Receive and Download Images on Incoming Media Messages with Node.js

You know how to receive and reply to incoming SMS messages. What if you receive an MMS message containing an image you'd like to download? Let's learn how we can grab that image and any other incoming MMS media using Node.js.

Create MMS processing project

Create an Express application

When Twilio receives a message for your phone number, it can make an HTTP call to a webhook that you create. The easiest way to handle HTTP requests with Node is to use Express.

Twilio expects, at the very least, for your webhook to return a 200 OK response if everything is peachy. Often, however, you will return some TwiML in your response as well. TwiML is just a set of XML commands telling Twilio how you'd like it to respond to your message. Rather than manually generating the XML, we'll use the Twilio.twiml.MessagingResponse module in the helper library to facilitate generating TwiML and the rest of the webhook plumbing.

To install the library, run:

npm install twilio

Create Router

Add a new router called MessagingRouter that handles an incoming SMS request.

Express Router

1const express = require('express');
2const Twilio = require('twilio');
3const extName = require('ext-name');
4const urlUtil = require('url');
5const path = require('path');
6const fs = require('fs');
7const fetch = require('node-fetch');
8const config = require('../config');
9
10const PUBLIC_DIR = './public/mms_images';
11const { twilioPhoneNumber, twilioAccountSid, twilioAuthToken } = config;
12const { MessagingResponse } = Twilio.twiml;
13const { NODE_ENV } = process.env;
14
15function MessagingRouter() {
16  let twilioClient;
17  let images = [];
18
19  if (!fs.existsSync(PUBLIC_DIR)) {
20    fs.mkdirSync(path.resolve(PUBLIC_DIR));
21  }
22
23  function getTwilioClient() {
24    return twilioClient || new Twilio(twilioAccountSid, twilioAuthToken);
25  }
26
27  function deleteMediaItem(mediaItem) {
28    const client = getTwilioClient();
29
30    return client
31      .api.accounts(twilioAccountSid)
32      .messages(mediaItem.MessageSid)
33      .media(mediaItem.mediaSid).remove();
34  }
35
36  async function SaveMedia(mediaItem) {
37    const { mediaUrl, filename } = mediaItem;
38    if (NODE_ENV !== 'test') {
39      const fullPath = path.resolve(`${PUBLIC_DIR}/${filename}`);
40
41      if (!fs.existsSync(fullPath)) {
42        const response = await fetch(mediaUrl);
43        const fileStream = fs.createWriteStream(fullPath);
44
45        response.body.pipe(fileStream);
46
47        deleteMediaItem(mediaItem);
48      }
49
50      images.push(filename);
51    }
52  }
53
54
55  async function handleIncomingSMS(req, res) {
56    const { body } = req;
57    const { NumMedia, From: SenderNumber, MessageSid } = body;
58    let saveOperations = [];
59    const mediaItems = [];
60
61    for (var i = 0; i < NumMedia; i++) {  // eslint-disable-line
62      const mediaUrl = body[`MediaUrl${i}`];
63      const contentType = body[`MediaContentType${i}`];
64      const extension = extName.mime(contentType)[0].ext;
65      const mediaSid = path.basename(urlUtil.parse(mediaUrl).pathname);
66      const filename = `${mediaSid}.${extension}`;
67
68      mediaItems.push({ mediaSid, MessageSid, mediaUrl, filename });
69      saveOperations = mediaItems.map(mediaItem => SaveMedia(mediaItem));
70    }
71
72    await Promise.all(saveOperations);
73
74    const messageBody = NumMedia === 0 ?
75    'Send us an image!' :
76    `Thanks for sending us ${NumMedia} file(s)`;
77
78    const response = new MessagingResponse();
79    response.message({
80      from: twilioPhoneNumber,
81      to: SenderNumber,
82    }, messageBody);
83
84    return res.send(response.toString()).status(200);
85  }
86
87
88  function getRecentImages() {
89    return images;
90  }
91
92  function clearRecentImages() {
93    images = [];
94  }
95
96  function fetchRecentImages(req, res) {
97    res.status(200).send(getRecentImages());
98    clearRecentImages();
99  }
100
101  /**
102   * Initialize router and define routes.
103   */
104  const router = express.Router();
105  router.post('/incoming', handleIncomingSMS);
106  router.get('/config', (req, res) => {
107    res.status(200).send({ twilioPhoneNumber });
108  });
109  router.get('/images', fetchRecentImages);
110
111  return router;
112}
113
114module.exports = {
115  MessagingRouter,
116};

Receive MMS message and images

Get Incoming Message Details

When Twilio calls your webhook, it sends a number of parameters about the message you just received. Most of these, such as the To phone number, the From phone number, and the Body of the message are available as properties of the request body.

