Publish and Subscribe API for Cocoa Swift SDK

This SDK has been replaced by a new PubNub Swift SDK written purely in Swift. Check it out here

Publish​

The publish() function is used to send a message to all subscribers of a channel. To publish a message you must first specify a valid publishKey at initialization. A successfully published message is replicated across the PubNub Real-Time Network and sent simultaneously to all subscribed clients on a channel.

Messages in transit can be secured from potential eavesdroppers with SSL/TLS by setting ssl to true during initialization.

Publish Anytime​

It's not required to be subscribed to a channel in order to publish to that channel.

Message Data​

The message argument can contain any JSON serializable data, including: Objects, Arrays, Ints and Strings. data should not contain special Swift classes or functions as these will not serialize. String content can include any single-byte or multi-byte UTF-8 character.

Don't JSON serialize

It is important to note that you should not JSON serialize when sending signals/messages via PUBNUB. Why? Because the serialization is done for you automatically. Instead just pass the full object as the message payload. PubNub takes care of everything for you.

Message Size​

The maximum number of characters per message is 32 KiB by default. The maximum message size is based on the final escaped character count, including the channel name. An ideal message size is under 1800 bytes which allows a message to be compressed and sent using single IP datagram (1.5 KiB) providing optimal network performance.

If the message you publish exceeds the configured size, you will receive the following message:

Message Too Large Error​

["PUBLISHED",[0,"Message Too Large","13524237335750949"]]

For further details, check Calculating Message Payload Size Before Publish.

Message Publish Rate​

Messages can be published as fast as bandwidth conditions will allow. There is a soft limit based on max throughput since messages will be discarded if the subscriber can't keep pace with the publisher.

For example, if 200 messages are published simultaneously before a subscriber has had a chance to receive any messages, the subscriber may not receive the first 100 messages because the message queue has a limit of only 100 messages stored in memory.

Publishing to Multiple Channels​

It is not possible to publish a message to multiple channels simultaneously. The message must be published to one channel at a time.

Publishing Messages Reliably​

There are some best practices to ensure messages are delivered when publishing to a channel:

  • Publish to any given channel in a serial manner (not concurrently).
  • Check that the return code is success (e.g. [1,"Sent","136074940..."])
  • Publish the next message only after receiving a success return code.
  • If a failure code is returned ([0,"blah","<timetoken>"]), retry the publish.
  • Avoid exceeding the in-memory queue's capacity of 100 messages. An overflow situation (aka missed messages) can occur if slow subscribers fail to keep up with the publish pace in a given period of time.
  • Throttle publish bursts in accordance with your app's latency needs e.g. Publish no faster than 5 msgs per second to any one channel.

Method(s)​

To Publish a message you can use the following method(s) in the Swift SDK:

Publish a message with closure​

open func publish(
    _ message: Any,
    toChannel channel: String,
    withCompletion block: PubNub.PNPublishCompletionBlock? = nil
)
* required
ParameterDescription
message *
Type: Any
The message may be any valid foundation object ( String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
closure
Type: PNPublishCompletionBlock
The completion closure which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Publish a message with compression and closure​

open func publish(
    _ message: Any,
    toChannel channel: String,
    compressed: Bool,
    withCompletion closure: PubNub.PNPublishCompletionBlock? = nil
)
* required
ParameterDescription
message *
Type: Any
The message may be any valid foundation object ( String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
compressed *
Type: Bool
If true the message will be compressed and sent with request body instead of the URI. Compression useful in case of large data, in another cases it will increase the packet size.
closure
Type: PNPublishCompletionBlock
The completion closure which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Publish a message with storage and closure​

open func publish(
    _ message: Any,
    toChannel channel: String,
    storeInHistory shouldStore: Bool,
    withCompletion closure: PubNub.PNPublishCompletionBlock? = nil
)
* required
ParameterDescription
message *
Type: Any
The message may be any valid foundation object ( String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
shouldStore *
Type: Bool
If false the messages will not be stored in Message Persistence, default true.
closure
Type: PNPublishCompletionBlock
The completion closure which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Publish a message with storage, compression, and closure​

open func publish(
    _ message: Any,
    toChannel channel: String,
    storeInHistory shouldStore: Bool,
    compressed: Bool,
    withCompletion closure: PubNub.PNPublishCompletionBlock? = nil
)
* required
ParameterDescription
message *
Type: Any
The message may be any valid foundation object ( String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
shouldStore *
Type: Bool
If false the messages will not be stored in Message Persistence, default true.
compressed *
Type: Bool
If true the message will be compressed and sent with request body instead of the URI. Compression useful in case of large data, in another cases it will increase the packet size.
closure
Type: PNPublishCompletionBlock
The completion closure which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Publish a message with payload and closure​

open func publish(
    _ message: Any?,
    toChannel channel: String,
    mobilePushPayload payloads: [String: Any]?,
    withCompletion closure: PubNub.PNPublishCompletionBlock? = nil
)
* required
ParameterDescription
message
Type: Any
The message may be any valid foundation object ( String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
payloads
Type: [String : Any]
Dictionary with payloads for different vendors (Apple with aps key and Google with gcm). Either payloads or message should be provided.
closure
Type: PNPublishCompletionBlock
The completion closure which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Publish a message with payload, compression, and closure​

