disabled', false).focus();
181  }
182
183  function setupChannel(channel) {
184    return leaveCurrentChannel()
185      .then(function() {
186        return initChannel(channel);
187      })
188      .then(function(_channel) {
189        return joinChannel(_channel);
190      })
191      .then(initChannelEvents);
192  }
193
194  tc.loadMessages = function() {
195    tc.currentChannel.getMessages(MESSAGES_HISTORY_LIMIT)
196      .then(function(messages) {
197        messages.items.forEach(tc.addMessageToList);
198    });
199  };
200
201  function leaveCurrentChannel() {
202    if (tc.currentChannel) {
203      return tc.currentChannel.leave().then(function(leftChannel) {
204        console.log('left ' + leftChannel.friendlyName);
205        leftChannel.removeListener('messageAdded', tc.addMessageToList);
206        leftChannel.removeListener('typingStarted', showTypingStarted);
207        leftChannel.removeListener('typingEnded', hideTypingStarted);
208        leftChannel.removeListener('memberJoined', notifyMemberJoined);
209        leftChannel.removeListener('memberLeft', notifyMemberLeft);
210      });
211    } else {
212      return Promise.resolve();
213    }
214  }
215
216  tc.addMessageToList = function(message) {
217    var rowDiv = $('<div>').addClass('row no-margin');
218    rowDiv.loadTemplate($('#message-template'), {
219      username: message.author,
220      date: dateFormatter.getTodayDate(message.dateCreated),
221      body: message.body
222    });
223    if (message.author === tc.username) {
224      rowDiv.addClass('own-message');
225    }
226
227    tc.$messageList.append(rowDiv);
228    scrollToMessageListBottom();
229  };
230
231  function notifyMemberJoined(member) {
232    notify(member.identity + ' joined the channel')
233  }
234
235  function notifyMemberLeft(member) {
236    notify(member.identity + ' left the channel');
237  }
238
239  function notify(message) {
240    var row = $('<div>').addClass('col-md-12');
241    row.loadTemplate('#member-notification-template', {
242      status: message
243    });
244    tc.$messageList.append(row);
245    scrollToMessageListBottom();
246  }
247
248  function showTypingStarted(member) {
249    $typingPlaceholder.text(member.identity + ' is typing...');
250  }
251
252  function hideTypingStarted(member) {
253    $typingPlaceholder.text('');
254  }
255
256  function scrollToMessageListBottom() {
257    tc.$messageList.scrollTop(tc.$messageList[0].scrollHeight);
258  }
259
260  function updateChannelUI(selectedChannel) {
261    var channelElements = $('.channel-element').toArray();
262    var channelElement = channelElements.filter(function(element) {
263      return $(element).data().sid === selectedChannel.sid;
264    });
265    channelElement = $(channelElement);
266    if (tc.currentChannelContainer === undefined && selectedChannel.uniqueName === GENERAL_CHANNEL_UNIQUE_NAME) {
267      tc.currentChannelContainer = channelElement;
268    }
269    tc.currentChannelContainer.removeClass('selected-channel').addClass('unselected-channel');
270    channelElement.removeClass('unselected-channel').addClass('selected-channel');
271    tc.currentChannelContainer = channelElement;
272  }
273
274  function showAddChannelInput() {
275    if (tc.messagingClient) {
276      $newChannelInputRow.addClass('showing').removeClass('not-showing');
277      $channelList.addClass('showing').removeClass('not-showing');
278      $newChannelInput.focus();
279    }
280  }
281
282  function hideAddChannelInput() {
283    $newChannelInputRow.addClass('not-showing').removeClass('showing');
284    $channelList.addClass('not-showing').removeClass('showing');
285    $newChannelInput.val('');
286  }
287
288  function addChannel(channel) {
289    if (channel.uniqueName === GENERAL_CHANNEL_UNIQUE_NAME) {
290      tc.generalChannel = channel;
291    }
292    var rowDiv = $('<div>').addClass('row channel-row');
293    rowDiv.loadTemplate('#channel-template', {
294      channelName: channel.friendlyName
295    });
296
297    var channelP = rowDiv.children().children().first();
298
299    rowDiv.on('click', selectChannel);
300    channelP.data('sid', channel.sid);
301    if (tc.currentChannel && channel.sid === tc.currentChannel.sid) {
302      tc.currentChannelContainer = channelP;
303      channelP.addClass('selected-channel');
304    }
305    else {
306      channelP.addClass('unselected-channel')
307    }
308
309    $channelList.append(rowDiv);
310  }
311
312  function deleteCurrentChannel() {
313    if (!tc.currentChannel) {
314      return;
315    }
316    if (tc.currentChannel.sid === tc.generalChannel.sid) {
317      alert('You cannot delete the general channel');
318      return;
319    }
320    tc.currentChannel.delete().then(function(channel) {
321      console.log('channel: '+ channel.friendlyName + ' deleted');
322      setupChannel(tc.generalChannel);
323    });
324  }
325
326  function selectChannel(event) {
327    var target = $(event.target);
328    var channelSid = target.data().sid;
329    var selectedChannel = tc.channelArray.filter(function(channel) {
330      return channel.sid === channelSid;
331    })[0];
332    if (selectedChannel === tc.currentChannel) {
333      return;
334    }
335    setupChannel(selectedChannel);
336  };
337
338  function disconnectClient() {
339    leaveCurrentChannel();
340    $channelList.text('');
341    tc.$messageList.text('');
342    channels = undefined;
343    $statusRow.addClass('disconnected').removeClass('connected');
344    tc.$messageList.addClass('disconnected').removeClass('connected');
345    $connectPanel.addClass('disconnected').removeClass('connected');
346    $inputText.removeClass('with-shadow');
347    $typingRow.addClass('disconnected').removeClass('connected');
348  }
349
350  tc.sortChannelsByName = function(channels) {
351    return channels.sort(function(a, b) {
352      if (a.friendlyName === GENERAL_CHANNEL_NAME) {
353        return -1;
354      }
355      if (b.friendlyName === GENERAL_CHANNEL_NAME) {
356        return 1;
357      }
358      return a.friendlyName.localeCompare(b.friendlyName);
359    });
360  };
361
362  return tc;
363})();
364

We've actually got a real chat app going here, but let's make it more interesting with multiple channels.

