Ably

A Ruby client library for ably.io, the realtime messaging service. This library currently targets the Ably 1.1 client library specification. You can jump to the 'Known Limitations' section to see the features this client library does not yet support or view our client library SDKs feature support matrix to see the list of all the available features.

Supported platforms

This SDK supports Ruby 1.9.3+.

We regression-test the SDK against a selection of Ruby versions (which we update over time, but usually consists of mainstream and widely used versions). Please refer to .travis.yml for the set of versions that currently undergo CI testing.

If you find any compatibility issues, please do raise an issue in this repository or contact Ably customer support for advice.

Known Limitations

This client library is currently not compatible with some of the Ably features:

Feature
Custom transportParams

Documentation

Visit https://www.ably.io/documentation for a complete API reference and more examples.

Installation

The client library is available as a gem from RubyGems.org.

Add this line to your application's Gemfile:

gem 'ably'

And then install this Bundler dependency:

$ bundle

Or install it yourself as:

$ gem install ably

Using with Rails or Sinatra

This ably gem provides both a Realtime and REST version of the Ably library. Realtime depends on EventMachine to provide an asynchronous evented framework to run the library in, whereas the REST library depends only on synchronous libraries such as Faraday.

If you are using Ably within your Rails or Sinatra apps, more often than not, you probably want to use the REST only version of the library that has no dependency on EventMachine and provides a synchronous API that you will be used to using within Rails and Sinatra. See the REST only Ruby version of the Ably library.

Using the Realtime API

Introduction

All examples must be run within an EventMachine reactor as follows:

EventMachine.run do
  # ...
end

All examples assume a client has been created using one of the following:

# basic auth with an API key
client = Ably::Realtime.new(key: 'xxxxx')

# using token auth
client = Ably::Realtime.new(token: 'xxxxx')

If you do not have an API key, sign up for a free API key now

Connection

Successful connection:

client.connection.connect do
  # successful connection
end

Failed connection:

connection_result = client.connection.connect
connection_result.errback = Proc.new do
  # failed connection
end

Subscribing to connection state changes:

client.connection.on do |state_change|
  state_change.current #=> :connected
  state_change.previous #=> :connecting
end

Subscribing to a channel

Given a channel is created as follows:

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

Subscribe to all events:

channel.subscribe do |message|
  message.name #=> "greeting"
  message.data #=> "Hello World!"
end

Only certain events:

channel.subscribe('myEvent') do |message|
  message.name #=> "myEvent"
  message.data #=> "myData"
end

Publishing a message to a channel

channel.publish('greeting', 'Hello World!')

Querying the History

channel.history do |messages_page|
  messages_page #=> #<Ably::Models::PaginatedResult ...>
  messages_page.items.first # #<Ably::Models::Message ...>
  messages_page.items.first.data # payload for the message
  messages_page.items.length # number of messages in the current page of history
  messages_page.next do |next_page|
    next_page #=> the next page => #<Ably::Models::PaginatedResult ...>
  end
  messages_page.has_next? # false, there are more pages
end

Presence on a channel

channel.presence.enter(data: 'metadata') do |presence|
  presence.get do |members|
    members #=> [Array of members present]
  end
end

Subscribing to presence events

channel.presence.subscribe do |member|
  member #=> { action: :enter, client_id: 'bob' }
end

Querying the Presence History

channel.presence.history do |presence_page|
  presence_page.items.first.action # Any of :enter, :update or :leave
  presence_page.items.first.client_id # client ID of member
  presence_page.items.first.data # optional data payload of member
  presence_page.next do |next_page|
    next_page #=> the next page => #<Ably::Models::PaginatedResult ...>
  end
  presence_page.has_next? # false, there are more pages
end

Symmetric end-to-end encrypted payloads on a channel

When a 128 bit or 256 bit key is provided to the library, all payloads are encrypted and decrypted automatically using that key on the channel. The secret key is never transmitted to Ably and thus it is the developer's responsibility to distribute a secret key to both publishers and subscribers.

secret_key = Ably::Util::Crypto.generate_random_key
channel = client.channels.get('test', cipher: { key: secret_key })
channel.subscribe do |message|
  message.data #=> "sensitive data (encrypted before being published)"
end
channel.publish "name (not encrypted)", "sensitive data (encrypted before being published)"

Using the REST API

Introduction

Unlike the Realtime API, all calls are synchronous and are not run within an EventMachine reactor.