open func publish(
    _ message: Any?,
    toChannel channel: String,
    mobilePushPayload payloads: [String: Any]?,
    compressed: Bool,
    withCompletion closure: PubNub.PNPublishCompletionBlock? = nil
)
* required
ParameterDescription
message
Type: Any
The message may be any valid foundation object ( String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
payloads
Type: [String : Any]
Dictionary with payloads for different vendors (Apple with aps key and Google with gcm). Either payloads or message should be provided.
compressed *
Type: Bool
If true the message will be compressed and sent with request body instead of the URI. Compression useful in case of large data, in another cases it will increase the packet size.
closure
Type: PNPublishCompletionBlock
The completion closure which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Publish a message with payload, storage, and closure​

open func publish(
    _ message: Any?,
    toChannel channel: String,
    mobilePushPayload payloads: [String: Any]?,
    storeInHistory shouldStore: Bool,
    withCompletion closure: PubNub.PNPublishCompletionBlock? = nil
)
* required
ParameterDescription
message
Type: Any
The message may be any valid foundation object ( String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
payloads
Type: [String : Any]
Dictionary with payloads for different vendors (Apple with aps key and Google with gcm). Either payloads or message should be provided.
shouldStore *
Type: Bool
If false the messages will not be stored in Message Persistence, default true.
closure
Type: PNPublishCompletionBlock
The completion closure which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Publish a message with payload, storage, compression, and closure​

open func publish(
    _ message: Any?,
    toChannel channel: String,
    mobilePushPayload payloads: [String: Any]?,
    storeInHistory shouldStore: Bool,
    compressed: Bool,
    withCompletion closure: PubNub.PNPublishCompletionBlock? = nil
)
* required
ParameterDescription
message
Type: Any
The message may be any valid foundation object ( String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
payloads
Type: [String : Any]
Dictionary with payloads for different vendors (Apple with aps key and Google with gcm). Either payloads or message should be provided.
shouldStore *
Type: Bool
If false the messages will not be stored in Message Persistence, default true.
compressed *
Type: Bool
If true the message will be compressed and sent with request body instead of the URI. Compression useful in case of large data, in another cases it will increase the packet size.
closure
Type: PNPublishCompletionBlock
The completion closure which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Publish a message with metadata and closure​

open func publish(
    _ message: Any,
    toChannel channel: String,
    withMetadata metadata: [String: Any]?,
    completion closure: PubNub.PNPublishCompletionBlock? = nil
)
* required
ParameterDescription
message *
Type: Any
The message may be any valid foundation object (String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
metadata
Type: [String : Any]
NSDictionary with values which should be used by PubNub service to filter messages.
closure
Type: PNPublishCompletionBlock
The completion closure which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Publish a message with compression, metadata, and closure​

open func publish(
    _ message: Any,
    toChannel channel: String,
    compressed: Bool,
    withMetadata metadata: [String: Any]?,
    completion closure: PubNub.PNPublishCompletionBlock? = nil
)
* required
ParameterDescription
message *
Type: Any
The message may be any valid foundation object (String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
compressed *
Type: Bool
If true the message will be compressed and sent with request body instead of the URI. Compression useful in case of large data, in another cases it will increase the packet size.
metadata
Type: [String : Any]
NSDictionary with values which should be used by PubNub service to filter messages.
closure
Type: PNPublishCompletionBlock
The completion closure which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Publish a message with storage, metadata, and closure​

open func publish(
    _ message: Any,
    toChannel channel: String,
    storeInHistory shouldStore: Bool,
    withMetadata metadata: [String: Any]?,
    completion closure: PubNub.PNPublishCompletionBlock? = nil
)
* required
ParameterDescription
message *
Type: Any
The message may be any valid foundation object (String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
shouldStore *
Type: Bool
If false the messages will not be stored in Message Persistence, default true.
metadata
Type: [String : Any]
NSDictionary with values which should be used by PubNub service to filter messages.
closure
Type: PNPublishCompletionBlock
The completion closure which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Publish a message with storage, compression, metadata, and closure​

open func publish(
    _ message: Any,
    toChannel channel: String,
    storeInHistory shouldStore: Bool,
    compressed: Bool,
    withMetadata metadata: [String: Any]?,
    completion closure: PubNub.PNPublishCompletionBlock? = nil
)
* required
ParameterDescription
message *
Type: Any
The message may be any valid foundation object (String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
shouldStore *
Type: Bool
If false the messages will not be stored in Message Persistence, default true.
compressed *
Type: Bool
If true the message will be compressed and sent with request body instead of the URI. Compression useful in case of large data, in another cases it will increase the packet size.
metadata
Type: [String : Any]
NSDictionary with values which should be used by PubNub service to filter messages.
closure
Type: PNPublishCompletionBlock
The completion closure which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Publish a message with payload, metadata, and closure​

open func publish(
    _ message: Any?,
    toChannel channel: String,
    mobilePushPayload payloads: [String: Any]?,
    withMetadata metadata: [String: Any]?,
    completion closure: PubNub.PNPublishCompletionBlock? = nil
)
* required
ParameterDescription
message
Type: Any
The message may be any valid foundation object (String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
payloads
Type: [String : Any]
Dictionary with payloads for different vendors (Apple with aps key and Google with gcm). Either payloads or message should be provided.
metadata
Type: [String : Any]
NSDictionary with values which should be used by PubNub service to filter messages.
closure
Type: PNPublishCompletionBlock
The completion closure which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Publish a message with payload, compression, metadata, and closure​

