Ably iOS, tvOS and macOS Objective-C and Swift client library SDK

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 an iOS, tvOS and macOS Objective-C and Swift client library SDK for Ably, written in Objective-C. The library currently targets the Ably client library features spec Version 1.2. 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
  • Acknowledgments
• Known Limitations
• Documentation
• Installation Guide
  • CocoaPods
  • Carthage
  • Manual
• Thread-safety Acknowledgments
• Push Notifications
• Using the Realtime API
  • Connection
  • Subscribing to a channel
  • Publishing to a channel
  • Querying the history
  • Presence on a channel
  • Querying the presence history
  • Using the authCallback
• Using the REST API
  • Publishing a message to a channel
  • Querying the history
  • Presence on a channel
  • Querying the presence history
  • Generate token
  • Fetching your application's stats
  • Fetching the Ably service time
• Support, feedback and troubleshooting
• Contributing
  • Development Flow
• Running tests
• Release Process

Supported platforms

This SDK is compatible with projects that target:

• iOS 10.0+
• tvOS 10.0+
• macOS 10.12+

We maintain compatibility and explicitly support these platform versions, including performing CI testing on all library revisions.

We do not explicitly maintain compatibility with older platform versions; we no longer perform CI testing on iOS 8 as of version 1.0.12 (released on January 31st 2018). Any known incompatibilities with older versions can be found here.

If you find any issues with unsupported platform versions, please 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
Remember fallback host during failures
ErrorInfo URLs to help debug issues

Documentation

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

Installation Guide

You can install Ably for iOS and macOS through Package Manager, CocoaPods, Carthage or manually.

Installation

Installing through Swift Package Manager

• To install the ably-cocoa package in your Xcode Project:
  • Paste https://github.com/ably/ably-cocoa in the Swift Packages search box. ( Xcode project → Swift Packages.. . → + button)
  • Select the Ably SDK for your target.
  • This apple guide explains the steps in more detail.
• To install the ably-cocoa package in another Swift Package, then add the following to your Package.Swift:

 .package(url: "https://github.com/ably/ably-cocoa", from: "1.3.0"),

Installing through CocoaPods

If you intend to use Swift, using use_frameworks! in your Podfile is recommended (this will create a Framework that can be used in Swift natively).

Add this line to your application's Podfile:

# For Xcode 7.3 and newer
pod 'Ably', '>= 1.2'

And then install the dependency:

$ pod install

Installing through Carthage

Add this line to your application's Cartfile:

# For Xcode 7.3 and newer
github "ably/ably-cocoa" >= 1.2

And then run

• for iOS: carthage update --use-xcframeworks --platform iOS --no-use-binaries
• for macOS: carthage update --use-xcframeworks --platform macOS --no-use-binaries
• for tvOS: carthage update --use-xcframeworks --platform tvOS --no-use-binaries

to build the framework and drag the built (in [PROJECT_ROOT]/Carthage/Build)

• Ably.xcframework
• AblyDeltaCodec.xcframework
• msgpack.xcframework

into your Xcode project.

If you see, for example, a dyld: Library not loaded: @rpath/AblyDeltaCodec.framework/AblyDeltaCodec error, then most likely you forgot to add all the dependencies to your project. You have more detailed information here.

NOTE: For macOS target you have to select Do Not Embed for Ably.xcframework in General tab for your target, and make sure the Ably.xcframework is on the Link Binary With Libraries list in Build Phases tab.

Manual installation

1. Get the code from GitHub from the release page, or clone it to get the latest, unstable and possibly underdocumented version: git clone git@github.com:ably/ably-cocoa.git
2. Drag the directory ably-cocoa/ably-cocoa into your project as a group.
3. Ably depends on our MessagePack Fork 0.2.0; get it from the releases page and link it into your project.

Thread-safety

The library makes the following thread-safety guarantees:

• The whole public interface can be safely accessed, both for read and writing, from any thread.
• "Value" objects (e. g. ARTTokenDetails, data from messages) returned by the library can be safely read from and written to.
• Objects passed to the library must not be mutated afterwards. They can be safely passed again, or read from; they won't be written to by the library.

All internal operations are dispatched to a single serial GCD queue. You can specify a custom queue for this, which must be serial, with ARTClientOptions.internalDispatchQueue.