Get URLs to the Media

Since an MMS message can have multiple attachments, Twilio will send us form variables named MediaUrlX, where X is a zero-based index. So, for example, the URL for the first media attachment will be in the MediaUrl0 parameter, the second in MediaUrl1, and so on.

In order to handle a dynamic number of attachments, we pull the URLs out of the body request like this:

Extract Media Urls From Request Body

1const express = require('express');
2const Twilio = require('twilio');
3const extName = require('ext-name');
4const urlUtil = require('url');
5const path = require('path');
6const fs = require('fs');
7const fetch = require('node-fetch');
8const config = require('../config');
9
10const PUBLIC_DIR = './public/mms_images';
11const { twilioPhoneNumber, twilioAccountSid, twilioAuthToken } = config;
12const { MessagingResponse } = Twilio.twiml;
13const { NODE_ENV } = process.env;
14
15function MessagingRouter() {
16  let twilioClient;
17  let images = [];
18
19  if (!fs.existsSync(PUBLIC_DIR)) {
20    fs.mkdirSync(path.resolve(PUBLIC_DIR));
21  }
22
23  function getTwilioClient() {
24    return twilioClient || new Twilio(twilioAccountSid, twilioAuthToken);
25  }
26
27  function deleteMediaItem(mediaItem) {
28    const client = getTwilioClient();
29
30    return client
31      .api.accounts(twilioAccountSid)
32      .messages(mediaItem.MessageSid)
33      .media(mediaItem.mediaSid).remove();
34  }
35
36  async function SaveMedia(mediaItem) {
37    const { mediaUrl, filename } = mediaItem;
38    if (NODE_ENV !== 'test') {
39      const fullPath = path.resolve(`${PUBLIC_DIR}/${filename}`);
40
41      if (!fs.existsSync(fullPath)) {
42        const response = await fetch(mediaUrl);
43        const fileStream = fs.createWriteStream(fullPath);
44
45        response.body.pipe(fileStream);
46
47        deleteMediaItem(mediaItem);
48      }
49
50      images.push(filename);
51    }
52  }
53
54
55  async function handleIncomingSMS(req, res) {
56    const { body } = req;
57    const { NumMedia, From: SenderNumber, MessageSid } = body;
58    let saveOperations = [];
59    const mediaItems = [];
60
61    for (var i = 0; i < NumMedia; i++) {  // eslint-disable-line
62      const mediaUrl = body[`MediaUrl${i}`];
63      const contentType = body[`MediaContentType${i}`];
64      const extension = extName.mime(contentType)[0].ext;
65      const mediaSid = path.basename(urlUtil.parse(mediaUrl).pathname);
66      const filename = `${mediaSid}.${extension}`;
67
68      mediaItems.push({ mediaSid, MessageSid, mediaUrl, filename });
69      saveOperations = mediaItems.map(mediaItem => SaveMedia(mediaItem));
70    }
71
72    await Promise.all(saveOperations);
73
74    const messageBody = NumMedia === 0 ?
75    'Send us an image!' :
76    `Thanks for sending us ${NumMedia} file(s)`;
77
78    const response = new MessagingResponse();
79    response.message({
80      from: twilioPhoneNumber,
81      to: SenderNumber,
82    }, messageBody);
83
84    return res.send(response.toString()).status(200);
85  }
86
87
88  function getRecentImages() {
89    return images;
90  }
91
92  function clearRecentImages() {
93    images = [];
94  }
95
96  function fetchRecentImages(req, res) {
97    res.status(200).send(getRecentImages());
98    clearRecentImages();
99  }
100
101  /**
102   * Initialize router and define routes.
103   */
104  const router = express.Router();
105  router.post('/incoming', handleIncomingSMS);
106  router.get('/config', (req, res) => {
107    res.status(200).send({ twilioPhoneNumber });
108  });
109  router.get('/images', fetchRecentImages);
110
111  return router;
112}
113
114module.exports = {
115  MessagingRouter,
116};

Determine content type of media

Attachments to MMS messages can be of many different file types. JPG and GIF images, as well as MP4 and 3GP files, are all common. Twilio handles the determination of the file type for you and you can get the standard mime type from the MediaContentTypeX parameter. If you are expecting photos, then you will likely see a lot of attachments with the mime type image/jpeg.