Create a Channel

When a user clicks on the "+ Channel" link we'll show an input text field where it's possible to type the name of the new channel. Creating a channel involves calling createChannel with an object that has the friendlyName key. You can create a channel with more options listed on the Channels section of the Programmable Chat documentation.

Create a Channel

src/main/webapp/js/twiliochat.js

1var twiliochat = (function() {
2  var tc = {};
3
4  var GENERAL_CHANNEL_UNIQUE_NAME = 'general';
5  var GENERAL_CHANNEL_NAME = 'General Channel';
6  var MESSAGES_HISTORY_LIMIT = 50;
7
8  var $channelList;
9  var $inputText;
10  var $usernameInput;
11  var $statusRow;
12  var $connectPanel;
13  var $newChannelInputRow;
14  var $newChannelInput;
15  var $typingRow;
16  var $typingPlaceholder;
17
18  $(document).ready(function() {
19    tc.$messageList = $('#message-list');
20    $channelList = $('#channel-list');
21    $inputText = $('#input-text');
22    $usernameInput = $('#username-input');
23    $statusRow = $('#status-row');
24    $connectPanel = $('#connect-panel');
25    $newChannelInputRow = $('#new-channel-input-row');
26    $newChannelInput = $('#new-channel-input');
27    $typingRow = $('#typing-row');
28    $typingPlaceholder = $('#typing-placeholder');
29    $usernameInput.focus();
30    $usernameInput.on('keypress', handleUsernameInputKeypress);
31    $inputText.on('keypress', handleInputTextKeypress);
32    $newChannelInput.on('keypress', tc.handleNewChannelInputKeypress);
33    $('#connect-image').on('click', connectClientWithUsername);
34    $('#add-channel-image').on('click', showAddChannelInput);
35    $('#leave-span').on('click', disconnectClient);
36    $('#delete-channel-span').on('click', deleteCurrentChannel);
37  });
38
39  function handleUsernameInputKeypress(event) {
40    if (event.keyCode === 13){
41      connectClientWithUsername();
42    }
43  }
44
45  function handleInputTextKeypress(event) {
46    if (event.keyCode === 13) {
47      tc.currentChannel.sendMessage($(this).val());
48      event.preventDefault();
49      $(this).val('');
50    }
51    else {
52      notifyTyping();
53    }
54  }
55
56  var notifyTyping = $.throttle(function() {
57    tc.currentChannel.typing();
58  }, 1000);
59
60  tc.handleNewChannelInputKeypress = function(event) {
61    if (event.keyCode === 13) {
62      tc.messagingClient.createChannel({
63        friendlyName: $newChannelInput.val()
64      }).then(hideAddChannelInput);
65      $(this).val('');
66      event.preventDefault();
67    }
68  };
69
70  function connectClientWithUsername() {
71    var usernameText = $usernameInput.val();
72    $usernameInput.val('');
73    if (usernameText == '') {
74      alert('Username cannot be empty');
75      return;
76    }
77    tc.username = usernameText;
78    fetchAccessToken(tc.username, connectMessagingClient);
79  }
80
81  function fetchAccessToken(username, handler) {
82    $.post('/twiliochat-servlets/token', {identity: username}, null, 'json')
83      .done(function(response) {
84        console.log('Successfully finished fetch of the Access Token.');
85        handler(response.token);
86      })
87      .fail(function(error) {
88        console.log('Failed to fetch the Access Token with error: ' + error);
89      });
90  }
91
92  function connectMessagingClient(token) {
93    // Initialize the Chat messaging client
94    tc.accessManager = new Twilio.AccessManager(token);
95    Twilio.Chat.Client.create(token).then(function(client) {
96      tc.messagingClient = client;
97      updateConnectedUI();
98      tc.loadChannelList(tc.joinGeneralChannel);
99      tc.messagingClient.on('channelAdded', $.throttle(tc.loadChannelList));
100      tc.messagingClient.on('channelRemoved', $.throttle(tc.loadChannelList));
101      tc.messagingClient.on('tokenExpired', refreshToken);
102    });
103  }
104
105  function refreshToken() {
106    fetchAccessToken(tc.username, setNewToken);
107  }
108
109  function setNewToken(tokenResponse) {
110    tc.accessManager.updateToken(tokenResponse.token);
111  }
112
113  function updateConnectedUI() {
114    $('#username-span').text(tc.username);
115    $statusRow.addClass('connected').removeClass('disconnected');
116    tc.$messageList.addClass('connected').removeClass('disconnected');
117    $connectPanel.addClass('connected').removeClass('disconnected');
118    $inputText.addClass('with-shadow');
119    $typingRow.addClass('connected').removeClass('disconnected');
120  }
121
122  tc.loadChannelList = function(handler) {
123    if (tc.messagingClient === undefined) {
124      console.log('Client is not initialized');
125      return;
126    }
127
128    tc.messagingClient.getPublicChannelDescriptors().then(function(channels) {
129      tc.channelArray = tc.sortChannelsByName(channels.items);
130      $channelList.text('');
131      tc.channelArray.forEach(addChannel);
132      if (typeof handler === 'function') {
133        handler();
134      }
135    });
136  };
137
138  tc.joinGeneralChannel = function() {
139    console.log('Attempting to join "general" chat channel...');
140    if (!tc.generalChannel) {
141      // If it doesn't exist, let's create it
142      tc.messagingClient.createChannel({
143        uniqueName: GENERAL_CHANNEL_UNIQUE_NAME,
144        friendlyName: GENERAL_CHANNEL_NAME
145      }).then(function(channel) {
146        console.log('Created general channel');
147        tc.generalChannel = channel;
148        tc.loadChannelList(tc.joinGeneralChannel);
149      });
150    }
151    else {
152      console.log('Found general channel:');
153      setupChannel(tc.generalChannel);
154    }
155  };
156
157  function initChannel(channel) {
158    console.log('Initialized channel ' + channel.friendlyName);
159    return tc.messagingClient.getChannelBySid(channel.sid);
160  }
161
162  function joinChannel(_channel) {
163    return _channel.join()
164      .then(function(joinedChannel) {
165        console.log('Joined channel ' + joinedChannel.friendlyName);
166        updateChannelUI(_channel);
167        tc.currentChannel = _channel;
168        tc.loadMessages();
169        return joinedChannel;
170      });
171  }
172
173  function initChannelEvents() {
174    console.log(tc.currentChannel.friendlyName + ' ready.');
175    tc.currentChannel.on('messageAdded', tc.addMessageToList);
176    tc.currentChannel.on('typingStarted', showTypingStarted);
