Custom HTTP Clients for the Twilio PHP Helper Library

If you are working with the Twilio PHP Helper Library and need to modify the HTTP requests that the library makes to the Twilio servers you’re in the right place. The most common place you'll need to alter the HTTP request is to connect and authenticate with an enterprise’s proxy server. We’ll provide sample code that you can drop right into your app to handle this use case.

Connect and authenticate with a proxy server

To connect and provide credentials to a proxy server between your app and Twilio, you need a way to modify the HTTP requests that the Twilio helper library makes to invoke the Twilio REST API.

In PHP, the Twilio helper library uses the cURL library under the hood to make HTTP requests. The Twilio Helper Library allows you to provide your own httpClient for making API requests.

How do we apply this to a typical Twilio REST API example?

$twilio = new Client($sid, $token);

$message = $twilio->messages
                  ->create("+15558675310",
                           array(
                               'body' => "Hey there!",
                               'from' => "+15017122661"
                           )
                  );

Where does httpCient get created and used?

Out of the box, the helper library is creating a default RequestClient for you, using the Twilio credentials you pass to the init method. However, there’s nothing stopping you from creating your own RequestClient.

Once you have your own RequestClient, you can pass it to any Twilio REST API resource action you want. Here’s an example of sending an SMS message with a custom client:

Create your custom TwilioRestClient

Take a closer look at the constructor for HttpClient and you'll see that the httpClient parameter is actually of type Twilio\Http\Client. Client is an abstraction that allows plugging in any HTTP client implementation you want (or even creating a mocking layer for unit testing).

However, within the helper library, there is an implementation of Twilio\Http\Client called CurlClient. This class wraps the Twilio\Http\Client and provides it to the Twilio helper library to make the necessary HTTP requests.

Call Twilio through a proxy server

Now that we understand how all the components fit together we can create our own HttpClient that can connect through a proxy server. To make this reusable, here’s a class that you can use to create this HttpClient whenever you need one.

In this example, we are using some environmental variables loaded at the program startup to retrieve various configuration settings:

• Your Twilio Account Sid and Auth Token (found here, in the Twilio console)

• A proxy address in IP:Port form, e.g. 127.0.0.1:8888

Place these setting in an .env file like so:

ACCOUNT_SID=ACxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
AUTH_TOKEN= your_auth_token

PROXY=127.0.0.1:8888

Here’s the full console program that loads the .env file and sends a text message to show everything fitting together.

What else can this technique be used for?

Now that you know how to inject your own httpClient into the Twilio API request pipeline, you could use this technique to add custom HTTP headers and authorization to the requests (perhaps as required by an upstream proxy server).

You could also implement your own httpClient to mock the Twilio API responses so your unit and integration tests can run without the need to make a connection to Twilio. In fact, there’s already an example online showing how to do this in C#.

We can’t wait to see what you build!