Map MIME Type To File Extension

1const express = require('express');
2const Twilio = require('twilio');
3const extName = require('ext-name');
4const urlUtil = require('url');
5const path = require('path');
6const fs = require('fs');
7const fetch = require('node-fetch');
8const config = require('../config');
9
10const PUBLIC_DIR = './public/mms_images';
11const { twilioPhoneNumber, twilioAccountSid, twilioAuthToken } = config;
12const { MessagingResponse } = Twilio.twiml;
13const { NODE_ENV } = process.env;
14
15function MessagingRouter() {
16  let twilioClient;
17  let images = [];
18
19  if (!fs.existsSync(PUBLIC_DIR)) {
20    fs.mkdirSync(path.resolve(PUBLIC_DIR));
21  }
22
23  function getTwilioClient() {
24    return twilioClient || new Twilio(twilioAccountSid, twilioAuthToken);
25  }
26
27  function deleteMediaItem(mediaItem) {
28    const client = getTwilioClient();
29
30    return client
31      .api.accounts(twilioAccountSid)
32      .messages(mediaItem.MessageSid)
33      .media(mediaItem.mediaSid).remove();
34  }
35
36  async function SaveMedia(mediaItem) {
37    const { mediaUrl, filename } = mediaItem;
38    if (NODE_ENV !== 'test') {
39      const fullPath = path.resolve(`${PUBLIC_DIR}/${filename}`);
40
41      if (!fs.existsSync(fullPath)) {
42        const response = await fetch(mediaUrl);
43        const fileStream = fs.createWriteStream(fullPath);
44
45        response.body.pipe(fileStream);
46
47        deleteMediaItem(mediaItem);
48      }
49
50      images.push(filename);
51    }
52  }
53
54
55  async function handleIncomingSMS(req, res) {
56    const { body } = req;
57    const { NumMedia, From: SenderNumber, MessageSid } = body;
58    let saveOperations = [];
59    const mediaItems = [];
60
61    for (var i = 0; i < NumMedia; i++) {  // eslint-disable-line
62      const mediaUrl = body[`MediaUrl${i}`];
63      const contentType = body[`MediaContentType${i}`];
64      const extension = extName.mime(contentType)[0].ext;
65      const mediaSid = path.basename(urlUtil.parse(mediaUrl).pathname);
66      const filename = `${mediaSid}.${extension}`;
67
68      mediaItems.push({ mediaSid, MessageSid, mediaUrl, filename });
69      saveOperations = mediaItems.map(mediaItem => SaveMedia(mediaItem));
70    }
71
72    await Promise.all(saveOperations);
73
74    const messageBody = NumMedia === 0 ?
75    'Send us an image!' :
76    `Thanks for sending us ${NumMedia} file(s)`;
77
78    const response = new MessagingResponse();
79    response.message({
80      from: twilioPhoneNumber,
81      to: SenderNumber,
82    }, messageBody);
83
84    return res.send(response.toString()).status(200);
85  }
86
87
88  function getRecentImages() {
89    return images;
90  }
91
92  function clearRecentImages() {
93    images = [];
94  }
95
96  function fetchRecentImages(req, res) {
97    res.status(200).send(getRecentImages());
98    clearRecentImages();
99  }
100
101  /**
102   * Initialize router and define routes.
103   */
104  const router = express.Router();
105  router.post('/incoming', handleIncomingSMS);
106  router.get('/config', (req, res) => {
107    res.status(200).send({ twilioPhoneNumber });
108  });
109  router.get('/images', fetchRecentImages);
110
111  return router;
112}
113
114module.exports = {
115  MessagingRouter,
116};

Process MMS images

Save the Media URLs

Depending on your use case, storing the URLs of the images (or videos or whatever) may be all you need. There are two key features to these URLs that make them very pliable for your use in your apps:

They are publicly accessible without any need for authentication to facilitate sharing.
They are permanent (unless you explicitly delete the media).

For example, if you are building a browser-based app that needs to display the images, all you need to do is drop an <img src="twilio url to your image"> tag into the page. If this works for you, then perhaps all you need is to store the URL in a database character field.