open func publish(
    _ message: Any?,
    toChannel channel: String,
    mobilePushPayload payloads: [String: Any]?,
    compressed: Bool,
    withMetadata metadata: [String: Any]?,
    completion closure: PubNub.PNPublishCompletionBlock? = nil
)
* required
ParameterDescription
message
Type: Any
The message may be any valid foundation object (String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
payloads
Type: [String : Any]
Dictionary with payloads for different vendors (Apple with aps key and Google with gcm). Either payloads or message should be provided.
compressed *
Type: Bool
If true the message will be compressed and sent with request body instead of the URI. Compression useful in case of large data, in another cases it will increase the packet size.
metadata
Type: [String : Any]
NSDictionary with values which should be used by PubNub service to filter messages.
closure
Type: PNPublishCompletionBlock
The completion closure which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Publish a message with payload, storage, metadata, and closure​

open func publish(
    _ message: Any?,
    toChannel channel: String,
    mobilePushPayload payloads: [String: Any]?,
    storeInHistory shouldStore: Bool,
    withMetadata metadata: [String: Any]?,
    completion closure: PubNub.PNPublishCompletionBlock? = nil
)
* required
ParameterDescription
message
Type: Any
The message may be any valid foundation object (String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
payloads
Type: [String : Any]
Dictionary with payloads for different vendors (Apple with aps key and Google with gcm). Either payloads or message should be provided.
shouldStore *
Type: Bool
If false the messages will not be stored in Message Persistence, default true.
metadata
Type: [String : Any]
NSDictionary with values which should be used by PubNub service to filter messages.
closure
Type: PNPublishCompletionBlock
The completion closure which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Basic Usage​

Publish a message to a channel​

self.client.publish("Hello from the PubNub Swift SDK", toChannel: "my_channel",
                    compressed: false, withCompletion: { (status) in

    if !status.isError {

        // Message successfully published to specified channel.
    }
    else{

        /**
         Handle message publish error. Check 'category' property to find
         out possible reason because of which request did fail.
         Review 'errorData' property (which has PNErrorData data type) of status
         object to get additional information about issue.

show all 19 lines
Subscribe to the channel

Before running the above publish example, either using the Debug Console or in a separate script running in a separate terminal window, subscribe to the same channel that is being published to.

Response​

Response objects which is returned by client when publish API is used:

open class PNPublishData : PNServiceData {

    open var timetoken: NSNumber { get }
    open var information: String { get }
}

open class PNPublishStatus : PNAcknowledgmentStatus {

    open var data: PNPublishData { get }
}

Other Examples​

Publish a JSON serialized message​

self.client.publish(["Dictionary": ["with", "array", "as", "value"]], toChannel: "pubnub",
                    withMetadata: ["senderID" : "bob"], completion: { (status) in

    if !status.isError {

        // Message successfully published to specified channel.
    }
    else{

        /**
            Handle message publish error. Check 'category' property to find
            out possible reason because of which request did fail.
            Review 'errorData' property (which has PNErrorData data type) of status
            object to get additional information about issue.

show all 19 lines

Publish with metadata​

self.client.publish("Hello from the PubNub Swift", toChannel: "chat_channel",
                    withMetadata: ["senderID" : "bob"], completion: { (status) in

    if !status.isError {

        // Message successfully published to specified channel.
    }
    else{

        /**
            Handle message publish error. Check 'category' property to find
            out possible reason because of which request did fail.
            Review 'errorData' property (which has PNErrorData data type) of status
            object to get additional information about issue.

show all 19 lines

Publish (Builder Pattern)​

This function publishes a message on a channel.

Optional arguments

This method uses the builder pattern, you can remove the args which are optional.

Method(s)​

To run Publish Builder you can use the following method(s) in the Swift SDK:

publish().message(Any)
    .channel(NSString)
    .shouldStore(Bool)
    .replicate(Bool)
    .compress(Bool)
    .ttl(UInt)
    .payloads([String: Any])
    .metadata([String: Any])
    .performWithCompletion(PNPublishCompletionBlock)

* required
ParameterDescription
message
Type: Any
The message may be any valid foundation object (String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
shouldStore
Type: Bool
If false the messages will not be stored in history.
Default true.
replicate
Type: Bool
Specify whether published message should be replicated across the PubNub Real-Time Network and sent simultaneously to all subscribed clients on a channel.
compress
Type: Bool
If true the message will be compressed and sent with request body instead of the URI. Compression useful in case of large data, in another cases it will increase the packet size.
ttl
Type: UInteger
Specify for how many hours published message should be stored.
payloads
Type: [String : Any]
Dictionary with payloads for different vendors (Apple with aps key and Google with gcm). Either payloads or message should be provided.
metadata
Type: [String : Any]
Dictionary with values which should be used by PubNub service to filter messages.
block
Type: PNPublishCompletionBlock
The completion block which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Basic Usage​

Publish message which will be stored in channel's Message Persistence for next 16 hours.

self.client.publish().channel("my_channel").message("Hello from the PubNub Swift SDK").compress(false).ttl(16).performWithCompletion({ (status) in

    if !status.isError {

        // Message successfully published to specified channel.
    }
    else{

        /**
         Handle message publish error. Check 'category' property to find
         out possible reason because of which request did fail.
         Review 'errorData' property (which has PNErrorData data type) of status
         object to get additional information about issue.