177    tc.currentChannel.on('typingEnded', hideTypingStarted);
178    tc.currentChannel.on('memberJoined', notifyMemberJoined);
179    tc.currentChannel.on('memberLeft', notifyMemberLeft);
180    $inputText.prop('disabled', false).focus();
181  }
182
183  function setupChannel(channel) {
184    return leaveCurrentChannel()
185      .then(function() {
186        return initChannel(channel);
187      })
188      .then(function(_channel) {
189        return joinChannel(_channel);
190      })
191      .then(initChannelEvents);
192  }
193
194  tc.loadMessages = function() {
195    tc.currentChannel.getMessages(MESSAGES_HISTORY_LIMIT)
196      .then(function(messages) {
197        messages.items.forEach(tc.addMessageToList);
198    });
199  };
200
201  function leaveCurrentChannel() {
202    if (tc.currentChannel) {
203      return tc.currentChannel.leave().then(function(leftChannel) {
204        console.log('left ' + leftChannel.friendlyName);
205        leftChannel.removeListener('messageAdded', tc.addMessageToList);
206        leftChannel.removeListener('typingStarted', showTypingStarted);
207        leftChannel.removeListener('typingEnded', hideTypingStarted);
208        leftChannel.removeListener('memberJoined', notifyMemberJoined);
209        leftChannel.removeListener('memberLeft', notifyMemberLeft);
210      });
211    } else {
212      return Promise.resolve();
213    }
214  }
215
216  tc.addMessageToList = function(message) {
217    var rowDiv = $('<div>').addClass('row no-margin');
218    rowDiv.loadTemplate($('#message-template'), {
219      username: message.author,
220      date: dateFormatter.getTodayDate(message.dateCreated),
221      body: message.body
222    });
223    if (message.author === tc.username) {
224      rowDiv.addClass('own-message');
225    }
226
227    tc.$messageList.append(rowDiv);
228    scrollToMessageListBottom();
229  };
230
231  function notifyMemberJoined(member) {
232    notify(member.identity + ' joined the channel')
233  }
234
235  function notifyMemberLeft(member) {
236    notify(member.identity + ' left the channel');
237  }
238
239  function notify(message) {
240    var row = $('<div>').addClass('col-md-12');
241    row.loadTemplate('#member-notification-template', {
242      status: message
243    });
244    tc.$messageList.append(row);
245    scrollToMessageListBottom();
246  }
247
248  function showTypingStarted(member) {
249    $typingPlaceholder.text(member.identity + ' is typing...');
250  }
251
252  function hideTypingStarted(member) {
253    $typingPlaceholder.text('');
254  }
255
256  function scrollToMessageListBottom() {
257    tc.$messageList.scrollTop(tc.$messageList[0].scrollHeight);
258  }
259
260  function updateChannelUI(selectedChannel) {
261    var channelElements = $('.channel-element').toArray();
262    var channelElement = channelElements.filter(function(element) {
263      return $(element).data().sid === selectedChannel.sid;
264    });
265    channelElement = $(channelElement);
266    if (tc.currentChannelContainer === undefined && selectedChannel.uniqueName === GENERAL_CHANNEL_UNIQUE_NAME) {
267      tc.currentChannelContainer = channelElement;
268    }
269    tc.currentChannelContainer.removeClass('selected-channel').addClass('unselected-channel');
270    channelElement.removeClass('unselected-channel').addClass('selected-channel');
271    tc.currentChannelContainer = channelElement;
272  }
273
274  function showAddChannelInput() {
275    if (tc.messagingClient) {
276      $newChannelInputRow.addClass('showing').removeClass('not-showing');
277      $channelList.addClass('showing').removeClass('not-showing');
278      $newChannelInput.focus();
279    }
280  }
281
282  function hideAddChannelInput() {
283    $newChannelInputRow.addClass('not-showing').removeClass('showing');
284    $channelList.addClass('not-showing').removeClass('showing');
285    $newChannelInput.val('');
286  }
287
288  function addChannel(channel) {
289    if (channel.uniqueName === GENERAL_CHANNEL_UNIQUE_NAME) {
290      tc.generalChannel = channel;
291    }
292    var rowDiv = $('<div>').addClass('row channel-row');
293    rowDiv.loadTemplate('#channel-template', {
294      channelName: channel.friendlyName
295    });
296
297    var channelP = rowDiv.children().children().first();
298
299    rowDiv.on('click', selectChannel);
300    channelP.data('sid', channel.sid);
301    if (tc.currentChannel && channel.sid === tc.currentChannel.sid) {
302      tc.currentChannelContainer = channelP;
303      channelP.addClass('selected-channel');
304    }
305    else {
306      channelP.addClass('unselected-channel')
307    }
308
309    $channelList.append(rowDiv);
310  }
311
312  function deleteCurrentChannel() {
313    if (!tc.currentChannel) {
314      return;
315    }
316    if (tc.currentChannel.sid === tc.generalChannel.sid) {
317      alert('You cannot delete the general channel');
318      return;
319    }
320    tc.currentChannel.delete().then(function(channel) {
321      console.log('channel: '+ channel.friendlyName + ' deleted');
322      setupChannel(tc.generalChannel);
323    });
324  }
325
326  function selectChannel(event) {
327    var target = $(event.target);
328    var channelSid = target.data().sid;
329    var selectedChannel = tc.channelArray.filter(function(channel) {
330      return channel.sid === channelSid;
331    })[0];
332    if (selectedChannel === tc.currentChannel) {
333      return;
334    }
335    setupChannel(selectedChannel);
336  };
337
338  function disconnectClient() {
339    leaveCurrentChannel();
340    $channelList.text('');
341    tc.$messageList.text('');
342    channels = undefined;
343    $statusRow.addClass('disconnected').removeClass('connected');
344    tc.$messageList.addClass('disconnected').removeClass('connected');
345    $connectPanel.addClass('disconnected').removeClass('connected');
346    $inputText.removeClass('with-shadow');
347    $typingRow.addClass('disconnected').removeClass('connected');
348  }
349
350  tc.sortChannelsByName = function(channels) {
351    return channels.sort(function(a, b) {
352      if (a.friendlyName === GENERAL_CHANNEL_NAME) {
353        return -1;
354      }
355      if (b.friendlyName === GENERAL_CHANNEL_NAME) {
356        return 1;
357      }
358      return a.friendlyName.localeCompare(b.friendlyName);
359    });
360  };
361
362  return tc;
363})();
364

