ably

Ably

A Javascript client library for Ably Realtime, a realtime data delivery platform.

Version: 1.0.7

This repo contains the Ably Javascript client library, for the browser (including IE8+), Nodejs, React Native, NativeScript and Cordova.

For complete API documentation, see the Ably documentation.

For node.js

Installation from npm

npm install ably

Usage

For the realtime library:

var realtime = require('ably').Realtime;

For the rest-only library:

var rest = require('ably').Rest;

For browsers

Include the Ably library in your HTML:

<script src="https://cdn.ably.io/lib/ably.min-1.js"></script>

The Ably client library follows Semantic Versioning. To lock into a major or minor version of the client library, you can specify a specific version number such as https://cdn.ably.io/lib/ably.min-1.js for all v1.* versions, or https://cdn.ably.io/lib/ably.min-1.0.js for all v1.0.* versions, or you can lock into a single release with https://cdn.ably.io/lib/ably.min-1.0.0.js. Note you can load the non-minified version by omitting min- from the URL such as https://cdn.ably.io/lib/ably-1.0.js. See https://github.com/ably/ably-js/tags for a list of tagged releases.

For the realtime library:

var realtime = Ably.Realtime;

For the REST only library:

var rest = Ably.Rest;

For React Native

For React Native, do not use this package. Instead use the ably-react-native package, which wraps ably-js and adds react-native-specific dependencies. See that repo for install instructions.

TypeScript support

The TypeScript typings are included in the package and so all you have to do is:

 import * as Ably from 'ably';
 let realtime = new Ably.Realtime(options);

Using WebPack

WebPack will search your node_modules folder by default, so if you include ably in your package.json file, when running Webpack the following will allow you to require Ably. Alternatively, you can reference the ably-commonjs.js static file directly if not in your node_modules folder.

var Ably = require('ably/browser/static/ably-commonjs.js');
var realtime = new Ably.Realtime(options);

If you are using ES6 and or a transpiler that suppots ES6 modules with WebPack, you can include Ably as follows:

import Ably from 'ably/browser/static/ably-commonjs.js'
let realtime = new Ably.Realtime(options)

For React Native

See the ably-js-react-native repo for React Native usage details.

For NativeScript

See the ably-js-nativescript repo for NativeScript usage details.

Using the Realtime API

Introduction

All examples assume a client has been created as follows:

// basic auth with an API key
var client = new Ably.Realtime(<key string>)

// using a token string
var client = new Ably.Realtime(<token string>)

// using an Options object, see https://www.ably.io/documentation/rest/usage#options
// which must contain at least one auth option, i.e. at least
// one of: key, token, tokenDetails, authUrl, or authCallback
var client = new Ably.Realtime(<options>)

Connection

Successful connection:

client.connection.on('connected', function() {
  # successful connection
});

Failed connection:

client.connection.on('failed', function() {
  # failed connection
});

Subscribing to a channel

Given:

var channel = client.channels.get('test');

Subscribe to all events:

channel.subscribe(function(message) {
  message.name // 'greeting'
  message.data // 'Hello World!'
});

Only certain events:

channel.subscribe('myEvent', function(message) {
  message.name // 'myEvent'
  message.data // 'myData'
});

Publishing to a channel

// Publish a single message with name and data
channel.publish('greeting', 'Hello World!');

// Optionally, you can use a callback to be notified of success or failure
channel.publish('greeting', 'Hello World!', function(err) {
  if(err) {
    console.log('publish failed with error ' + err);
  } else {
    console.log('publish succeeded');
  }
})

// Publish several messages at once
channel.publish([{name: 'greeting', data: 'Hello World!'}, ...], callback);

Querying the History

channel.history(function(err, messagesPage) {
  messagesPage                                    // PaginatedResult
  messagesPage.items                              // array of Message
  messagesPage.items[0].data                      // payload for first message
  messagesPage.items.length                       // number of messages in the current page of history
  messagesPage.hasNext()                          // true if there are further pages
  messagesPage.isLast()                           // true if this page is the last page
  messagesPage.next(function(nextPage) { ... });  // retrieves the next page as PaginatedResult
});

// Can optionally take an options param, see https://www.ably.io/documentation/rest-api/#message-history
channel.history({start: ..., end: ..., limit: ..., direction: ...}, function(err, messagesPage) { ...});

Presence on a channel

Getting presence:

channel.presence.get(function(err, presenceSet) {
  presenceSet                                     // array of PresenceMessages
});

Note that presence#get on a realtime channel does not return a PaginatedResult, as the library maintains a local copy of the presence set.

