Channel Groups API for Objective-C SDK

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

Channel group operations

You can't publish to a channel group. You can only subscribe to it. To publish within the channel group, you need to publish to each channel individually.

Add channels to a channel group

Requires Stream Controller add-on

This method requires that the Stream Controller add-on is enabled for your key in the PubNub Admin Portal. See Enable the features your app calls.

This function adds channels to a channel group.

Method(s)

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

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

* required

Parameter	Description
channels * Type: NSArray	List of channel names which should be added to the group.
group * Type: NSString	Name of the group into which channels should be added.
block Type: PNChannelGroupChangeCompletionBlock	Channels addition process completion block which pass only one argument - request processing status to report about how data pushing was successful or not.

Sample code

Add channels

1// Initialize PubNub client with your keys
2PNConfiguration *configuration = [PNConfiguration configurationWithPublishKey:@"demo" 
3                                                                 subscribeKey:@"demo"
4                                                                       userID:@"testUser"];
5PubNub *client = [PubNub clientWithConfiguration:configuration];
6

7// Define channel group and channels to add
8NSString *channelGroup = @"family";
9NSArray *channels = @[@"wife", @"husband", @"children"];
10

11NSLog(@"Adding channels %@ to channel group: %@", channels, channelGroup);
12

13// Add channels to the channel group
14PNChannelGroupManageRequest *request = [PNChannelGroupManageRequest requestToAddChannels:channels 
15                                                                          toChannelGroup:channelGroup];
16

17[client manageChannelGroupWithRequest:request completion:^(PNAcknowledgmentStatus *status) {
18    if (!status.isError) {
19        NSLog(@"Channels successfully added to channel group!");
20        
21        // Verify by listing channels in the group
22        PNChannelGroupFetchRequest *request = [PNChannelGroupFetchRequest requestWithChannelGroup:channelGroup];
23        [client fetchChannelsForChannelGroupWithRequest:request
24            completion:^(PNChannelGroupChannelsResult *result, PNErrorStatus *status) {
25            if (!status.isError) {
26                NSLog(@"Channels in group '%@': %@", channelGroup, result.data.channels);
27            } else {
28                NSLog(@"Error listing channels in group: %@", status.errorData.information);
29            }
30        }];
31    } else {
32        NSLog(@"Error adding channels to group: %@", status.errorData.information);
33        NSLog(@"Error category: %@", @(status.category));
34    }
35}];

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Response

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

1@interface PNAcknowledgmentStatus : PNErrorStatus
2

3@end

List channels in a 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. See Enable the features your app calls.

This function lists all channels in a channel group.

Method(s)

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

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

* required

Parameter	Description
group * Type: NSString	Name of the group from which channels should be fetched.
block * Type: PNClientChannelsForGroupRequestHandlingBlock	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.

Sample code

List channels

1NSString *channelGroup = @"family";

1[self.client channelsForGroup:channelGroup withCompletion:^(PNChannelGroupChannelsResult *result,
2                                                            PNErrorStatus *status) {
3

4    if (!status) {
5

6        // Handle downloaded list of chanels using: result.data.channels
7    }
8    else {
9

10        /**
11         Handle channels for group audition error. Check 'category' property
12         to find out possible reason because of which request did fail.
13         Review 'errorData' property (which has PNErrorData data type) of status
14         object to get additional information about issue.
15

16         Request can be resent using: [status retry];
17         */
18    }
19}];

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Response

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

1@interface PNChannelGroupChannelsData : PNServiceData
2

3// Registered channels within channel group.
4@property (nonatomic, readonly, strong) NSArray<NSString *> *channels;
5

6@end
7

8@interface PNChannelGroupChannelsResult : PNResult
9

10// Stores reference on channel group's channels list audit request processing information.
11@property (nonatomic, nonnull, readonly, strong) PNChannelGroupChannelsData *data;
12

13@end

Remove channels from a 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. See Enable the features your app calls.

This function removes channels from a channel group.

Method(s)

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

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

* required

Parameter	Description
channels * Type: NSArray	List of channel names which should be removed from group. If empty list passed whole channel group will be removed.
group * Type: NSString	Channel group from which channels should be removed.
block Type: PNChannelGroupChangeCompletionBlock	Channels removal process completion block which pass only one argument - request processing status to report about how data pushing was successful or not.

Sample code

Remove channels

1NSString *channelGroup = @"family";

1[self.client removeChannels:@[@"son"] fromGroup:channelGroup
2             withCompletion:^(PNAcknowledgmentStatus *status) {
3

4    if (!status.isError) {
5

6        // Handle successful channels list modification for group.
7    }
8    else {
9

10        /**
11         Handle channels list modification for group error. Check 'category' property
12         to find out possible reason because of which request did fail.
13         Review 'errorData' property (which has PNErrorData data type) of status
14         object to get additional information about issue.
15

16         Request can be resent using: [status retry];
17         */
18    }
19}];

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Response

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

1@interface PNAcknowledgmentStatus : PNErrorStatus
2

3@end

Delete a 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. See Enable the features your app calls.

This function deletes a channel group.

Method(s)

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

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

* required

Parameter	Description
group * Type: NSString	Name of the group from which all channels should be removed.
block Type: PNChannelGroupChangeCompletionBlock	Channel group removal process completion block which pass only one argument - request processing status to report about how data pushing was successful or not.

Sample code

Deleting Channel Group :

1NSString *channelGroup = @"family";

1[self.client removeChannelsFromGroup:channelGroup withCompletion:^(PNAcknowledgmentStatus *status) {
2

3    if (!status.isError) {
4

5        // Handle successful channel group removal.
6    }
7    else {
8

9        /**
10         Handle channel group removal error. Check 'category' property
11         to find out possible reason because of which request did fail.
12         Review 'errorData' property (which has PNErrorData data type) of status
13         object to get additional information about issue.
14

15         Request can be resent using: [status retry];
16         */
17    }
18}];

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Response

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

1@interface PNAcknowledgmentStatus : PNErrorStatus
2

3@end