Next, we will see how we can switch between channels.

Join Other Channels

When you tap on the name of a channel from the sidebar, that channel is set as the selectedChannel. The selectChannel method takes care of joining to the selected channel and setting up the selectedChannel.

Join Other Channels

src/main/webapp/js/twiliochat.js

1var twiliochat = (function() {
2  var tc = {};
3
4  var GENERAL_CHANNEL_UNIQUE_NAME = 'general';
5  var GENERAL_CHANNEL_NAME = 'General Channel';
6  var MESSAGES_HISTORY_LIMIT = 50;
7
8  var $channelList;
9  var $inputText;
10  var $usernameInput;
11  var $statusRow;
12  var $connectPanel;
13  var $newChannelInputRow;
14  var $newChannelInput;
15  var $typingRow;
16  var $typingPlaceholder;
17
18  $(document).ready(function() {
19    tc.$messageList = $('#message-list');
20    $channelList = $('#channel-list');
21    $inputText = $('#input-text');
22    $usernameInput = $('#username-input');
23    $statusRow = $('#status-row');
24    $connectPanel = $('#connect-panel');
25    $newChannelInputRow = $('#new-channel-input-row');
26    $newChannelInput = $('#new-channel-input');
27    $typingRow = $('#typing-row');
28    $typingPlaceholder = $('#typing-placeholder');
29    $usernameInput.focus();
30    $usernameInput.on('keypress', handleUsernameInputKeypress);
31    $inputText.on('keypress', handleInputTextKeypress);
32    $newChannelInput.on('keypress', tc.handleNewChannelInputKeypress);
33    $('#connect-image').on('click', connectClientWithUsername);
34    $('#add-channel-image').on('click', showAddChannelInput);
35    $('#leave-span').on('click', disconnectClient);
36    $('#delete-channel-span').on('click', deleteCurrentChannel);
37  });
38
39  function handleUsernameInputKeypress(event) {
40    if (event.keyCode === 13){
41      connectClientWithUsername();
42    }
43  }
44
45  function handleInputTextKeypress(event) {
46    if (event.keyCode === 13) {
47      tc.currentChannel.sendMessage($(this).val());
48      event.preventDefault();
49      $(this).val('');
50    }
51    else {
52      notifyTyping();
53    }
54  }
55
56  var notifyTyping = $.throttle(function() {
57    tc.currentChannel.typing();
58  }, 1000);
59
60  tc.handleNewChannelInputKeypress = function(event) {
61    if (event.keyCode === 13) {
62      tc.messagingClient.createChannel({
63        friendlyName: $newChannelInput.val()
64      }).then(hideAddChannelInput);
65      $(this).val('');
66      event.preventDefault();
67    }
68  };
69
70  function connectClientWithUsername() {
71    var usernameText = $usernameInput.val();
72    $usernameInput.val('');
73    if (usernameText == '') {
74      alert('Username cannot be empty');
75      return;
76    }
77    tc.username = usernameText;
78    fetchAccessToken(tc.username, connectMessagingClient);
79  }
80
81  function fetchAccessToken(username, handler) {
82    $.post('/twiliochat-servlets/token', {identity: username}, null, 'json')
83      .done(function(response) {
84        console.log('Successfully finished fetch of the Access Token.');
85        handler(response.token);
86      })
87      .fail(function(error) {
88        console.log('Failed to fetch the Access Token with error: ' + error);
89      });
90  }
91
92  function connectMessagingClient(token) {
93    // Initialize the Chat messaging client
94    tc.accessManager = new Twilio.AccessManager(token);
95    Twilio.Chat.Client.create(token).then(function(client) {
96      tc.messagingClient = client;
97      updateConnectedUI();
98      tc.loadChannelList(tc.joinGeneralChannel);
99      tc.messagingClient.on('channelAdded', $.throttle(tc.loadChannelList));
100      tc.messagingClient.on('channelRemoved', $.throttle(tc.loadChannelList));
101      tc.messagingClient.on('tokenExpired', refreshToken);
102    });
103  }
104
105  function refreshToken() {
106    fetchAccessToken(tc.username, setNewToken);
107  }
108
109  function setNewToken(tokenResponse) {
110    tc.accessManager.updateToken(tokenResponse.token);
111  }
112
113  function updateConnectedUI() {
114    $('#username-span').text(tc.username);
115    $statusRow.addClass('connected').removeClass('disconnected');
116    tc.$messageList.addClass('connected').removeClass('disconnected');
117    $connectPanel.addClass('connected').removeClass('disconnected');
118    $inputText.addClass('with-shadow');
119    $typingRow.addClass('connected').removeClass('disconnected');
120  }
121
122  tc.loadChannelList = function(handler) {
123    if (tc.messagingClient === undefined) {
124      console.log('Client is not initialized');
125      return;
126    }
127
128    tc.messagingClient.getPublicChannelDescriptors().then(function(channels) {
129      tc.channelArray = tc.sortChannelsByName(channels.items);
130      $channelList.text('');
131      tc.channelArray.forEach(addChannel);
132      if (typeof handler === 'function') {
133        handler();
134      }
135    });
136  };
137
138  tc.joinGeneralChannel = function() {
139    console.log('Attempting to join "general" chat channel...');
140    if (!tc.generalChannel) {
141      // If it doesn't exist, let's create it
142      tc.messagingClient.createChannel({
143        uniqueName: GENERAL_CHANNEL_UNIQUE_NAME,
144        friendlyName: GENERAL_CHANNEL_NAME
145      }).then(function(channel) {
146        console.log('Created general channel');
147        tc.generalChannel = channel;
148        tc.loadChannelList(tc.joinGeneralChannel);
149      });
150    }
151    else {
152      console.log('Found general channel:');
153      setupChannel(tc.generalChannel);
154    }
155  };
156
157  function initChannel(channel) {
158    console.log('Initialized channel ' + channel.friendlyName);
159    return tc.messagingClient.getChannelBySid(channel.sid);
160  }
161
162  function joinChannel(_channel) {
163    return _channel.join()
164      .then(function(joinedChannel) {
165        console.log('Joined channel ' + joinedChannel.friendlyName);
166        updateChannelUI(_channel);
167        tc.currentChannel = _channel;
168        tc.loadMessages();
169        return joinedChannel;
170      });
171  }
172
173  function initChannelEvents() {
174    console.log(tc.currentChannel.friendlyName + ' ready.');
175    tc.currentChannel.on('messageAdded', tc.addMessageToList);
176    tc.currentChannel.on('typingStarted', showTypingStarted);
