iOS SDK V4 Channel Groups API Reference for Realtime Apps

Channel Groups allows PubNub developers to bundle thousands of channels into a group that can be identified by name. These Channel Groups can then be subscribed to, receiving data from the many backend-channels the channel group contains.

Learn more about our Channel Groups here.

Adding Channels

Requires Stream Controller add-onRequires that the Stream Controller add-on is enabled for your key. See this page on enabling add-on features on your keys:
https://support.pubnub.com/hc/en-us/articles/360051974791-How-do-I-enable-add-on-features-for-my-keys-

Description

This function adds a channel to a channel group.

Method(s)

Adding Channels is accomplished by using the following method(s) in the Objective-C SDK:

- (void)addChannels:(NSArray<NSString *> *)channels toGroup:(NSString *)group withCompletion:(nullable PNChannelGroupChangeCompletionBlock)block;

Parameter	Type	Required	Description
`channels`	NSArray	Yes	List of channel names which should be added to the group.
`group`	NSString	Yes	Name of the group into which channels should be added.
`block`	PNChannelGroupChangeCompletionBlock	No	`Channels` addition process completion block which pass only one argument - request processing status to report about how data pushing was successful or not.

Basic Usage

Adding Channels :

NSString *channelGroup = @"family";

[self.client addChannels: @[@"wife"] toGroup:channelGroup
          withCompletion:^(PNAcknowledgmentStatus *status) {

    if (!status.isError) {

        // Handle successful channels list modification for group.
    }
    else {

        /**
         Handle channels list modification for group 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];
         */
    }
}];

Response

Response objects which is returned by client when Add Channels to Group API is used:

@interface PNAcknowledgmentStatus : PNErrorStatus

@end

Listing Channels

Description

This function lists all the channels of the channel group.

Method(s)

Listing Channels is accomplished by using the following method(s) in the Objective-C SDK:

- (void)channelsForGroup:(NSString *)group withCompletion:(PNGroupChannelsAuditCompletionBlock)block;

Parameter	Type	Required	Description
`group`	NSString	Yes	Name of the group from which `channels` should be fetched.
`block`	PNClientChannelsForGroupRequestHandlingBlock	Yes	`Channels` audition process completion `block` which pass two arguments: result - in case of successful request processing data field will contain results of channel groups `channels` audition operation; status - in case if error occurred during request processing.

Basic Usage

Listing Channels :

NSString *channelGroup = @"family";

[self.client channelsForGroup:channelGroup withCompletion:^(PNChannelGroupChannelsResult *result,
                                                            PNErrorStatus *status) {

    if (!status) {

        // Handle downloaded list of chanels using: result.data.channels
    }
    else {

        /**
         Handle channels for group audition 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];
         */
    }
}];

Response

Response objects which is returned by client when Add Channels to Group API is used:

@interface PNChannelGroupChannelsData : PNServiceData

// Registered channels within channel group.
@property (nonatomic, readonly, strong) NSArray<NSString *> *channels;

@end

@interface PNChannelGroupChannelsResult : PNResult

// Stores reference on channel group's channels list audit request processing information.
@property (nonatomic, nonnull, readonly, strong) PNChannelGroupChannelsData *data;

@end

Removing Channels

Description

This function removes the channels from the channel group.

Method(s)

Removing Channels is accomplished by using the following method(s) in the Objective-C SDK:

- (void)removeChannels:(NSArray<NSString *> *)channels fromGroup:(NSString *)group withCompletion:(nullable PNChannelGroupChangeCompletionBlock)block;

Parameter	Type	Required	Description
`channels`	NSArray	Yes	List of channel names which should be removed from group. `If empty list passed whole channel group will be removed.`
`group`	NSString	Yes	Channel group from which channels should be removed.
`block`	PNChannelGroupChangeCompletionBlock	No	Channels removal process completion block which pass only one argument - request processing status to report about how data pushing was successful or not.

Basic Usage

Removing channels :

NSString *channelGroup = @"family";

[self.client removeChannels:@[@"son"] fromGroup:channelGroup
             withCompletion:^(PNAcknowledgmentStatus *status) {

    if (!status.isError) {

        // Handle successful channels list modification for group.
    }
    else {

        /**
         Handle channels list modification for group 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];
         */
    }
}];

Response

Response objects which is returned by client when Remove Channels to Group API is used:

@interface PNAcknowledgmentStatus : PNErrorStatus

@end

Deleting Channel Group

Description

This function removes the channel group.

Method(s)

Deleting Channel Group is accomplished by using the following method(s) in the Objective-C SDK:

- (void)removeChannelsFromGroup:(NSString *)group withCompletion:(nullable PNChannelGroupChangeCompletionBlock)block;

Parameter	Type	Required	Description
`group`	NSString	Yes	Name of the `group` from which all `channels` should be removed.
`block`	PNChannelGroupChangeCompletionBlock	No	Channel group removal process completion `block` which pass only one argument - request processing status to report about how data pushing was successful or not.

Basic Usage

Deleting Channel Group :

NSString *channelGroup = @"family";

[self.client removeChannelsFromGroup:channelGroup withCompletion:^(PNAcknowledgmentStatus *status) {

    if (!status.isError) {

        // Handle successful channel group removal.
    }
    else {

        /**
         Handle channel group removal 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];
         */
    }
}];

Response

Response objects which is returned by client when Remove Channel Group API is used:

@interface PNAcknowledgmentStatus : PNErrorStatus

@end