Entering (and leaving) the presence set:

channel.presence.enter('my status', function(err) {
  // now I am entered
});

channel.presence.update('new status', function(err) {
  // my presence data is updated
});

channel.presence.leave(function(err) {
  // I've left the presence set
});

If you are using a client which is allowed to use any clientId -- that is, if you didn't specify a clientId when initializing the client, and are using basic auth or a token witha wildcard clientId (see https://www.ably.io/documentation/general/authentication for more information), you can use

channel.presence.enterClient('myClientId', 'status', function(err) { ... });
// and similiarly, updateClient and leaveClient

Querying the Presence History

channel.presence.history(function(err, messagesPage) { // PaginatedResult
  messagesPage.items                              // array of PresenceMessage
  messagesPage.items[0].data                      // payload for first message
  messagesPage.items.length                       // number of messages in the current page of history
  messagesPage.hasNext()                           // true if there are further pages
  messagesPage.isLast()                           // true if this page is the last page
  messagesPage.next(function(nextPage) { ... });  // retrieves the next page as PaginatedResult
});

// Can optionally take an options param, see https://www.ably.io/documentation/rest-api/#message-history
channel.presence.history({start: ..., end: ..., limit: ..., direction: ...}, function(err, messagesPage) { ...});

Symmetrical end-to-end encrypted payloads on a channel

When a 128 bit or 256 bit key is provided to the library, the data attributes of all messages are encrypted and decrypted automatically using that key. The secret key is never transmitted to Ably. See https://www.ably.io/documentation/realtime/encryption

// Generate a random 256-bit key for demonstration purposes (in
// practice you need to create one and distribute it to clients yourselves)
Ably.Realtime.Crypto.generateRandomKey(function(err, key) {
	var channel = client.channels.get('channelName', { cipher: { key: key } })

	channel.subscribe(function(message) {
		message.name // 'name is not encrypted'
		message.data // 'sensitive data is encrypted'
	});

	channel.publish('name is not encrypted', 'sensitive data is encrypted');
})

You can also change the key on an existing channel using setOptions (which takes a callback which is called after the new encryption settings have taken effect):

channel.setOptions({cipher: {key: <key>}}, function() {
	// New encryption settings are in effect
})

Using the REST API

Introduction

All examples assume a client and/or channel has been created as follows:

// basic auth with an API key
var client = new Ably.Rest(<key string>)

// using token auth
var client = new Ably.Rest(<token string>)

// using an Options object, see https://www.ably.io/documentation/realtime/usage#client-options
// which must contain at least one auth option, i.e. at least
// one of: key, token, tokenDetails, authUrl, or authCallback
var client = new Ably.Rest(<options>)

Given:

var channel = client.channels.get('test');

Publishing to a channel

// Publish a single message with name and data
channel.publish('greeting', 'Hello World!');

// Optionally, you can use a callback to be notified of success or failure
channel.publish('greeting', 'Hello World!', function(err) {
  if(err) {
    console.log('publish failed with error ' + err);
  } else {
    console.log('publish succeeded');
  }
})

// Publish several messages at once
channel.publish([{name: 'greeting', data: 'Hello World!'}, ...], callback);

Querying the History

channel.history(function(err, messagesPage) {
  messagesPage                                    // PaginatedResult
  messagesPage.items                              // array of Message
  messagesPage.items[0].data                      // payload for first message
  messagesPage.items.length                       // number of messages in the current page of history
  messagesPage.hasNext()                          // true if there are further pages
  messagesPage.isLast()                           // true if this page is the last page
  messagesPage.next(function(nextPage) { ... });  // retrieves the next page as PaginatedResult
});

// Can optionally take an options param, see https://www.ably.io/documentation/rest-api/#message-history
channel.history({start: ..., end: ..., limit: ..., direction: ...}, function(err, messagesPage) { ...});

Presence on a channel

channel.presence.get(function(err, presencePage) { // PaginatedResult
  presencePage.items                              // array of PresenceMessage
  presencePage.items[0].data                      // payload for first message
  presencePage.items.length                       // number of messages in the current page of members
  presencePage.hasNext()                          // true if there are further pages
  presencePage.isLast()                           // true if this page is the last page
  presencePage.next(function(nextPage) { ... });  // retrieves the next page as PaginatedResult
});

Querying the Presence History

channel.presence.history(function(err, messagesPage) { // PaginatedResult
  messagesPage.items                              // array of PresenceMessage
  messagesPage.items[0].data                      // payload for first message
  messagesPage.items.length                       // number of messages in the current page of history
  messagesPage.hasNext()                          // true if there are further pages
  messagesPage.isLast()                           // true if this page is the last page
  messagesPage.next(function(nextPage) { ... });  // retrieves the next page as PaginatedResult
});

// Can optionally take an options param, see https://www.ably.io/documentation/rest-api/#message-history
channel.history({start: ..., end: ..., limit: ..., direction: ...}, function(err, messagesPage) { ...});

Generate Token and Token Request

See https://www.ably.io/documentation/general/authentication for an explanation of Ably's authentication mechanism.

