Create an SMS Conversation in Python

Just like in web applications, a cookie is a small file that your application can store on Twilio's servers to keep track of information, such as a username or account.

For Twilio Programmable Messaging, cookies are scoped to the "conversation" between two parties — you can have a unique cookie for each To/From phone number pair. For example, you can store a unique cookie for any messages sent between 415-555-2222 and 415-555-1111, which will be different than the cookie used between 415-555-3333 and 415-555-1111.

In a web app, you write a cookie to keep "statefulness" between separate requests from the same browser.

Similarly, SMS messages are independent communications between two parties, so Twilio allows you to tie them together as a logical session via cookies. This means you can use server-side sessions to keep track of application state between requests. (How cool is that?)

Twilio will expire the cookies for that conversation after four hours of inactivity, as if the user "closed the browser."

The cookies let you share state across multiple messages allowing you to treat separate messages as a conversation, and store data about the conversation in the cookies for future reference.

You can store the data directly in a cookie, or you can use a session state management framework. We'll use Flask's built-in session library for this example.

Now let's try using session counters to see if a particular user has messaged us before. If they're a new sender, we'll thank them for the new message. If they've sent us messages before, we'll specify how many messages we've gotten from them.

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from flask import Flask, request, session
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from twilio.twiml.messaging_response import MessagingResponse
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# The session object makes use of a secret key.
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SECRET_KEY = 'a secret key'
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app = Flask(__name__)
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app.config.from_object(__name__)
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# Try adding your own number to this list!
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callers = {
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    "+14158675308": "Rey",
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    "+12349013030": "Finn",
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    "+12348134522": "Chewy",
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}
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@app.route("/", methods=['GET', 'POST'])
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def hello():
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    """Respond with the number of text messages sent between two parties."""
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    # Increment the counter
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    counter = session.get('counter', 0)
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    counter += 1
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    # Save the new counter value in the session
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    session['counter'] = counter
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    from_number = request.values.get('From')
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    if from_number in callers:
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        name = callers[from_number]
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    else:
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        name = "Friend"
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    # Build our reply
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    message = '{} has messaged {} {} times.' \
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        .format(name, request.values.get('To'), counter)
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    # Put it in a TwiML response
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    resp = MessagingResponse()
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    resp.message(message)
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    return str(resp)
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if __name__ == "__main__":
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    app.run(debug=True)