opentok-network-test-js

OpenTok Network Test

This Node module lets you check network connectivity to resources and services required to use OpenTok. Run this on a web client to get the following information:

• Whether the client will be able to succeed in connecting to an OpenTok session

• A MOS estimate for the session quality the client will experience

• A recommended frame rate and resolution to use for publishing to a session

For a sample that uses this module, see the OpenTok Pre-call Test tool.

Example Usage in Node/Browserify/Webpack

First, install the package:

$ npm install opentok-network-test-js

Now load the OpenTok Network Test in your project:

const OTNetworkTest = require('opentok-network-test-js');

Load the OpenTok.js library.

Instantiate an instance of the test object, passing in the OpenTok.js OT object and a configuration object. The configuration object contains an API key for your app's OpenTok project, a session ID for a test session, and a token for that session:

const otNetworkTest = new NetworkTest(OT, {
  apiKey: '123456', // Add the API key for your OpenTok project here.
  sessionId: '1_MX40NzIwMzJ-fjE1MDElGQkJJfn4', // Add a test session ID for that project
  token: 'T1==cGFydG5lcXN0PQ==' // Add a token for that session here
});

Use the OpenTok server SDKs to generate a unique session ID for each client. This session ID is used for the network test, and it must be different than the session ID used for communication in the app. The test session must be a routed session -- one that uses the OpenTok Media Router. Also generate a test token that has publish privileges.

Then run the test methods:

otNetworkTest.testConnectivity().then((results) => {
  console.log('OpenTok connectivity test results', results);
  otNetworkTest.testQuality(updateCallback(stats) {
    // This function is called repeatedly as the quality test runs.
    // It includes cumulative audio and video statistics for the test.
    const currentStats = stats[stats.length - 1];
    console.log('testQuality stats', currentStats);
  }).then((results) => {
    // This function is called when the quality test is completed.
    console.log('OpenTok quality results', results);
    let publisherSettings = {};
    if (results.video.reason) {
      console.log('Video not supported:', results.video.reason);
      publisherSettings.videoSource = null; // audio-only
    } else {
      publisherSettings.frameRate = results.video.recommendedFrameRate;
      publisherSettings.resolution = results.video.recommendedResolution;
    }
    if (!results.audio.supported) {
      console.log('Audio not supported:', results.audio.reason);
      publisherSettings.audioSource = null;
      // video-only, but you probably don't want this -- notify the user?
    }
    if (!publisherSettings.videoSource && !publisherSettings.audioSource) {
      // Do not publish. Notify the user.
    } else {
      // Publish to the "real" session, using the publisherSettings object.
    }
  }).catch((error) => {
    console.log('OpenTok quality test error', error);
  });
}).catch(function(error) {
  console.log('OpenTok connectivity test error', error);
});

This code uses Promises returned by the OTNetworkTest.testConnectivity() and OTNetworkTest.testQuality() methods. Alternatively, you can pass completion handler functions into each of these methods.

See the following section for details on using the test results.

See the /sample subdirectory (and the /sample/README.md file) for a sample app.

Supported browsers

The OTNetworkTest.testConnectivity() method is supported in Chrome, Firefox, Safari, and Internet Explorer.

The OTNetworkTest.testQuality() method is supported in Chrome and Firefox. It is not supported in Safari or Internet Explorer.

API reference

The OTNetworkTest NPM module includes three public methods:

• The OTNetworkTest() constructor method

• The OTNetworkTest.testConnectivity() method

• The OTNetworkTest.testQuality() method

OTNetworkTest() constructor

The OTNetworkTest() constructor includes the following parameters (both required):

• ot -- A reference to the OpenTok.js OT object. You must load OpenTok.js into the web page and pass the OpenTok.js OT into the OTNetworkTest() constructor.

  Note that you may load OpenTok.js from the opentok.com server (https://static.opentok.com/v2/js/opentok.js) or via NPM (https://www.npmjs.com/package/@opentok/client). Or if your OpenTok project uses the enterprise environment, you will load OpenTok.js from the enterprise URL.

  Passing the OT object into the OTNetworkTest() constructor ensures that the tests will use the same version of OpenTok and the same OpenTok environment that will be used by the main OpenTok session in your application.

• sessionInfo -- An object containing the following:

  • apiKey -- The API key corresponding to the OpenTok project the app uses.

  • sessionId -- A test session ID. This must be an ID for a different session than the one that your application will be used for communication. Generate a unique session ID for each client. This session ID is used for the network test, and it must be different than the session ID used for communication in the app. The test session must be a routed session -- one that uses the OpenTok Media Router.

    To test connectivity in a specific region, specify a location hint when creating the test session.

  • token -- A token corresponding to the test session. The role of the token must be either publisher or moderator.

OTNetworkTest.testConnectivity(callback)

This method checks to see if the client can connect to OpenTok servers. It includes one parameter: callback.

The callback parameter is the function to be called when the connectivity check completes. This callback function takes two parameters:

• error -- An Error object. The name Property of this object is set to ConnectivityError. The message property describes the reason for the error. This will usually result from an invalid API key, session ID, or token passed into the OTNetworkTest() constructor. This is only set when the test could not run because of an error. If the connectivity can run (even if it results in failed tests), this property is undefined.

• results -- An object that contains the following properties:

  • success (Boolean) -- true if connectivity to OpenTok servers succeeded; false if any connectivity test failed.

  • failedTests (Array) -- If connectivity failed, this array contains a list of strings defining the failure types: 'api', 'messaging', 'media', 'logging'.