         Request can be resent using: status.retry()
show all 18 lines

Fire (Builder Pattern)​

The fire endpoint allows the client to send a message to BLOCKS Event Handlers. These messages will go directly to any Event Handlers registered on the channel that you fire to and will trigger their execution. The content of the fired request will be available for processing within the Event Handler. The message sent via fire() is not replicated, and so will not be received by any subscribers to the channel. The message is also not stored in history.

Optional arguments

This method uses the builder pattern, you can remove the args which are optional.

Method(s)​

To Fire a message you can use the following method(s) in the Swift SDK:

fire().message(Any)
    .channel(NSString)
    .compress(Bool)
    .ttl(UInt)
    .payloads([String: Any])
    .metadata([String: Any])
    .performWithCompletion(PNPublishCompletionBlock)

* required
ParameterDescription
message
Type: Any
The message may be any valid foundation object (String, NSNumber, Array, Dictionary).
channel *
Type: String
Specifies channel name to publish messages to.
compress
Type: Bool
If true the message will be compressed and sent with request body instead of the URI. Compression useful in case of large data, in another cases it will increase the packet size.
ttl
Type: UInt
Specify for how many hours published message should be stored.
payloads
Type: [String : Any]
Dictionary with payloads for different vendors (Apple with aps key and Google with gcm). Either payloads or message should be provided.
metadata
Type: [String : Any]
Dictionary with values which should be used by PubNub service to filter messages.
block
Type: PNPublishCompletionBlock
The completion block which will be called when the processing is complete, has one argument: - request status reports the publish was successful or not (errorData contains error information in case of failure).

Basic Usage​

self.client.fire().channel("my_channel").message("Hello from the PubNub Swift SDK").compress(false).ttl(16).performWithCompletion({ (status) in

    if !status.isError {

        // Message successfully published to specified channel.
    }
    else{

        /**
         Handle message publish error. Check 'category' property to find
         out possible reason because of which request did fail.
         Review 'errorData' property (which has PNErrorData data type) of status
         object to get additional information about issue.

         Request can be resent using: status.retry()
show all 18 lines

Signal​

The signal() function is used to send a signal to all subscribers of a channel.

By default, signals are limited to a message payload size of 64 bytes. This limit applies only to the payload, and not to the URI or headers. If you require a larger payload size, please contact support.

Method(s)​

To Signal a message you can use the following method(s) in the Swift SDK:

open func signal(
    _ message: Any,
    channel: String,
    withCompletion: PNSignalCompletionBlock?
)
* required
ParameterDescription
message *
Type: Any
Object (String, Number, Array, Dictionary) which will be sent with signal.
channel *
Type: String
Name of the channel to which signal should be sent.
closure
Type: PNSignalCompletionBlock
Signal processing completion closure which pass only one argument - request processing status to report about how data pushing was successful or not.

Basic Usage​

Signal a message to a channel​

self.client.signal(["Hello": "world"], channel: "announcement", withCompletion: { status in

    if !status.isError {
        // Signal successfully sent to specified channel.
    } else {
        /**
         * Handle signal sending error. Check 'category' property to find out possible issue
         * because of which request did fail.
         *
         * Request can be resent using: status.retry();
         */
    }
})

Response​

Response objects returned by the client when Signal API is used:

open class PNSignalStatusData : PNServiceData {

    open var timetoken: NSNumber { get }
    open var information: String { get }
}

open class PNSignalStatus : PNAcknowledgmentStatus {

    open var data: PNSignalStatusData { get }
}

Signal (Builder Pattern)​

Optional arguments

This method uses the builder pattern, you can remove the args which are optional.

Method(s)​

To run Signal Builder you can use the following method(s) in the Swift SDK:

signal()
    .message(id)
    .channel(NSString *)
    .performWithCompletion(PNSignalCompletionBlock)
* required
ParameterDescription
message *
Type: Any
Object (String, Number, Array, Dictionary) which will be sent with signal.
channel *
Type: String
Name of the channel to which signal should be sent.
closure
Type: PNSignalCompletionBlock
Signal processing completion closure which pass only one argument - request processing status to report about how data pushing was successful or not.

Basic Usage​

Signal a message to a channel​

self.client.signal().message(["Hello": "world"]).channel("announcement")
    .performWithCompletion({ status in

    if !status.isError {
        // Signal successfully sent to specified channel.
    } else {
        /**
         * Handle signal sending error. Check 'category' property to find out possible issue
         * because of which request did fail.
         *
         * Request can be resent using: status.retry();
         */
    }
})

Response​

Response objects which is returned by client when Signal API is used::

open class PNSignalStatusData : PNServiceData {

    open var timetoken: NSNumber { get }
    open var information: String { get }
}

open class PNSignalStatus : PNAcknowledgmentStatus {

    open var data: PNSignalStatusData { get }
}

Subscribe​

This function causes the client to create an open TCP socket to the PubNub Real-Time Network and begin listening for messages on a specified channel. To subscribe to a channel the client must send the appropriate subscribeKey at initialization. By default a newly subscribed client will only receive messages published to the channel after the subscribeToChannels() call completes.