177    tc.currentChannel.on('typingEnded', hideTypingStarted);
178    tc.currentChannel.on('memberJoined', notifyMemberJoined);
179    tc.currentChannel.on('memberLeft', notifyMemberLeft);
180    $inputText.prop('disabled', false).focus();
181  }
182
183  function setupChannel(channel) {
184    return leaveCurrentChannel()
185      .then(function() {
186        return initChannel(channel);
187      })
188      .then(function(_channel) {
189        return joinChannel(_channel);
190      })
191      .then(initChannelEvents);
192  }
193
194  tc.loadMessages = function() {
195    tc.currentChannel.getMessages(MESSAGES_HISTORY_LIMIT)
196      .then(function(messages) {
197        messages.items.forEach(tc.addMessageToList);
198    });
199  };
200
201  function leaveCurrentChannel() {
202    if (tc.currentChannel) {
203      return tc.currentChannel.leave().then(function(leftChannel) {
204        console.log('left ' + leftChannel.friendlyName);
205        leftChannel.removeListener('messageAdded', tc.addMessageToList);
206        leftChannel.removeListener('typingStarted', showTypingStarted);
207        leftChannel.removeListener('typingEnded', hideTypingStarted);
208        leftChannel.removeListener('memberJoined', notifyMemberJoined);
209        leftChannel.removeListener('memberLeft', notifyMemberLeft);
210      });
211    } else {
212      return Promise.resolve();
213    }
214  }
215
216  tc.addMessageToList = function(message) {
217    var rowDiv = $('<div>').addClass('row no-margin');
218    rowDiv.loadTemplate($('#message-template'), {
219      username: message.author,
220      date: dateFormatter.getTodayDate(message.dateCreated),
221      body: message.body
222    });
223    if (message.author === tc.username) {
224      rowDiv.addClass('own-message');
225    }
226
227    tc.$messageList.append(rowDiv);
228    scrollToMessageListBottom();
229  };
230
231  function notifyMemberJoined(member) {
232    notify(member.identity + ' joined the channel')
233  }
234
235  function notifyMemberLeft(member) {
236    notify(member.identity + ' left the channel');
237  }
238
239  function notify(message) {
240    var row = $('<div>').addClass('col-md-12');
241    row.loadTemplate('#member-notification-template', {
242      status: message
243    });
244    tc.$messageList.append(row);
245    scrollToMessageListBottom();
246  }
247
248  function showTypingStarted(member) {
249    $typingPlaceholder.text(member.identity + ' is typing...');
250  }
251
252  function hideTypingStarted(member) {
253    $typingPlaceholder.text('');
254  }
255
256  function scrollToMessageListBottom() {
257    tc.$messageList.scrollTop(tc.$messageList[0].scrollHeight);
258  }
259
260  function updateChannelUI(selectedChannel) {
261    var channelElements = $('.channel-element').toArray();
262    var channelElement = channelElements.filter(function(element) {
263      return $(element).data().sid === selectedChannel.sid;
264    });
265    channelElement = $(channelElement);
266    if (tc.currentChannelContainer === undefined && selectedChannel.uniqueName === GENERAL_CHANNEL_UNIQUE_NAME) {
267      tc.currentChannelContainer = channelElement;
268    }
269    tc.currentChannelContainer.removeClass('selected-channel').addClass('unselected-channel');
270    channelElement.removeClass('unselected-channel').addClass('selected-channel');
271    tc.currentChannelContainer = channelElement;
272  }
273
274  function showAddChannelInput() {
275    if (tc.messagingClient) {
276      $newChannelInputRow.addClass('showing').removeClass('not-showing');
277      $channelList.addClass('showing').removeClass('not-showing');
278      $newChannelInput.focus();
279    }
280  }
281
282  function hideAddChannelInput() {
283    $newChannelInputRow.addClass('not-showing').removeClass('showing');
284    $channelList.addClass('not-showing').removeClass('showing');
285    $newChannelInput.val('');
286  }
287
288  function addChannel(channel) {
289    if (channel.uniqueName === GENERAL_CHANNEL_UNIQUE_NAME) {
290      tc.generalChannel = channel;
291    }
292    var rowDiv = $('<div>').addClass('row channel-row');
293    rowDiv.loadTemplate('#channel-template', {
294      channelName: channel.friendlyName
295    });
296
297    var channelP = rowDiv.children().children().first();
298
299    rowDiv.on('click', selectChannel);
300    channelP.data('sid', channel.sid);
301    if (tc.currentChannel && channel.sid === tc.currentChannel.sid) {
302      tc.currentChannelContainer = channelP;
303      channelP.addClass('selected-channel');
304    }
305    else {
306      channelP.addClass('unselected-channel')
307    }
308
309    $channelList.append(rowDiv);
310  }
311
312  function deleteCurrentChannel() {
313    if (!tc.currentChannel) {
314      return;
315    }
316    if (tc.currentChannel.sid === tc.generalChannel.sid) {
317      alert('You cannot delete the general channel');
318      return;
319    }
320    tc.currentChannel.delete().then(function(channel) {
321      console.log('channel: '+ channel.friendlyName + ' deleted');
322      setupChannel(tc.generalChannel);
323    });
324  }
325
326  function selectChannel(event) {
327    var target = $(event.target);
328    var channelSid = target.data().sid;
329    var selectedChannel = tc.channelArray.filter(function(channel) {
330      return channel.sid === channelSid;
331    })[0];
332    if (selectedChannel === tc.currentChannel) {
333      return;
334    }
335    setupChannel(selectedChannel);
336  };
337
338  function disconnectClient() {
339    leaveCurrentChannel();
340    $channelList.text('');
341    tc.$messageList.text('');
342    channels = undefined;
343    $statusRow.addClass('disconnected').removeClass('connected');
344    tc.$messageList.addClass('disconnected').removeClass('connected');
345    $connectPanel.addClass('disconnected').removeClass('connected');
346    $inputText.removeClass('with-shadow');
347    $typingRow.addClass('disconnected').removeClass('connected');
348  }
349
350  tc.sortChannelsByName = function(channels) {
351    return channels.sort(function(a, b) {
352      if (a.friendlyName === GENERAL_CHANNEL_NAME) {
353        return -1;
354      }
355      if (b.friendlyName === GENERAL_CHANNEL_NAME) {
356        return 1;
357      }
358      return a.friendlyName.localeCompare(b.friendlyName);
359    });
360  };
361
362  return tc;
363})();
364

