Ably
A Javascript client library for Ably Realtime, a realtime data delivery platform.
Supported platforms
This SDK supports the following platforms:
Browsers: All major desktop and mobile browsers, including (but not limited to) Chrome, Firefox, IE (only version 8 or newer), Safari on iOS and macOS, Opera, and Android browsers.
Node.js: version 4 or newer
React Native: see ably-js-react-native
NativeScript: see ably-js-nativescript
TypeScript: see below
We regression-test the library against a selection of those (which will change over time, but usually consists of the versions that are supported upstream, plus old versions of IE).
However, we aim to be compatible with a much wider set of platforms and browsers than we can possibly test on. That means we'll happily support (and investigate reported problems with) any reasonably-widely-used browser. So if you find any compatibility issues, please do raise an issue in this repository or contact Ably customer support for advice.
Ably-js has fallback mechanisms in order to be able to support older browsers; specifically it supports comet-based connections for browsers that do not support websockets, and this includes JSONP for browsers that do not support cross-origin XHR. Each of these fallback transport mechanisms is supported and tested on all the browsers we test against, even when those browsers do not themselves require those fallbacks. These mean that the library should be compatible with nearly any browser on most platforms. Any known browser incompatibilities can be found here.
Version: 1.0.13
The latest stable version of the Ably Javascript client library is 1.0.13
.
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-1.0.9.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;
TypeScript
The TypeScript typings are included in the package and so all you have to do is:
import * as Ably from 'ably';
let options : Ably.Types.ClientOptions = { key: 'foo' };
let client = new Ably.Realtime(options); /* inferred type Ably.Realtime */
let channel = client.channels.get('feed'); /* inferred type Ably.Types.RealtimeChannel */
Intellisense in IDEs with TypeScript support is supported:
If you need to explicitly import the type definitions, see ably.d.ts.
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)
React Native
See the ably-js-react-native repo for React Native usage details.
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 using 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 80ABLY_TLS_PORT
- TLS port to use for the tests, defaults to 443ABLY_USE_TLS
- true or false to enable/disable use of TLS respectivelyABLY_LOG_LEVEL
- Log level for the client libraries, defaults to 2, 4 isMICRO
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 80tls_port
- TLS port to use for the tests, defaults to 443tls
- true or false to enable/disable use of TLS respectivelylog_level
- Log level for the client libraries, defaults to 2, 4 isMICRO
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
Contributing
- Fork it
- When pulling to local, make sure to also pull the
ably-common
repo (git submodule init && git submodule update
) - Make sure you have installed the right version of Node (see the
.nvmrc
file to find the version of Node required to develop this project) - Create your feature branch (
git checkout -b my-new-feature
) - Commit your changes (
git commit -am 'Add some feature'
) Note: don't commit files generated inbrowser/static/*
, unless you are about to make a release. - Ensure you have added suitable tests and the test suite is passing(
grunt test
) - Ensure the type definitions have been updated if the public API has changed
- Push to the branch (
git push origin my-new-feature
) - 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
. (If you later get an error that it can't find it, it may have installed with an unexpected filename; try runningmv ably-js/tools/closure-compiler/build/*.jar ably-js/tools/closure-compiler/build/compiler.jar
) - Make sure the tests are passing in ci for the branch you're building
- Update the CHANGELOG.md with any customer-affecting changes since the last release
- Run
grunt release:patch
(or: "major", "minor", "patch", "prepatch") - Run
grunt release:deploy
- Visit https://github.com/ably/ably-js/tags and add release notes to the release (generally you can just copy the notes you added to the CHANGELOG)
- If the type definitions have changed, submit a PR to DefinitelyTyped.
- For nontrivial releases: update the ably-js submodule ref in the realtime repo
Warning: if publishing to npm, please use npm version 5.1 (npm install -g npm@5.1
), as 5.5 has a bug that results in the creation of an invalid package, see ably#422 and npm/npm#18870 for more info
License
Copyright (c) 2017 Ably Real-time Ltd, Licensed under the Apache License, Version 2.0. Refer to LICENSE for the license terms.