Setting up your environment
Before moving on, make sure to have your environment setup. Getting everything working correctly, especially with respect to virtual environments is important for isolating your dependencies if you have multiple projects running on the same machine.
You can also run through this guide to make sure you’re good to go before moving on.
Now that your environment is set up, you’re going to need to install the libraries needed for this app. The code in this post will run on both Python 2 and 3. We’re going to use:
- Django for our web framework
- Twilio’s Python library to interact with the Twilio API for sending and receiving SMS.
Navigate to the directory where you want this code to live and run the following command in your terminal with your virtual environment activated to install these dependencies:
pip install django==1.11.5 twilio==6.7.0
Building a basic Django app
First, generate a barebones Django starter project with the following terminal command in the directory where you want your project to live:
django-admin startproject mysite
This will generate a new Django project from scratch and create a
mysite directory in your current directory. Before moving on, run the following command if you want to make sure everything works (don’t worry if you see an error message about unapplied migrations):
cd mysite python manage.py runserver
Visit http://localhost:8000 and you should see the following:
Now create a Django app within the project. Instead of the polls web app from the Django tutorial, we will make one that responds to text messages. Run the following command from the same directory as
python manage.py startapp sms
As in the Django tutorial, let’s create a view for this app. If you’re familiar with the Model-View-Controller pattern, Django views might confuse you at first because they behave more similarly to Controllers in the traditional MVC app. Open
sms/views.py and add the following code:
from django.http import HttpResponse def sms_response(request): return HttpResponse("Hello, world.")
Now add a route to this view by creating the file,
sms/urls.py and adding the following code:
from django.conf.urls import url from . import views urlpatterns = [ url(r'^$', views.sms_response, name='sms'), ]
As in the Django tutorial, the next step is to point the root url at the
sms.urls module. In
mysite/urls.py, add an import for
django.conf.urls.include and insert an include() in the urlpatterns list, so you have:
from django.conf.urls import include, url from django.contrib import admin urlpatterns = [ url(r'^sms/', include('sms.urls')), url(r'^admin/', admin.site.urls), ]
Now run the project and visit http://localhost:8000/sms/ to see “Hello, World.” on the screen.
Setting up your Twilio account
Before being able to respond to messages, you’ll need a Twilio phone number. You can buy a phone number here (it’s free if you’re using the number to test your code during development). Your Django app will need to be visible from the Internet in order for Twilio to send requests to it. We will use ngrok for this, which you’ll need to install if you don’t have it. In your terminal run the following command:
ngrok http 8000
This provides us with a publicly accessible URL to the Flask app. Configure your phone number as seen in this image by adding your ngrok URL with a
/sms/ route appended to it to the “Messaging” section (make sure you don’t forget the extra slash at the end):
You are now ready to receive a text message to your new Twilio number.
Adding SMS to your Django app
Now that you have a Twilio number you want to allow users to send a text message to it and get a response.
We only need one route on this app:
/sms/ to handle incoming text messages. Let’s replace the code in
sms/views.py with the following:
from django.http import HttpResponse from django.views.decorators.csrf import csrf_exempt from twilio.twiml.messaging_response import MessagingResponse @csrf_exempt def sms_response(request): # Start our TwiML response resp = MessagingResponse() # Add a text message msg = resp.message("Check out this sweet owl!") # Add a picture message msg.media("https://demo.twilio.com/owl.png") return HttpResponse(str(resp))
If you’re confused by the
@csrf_exempt decorator, their documentation explains things pretty well.
Before being able to respond to messages, you’ll have to add ngrok.io to your ALLOWED_HOSTS in your Django site’s settings. Open
mysite/settings.py, find the line where the
ALLOWED_HOSTS are set and replace it with the following:
ALLOWED_HOSTS = ['.ngrok.io']
Run your code again:
python manage.py runserver
Now text your Twilio number and you should get a response!
What just happened?
With this app running on port 8000, sitting behind a public ngrok URL, Twilio can see your application. Upon receiving a text message:
- Twilio will send a
smsview function will be called.
/smsview responds to Twilio’s request with TwiML telling Twilio to send a message back in response (containing this sweet owl pic).
Feel free to reach out if you have any questions or comments or just want to show off the cool stuff you’ve built.