Publish Subscribe on iOS

This page is part of the Cobalt Publish/Subscribe pages. Don't miss the others.

• Introduction to Cobalt PubSub messages
• Publish/Subscribe on the Web side
• Publish/Subscribe on Android
• Web Lifecycle messages

Using Cobalt Publish

first, import the Cobalt class in your .h file :

#import <Cobalt/Cobalt.h>

[Cobalt publishMessage:message toChannel:channel];

• message : (NSDictionary) The message that will be sent in the channel.
• channel : (string) The name of the channel in which you want to send your message.

Example :

[Cobalt publishMessage:@{@"myValue": @42}
             toChannel:@"myChannel"];

Using Cobalt Subscribe

Subscribe needs a delegate to catch the message. Add the delegate to your class :

@interface MyClass : MyParentClass <PubSubDelegate>

[Cobalt subscribeDelegate:delegate toChannel:channel];

• channel : (string) The name of the channel you want to subscribe.
• delegate : (PubSubDelegate) A Cobalt PubSubDelegate to handle the messages when they'll come. This PubSubDelegate has one method didReceiveMessage receiving message and channel.

Example with the current class as PubSubDelegate :

@implementation MyClass {
...
// later somewhere : 
- (void)myFunction:() {
    [Cobalt subscribeDelegate:self
                    toChannel:@"myChannel"];
}
...
// later again : 
- (void)didReceiveMessage:(nullable NSDictionary *)message
                onChannel:(nonnull NSString *)channel {
    if ([channel isEqualToString:@"myChannel"]) {
        // Do something with the message
    }
}   

Using Cobalt Unsubscribe

Unsubscribe a PubSubDelegate to messages from the specified channel.

[Cobalt unsubscribeDelegate:delegate fromChannel:channel];

• channel : (string) The name of the channel you want to unsubscribe.
• delegate : (PubSubDelegate) The Cobalt PubSubDelegate you used to handle the messages.

Example :

[Cobalt unsubscribeDelegate:self
                fromChannel:@"myChannel"];