Save Media to Local File System

If you want to save the media attachments to a file, then you will need to make an HTTP request to the media URL and write the response stream to a file. If you need a unique filename, you can use the last part of the media URL. For example, suppose your media URL is the following:

https://api.twilio.com/2010-04-01/Accounts/ACxxxx/Messages/MMxxxx/Media/ME27be8a708784242c0daee207ff73db67

You can use that last part of the URL as a unique filename and look up the corresponding file extension for the mime type.

Save Media From Url

1const express = require('express');
2const Twilio = require('twilio');
3const extName = require('ext-name');
4const urlUtil = require('url');
5const path = require('path');
6const fs = require('fs');
7const fetch = require('node-fetch');
8const config = require('../config');
9
10const PUBLIC_DIR = './public/mms_images';
11const { twilioPhoneNumber, twilioAccountSid, twilioAuthToken } = config;
12const { MessagingResponse } = Twilio.twiml;
13const { NODE_ENV } = process.env;
14
15function MessagingRouter() {
16  let twilioClient;
17  let images = [];
18
19  if (!fs.existsSync(PUBLIC_DIR)) {
20    fs.mkdirSync(path.resolve(PUBLIC_DIR));
21  }
22
23  function getTwilioClient() {
24    return twilioClient || new Twilio(twilioAccountSid, twilioAuthToken);
25  }
26
27  function deleteMediaItem(mediaItem) {
28    const client = getTwilioClient();
29
30    return client
31      .api.accounts(twilioAccountSid)
32      .messages(mediaItem.MessageSid)
33      .media(mediaItem.mediaSid).remove();
34  }
35
36  async function SaveMedia(mediaItem) {
37    const { mediaUrl, filename } = mediaItem;
38    if (NODE_ENV !== 'test') {
39      const fullPath = path.resolve(`${PUBLIC_DIR}/${filename}`);
40
41      if (!fs.existsSync(fullPath)) {
42        const response = await fetch(mediaUrl);
43        const fileStream = fs.createWriteStream(fullPath);
44
45        response.body.pipe(fileStream);
46
47        deleteMediaItem(mediaItem);
48      }
49
50      images.push(filename);
51    }
52  }
53
54
55  async function handleIncomingSMS(req, res) {
56    const { body } = req;
57    const { NumMedia, From: SenderNumber, MessageSid } = body;
58    let saveOperations = [];
59    const mediaItems = [];
60
61    for (var i = 0; i < NumMedia; i++) {  // eslint-disable-line
62      const mediaUrl = body[`MediaUrl${i}`];
63      const contentType = body[`MediaContentType${i}`];
64      const extension = extName.mime(contentType)[0].ext;
65      const mediaSid = path.basename(urlUtil.parse(mediaUrl).pathname);
66      const filename = `${mediaSid}.${extension}`;
67
68      mediaItems.push({ mediaSid, MessageSid, mediaUrl, filename });
69      saveOperations = mediaItems.map(mediaItem => SaveMedia(mediaItem));
70    }
71
72    await Promise.all(saveOperations);
73
74    const messageBody = NumMedia === 0 ?
75    'Send us an image!' :
76    `Thanks for sending us ${NumMedia} file(s)`;
77
78    const response = new MessagingResponse();
79    response.message({
80      from: twilioPhoneNumber,
81      to: SenderNumber,
82    }, messageBody);
83
84    return res.send(response.toString()).status(200);
85  }
86
87
88  function getRecentImages() {
89    return images;
90  }
91
92  function clearRecentImages() {
93    images = [];
94  }
95
96  function fetchRecentImages(req, res) {
97    res.status(200).send(getRecentImages());
98    clearRecentImages();
99  }
100
101  /**
102   * Initialize router and define routes.
103   */
104  const router = express.Router();
105  router.post('/incoming', handleIncomingSMS);
106  router.get('/config', (req, res) => {
107    res.status(200).send({ twilioPhoneNumber });
108  });
109  router.get('/images', fetchRecentImages);
110
111  return router;
112}
113
114module.exports = {
115  MessagingRouter,
116};

Another idea for these image files could be uploading them to a cloud storage service like Azure Blob Storage or Amazon S3. You could also save them to a database, if necessary. They're just regular files at this point. Go crazy. In this case, we are saving them to the public directory in order to serve them later.