Connectivity notification

You can be notified of connectivity via the connect callback. By waiting for the connect callback to return before attempting to publish, you can avoid a potential race condition on clients that subscribe and immediately publish messages before the subscribe has completed.

Using Swift SDK, if a client becomes disconnected from a channel, it can automatically attempt to reconnect to that channel and retrieve any available messages that were missed during that period by setting restore to true. By default a client will attempt to reconnect after exceeding a 320 second connection timeout.

Unsubscribing from all channels

Unsubscribing from all channels, and then subscribing to a new channel Y is not the same as subscribing to channel Y and then unsubscribing from the previously-subscribed channel(s). Unsubscribing from all channels resets the last-received timetoken and thus, there could be some gaps in the subscription that may lead to message loss.

Method(s)​

To Subscribe to a channel you can use the following method(s) in the Swift SDK:

Subscribe to channels with presence​

open func subscribeToChannels(
    _ channels: [String],
    withPresence shouldObservePresence: Bool
)
* required
ParameterDescription
channels *
Type: [String]
List of channel names on which client should try to subscribe.
shouldObservePresence *
Type: Bool
If true presence observation will be enabled for channels.

Subscribe to channels with state​

open func subscribeToChannels(
    _ channels: [String],
    withPresence shouldObservePresence: Bool,
    clientState state: [String: Any]?
)
* required
ParameterDescription
channels *
Type: [String]
List of channel names on which client should try to subscribe.
shouldObservePresence *
Type: Bool
If true presence observation will be enabled for channels.
state
Type: [String : Any]
Dictionary object containing the state for the channel.

Subscribe to channels with timetoken​

open func subscribeToChannels(
    _ channels: [String],
    withPresence shouldObservePresence: Bool,
    usingTimeToken timeToken: NSNumber?
)
* required
ParameterDescription
channels *
Type: [String]
List of channel names on which client should try to subscribe.
shouldObservePresence *
Type: Bool
If true presence observation will be enabled for channels.
timeToken
Type: NSNumber
Specifies time from which to start returning any available cached messages. Message retrieval with timetoken is not guaranteed and should only be considered a best-effort service.

Subscribe to channels with timetoken and state​

open func subscribeToChannels(
    _ channels: [String],
    withPresence shouldObservePresence: Bool,
    usingTimeToken timeToken: NSNumber?,
    clientState state: [String: Any]?
)
* required
ParameterDescription
channels *
Type: [String]
List of channel names on which client should try to subscribe.
shouldObservePresence *
Type: Bool
If true presence observation will be enabled for channels.
timeToken
Type: NSNumber
Specifies time from which to start returning any available cached messages. Message retrieval with timetoken is not guaranteed and should only be considered a best-effort service.
state
Type: [String : Any]
Dictionary object containing the state for the channel.

Basic Usage​

Subscribe to a channel:

/**
 Subscription results arrive to a listener which should implement the PNObjectEventListener protocol and be registered as follows:
 */
self.client.addListener(self)
self.client.subscribeToChannels(["my_channel1","my_channel2"], withPresence: false)

// Handle a new message from a subscribed channel
func client(_ client: PubNub, didReceiveMessage message: PNMessageResult) {
    // Reference to the channel group containing the chat the message was sent to
    let subscription = message.data.subscription
    print("\(message.data.publisher) sent message to '\(message.data.channel)' at
           \(message.data.timetoken): \(message.data.message)")
}

// Handle a subscription status change
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Response​

open class PNSubscriberData : PNServiceData {

    // Name of channel for which the subscriber received data.
    open var channel: String { get }

    // Name of channel or channel group (if not equal to channel name).
    open var subscription: String? { get }

    // Time at which the event arrived.
    open var timetoken: NSNumber { get }

    // Stores reference to metadata information passed along with the received event.
    open var userMetadata: [String : Any]? { get }
}

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Other Examples​

Subscribing to a Presence channel​

Requires Presence

This method requires that the Presence add-on is enabled for your key in the Admin Portal.

For any given channel there is an associated Presence channel. You can subscribe directly to the channel by appending -pnpres to the channel name. For example the channel named my_channel would have the presence channel named my_channel-pnpres.

/**
    Subscription process results arrive to listener which should adopt to
    PNObjectEventListener protocol and registered using:
    */
self.client.addListener(self)
self.client.subscribeToPresenceChannels(["my_channel"])

// New presence event handling.
func client(_ client: PubNub, didReceivePresenceEvent event: PNPresenceEventResult) {

    // Handle presence event event.data.presenceEvent (one of: join, leave, timeout, state-change).
    if event.data.channel != event.data.subscription {

        // Presence event has been received on channel group stored in event.data.subscription.
    }
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Sample Responses​

Join Event​
{
    "action": "join",
    "timestamp": 1345546797,
    "uuid": "175c2c67-b2a9-470d-8f4b-1db94f90e39e",
    "occupancy": 2
}
Leave Event​
{
    "action" : "leave",
    "timestamp" : 1345549797,
    "uuid" : "175c2c67-b2a9-470d-8f4b-1db94f90e39e",
    "occupancy" : 1
}
Timeout Event​
{
    "action": "timeout",
    "timestamp": 1345549797,
    "uuid": "76c2c571-9a2b-d074-b4f8-e93e09f49bd",
    "occupancy": 0
}
Custom Presence Event (State Change)​
{
    "action": "state-change",
    "uuid": "76c2c571-9a2b-d074-b4f8-e93e09f49bd",
    "timestamp": 1345549797,
    "data": {
        "isTyping": true
    }
}
Interval Event​
{
    "action":"interval",
    "timestamp":1474396578,
    "occupancy":2
}

When a channel is in interval mode with presence_deltas pnconfig flag enabled, the interval message may also include the following fields which contain an array of changed UUIDs since the last interval message.