    • 'api' -- The test could not connect to the OpenTok API server. Connection to this server is required to connect to an OpenTok session.

    • 'messaging' -- The test could not establish a connection to the OpenTok messaging WebSocket. This connection is required to connect to an OpenTok session. In addition to other causes for WebSocket connectivity failures, this failure type will occur if you pass an invalid OpenTok API key, session ID, or token into the OTNetworkTest() constructor.

    • 'media' -- The test could not connect to the OpenTok Media Router. If your app uses a routed session, it will not succeed in using OpenTok. However, if your app uses a relayed session, the client may still succeed in using the OpenTok session, although it may fail if the relayed session requires use of a TURN server.

    • 'logging' -- The test could not connect to the OpenTok logging server. The OpenTok.js library periodically logs data (such as video and audio quality) to this server. The client can still connect to an OpenTok session, however TokBox will not collect data that may help you debug issues with the session, using tools like OpenTok Inspector.

    If all connectivity tests succeed, this property is undefined.

  results is undefined if there was an error in running the tests (and the error parameter is unset).

The callback function is optional. The testConnectivity() method returns a JavaScript promise. The promise is resolved on success, and the results object is passed into the success callback method of the promise's then() function, or the error object is passed into the promise's catch() function.

OTNetworkTest.testQuality(options, updateCallback, completionCallback)

This function runs a test publisher (using the API key, session ID and token provided in the constructor). Based on the measured video bitrate, audio bitrate, and the audio packet loss for the published stream, it provides the following results:

• The MOS estimate (from 0 - 5) for the client participating in an OpenTok session.

• The recommended supported publisher settings. These settings include the recommended video frame rate and resolution for a stream published by the client. Or, if the stats do not support video, the results indicate whether an audio-only published is recommended or not, based on the measured audio bitrate and packet loss.

This method includes two parameters: updateCallback and completionCallback.

updateCallback

The updateCallback function is called periodically during the test (at a 1-second test interval).

The object passed into the updateCallback function includes statistics about the audio and video in the test stream. The object has the following data:

{
  audio: {
    timestamp: 1509747314,
    bytesReceived: 434349, // The total number of audio bytes received, cumulative
    packetsReceived: 24234,  // The total number of audio packets received, cumulative
    packetsLost: 0   // The total number of audio packets lost, cumulative
  },
  video: {
    timestamp: 1509747314,
    bytesReceived: 434349, // The total number of video bytes received, cumulative
    frameRate: 15,   // The video frame rate
    packetsReceived: 24234,  // The total number of video packets received, cumulative
    packetsLost: 0   // The total number of video packets lost, cumulative
  },
  timestamp: 1512679143897, // The timestamp of the sample
  phase: 'audio-video' // Either 'audio-video' or 'audio-only'
}

The phase property is set to 'audio-video' during the initial audio-video test. If a secondary audio-only test is required (because audio quality was not acceptable during the audio-video test), the property is set to 'audio-only'.

Pass in a null value if you do not want to register an updateCallback function.

completionCallback

The completionCallback parameter of the OTNetworkTest.testQuality() method is a function that is invoked when the connectivity check completes. This callback function takes two parameters:

• error -- An Error object. The name property of this object is set to testQualityError. The message property describes the reason for the error. This may result from an invalid API key, session ID, or token passed into the OTNetworkTest() constructor. This is only set when the test could not run because of an error. If the connectivity can run (even if it results in failed tests), this property is undefined.

• results -- An object that contains the following properties:

  • mos (Number) -- The MOS for the call quality. This will be in a range from 0 to 5. Values less than 1 indicate inadequate quality. Values greater than 4 are considered excellent quality.

  • video (Object) -- Contains the following properties:

    • supported (Boolean) -- Whether the results indicate that video is supported.

    • recommendedFrameRate (Number) -- The recommended video frame rate. However, if video is unsupported, this is set to null.

    • recommendedResolution (String) -- The recommended video resolution. This will be set to '1280x720', '640x480', or '320x240. However, if video is unsupported, this is set to null.

    • reason (String) -- A string describing the reason for an unsupported video recommendation. For example, 'No microphone was found.'

    • bitrate (Number) -- The average number of video bits per second during the last five seconds of the test.

    • frameRate (Number) -- The average number of frames per second during the last five seconds of the test. Note that this is different than the recommendedFrameRate. The frameRate value is the actual frame rate observed during the test, and the recommendedFrameRate is the recommended frame rate.

    • packetLossRatio (Number) -- The audio packet loss ratio during the last five seconds of the test.

  • audio (Object) -- Contains the following properties:

    • supported (Boolean) -- Whether audio will be supported (true) or not (false).

    • reason (String) -- A string describing the reason for an unsupported audio recommendation. For example, 'No microphone was found.'

    • bitrate (Number) -- The average number of audio bits per second during the last five seconds of the test.

    • packetLossRatio (Number) -- The video packet loss ratio during the last five seconds of the test.

  results is undefined if there was an error in running the tests (and the error parameter is unset).

The completionCallback function is optional. The testConnectivity() method returns a JavaScript promise. The promise is resolved on success, and the results object is passed into the success callback method of the promise's then() function, or the error object is passed into the promise's catch() function.

The results, including the MOS score and the recommended video resolution and frame rate are subjective. You can adjust the values used in the source code, or you can use the data passed into the updateCallback() function and apply your own quality analysis algorithm.

Building the module

To build the module:

$ npm install
$ npm run build

Sample app

See the /sample subdirectory (and the /sample/README.md file) for a sample app.