Ably
Ably is the platform that powers synchronized digital experiences in realtime. Whether attending an event in a virtual venue, receiving realtime financial information, or monitoring live car performance data – consumers simply expect realtime digital experiences as standard. Ably provides a suite of APIs to build, extend, and deliver powerful digital experiences in realtime for more than 250 million devices across 80 countries each month. Organizations like Bloomberg, HubSpot, Verizon, and Hopin depend on Ably’s platform to offload the growing complexity of business-critical realtime data synchronization at global scale. For more information, see the Ably documentation.
This is a Ruby client library for Ably. The library currently targets the Ably 2.0.0 client library specification. You can see the complete list of features this client library supports in our client library SDKs feature support matrix.
Supported platforms
This SDK supports Ruby 2.7 and 3.x. For eventmachine and Ruby 3.x note please visit Ruby 3.0 support section.
As of v1.1.5 this library requires libcurl
as a system dependency. On most systems this is already installed but in rare cases where it isn't (for example debian-slim Docker images such as ruby-slim) you will need to install it yourself. On debian you can install it with the command sudo apt-get install libcurl4
.
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 .github/workflows/check.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.
Documentation
Visit https://ably.com/documentation for a complete API reference and code 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
Retrieve connection id, state etc
connection_id = client.connection.id
state = client.connection.state
recovery_key = client.connection.create_recovery_key # https://ably.com/docs/connect/states?q=recovery#connection-state-recover-options
Subscribing to a channel
Given a channel is created as follows:
channel = client.channels.get('test')
Subscribe to all events:
channel.subscribe do ||
.name #=> "greeting"
.data #=> "Hello World!"
end
Only certain events:
channel.subscribe('myEvent') do ||
.name #=> "myEvent"
.data #=> "myData"
end
Publishing a message to a channel
channel.publish('greeting', 'Hello World!')
Querying the History
channel.history do ||
#=> #<Ably::Models::PaginatedResult ...>
.items.first # #<Ably::Models::Message ...>
.items.first.data # payload for the message
.items.length # number of messages in the current page of history
.next do |next_page|
next_page #=> the next page => #<Ably::Models::PaginatedResult ...>
end
.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 ||
.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
= channel.history #=> #<Ably::Models::PaginatedResult ...>
.items.first #=> #<Ably::Models::Message ...>
.items.first.data # payload for the message
.next # retrieves the next page => #<Ably::Models::PaginatedResult ...>
.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
= channel.history
.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
Ruby 3.0 support
If you cannot install ably realtime gem because of eventmachine openssl problems, please try to set your openssl-dir
, i.e.:
gem install eventmachine -- --with-openssl-dir=/usr/local/opt/openssl@1.1
More about eventmachine and ruby 3.0 support here https://github.com/eventmachine/eventmachine/issues/932
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
Support, feedback and troubleshooting
Please visit https://ably.com/support 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
- Fork it
- When pulling to local, make sure to also pull the
ably-common
repo (git submodule init && git submodule update
) - Create your feature branch (
git checkout -b my-new-feature
) - Commit your changes (
git commit -am 'Add some feature'
) - Ensure you have added suitable tests and the test suite is passing(
bundle exec rspec
) - Push to the branch (
git push origin my-new-feature
) - Create a new Pull Request
Release process
This library uses semantic versioning. For each release, the following needs to be done:
- Create a branch for the release, named like
release/1.2.3
(where1.2.3
is the new version number) - Update the version number in version.rb and commit the change.
- Run
github_changelog_generator
to automate the update of the CHANGELOG. This may require some manual intervention, both in terms of how the command is run and how the change log file is modified. Your mileage may vary:- The command you will need to run will look something like this:
github_changelog_generator -u ably -p ably-ruby --since-tag v1.2.3 --output delta.md --token $GITHUB_TOKEN_WITH_REPO_ACCESS
. Generate token here. - Using the command above,
--output delta.md
writes changes made after--since-tag
to a new file - The contents of that new file (
delta.md
) then need to be manually inserted at the top of theCHANGELOG.md
, changing the "Unreleased" heading and linking with the current version numbers - Also ensure that the "Full Changelog" link points to the new version tag instead of the
HEAD
- The command you will need to run will look something like this:
- Commit this change:
git add CHANGELOG.md && git commit -m "Update change log."
- Ideally, run
rake doc:spec
to generate a new spec file. Then commit these changes. - Make a PR against
main
. Once the PR is approved, merge it intomain
. - Add a tag to the new
main
head commit and push to origin such asgit tag v1.0.3 && git push origin v1.0.3
. - 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
. - Create the entry on the Ably Changelog (via headwayapp).