At some point, your users will want to delete a channel. Let's have a look at how that can be done.

Delete a Channel

The application lets the user delete the channel they are currently joining through the "delete current channel" link. The only thing you need to do to actually delete the channel from Twilio is call the delete method on the channel you are trying to delete. Like other methods on the Channel object, it'll return a promise where you can set the success handler.

Delete a Channel

src/main/webapp/js/twiliochat.js

1var twiliochat = (function() {
2  var tc = {};
3
4  var GENERAL_CHANNEL_UNIQUE_NAME = 'general';
5  var GENERAL_CHANNEL_NAME = 'General Channel';
6  var MESSAGES_HISTORY_LIMIT = 50;
7
8  var $channelList;
9  var $inputText;
10  var $usernameInput;
11  var $statusRow;
12  var $connectPanel;
13  var $newChannelInputRow;
14  var $newChannelInput;
15  var $typingRow;
16  var $typingPlaceholder;
17
18  $(document).ready(function() {
19    tc.$messageList = $('#message-list');
20    $channelList = $('#channel-list');
21    $inputText = $('#input-text');
22    $usernameInput = $('#username-input');
23    $statusRow = $('#status-row');
24    $connectPanel = $('#connect-panel');
25    $newChannelInputRow = $('#new-channel-input-row');
26    $newChannelInput = $('#new-channel-input');
27    $typingRow = $('#typing-row');
28    $typingPlaceholder = $('#typing-placeholder');
29    $usernameInput.focus();
30    $usernameInput.on('keypress', handleUsernameInputKeypress);
31    $inputText.on('keypress', handleInputTextKeypress);
32    $newChannelInput.on('keypress', tc.handleNewChannelInputKeypress);
33    $('#connect-image').on('click', connectClientWithUsername);
34    $('#add-channel-image').on('click', showAddChannelInput);
35    $('#leave-span').on('click', disconnectClient);
36    $('#delete-channel-span').on('click', deleteCurrentChannel);
37  });
38
39  function handleUsernameInputKeypress(event) {
40    if (event.keyCode === 13){
41      connectClientWithUsername();
42    }
43  }
44
45  function handleInputTextKeypress(event) {
46    if (event.keyCode === 13) {
47      tc.currentChannel.sendMessage($(this).val());
48      event.preventDefault();
49      $(this).val('');
50    }
51    else {
52      notifyTyping();
53    }
54  }
55
56  var notifyTyping = $.throttle(function() {
57    tc.currentChannel.typing();
58  }, 1000);
59
60  tc.handleNewChannelInputKeypress = function(event) {
61    if (event.keyCode === 13) {
62      tc.messagingClient.createChannel({
63        friendlyName: $newChannelInput.val()
64      }).then(hideAddChannelInput);
65      $(this).val('');
66      event.preventDefault();
67    }
68  };
69
70  function connectClientWithUsername() {
71    var usernameText = $usernameInput.val();
72    $usernameInput.val('');
73    if (usernameText == '') {
74      alert('Username cannot be empty');
75      return;
76    }
77    tc.username = usernameText;
78    fetchAccessToken(tc.username, connectMessagingClient);
79  }
80
81  function fetchAccessToken(username, handler) {
82    $.post('/twiliochat-servlets/token', {identity: username}, null, 'json')
83      .done(function(response) {
84        console.log('Successfully finished fetch of the Access Token.');
85        handler(response.token);
86      })
87      .fail(function(error) {
88        console.log('Failed to fetch the Access Token with error: ' + error);
89      });
90  }
91
92  function connectMessagingClient(token) {
93    // Initialize the Chat messaging client
94    tc.accessManager = new Twilio.AccessManager(token);
95    Twilio.Chat.Client.create(token).then(function(client) {
96      tc.messagingClient = client;
97      updateConnectedUI();
98      tc.loadChannelList(tc.joinGeneralChannel);
99      tc.messagingClient.on('channelAdded', $.throttle(tc.loadChannelList));
100      tc.messagingClient.on('channelRemoved', $.throttle(tc.loadChannelList));
101      tc.messagingClient.on('tokenExpired', refreshToken);
102    });
103  }
104
105  function refreshToken() {
106    fetchAccessToken(tc.username, setNewToken);
107  }
108
109  function setNewToken(tokenResponse) {
110    tc.accessManager.updateToken(tokenResponse.token);
111  }
112
113  function updateConnectedUI() {
114    $('#username-span').text(tc.username);
115    $statusRow.addClass('connected').removeClass('disconnected');