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

client = Ably::Rest.new(key: 'xxxxx')
channel = client.channel('test')

Publishing a message to a channel

channel.publish('myEvent', 'Hello!') #=> true

Querying the History

messages_page = channel.history #=> #<Ably::Models::PaginatedResult ...>
messages_page.items.first #=> #<Ably::Models::Message ...>
messages_page.items.first.data # payload for the message
messages_page.next # retrieves the next page => #<Ably::Models::PaginatedResult ...>
messages_page.has_next? # false, there are more pages

Current presence members on a channel

members_page = channel.presence.get # => #<Ably::Models::PaginatedResult ...>
members_page.items.first # first member present in this page => #<Ably::Models::PresenceMessage ...>
members_page.items.first.client_id # client ID of first member present
members_page.next # retrieves the next page => #<Ably::Models::PaginatedResult ...>
members_page.has_next? # false, there are more pages

Querying the presence history

presence_page = channel.presence.history #=> #<Ably::Models::PaginatedResult ...>
presence_page.items.first #=> #<Ably::Models::PresenceMessage ...>
presence_page.items.first.client_id # client ID of first member
presence_page.next # retrieves the next page => #<Ably::Models::PaginatedResult ...>

Symmetric end-to-end encrypted payloads on a channel

When a 128 bit or 256 bit key is provided to the library, all payloads are encrypted and decrypted automatically using that key on the channel. The secret key is never transmitted to Ably and thus it is the developer's responsibility to distribute a secret key to both publishers and subscribers.

secret_key = Ably::Util::Crypto.generate_random_key
channel = client.channels.get('test', cipher: { key: secret_key })
channel.publish nil, "sensitive data" # data will be encrypted before publish
messages_page = channel.history
messages_page.items.first.data #=> "sensitive data"

Generate a Token

Tokens are issued by Ably and are readily usable by any client to connect to Ably:

token_details = client.auth.request_token
# => #<Ably::Models::TokenDetails ...>
token_details.token # => "xVLyHw.CLchevH3hF....MDh9ZC_Q"
client = Ably::Rest.new(token: token_details)

Generate a TokenRequest

Token requests are issued by your servers and signed using your private API key. This is the preferred method of authentication as no secrets are ever shared, and the token request can be issued to trusted clients without communicating with Ably.

token_request = client.auth.create_token_request(ttl: 3600, client_id: 'jim')
# => {"id"=>...,
#     "clientId"=>"jim",
#     "ttl"=>3600,
#     "timestamp"=>...,
#     "capability"=>"{\"*\":[\"*\"]}",
#     "nonce"=>...,
#     "mac"=>...}

client = Ably::Rest.new(token: token_request)

Fetching your application's stats

stats_page = client.stats #=> #<Ably::Models::PaginatedResult ...>
stats_page.items.first = #<Ably::Models::Stats ...>
stats_page.next # retrieves the next page => #<Ably::Models::PaginatedResult ...>

Fetching the Ably service time

client.time #=> 2013-12-12 14:23:34 +0000

Dependencies

If you only need to use the REST features of this library and do not want EventMachine as a dependency, then you should consider using the Ably Ruby REST gem.

Upgrading from an older version

• Release and upgrade notes for v0.8 -> v1.0

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 of Bundler, see the CHANGELOG.

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(bundle exec rspec)
6. Push to the branch (git push origin my-new-feature)
7. Create a new Pull Request

Release process

This library uses semantic versioning. For each release, the following needs to be done:

• Update the version number in version.rb and commit the change.
• Run github_changelog_generator to automate the update of the CHANGELOG. Once the CHANGELOG update has completed, manually change the Unreleased heading and link with the current version number such as v1.0.0. Also ensure that the Full Changelog link points to the new version tag instead of the HEAD. Ideally, run rake doc:spec to generate a new spec file. Then commit these changes.
• Add a tag and push to origin such as git tag v1.0.0 && git push origin v1.0.0
• Visit https://github.com/ably/ably-ruby/tags and Add release notes for the release including links to the changelog entry.
• Run rake release to publish the gem to Rubygems
• Release the REST-only library ably-ruby-rest

License

Copyright (c) 2017 Ably Real-time Ltd, Licensed under the Apache License, Version 2.0. Refer to LICENSE for the license terms.