  • joined
  • left
  • timedout

For example, this interval message indicates there were 2 new UUIDs that joined and 1 timed out UUID since the last interval:

{
    "action" : "interval",
    "occupancy" : <# users in channel>,
    "timestamp" : <unix timestamp>,
    "joined" : ["uuid2", "uuid3"],
    "timedout" : ["uuid1"]
}

If the full interval message is greater than 30KB (since the max publish payload is ∼32KB), none of the extra fields will be present. Instead there will be a here_now_refresh boolean field set to true. This indicates to the user that they should do a hereNow request to get the complete list of users present in the channel.

{
    "action" : "interval",
    "occupancy" : <# users in channel>,
    "timestamp" : <unix timestamp>,
    "here_now_refresh" : true
}

Subscribing with State​

Requires Presence

This method requires that the Presence add-on is enabled for your key in the Admin Portal.

Required UUID

Always set the UUID to uniquely identify the user or device that connects to PubNub. This UUID should be persisted, and should remain unchanged for the lifetime of the user or the device. If you don't set the UUID, you won't be able to connect to PubNub.

// Initialize and configure PubNub client instance
let configuration = PNConfiguration(publishKey: "demo", subscribeKey: "demo")
self.client = PubNub.clientWithConfiguration(configuration)
self.client.addListener(self)

// Subscribe to demo channel with presence observation
self.client.subscribeToChannels(["my_channel"], withPresence: true)

func client(_ client: PubNub, didReceive status: PNStatus) {

    if status.category == .PNConnectedCategory {
        self.client.setState(["Key": "Value"], forUUID: self.client.uuid(), onChannel: "my_channel",
                                withCompletion: { (status) in

            if !status.isError {
show all 46 lines

Subscribe Channel Group​

Requires Stream Controller add-on

This method requires that the Stream Controller add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

This functions subscribes to a channel group.

Method(s)​

To Subscribe to a Channel Group you can use the following method(s) in the Swift SDK:

Subscribe to a channel group with presence​

open func subscribeToChannelGroups(
    _ groups: [String],
    withPresence shouldObservePresence: Bool
)
* required
ParameterDescription
groups *
Type: [String]
List of channel group names on which client should try to subscribe.
shouldObservePresence *
Type: Bool
If true presence observation will be enabled for channels groups.

Subscribe to a channel group with presence and state​

open func subscribeToChannelGroups(
    _ groups: [String],
    withPresence shouldObservePresence: Bool,
    clientState state: [String: Any]?
)
* required
ParameterDescription
groups *
Type: [String]
List of channel group names on which client should try to subscribe.
shouldObservePresence *
Type: Bool
If true presence observation will be enabled for channels groups.
state
Type: [String : Any]
Reference on dictionary which stores key-value pairs based on channel group name and value which should be assigned to it.

Basic Usage​

Subscribe to a channel group.

let channelGroup = "family"
/**
 Subscription process results arrive to listener which should adopt to PNObjectEventListener protocol
 and registered using:
 */
self.client.addListener(self)
self.client.subscribeToChannelGroups([channelGroup], withPresence: false)

// Handle new message from one of channels on which client has been subscribed.
func client(_ client: PubNub, didReceiveMessage message: PNMessageResult) {

    // Handle new message stored in message.data.message
    if message.data.channel != message.data.subscription {

        // Message has been received on channel group stored in message.data.subscription.
    }
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Response​

open class PNSubscriberData : PNServiceData {

    // Name of channel for which subscriber received data.
    open var channel: String { get }
    // Name of channel or channel group (in case if not equal to channel).
    open var subscription: String? { get }
    // Time at which event arrived.
    open var timetoken: NSNumber { get }
    // Stores reference on metadata information which has been passed along with received event.
    open var userMetadata: [String : Any]? { get }
}

open class PNSubscribeStatus : PNErrorStatus {

    // Timetoken which has been used to establish current subscription cycle.
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Other Examples​

Subscribe to the presence channel of a channel group​

note
Requires Stream Controller and Presence add-ons

This method requires both the Stream Controller and Presence add-ons are enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

/**
    Subscription process results arrive to listener which should adopt to
    PNObjectEventListener protocol and registered using:
    */
self.client.addListener(self)
self.client.subscribeToChannelGroups([channelGroup], withPresence: true)

// Handle new message from one of channels on which client has been subscribed.
func client(_ client: PubNub, didReceiveMessage message: PNMessageResult) {

    // Handle new message stored in message.data.message
    if message.data.channel != message.data.subscription {

        // Message has been received on channel group stored in message.data.subscription.
    }
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Unsubscribe​

When subscribed to a single channel, this function causes the client to issue a leave from the channel and close any open socket to the PubNub Network. For multiplexed channels, the specified channel(s) will be removed and the socket remains open until there are no more channels remaining in the list.

