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This SDK has been replaced by a new PubNub Swift SDK written purely in Swift.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
)
Parameter | Description |
---|---|
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
)
Parameter | Description |
---|---|
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
)
Parameter | Description |
---|---|
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
)
Parameter | Description |
---|---|
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
)
Parameter | Description |
---|---|
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
)
Parameter | Description |
---|---|
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
)
Parameter | Description |
---|---|
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
)
Parameter | Description |
---|---|
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
)
Parameter | Description |
---|---|
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
)
Parameter | Description |
---|---|
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
)
Parameter | Description |
---|---|
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). |