Delete media from Twilio

If you are downloading the attachments and no longer need them to be stored by Twilio, you can delete them. You can send an HTTP DELETE request to the media URL and it will be deleted, but you will need to be authenticated to do this. The Twilio Node Helper Library can help with this, as shown here:

Delete Media From Twilio Servers

1const express = require('express');
2const Twilio = require('twilio');
3const extName = require('ext-name');
4const urlUtil = require('url');
5const path = require('path');
6const fs = require('fs');
7const fetch = require('node-fetch');
8const config = require('../config');
9
10const PUBLIC_DIR = './public/mms_images';
11const { twilioPhoneNumber, twilioAccountSid, twilioAuthToken } = config;
12const { MessagingResponse } = Twilio.twiml;
13const { NODE_ENV } = process.env;
14
15function MessagingRouter() {
16  let twilioClient;
17  let images = [];
18
19  if (!fs.existsSync(PUBLIC_DIR)) {
20    fs.mkdirSync(path.resolve(PUBLIC_DIR));
21  }
22
23  function getTwilioClient() {
24    return twilioClient || new Twilio(twilioAccountSid, twilioAuthToken);
25  }
26
27  function deleteMediaItem(mediaItem) {
28    const client = getTwilioClient();
29
30    return client
31      .api.accounts(twilioAccountSid)
32      .messages(mediaItem.MessageSid)
33      .media(mediaItem.mediaSid).remove();
34  }
35
36  async function SaveMedia(mediaItem) {
37    const { mediaUrl, filename } = mediaItem;
38    if (NODE_ENV !== 'test') {
39      const fullPath = path.resolve(`${PUBLIC_DIR}/${filename}`);
40
41      if (!fs.existsSync(fullPath)) {
42        const response = await fetch(mediaUrl);
43        const fileStream = fs.createWriteStream(fullPath);
44
45        response.body.pipe(fileStream);
46
47        deleteMediaItem(mediaItem);
48      }
49
50      images.push(filename);
51    }
52  }
53
54
55  async function handleIncomingSMS(req, res) {
56    const { body } = req;
57    const { NumMedia, From: SenderNumber, MessageSid } = body;
58    let saveOperations = [];
59    const mediaItems = [];
60
61    for (var i = 0; i < NumMedia; i++) {  // eslint-disable-line
62      const mediaUrl = body[`MediaUrl${i}`];
63      const contentType = body[`MediaContentType${i}`];
64      const extension = extName.mime(contentType)[0].ext;
65      const mediaSid = path.basename(urlUtil.parse(mediaUrl).pathname);
66      const filename = `${mediaSid}.${extension}`;
67
68      mediaItems.push({ mediaSid, MessageSid, mediaUrl, filename });
69      saveOperations = mediaItems.map(mediaItem => SaveMedia(mediaItem));
70    }
71
72    await Promise.all(saveOperations);
73
74    const messageBody = NumMedia === 0 ?
75    'Send us an image!' :
76    `Thanks for sending us ${NumMedia} file(s)`;
77
78    const response = new MessagingResponse();
79    response.message({
80      from: twilioPhoneNumber,
81      to: SenderNumber,
82    }, messageBody);
83
84    return res.send(response.toString()).status(200);
85  }
86
87
88  function getRecentImages() {
89    return images;
90  }
91
92  function clearRecentImages() {
93    images = [];
94  }
95
96  function fetchRecentImages(req, res) {
97    res.status(200).send(getRecentImages());
98    clearRecentImages();
99  }
100
101  /**
102   * Initialize router and define routes.
103   */
104  const router = express.Router();
105  router.post('/incoming', handleIncomingSMS);
106  router.get('/config', (req, res) => {
107    res.status(200).send({ twilioPhoneNumber });
108  });
109  router.get('/images', fetchRecentImages);
110
111  return router;
112}
113
114module.exports = {
115  MessagingRouter,
116};

(warning)

Protect your webhooks

Twilio supports HTTP Basic and Digest Authentication. Authentication allows you to password protect your TwiML URLs on your web server so that only you and Twilio can access them. Learn more about HTTP authentication and validating incoming requests here.

What's Next?

All the code, in a complete working project, is available on GitHub. If you need to dig a bit deeper, you can head over to our API Reference and learn more about the Twilio webhook request and the REST API Media resource. Also, you will want to be aware of the pricing for storage of all the media files that you keep on Twilio's servers.

We'd love to hear what you build with this.