All calls to callbacks provided by the user are dispatched to the main queue by default. This allows you to react to Ably's output by doing UI operations directly. You can specify a different queue with ARTClientOptions.dispatchQueue. It shouldn't be the same queue as the ARTClientOptions.internalDispatchQueue, since that can lead to deadlocks.

Push Notifications

If you haven’t yet, you should first check the detailed documentation. An example app for push notifications is also available.

Activation and device registration

For more information, see Push Notifications - Device activation and subscription.

ARTPushRegistererDelegate defines 3 delegate methods to handle the outcome of push activation, deactivation and update events. By default, the Ably SDK will check if UIApplication.sharedApplication.delegate conforms to ARTPushRegistererDelegate, and call the delegate methods when appropriate. Therefore, specifying the ARTPushRegistererDelegate is optional. To use a different class implementing ARTPushRegistererDelegate, you must provide this class to Ably, by setting the ARTClientOptions#pushRegistererDelegate delegate. In SwiftUI applications, you must set the ARTClientOptions#pushRegistererDelegate delegate property.

Do not forget that ARTPush has two corresponding methods that you should call from yours application(_:didRegisterForRemoteNotificationsWithDeviceToken:) and application(_:didFailToRegisterForRemoteNotificationsWithError:), passing to them also an ARTRest or ARTRealtime instance, configured with the authentication setup and other options you need:

func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
    ARTPush.didRegisterForRemoteNotifications(withDeviceToken: deviceToken, rest: rest)
}

func application(_ application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: Error) {
    ARTPush.didFailToRegisterForRemoteNotificationsWithError(error, rest: rest)
}

Only one instance of ARTRest or ARTRealtime at a time must be activated for receiving push notifications. Having more than one activated instance at a time may have unexpected consequences.

macOS & tvOS

Be aware that Push Notifications are currently unsupported for macOS and tvOS. You can only use the Push Admin functionalities, for example:

let recipient: [String: Any] = [
    "clientId": "C04BC116-8004-4D78-A71F-8CA3122734DB"
]
let data: [String: Any] = [
    "notification": [
        "title": "Hello from Ably!",
        "body": "Example push notification from Ably."
    ],
    "data": [
        "foo": "bar",
        "baz": "qux"
    ]
]
realtime.push.admin.publish(recipient, data: data) { error in
    print("Push published:", error ?? "nil")
}

Available demos: macOS and tvOS.

Using the Realtime API

Introduction

All examples assume a client has been created as follows:

Swift

// basic auth with an API key
let client = ARTRealtime(key: "xxxx:xxxx")

// using token auth
let client = ARTRealtime(token: "xxxx")

Objective-C

// basic auth with an API key
ARTRealtime* client = [[ARTRealtime alloc] initWithKey:@"xxxx:xxxx"];

// using token auth
ARTRealtime* client = [[ARTRealtime alloc] initWithToken:@"xxxx"];

Connection

Instantiating ARTRealtime starts a connection by default. You can catch connection success or error by listening to the connection's state changes:

Swift

client.connection.on { stateChange in
    let stateChange = stateChange!
    switch stateChange.current {
    case .Connected:
        print("connected!")
    case .Failed:
        print("failed! \(stateChange.reason)")
    default:
        break
    }
}

Objective-C

[client.connection on:^(ARTConnectionStateChange *stateChange) {
    switch (stateChange.current) {
        case ARTRealtimeConnected:
            NSLog(@"connected!");
            break;
        case ARTRealtimeFailed:
            NSLog(@"failed! %@", stateChange.reason);
            break;
        default:
            break;
    }
}];

You can also connect manually by setting the appropriate option.

Swift

let options = ARTClientOptions(key: "xxxx:xxxx")
options.autoConnect = false
let client = ARTRealtime(options: options)
client.connection.connect()

Objective-C

ARTClientOptions *options = [[ARTClientOptions alloc] initWithKey:@"xxxx:xxxx"];
options.autoConnect = false;
ARTRealtime *client = [[ARTRealtime alloc] initWithOptions:options];
[client.connection connect];

Subscribing to a channel

Given:

Swift

let channel = client.channels.get("test")

Objective-C

ARTRealtimeChannel *channel = [client.channels get:@"test"];

Subscribe to all events:

Swift

channel.subscribe { message in
    print(message.name)
    print(message.data)
}

Objective-C

[channel subscribe:^(ARTMessage *message) {
    NSLog(@"%@", message.name);
    NSLog(@"%@", message.data);
}];

Only certain events:

Swift

channel.subscribe("myEvent") { message in
    print(message.name)
    print(message.data)
}

Objective-C

[channel subscribe:@"myEvent" callback:^(ARTMessage *message) {
    NSLog(@"%@", message.name);
    NSLog(@"%@", message.data);
}];

Subscribing to a channel in delta mode

Subscribing to a channel in delta mode enables delta compression. This is a way for a client to subscribe to a channel so that message payloads sent contain only the difference (ie the delta) between the present message and the previous message on the channel.