116    tc.$messageList.addClass('connected').removeClass('disconnected');
117    $connectPanel.addClass('connected').removeClass('disconnected');
118    $inputText.addClass('with-shadow');
119    $typingRow.addClass('connected').removeClass('disconnected');
120  }
121
122  tc.loadChannelList = function(handler) {
123    if (tc.messagingClient === undefined) {
124      console.log('Client is not initialized');
125      return;
126    }
127
128    tc.messagingClient.getPublicChannelDescriptors().then(function(channels) {
129      tc.channelArray = tc.sortChannelsByName(channels.items);
130      $channelList.text('');
131      tc.channelArray.forEach(addChannel);
132      if (typeof handler === 'function') {
133        handler();
134      }
135    });
136  };
137
138  tc.joinGeneralChannel = function() {
139    console.log('Attempting to join "general" chat channel...');
140    if (!tc.generalChannel) {
141      // If it doesn't exist, let's create it
142      tc.messagingClient.createChannel({
143        uniqueName: GENERAL_CHANNEL_UNIQUE_NAME,
144        friendlyName: GENERAL_CHANNEL_NAME
145      }).then(function(channel) {
146        console.log('Created general channel');
147        tc.generalChannel = channel;
148        tc.loadChannelList(tc.joinGeneralChannel);
149      });
150    }
151    else {
152      console.log('Found general channel:');
153      setupChannel(tc.generalChannel);
154    }
155  };
156
157  function initChannel(channel) {
158    console.log('Initialized channel ' + channel.friendlyName);
159    return tc.messagingClient.getChannelBySid(channel.sid);
160  }
161
162  function joinChannel(_channel) {
163    return _channel.join()
164      .then(function(joinedChannel) {
165        console.log('Joined channel ' + joinedChannel.friendlyName);
166        updateChannelUI(_channel);
167        tc.currentChannel = _channel;
168        tc.loadMessages();
169        return joinedChannel;
170      });
171  }
172
173  function initChannelEvents() {
174    console.log(tc.currentChannel.friendlyName + ' ready.');
175    tc.currentChannel.on('messageAdded', tc.addMessageToList);
176    tc.currentChannel.on('typingStarted', showTypingStarted);
177    tc.currentChannel.on('typingEnded', hideTypingStarted);
178    tc.currentChannel.on('memberJoined', notifyMemberJoined);
179    tc.currentChannel.on('memberLeft', notifyMemberLeft);
180    $inputText.prop('disabled', false).focus();
181  }
182
183  function setupChannel(channel) {
184    return leaveCurrentChannel()
185      .then(function() {
186        return initChannel(channel);
187      })
188      .then(function(_channel) {
189        return joinChannel(_channel);
190      })
191      .then(initChannelEvents);
192  }
193
194  tc.loadMessages = function() {
195    tc.currentChannel.getMessages(MESSAGES_HISTORY_LIMIT)
196      .then(function(messages) {
197        messages.items.forEach(tc.addMessageToList);
198    });
199  };
200
201  function leaveCurrentChannel() {
202    if (tc.currentChannel) {
203      return tc.currentChannel.leave().then(function(leftChannel) {
204        console.log('left ' + leftChannel.friendlyName);
205        leftChannel.removeListener('messageAdded', tc.addMessageToList);
206        leftChannel.removeListener('typingStarted', showTypingStarted);
207        leftChannel.removeListener('typingEnded', hideTypingStarted);
208        leftChannel.removeListener('memberJoined', notifyMemberJoined);
209        leftChannel.removeListener('memberLeft', notifyMemberLeft);
210      });
211    } else {
212      return Promise.resolve();
213    }
214  }
215
216  tc.addMessageToList = function(message) {
217    var rowDiv = $('<div>').addClass('row no-margin');
218    rowDiv.loadTemplate($('#message-template'), {
219      username: message.author,
220      date: dateFormatter.getTodayDate(message.dateCreated),
221      body: message.body
222    });
223    if (message.author === tc.username) {
224      rowDiv.addClass('own-message');
225    }
226
227    tc.$messageList.append(rowDiv);
228    scrollToMessageListBottom();
229  };
230
231  function notifyMemberJoined(member) {
232    notify(member.identity + ' joined the channel')
233  }
234
235  function notifyMemberLeft(member) {
236    notify(member.identity + ' left the channel');
237  }
238
239  function notify(message) {
240    var row = $('<div>').addClass('col-md-12');
