XUtils

Ably

Ruby library for realtime communication over Ably.

Ruby
https://github.com/ably/ably-ruby

Documentation

Visit https://ably.com/documentation for a complete API reference and code examples.

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 EventMachine.

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 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

Articles

  • coming soon...