Requesting a token:

client.auth.requestToken(function(err, tokenDetails) {
  // tokenDetails is instance of TokenDetails
  // see https://www.ably.io/documentation/rest/authentication/#token-details for its properties

  // Now we have the token, we can send it to someone who can instantiate a client with it:
  var clientUsingToken = new Ably.Realtime(tokenDetails.token);
});

// requestToken can take two optional params
// tokenParams: https://www.ably.io/documentation/rest/authentication/#token-params
// authOptions: https://www.ably.io/documentation/rest/authentication/#auth-options
client.auth.requestToken(tokenParams, authOptions, function(err, tokenDetails) { ... });

Creating a token request (for example, on a server in response to a request by a client using the authCallback or authUrl mechanisms):

client.auth.createTokenRequest(function(err, tokenRequest) {
  // now send the tokenRequest back to the client, which will
  // use it to request a token and connect to Ably
});

// createTokenRequest can take two optional params
// tokenParams: https://www.ably.io/documentation/rest/authentication/#token-params
// authOptions: https://www.ably.io/documentation/rest/authentication/#auth-options
client.auth.createTokenRequest(tokenParams, authOptions, function(err, tokenRequest) { ... });

Fetching your application's stats

client.stats(function(err, statsPage) {        // statsPage as PaginatedResult
  statsPage.items                              // array of Stats
  statsPage.items[0].inbound.rest.messages.count; // total messages published over REST
  statsPage.items.length;                      // number of stats in the current page of history
  statsPage.hasNext()                          // true if there are further pages
  statsPage.isLast()                           // true if this page is the last page
  statsPage.next(function(nextPage) { ... });  // retrieves the next page as PaginatedResult
});

Fetching the Ably service time

client.time(function(err, time) { ... }); // time is in ms since epoch

Test suite

To run both the NodeUnit & Karma Browser tests, simply run the following command:

grunt test

NodeUnit Tests

Run the NodeUnit test suite

grunt test:nodeunit

Or run just one or more test files

grunt test:nodeunit --test spec/realtime/auth.test.js

Browser Tests

Browser tests are run using Karma test runner.

To build & run the tests in a single step

grunt test:karma

Debugging the tests in your browser with NodeUnit test runner

Simply open spec/nodeunit.html in your browser to run the test suite with a nice GUI.

Note: If any files have been added or remove, running the task grunt requirejs will ensure all the necessary RequireJS dependencies are loaded into the browser by updating spec/support/browser_file_list.js

Debugging the tests in a remote browser with NodeUnit test runner

Run the following command to start a local Nodeunit test runner web server

grunt test:webserver

Open your browser to http://localhost:3000. If you are usig a remote browser, refer to https://docs.saucelabs.com/reference/sauce-connect/ for instructions on setting up a local tunnel to your Nodeunit runner web server.

Debugging the tests in your browser with Karma

If you would like to run the tests through Karma, then:

Start a Karma server

karma server

You can optionally connect your browser to the server, visit http://localhost:9876/

Click on the Debug button in the top right, and open your browser's debugging console.

Then run the tests against the Karma server. The test:karma:run command will concatenate the Ably files beforehand so any changes made in the source will be reflected in the test run.

grunt test:karma:run

Testing environment variables for Node.js

All tests are run against the sandbox environment by default. However, the following environment variables can be set before running the Karma server to change the environment the tests are run against.

• ABLY_ENV - defaults to sandbox, however this can be set to another known environment such as 'staging'
• ABLY_REALTIME_HOST - explicitly tell the client library to use an alternate host for real-time websocket communication.
• ABLY_REST_HOST - explicitly tell the client library to use an alternate host for REST communication.
• ABLY_PORT - non-TLS port to use for the tests, defaults to 80
• ABLY_TLS_PORT - TLS port to use for the tests, defaults to 443
• ABLY_USE_TLS - true or false to enable/disable use of TLS respectively
• ABLY_LOG_LEVEL - Log level for the client libraries, defaults to 2, 4 is MICRO

Testing environment variables for browser tests

When using the test webserver grunt test:webserver the following test variables can be configured by appending them as params in the URL such as http://localhost:3000/nodeunit.html?log_level=4.

• env - defaults to sandbox, however this can be set to another known environment such as 'staging'
• realtime_host - explicitly tell the client library to use an alternate host for real-time websocket communication.
• host - explicitly tell the client library to use an alternate host for REST communication.
• port - non-TLS port to use for the tests, defaults to 80
• tls_port - TLS port to use for the tests, defaults to 443
• tls - true or false to enable/disable use of TLS respectively
• log_level - Log level for the client libraries, defaults to 2, 4 is MICRO

Support, feedback and troubleshooting

Please visit http://support.ably.io/ for access to our knowledgebase and to ask for any assistance.

You can also view the community reported Github issues.

To see what has changed in recent versions, see the CHANGELOG.

Browser-specific issues

• "Unable to parse request body" error when publishing large messages from old versions of Internet Explorer

Contributing

1. Fork it
2. When pulling to local, make sure to also pull the ably-common repo (git submodule init && git submodule update)
3. Create your feature branch (git checkout -b my-new-feature)
4. Commit your changes (git commit -am 'Add some feature')
5. Ensure you have added suitable tests and the test suite is passing(grunt test)
6. Push to the branch (git push origin my-new-feature)
7. Create a new Pull Request

Release Process

• Make sure you have the closure compiler installed, needed to generate the minified library. You can install it with grunt compiler
• grunt release:patch (or: "major", "minor", "patch", "prepatch")
• grunt release:deploy
• Visit https://github.com/ably/ably-js/tags and add release notes for the release including links to the changelog entry.

License

Copyright (c) 2016 Ably Real-time Ltd, Licensed under the Apache License, Version 2.0. Refer to LICENSE for the license terms.