Request a Vcdiff formatted delta stream using channel options when you get the channel:

Swift

let channelOptions = ARTRealtimeChannelOptions()
channelOptions.params = [
    "delta": "vcdiff"
]

let channel = client.channels.get("test", options: channelOptions)

Objective-C

ARTRealtimeChannelOptions *channelOptions = [[ARTRealtimeChannelOptions alloc] init];
channelOptions.params = @{
    @"delta": @"vcdiff"
};

ARTRealtimeChannel *channel = [client.channels get:@"test" options:channelOptions];

Beyond specifying channel options, the rest is transparent and requires no further changes to your application. The message.data instances that are delivered to your subscription callback continue to contain the values that were originally published.

If you would like to inspect the ARTMessage instances in order to identify whether the data they present was rendered from a delta message from Ably then you can see if message.extras["delta"]["format"] equals "vcdiff".

Publishing to a channel

Swift

channel.publish("greeting", data: "Hello World!")

Objective-C

[channel publish:@"greeting" data:@"Hello World!"];

Querying the history

Swift

channel.history { messagesPage, error in
    let messagesPage = messagesPage!
    print(messagesPage.items)
    print(messagesPage.items.first)
    print((messagesPage.items.first as? ARTMessage)?.data) // payload for the message
    print(messagesPage.items.count) // number of messages in the current page of history
    messagesPage.next { nextPage, error in
        // retrieved the next page in nextPage
    }
    print(messagesPage.hasNext) // true, there are more pages
}

Objective-C

[channel history:^(ARTPaginatedResult<ARTMessage *> *messagesPage, ARTErrorInfo *error) {
    NSLog(@"%@", messagesPage.items);
    NSLog(@"%@", messagesPage.items.firstObject);
    NSLog(@"%@", messagesPage.items.firstObject.data); // payload for the message
    NSLog(@"%lu", (unsigned long)[messagesPage.items count]); // number of messages in the current page of history
    [messagesPage next:^(ARTPaginatedResult<ARTMessage *> *nextPage, ARTErrorInfo *error) {
        // retrieved the next page in nextPage
    }];
    NSLog(@"%d", messagesPage.hasNext); // true, there are more pages
}];

Presence on a channel

Swift

let channel = client.channels.get("test")

channel.presence.enter("john.doe") { errorInfo in
    channel.presence.get { members, errorInfo in
        // members is the array of members present
    }
}

Objective-C

[channel.presence enter:@"john.doe" callback:^(ARTErrorInfo *errorInfo) {
    [channel.presence get:^(ARTPaginatedResult<ARTPresenceMessage *> *result, ARTErrorInfo *error) {
        // members is the array of members present
    }];
}];

Querying the presence history

Swift

channel.presence.history { presencePage, error in
    let presencePage = presencePage!
    if let first = presencePage.items.first as? ARTPresenceMessage {
        print(first.action) // Any of .Enter, .Update or .Leave
        print(first.clientId) // client ID of member
        print(first.data) // optional data payload of member
        presencePage.next { nextPage, error in
            // retrieved the next page in nextPage
        }
    }
}

Objective-C

[channel.presence history:^(ARTPaginatedResult<ARTPresenceMessage *> *presencePage, ARTErrorInfo *error) {
    ARTPresenceMessage *first = (ARTPresenceMessage *)presencePage.items.firstObject;
    NSLog(@"%lu", (unsigned long)first.action); // Any of ARTPresenceEnter, ARTPresenceUpdate or ARTPresenceLeave
    NSLog(@"%@", first.clientId); // client ID of member
    NSLog(@"%@", first.data); // optional data payload of member
    [presencePage next:^(ARTPaginatedResult<ARTPresenceMessage *> *nextPage, ARTErrorInfo *error) {
        // retrieved the next page in nextPage
    }];
}];

Using the authCallback

A callback to call to obtain a signed token request.
ARTClientOptions and ARTRealtime objects can be instantiated as follow:

Swift

let clientOptions = ARTClientOptions()
clientOptions.authCallback = { params, callback in
    getTokenRequestJSONFromYourServer(params) { json, error in
        //handle error
        do {
            callback(try ARTTokenRequest.fromJson(json), nil)
        } catch let error as NSError {
            callback(nil, error)
        }
    }
}

let client = ARTRealtime(options:clientOptions)

Objective-C

ARTClientOptions *clientOptions = [[ARTClientOptions alloc] init];
clientOptions.authCallback = ^(ARTTokenParams *params, void(^callback)(id<ARTTokenDetailsCompatible>, NSError*)) {
    [self getTokenRequestJSONFromYourServer:params completion:^(NSDictionary *json, NSError *error) {
        //handle error
        ARTTokenRequest *tokenRequest = [ARTTokenRequest fromJson:json error:&error];
        callback(tokenRequest, error);
    }];
};

ARTRealtime *client = [[ARTRealtime alloc] initWithOptions:clientOptions];

Using the REST API

Introduction

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

Swift

let client = ARTRest(key: "xxxx:xxxx")
let channel = client.channels.get("test")

Objective-C

ARTRest *client = [[ARTRest alloc] initWithKey:@"xxxx:xxxx"];
ARTRestChannel *channel = [client.channels get:@"test"];

Publishing a message to a channel

Swift

channel.publish("myEvent", data: "Hello!")

Objective-C

[channel publish:@"myEvent" data:@"Hello!"];

Querying the history

Swift

channel.history { messagesPage, error in
    let messagesPage = messagesPage!
    print(messagesPage.items.first)
    print((messagesPage.items.first as? ARTMessage)?.data) // payload for the message
    messagesPage.next { nextPage, error in
        // retrieved the next page in nextPage
    }
    print(messagesPage.hasNext) // true, there are more pages
}

Objective-C

[channel history:^(ARTPaginatedResult<ARTMessage *> *messagesPage, ARTErrorInfo *error) {
    NSLog(@"%@", messagesPage.items.firstObject);
    NSLog(@"%@", messagesPage.items.firstObject.data); // payload for the message
    NSLog(@"%lu", (unsigned long)[messagesPage.items count]); // number of messages in the current page of history
    [messagesPage next:^(ARTPaginatedResult<ARTMessage *> *nextPage, ARTErrorInfo *error) {
        // retrieved the next page in nextPage
    }];
    NSLog(@"%d", messagesPage.hasNext); // true, there are more pages
}];

Presence on a channel

Swift

channel.presence.get { membersPage, error in
    let membersPage = membersPage!
    print(membersPage.items.first)
    print((membersPage.items.first as? ARTPresenceMessage)?.data) // payload for the message
    membersPage.next { nextPage, error in
        // retrieved the next page in nextPage
    }
    print(membersPage.hasNext) // true, there are more pages
}

Objective-C

[channel.presence get:^(ARTPaginatedResult<ARTPresenceMessage *> *membersPage, ARTErrorInfo *error) {
    NSLog(@"%@", membersPage.items.firstObject);
    NSLog(@"%@", membersPage.items.firstObject.data); // payload for the message
    [membersPage next:^(ARTPaginatedResult<ARTMessage *> *nextPage, ARTErrorInfo *error) {
        // retrieved the next page in nextPage
    }];
    NSLog(@"%d", membersPage.hasNext); // true, there are more pages
}];

Querying the presence history

Swift

channel.presence.history { presencePage, error in
    let presencePage = presencePage!
    if let first = presencePage.items.first as? ARTPresenceMessage {
        print(first.clientId) // client ID of member
        presencePage.next { nextPage, error in
            // retrieved the next page in nextPage
        }
    }
}

Objective-C

[channel.presence history:^(ARTPaginatedResult<ARTPresenceMessage *> *presencePage, ARTErrorInfo *error) {
    ARTPresenceMessage *first = (ARTPresenceMessage *)presencePage.items.firstObject;
    NSLog(@"%@", first.clientId); // client ID of member
    NSLog(@"%@", first.data); // optional data payload of member
    [presencePage next:^(ARTPaginatedResult<ARTPresenceMessage *> *nextPage, ARTErrorInfo *error) {
        // retrieved the next page in nextPage
    }];
}];

Generate token

Swift

client.auth.requestToken(nil, withOptions: nil) { tokenDetails, error in
    let tokenDetails = tokenDetails!
    print(tokenDetails.token) // "xVLyHw.CLchevH3hF....MDh9ZC_Q"
    let client = ARTRest(token: tokenDetails.token)
}