Warning

Unsubscribing from all channels, and then subscribing to a new channel Y is not the same as subscribing to channel Y and then unsubscribing from the previously-subscribed channel(s). Unsubscribing from all channels resets the last-received timetoken and thus, there could be some gaps in the subscription that may lead to message loss.

Method(s)​

To Unsubscribe from a channel you can use the following method(s) in the Swift SDK:

open func unsubscribeFromChannels(
    _ channels: [String],
    withPresence shouldObservePresence: Bool
)
* required
ParameterDescription
group *
Type: [String]
List of channel group names from which client should try to unsubscribe.
shouldObservePresence *
Type: Bool
If true the presence observation will also be unsubscribed on specified channels.

Basic Usage​

Unsubscribe from a channel:

/**
 Subscription process results arrive to listener which should adopt to
 PNObjectEventListener protocol and registered using:
 */
self.client.addListener(self)
self.client.unsubscribeFromChannels(["my_channel1", "my_channel2"], withPresence: false)

// Handle subscription status change.
func client(_ client: PubNub, didReceive status: PNStatus) {

    if status.operation == .unsubscribeOperation && status.category == .PNDisconnectedCategory {

        /**
         This is the expected category for an unsubscribe. This means there was no error in
         unsubscribing from everything.
show all 18 lines

Response​

open class PNSubscriberData : PNServiceData {

    // Name of channel for which subscriber received data.
    open var channel: String { get }
    // Name of channel or channel group (in case if not equal to channel).
    open var subscription: String? { get }
    // Time at which event arrived.
    open var timetoken: NSNumber { get }
    // Stores reference on metadata information which has been passed along with received event.
    open var userMetadata: [String : Any]? { get }
}

open class PNSubscribeStatus : PNErrorStatus {

    // Timetoken which has been used to establish current subscription cycle.
show all 26 lines

Unsubscribe All​

Unsubscribe from all channels and all channel groups

Method(s)​

open func unsubscribeFromAll()

Basic Usage​

/**
 Subscription process results arrive to listener which should adopt to
 PNObjectEventListener protocol and registered using:
 */
self.client?.addListener(self)
self.client?.unsubscribeFromAll()

// Handle subscription status change.
func client(client: PubNub, didReceiveStatus status: PNStatus) {

    if status.operation == .unsubscribeOperation && status.category == .PNDisconnectedCategory {

        /**
         This is the expected category for an unsubscribe. This means there was no error in
         unsubscribing from everything.
show all 18 lines

Returns​

None

Unsubscribe from a Channel Group​

This function lets you Unsubscribe from a Channel Group

Method(s)​

To run Unsubscribe from a Channel Group you can use the following method(s) in the Swift SDK:

open func unsubscribeFromChannelGroups(
    _ groups: [String],
    withPresence shouldObservePresence: Bool
)
* required
ParameterDescription
group *
Type: [String]
List of channel group names from which client should try to unsubscribe.
shouldObservePresence *
Type: Bool
Whether client should disable presence observation on specified channel groups or keep listening for presence event on them.

Basic Usage​

Unsubscribe from a Channel Group: 

/**
 Unsubscription process results arrive to listener which should adopt to
 PNObjectEventListener protocol and registered using:
 */
self.client.addListener(self)
self.client.unsubscribeFromChannelGroups(["developers"], withPresence: true)

// Handle subscription status change.
func client(client: PubNub, didReceiveStatus status: PNStatus) {

    if status.operation == .unsubscribeOperation && status.category == .PNDisconnectedCategory {

        /**
         This is the expected category for an unsubscribe. This means there was no error in
         unsubscribing from everything.
show all 18 lines

Response​

open class PNSubscriberData : PNServiceData {

    // Name of channel for which subscriber received data.
    open var channel: String { get }
    // Name of channel or channel group (in case if not equal to channel).
    open var subscription: String? { get }
    // Time at which event arrived.
    open var timetoken: NSNumber { get }
    // Stores reference on metadata information which has been passed along with received event.
    open var userMetadata: [String : Any]? { get }
}

open class PNSubscribeStatus : PNErrorStatus {

    // Timetoken which has been used to establish current subscription cycle.
show all 26 lines

Presence​

This function is used to subscribe to the presence channel. Using Swift SDK, if a client becomes disconnected from a channel, it can automatically attempt to reconnect to that channel and retrieve any available messages that were missed during that period by setting restore to true. By default a client will attempt to reconnect after exceeding a 320 second connection timeout.

Method(s)​

To do Presence you can use the following method(s) in the Swift SDK:

open func subscribeToPresenceChannels(_ channels: [String])
* required
ParameterDescription
channels *
Type: [String]
Specifies the channel(s) to subscribe to presence channel. It is possible to specify multiple channels.