241    row.loadTemplate('#member-notification-template', {
242      status: message
243    });
244    tc.$messageList.append(row);
245    scrollToMessageListBottom();
246  }
247
248  function showTypingStarted(member) {
249    $typingPlaceholder.text(member.identity + ' is typing...');
250  }
251
252  function hideTypingStarted(member) {
253    $typingPlaceholder.text('');
254  }
255
256  function scrollToMessageListBottom() {
257    tc.$messageList.scrollTop(tc.$messageList[0].scrollHeight);
258  }
259
260  function updateChannelUI(selectedChannel) {
261    var channelElements = $('.channel-element').toArray();
262    var channelElement = channelElements.filter(function(element) {
263      return $(element).data().sid === selectedChannel.sid;
264    });
265    channelElement = $(channelElement);
266    if (tc.currentChannelContainer === undefined && selectedChannel.uniqueName === GENERAL_CHANNEL_UNIQUE_NAME) {
267      tc.currentChannelContainer = channelElement;
268    }
269    tc.currentChannelContainer.removeClass('selected-channel').addClass('unselected-channel');
270    channelElement.removeClass('unselected-channel').addClass('selected-channel');
271    tc.currentChannelContainer = channelElement;
272  }
273
274  function showAddChannelInput() {
275    if (tc.messagingClient) {
276      $newChannelInputRow.addClass('showing').removeClass('not-showing');
277      $channelList.addClass('showing').removeClass('not-showing');
278      $newChannelInput.focus();
279    }
280  }
281
282  function hideAddChannelInput() {
283    $newChannelInputRow.addClass('not-showing').removeClass('showing');
284    $channelList.addClass('not-showing').removeClass('showing');
285    $newChannelInput.val('');
286  }
287
288  function addChannel(channel) {
289    if (channel.uniqueName === GENERAL_CHANNEL_UNIQUE_NAME) {
290      tc.generalChannel = channel;
291    }
292    var rowDiv = $('<div>').addClass('row channel-row');
293    rowDiv.loadTemplate('#channel-template', {
294      channelName: channel.friendlyName
295    });
296
297    var channelP = rowDiv.children().children().first();
298
299    rowDiv.on('click', selectChannel);
300    channelP.data('sid', channel.sid);
301    if (tc.currentChannel && channel.sid === tc.currentChannel.sid) {
302      tc.currentChannelContainer = channelP;
303      channelP.addClass('selected-channel');
304    }
305    else {
306      channelP.addClass('unselected-channel')
307    }
308
309    $channelList.append(rowDiv);
310  }
311
312  function deleteCurrentChannel() {
313    if (!tc.currentChannel) {
314      return;
315    }
316    if (tc.currentChannel.sid === tc.generalChannel.sid) {
317      alert('You cannot delete the general channel');
318      return;
319    }
320    tc.currentChannel.delete().then(function(channel) {
321      console.log('channel: '+ channel.friendlyName + ' deleted');
322      setupChannel(tc.generalChannel);
323    });
324  }
325
326  function selectChannel(event) {
327    var target = $(event.target);
328    var channelSid = target.data().sid;
329    var selectedChannel = tc.channelArray.filter(function(channel) {
330      return channel.sid === channelSid;
331    })[0];
332    if (selectedChannel === tc.currentChannel) {
333      return;
334    }
335    setupChannel(selectedChannel);
336  };
337
338  function disconnectClient() {
339    leaveCurrentChannel();
340    $channelList.text('');
341    tc.$messageList.text('');
342    channels = undefined;
343    $statusRow.addClass('disconnected').removeClass('connected');
344    tc.$messageList.addClass('disconnected').removeClass('connected');
345    $connectPanel.addClass('disconnected').removeClass('connected');
346    $inputText.removeClass('with-shadow');
347    $typingRow.addClass('disconnected').removeClass('connected');
348  }
349
350  tc.sortChannelsByName = function(channels) {
351    return channels.sort(function(a, b) {
352      if (a.friendlyName === GENERAL_CHANNEL_NAME) {
353        return -1;
354      }
355      if (b.friendlyName === GENERAL_CHANNEL_NAME) {
356        return 1;
357      }
358      return a.friendlyName.localeCompare(b.friendlyName);
359    });
360  };
361
362  return tc;
363})();
364

That's it! We've just implemented a chat application for Java using the Servlet API.

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