Objective-C

[client.auth requestToken:nil withOptions:nil callback:^(ARTTokenDetails *tokenDetails, NSError *error) {
    NSLog(@"%@", tokenDetails.token); // "xVLyHw.CLchevH3hF....MDh9ZC_Q"
    ARTRest *client = [[ARTRest alloc] initWithToken:tokenDetails.token];
}];

Fetching your application's stats

Swift

client.stats { statsPage, error in
    let statsPage = statsPage!
    print(statsPage.items.first)
    statsPage.next { nextPage, error in
        // retrieved the next page in nextPage
    }
}

Objective-C

[client stats:^(ARTPaginatedResult<ARTStats *> *statsPage, ARTErrorInfo *error) {
    NSLog(@"%@", statsPage.items.firstObject);
    [statsPage next:^(ARTPaginatedResult<ARTStats *> *nextPage, ARTErrorInfo *error) {
        // retrieved the next page in nextPage
    }];
}];

Fetching the Ably service time

Swift

client.time { time, error in
    print(time) // 2016-02-09 03:59:24 +0000
}

Objective-C

[client time:^(NSDate *time, NSError *error) {
    NSLog(@"%@", time); // 2016-02-09 03:59:24 +0000
}];

Support, feedback and troubleshooting

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

You can also view the community reported Github issues.

Contributing

In this repository the main branch contains the latest development version of the Ably SDK. All development (bug fixing, feature implementation, etc.) is done against the main branch, which you should branch from whenever you'd like to make modifications. Here's the steps to follow when contributing to this repository.

• Fork it
• Install Carthage: brew install carthage
• Install gems: bundle install
• Setup or update your machine by running make update
• Create your feature branch from main (git checkout main && git checkout -b my-new-feature-branch)
• Commit your changes (git commit -am 'Add some feature')
• Ensure you have added suitable tests and the test suite is passing
• Push to the branch (git push origin my-new-feature-branch)
• Create a new Pull Request

Releases of the Ably SDK built by the sources in this repository are tagged with their semantic version numbers.

Development Flow

When you first clone the repository then you will need to run make update in order to bring in Git submodules and Carthage dependencies.

Code can then be modified, built and tested by loading Ably.xcodeproj in your Xcode IDE.

The Xcode project relies upon dependencies resolved by Carthage. If you make changes to the Cartfile then you will need to run make update_carthage_dependencies from the command line and then do a clean rebuild in Xcode.

Changes made to dependencies in the Cartfile need to be reflected in Ably.podspec and vice-versa.

Running tests

To run tests use make test_[iOS|tvOS|macOS].

Release Process

For each release, the following needs to be done:

• Create a new branch release/x.x.x (where x.x.x is the new version number) from the main branch
• Run make bump_[major|minor|patch] to bump the new version number (creates a Git commit)
• 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-cocoa --since-tag 1.2.7 --output delta.md
  • 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 the CHANGELOG.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
  • Commit this change: git add CHANGELOG.md && git commit -m "Update change log."
• Push both commits to origin: git push -u origin release/x.x.x
• Make a pull request against main and await approval of reviewer(s)
• Once approved and/or any additional commits have been added, merge the PR (f you do this from Github's web interface then use the "Rebase and merge" option)
• Steps to perform before pushing a release tag up:
  1. Checkout main locally, pulling in changes from above using git checkout main && git pull
  2. Run make update to ensure Carthage dependencies are in sync
  3. Generate the prebuilt framework for Carthage using make carthage_package (the output from this, Ably.framework.zip, will be attached to the release later on)
  4. Validate that the CocoaPods build should succeed using pod lib lint
• If any fixes are needed (e.g. the lint fails with warnings) then either commit them to main branch now if they are simple warning fixes or perhaps consider raising a new PR if they are complex or likely to need review.
• Create a tag for this version number using git tag x.x.x
• Push the tag using git push origin x.x.x
• Release an update for CocoaPods using pod trunk push Ably.podspec. Details on this command, as well as instructions for adding other contributors as maintainers, are at Getting setup with Trunk in the CocoaPods Guides
• Add to releases
  • refer to previous releases for release notes format
  • attach the prebuilt framework file generated by Carthage to the release: Ably.framework.zip
• Test the integration of the library in a Xcode project using Carthage and CocoaPods using the installation guide