Basic Usage​

Subscribe to the presence channel: For any given channel there is an associated Presence channel. You can subscribe directly to the channel by appending -pnpres to the channel name. For example the channel named my_channel would have the presence channel named my_channel-pnpres

/**
 Subscription process results arrive to listener which should adopt to
 PNObjectEventListener protocol and registered using:
 */
self.client.addListener(self)
self.client.subscribeToPresenceChannels(["my_channel"])

// New presence event handling.
func client(_ client: PubNub, didReceivePresenceEvent event: PNPresenceEventResult) {

    // Handle presence event event.data.presenceEvent (one of: join, leave, timeout, state-change).
    if event.data.channel != event.data.subscription {

        // Presence event has been received on channel group stored in event.data.subscription.
    }
show all 33 lines

Response​

open class PNSubscriberData : PNServiceData {

    // Name of channel for which subscriber received data.
    open var channel: String { get }
    // Name of channel or channel group (in case if not equal to channel).
    open var subscription: String? { get }
    // Time at which event arrived.
    open var timetoken: NSNumber { get }
    // Stores reference on metadata information which has been passed along with received event.
    open var userMetadata: [String : Any]? { get }
}

open class PNSubscribeStatus : PNErrorStatus {

    // Timetoken which has been used to establish current subscription cycle.
show all 60 lines

Presence Unsubscribe​

This function lets you stop monitoring the presence of the channel(s). The channel(s) will be removed and the socket remains open until there are no more channels remaining in the list.

Method(s)​

To Unsubscribe from Presence of a channel you can use the following method(s) in the Swift SDK:

open func unsubscribeFromPresenceChannels(_ channels: [String])
* required
ParameterDescription
channels *
Type: [String]
List of channel names for which client should try to unsubscribe from presence observing channels

Basic Usage​

Unsubscribe from the presence channel:

// Unsubscribe from one of channels presence channels.
self.client.unsubscribeFromPresenceChannels(["my_channel"])

Response​

open class PNSubscriberData : PNServiceData {

    // Name of channel for which subscriber received data.
    open var channel: String { get }
    // Name of channel or channel group (in case if not equal to channel).
    open var subscription: String? { get }
    // Time at which event arrived.
    open var timetoken: NSNumber { get }
    // Stores reference on metadata information which has been passed along with received event.
    open var userMetadata: [String : Any]? { get }
}

open class PNSubscribeStatus : PNErrorStatus {

    // Timetoken which has been used to establish current subscription cycle.
show all 26 lines

Listeners​

You can be notified of connectivity status, message and presence notifications via the listeners.

Listeners should be added before calling the method.

Add Listeners​

/**
 Subscription results arrive to a listener which should implement the PNObjectEventListener protocol and be registered as follows:
 */
self.client.addListener(self)
self.client.subscribeToChannels(["my_channel1","my_channel2"], withPresence: false)

// Handle a new message from a subscribed channel
func client(_ client: PubNub, didReceiveMessage message: PNMessageResult) {
    // Reference to the channel group containing the chat the message was sent to
    let subscription = message.data.subscription
    print("\(message.data.publisher) sent message to '\(message.data.channel)' at
           \(message.data.timetoken): \(message.data.message)")
}

// Handle a subscription status change
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Listener status events​

This is the list of categories which can be received by an event listener:

CategoryDescription
PNAccessDeniedCategory
Subscribe request failed because of access error (active Access Manager). status.errorData.channels or status.errorData.channelGroups contain list of channels and/or groups to which user with specified auth key doesn't have access.
PNDecryptionErrorCategory
Subscribe request returned messages which can't be decrypted with configured cipherKey. Unencrypted message will be returned in status.associatedObject where associatedObject is PNMessageData which contain channel and message properties.
PNNetworkIssuesCategory
Subscribe request failed because there was no network connection at the moment when request has been sent.
PNConnectedCategory
Subscribe request successfully completed and client connected to real-time data channels.
PNReconnectedCategory
Subscribe request successfully completed and client has been reconnected to real-time data channels after unexpected disconnection (PNUnexpectedDisconnectCategory).
PNDisconnectedCategory
Client did unsubscribe from specified real-time data channels.
PNUnexpectedDisconnectCategory
Previously started subscribe loop did fail and at this moment client disconnected from real-time data channels.
PNRequestMessageCountExceededCategory
If requestMessageCountThreshold is set, this status event will arrive each time when client receive more messages when it has been specified for PNConfiguration property.
PNMalformedFilterExpressionCategory
Subscription request can't be processed by PubNub service because filter expression malformed and can't be evaluated.
PNHeartbeatOperation
In case if presence heartbeat value is set, client will sent this status category at specified periods. If status.isError set to YES it mean what heartbeat request did fail (potentially because of network issues).

This is list of categories which can be received in API completion blocks (non-subscribe):

CategoryDescription
PNAcknowledgmentCategory
An API call was successful. This status has additional details based on the type of the successful operation.
PNAccessDeniedCategory
Request failed because of access error (active Access Manager). status.errorData.channels or status.errorData.channelGroups contain list of channels and/or groups to which user with specified auth key doesn't have access.
PNTimeoutCategory
Used API didn't received response from server in time.
PNNetworkIssuesCategory
API did fail because there was no network connection at the moment when request has been sent.
PNMalformedResponseCategory
Request received in response non-JSON data. It can be because of publish WiFi hotspot which require authorization or proxy server message.
PNBadRequestCategory
Request can't be completed because not all required values has been passed or passed values has unexpected data type.
PNDecryptionErrorCategory
Message Persistence API may return this status category in case if some messages can't be decrypted. Unencrypted message will be returned in status.associatedObject where associatedObject is PNMessageData which contain channel and message properties.
PNTLSConnectionFailedCategory
TLS handshake issues and in most cases because of poor connection quality and packets loss and delays.
PNTLSUntrustedCertificateCategory
Origin to which client tried to connect has untrusted certificate.
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