License Server Authentication

Your application's license server may require some form of authentication so that it only delivers licenses to paying users. In this tutorial, we're going to use various license server endpoints that require various forms of authentication.

Please note that the license server we are using in this tutorial is a Widevine license server, so you will need to use Chrome to follow along. Because EME requires a secure URL, you will also need to use localhost or https for this tutorial. See the note at the top of DRM Configuration for more information.

To start, we're going to use the code from Basic Usage, but use this manifest and license server:

const manifestUri =
    'https://storage.googleapis.com/shaka-demo-assets/sintel-widevine/dash.mpd';
const licenseServer = 'https://cwip-shaka-proxy.appspot.com/no_auth';

We'll also need to configure the player to use this license server before it loads the manifest:

  player.configure({
    drm: {
      servers: { 'com.widevine.alpha': licenseServer }
    }
  });

  // Try to load a manifest.
  try {
    await player.load(manifestUri);
    // The video should now be playing!  
  } catch (e) {
    onError(e);
  }

Since the endpoint is /no_auth, this should play without authentication.

Header authentication

First, we'll try authentication using headers. Change the license server to:

const licenseServer = 'https://cwip-shaka-proxy.appspot.com/header_auth';

This endpoint requires a specific header value to deliver a license. If you try to use it without setting the authentication header, you will see Error code 6007, which means LICENSE_REQUEST_FAILED. The JavaScript console will show you a failed HTTP request with HTTP status code 401 (Unauthorized), and playback will hang when you get to the encrypted part of the stream (10 seconds in).

To authenticate to this endpoint, we must send a special header. You can add arbitrary headers to Shaka's requests through a request filter callback. Register the filter before calling player.load():

  player.getNetworkingEngine().registerRequestFilter(function(type, request) {
    // Only add headers to license requests:
    if (type == shaka.net.NetworkingEngine.RequestType.LICENSE) {
      // This is the specific header name and value the server wants:
      request.headers['CWIP-Auth-Header'] = 'VGhpc0lzQVRlc3QK';
    }
  });

Load the page again, and the license request will succeed. Although we are using a fixed value for the purposes of this tutorial, your application can derive appropriate authentication header(s) before or during the callback.

Parameter Authentication

Next, we'll try authentication using URL parameters. Change the license server to:

const licenseServer = 'https://cwip-shaka-proxy.appspot.com/param_auth';

This endpoint requires a specific URL parameter to deliver a license. If you try to use it without setting the parameter, you will see Error code 6007 (LICENSE_REQUEST_FAILED) just as before with header authentication.

We can use a request filter to modify the URL and add the required parameter:

  player.getNetworkingEngine().registerRequestFilter(function(type, request) {
    // Only add headers to license requests:
    if (type == shaka.net.NetworkingEngine.RequestType.LICENSE) {
      // This is the specific parameter name and value the server wants:
      // Note that all network requests can have multiple URIs (for fallback),
      // and therefore this is an array. But there should only be one license
      // server URI in this tutorial.
      request.uris[0] += '?CWIP-Auth-Param=VGhpc0lzQVRlc3QK';
    }
  });

Load the page again, and the license request will succeed.

Finally, let's try using cookies for authentication. Change the license server to:

const licenseServer = 'https://cwip-shaka-proxy.appspot.com/cookie_auth';

This endpoint requires a specific cookie to deliver a license. If you try to use it without setting the parameter, you will see Error code 6007 (LICENSE_REQUEST_FAILED) just as with the other endpoints.

Cookies are set by a server to be returned to that server, and are not sent by the JavaScript application. So to set the required cookie value, point your browser to the server's set_cookie page.

Open the JavaScript console and check the value of document.cookie to confirm that you have the cookie. You should see "CWIP-Auth-Cookie=VGhpc0lzQVRlc3QK".

Now load the Shaka page again, and ... we still get error code 6007. What happened?

Cookies are considered "credentials" by the browser's XmlHttpRequest API, and credentials may not be sent cross-origin unless:

Our cookie_auth endpoint sends back headers that allow credentialed requests, so we set a flag in our request filter to send credentials cross-site:

  player.getNetworkingEngine().registerRequestFilter(function(type, request) {
    if (type == shaka.net.NetworkingEngine.RequestType.LICENSE) {
      request.allowCrossSiteCredentials = true;
    }
  });

Load the page again, and the license request will succeed.

Always Sending Credentials

Now, you may be asking yourself: "Why not just make true the default and always send credentials when we have them?"

If a server does not explicitly allow credentials to be sent cross-origin, setting this flag would cause the request to fail even if the client has no cookies to send. If you'd like to try this out, clear your cookies by pointing your browser to the server's delete_cookie page. Then set your license server back to:

const licenseServer = 'https://cwip-shaka-proxy.appspot.com/no_auth';

Since allowCrossSiteCredentials is true and that endpoint doesn't explicitly allow credentials, you'll get a failure. The JavaScript console will show a message from the browser that says something like:

Credentials flag is 'true', but the 'Access-Control-Allow-Credentials' header
is ''. It must be 'true' to allow credentials. Origin 'http://localhost' is
therefore not allowed access.

Asynchronous Credentials

In some scenarios, you may not know the credentials right away. You would like to make an additional request to get those credentials before you attach them to the request Shaka Player wants to make.

Since v2.1.0, we support asynchronous filters. This allows you to pause a license request, make an additional request for an authorization token, then use that token to complete the license request.

Any filter that returns a Promise is an asynchronous filter. NetworkingEngine uses Promises for requests, so it is easy to make an additional request as part of an asynchronous filter.

To start, change the license server and add two additional variables:

const licenseServer = 'https://cwip-shaka-proxy.appspot.com/header_auth';
const authTokenServer = 'https://cwip-shaka-proxy.appspot.com/get_auth_token';
const authToken = null;

Now change the request filter:

  player.getNetworkingEngine().registerRequestFilter(function(type, request) {
    // Only add headers to license requests:
    if (type != shaka.net.NetworkingEngine.RequestType.LICENSE) return;

    // If we already know the token, attach it right away:
    if (authToken) {
      console.log('Have auth token, attaching to license request.');
      request.headers['CWIP-Auth-Header'] = authToken;
      return;
    }

    console.log('Need auth token.');
    // Start an asynchronous request, and return a Promise chain based on that.
    const authRequest = {
      uris: [authTokenServer],
      method: 'POST',
    };
    const requestType = shaka.net.NetworkingEngine.RequestType.APP;
    return player.getNetworkingEngine().request(requestType, authRequest)
        .promise.then(function(response) {
          // This endpoint responds with the value we should use in the header.
          authToken = shaka.util.StringUtils.fromUTF8(response.data);
          console.log('Received auth token', authToken);
          request.headers['CWIP-Auth-Header'] = authToken;
          console.log('License request can now continue.');
        });
  });

Load the page again. The license request will be delayed, an additional request will be made for the auth token, and then the license request will continue. You should see these messages in the JavaScript console:

Need auth token.
Received auth token VGhpc0lzQVRlc3QK
License request can now continue.

If you need them, you can also create asynchronous response filters in the same way.

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