Configuration API for PubNub Objective-C SDK

Objective-C complete API reference for building real-time applications on PubNub, including basic usage and sample code.

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Configuration

Description

PNConfiguration instance is storage for user-provided information which describe further PubNub client behavior. Configuration instance contain additional set of properties which allow to perform precise PubNub client configuration.

Method(s)

To create configuration instance you can use the following function in the Objective-C SDK:

+ (instancetype)configurationWithPublishKey:(NSString *)publishKey subscribeKey:(NSString *)subscribeKey;

Parameter	Type	Required	Description
`publishKey`	NSString	Yes	Key which allow client to use data push API.
`subscribeKey`	NSString	Yes	Key which allow client to subscribe on live feeds pushed from PubNub service.
`heartbeatNotificationOptions`	PNHeartbeatNotificationOptions	No	These are bitmask options, they can be combined. When client instances are notified about heartbeat operations, this happens through the `PNObjectEventListener` callback for statuses. `PNHeartbeatNotifySuccess`: explicitly tells client to notify on successful heartbeat operations. `PNHeartbeatNotifyFailure`: explicitly tells client to notify on failed heartbeat operations (default is only this option) `PNHeartbeatNotifyAll`: This is a combination of `PNHeartbeatNotifySuccess` and `PNHeartbeatNotifyFailure` `PNHeartbeatNotifyNone`: This means the client will not provide any callback notifications for heartbeat operations.
`stripMobilePayload`	BOOL	No	Stores whether client should strip out received messages (real-time and history) from data which has been appended by client (like mobile payload for push notifications).
`cipherKey`	NSString	No	`Key` which is used to encrypt `messages` pushed to `PubNub` service and decrypt `messages` received from live feeds on which client subscribed at this moment.
`subscribeMaximumIdleTime`	NSTimeInterval	No	Maximum number of seconds which client should wait for events from live feed. Default `310`.
`nonSubscribeRequestTimeout`	NSTimeInterval	No	Number of seconds which is used by client during non-subscription operations to check whether response potentially failed with `timeout` or not. Default `10`.
`presenceHeartbeatValue`	NSInteger	No	Number of seconds which is used by server to track whether client still subscribed on remote data objects live feed or not.
`presenceHeartbeatInterval`	NSInteger	No	Number of seconds which is used by client to issue heartbeat requests to `PubNub` service.
`keepTimeTokenOnListChange`	BOOL	No	Whether client should keep previous timetoken when subscribe on new set of remote data objects live feeds. Default `YES`.
`catchUpOnSubscriptionRestore`	BOOL	No	Whether client should try to catch up for events which occurred on previously subscribed remote data objects feed while client was off-line. Default `YES`.
`applicationExtensionSharedGroupIdentifier`	NSString	No	Reference on group identifier which is used to share request cache between application extension and it's containing application. This property should be set to valid registered group only if `PubNub` client is used inside of application's extension (iOS 8.0+, macOS 10.10+).
`requestMessageCountThreshold`	NSUInteger	No	Number of maximum expected messages from `PubNub` service in single response.
`maximumMessagesCacheSize`	NSUInteger	No	Messages de-duplication cache size Default `100`.
`completeRequestsBeforeSuspension`	BOOL	No	Whether client should try complete all API call which is done before application will be completely suspended. Default `YES`.
`suppressLeaveEvents`	BOOL	No	If `YES`, the client shouldn't send presence leave events during the unsubscribe process.
`origin`	NSString	No	If a custom domain is required, SDK accepts it here.
`useRandomInitializationVector`	BOOL	No	When `YES` the initialization vector (IV) is random for all requests (not just for file upload). When `NO` the IV is hard-coded for all requests except for file upload. By default, using the random initialization vector is enabled.

Disabling random initialization vector

Disable random initialization vector (IV) only for backward compatibility (<4.16.0) with existing applications. Never disable random IV on new applications.

Basic Usage

Note

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. Not setting the UUID can significantly impact your billing if your account uses the Monthly Active Users (MAUs) based pricing model, and can also lead to unexpected behavior if you have Presence enabled.

PNConfiguration *config = [PNConfiguration configurationWithPublishKey:@"demo"
                                                          subscribeKey:@"demo"];
config.uuid = @"myUniqueUUID";
self.client = [PubNub clientWithConfiguration:config];
[self.client addListener:self];

Returns

Configured and ready to use client configuration instance.

Other Examples

Configure heartbeat notifications

PNConfiguration:

PNConfiguration *config = [PNConfiguration configurationWithPublishKey:@"<pub key>" subscribeKey:@"<sub key>"];
/**
 This is where you need to adjust the PNConfiguration object for the types of heartbeat notifications you want.
 This is a bitmask of options located at https://github.com/pubnub/objective-c/blob/1f1c7a41a3bd8c32b644a6ad98fe179d45397c2b/PubNub/Misc/PNStructures.h#L24
 */
config.heartbeatNotificationOptions = PNHeartbeatNotifyAll;

self.client = [PubNub clientWithConfiguration:config];
[self.client addListener:self];

Listener:

- (void)client:(PubNub *)client didReceiveStatus:(PNStatus *)status {

    if (status.operation == PNHeartbeatOperation) {

        /**
         Heartbeat operations can in fact have errors, so it is important to check first for an error.
         For more information on how to configure heartbeat notifications through the status
         PNObjectEventListener callback, consult http://www.pubnub.com/docs/sdks/objective-c/api-reference/configuration#configuration_basic_usage
         */

        if (!status.isError) { /* Heartbeat operation was successful. */ }
        else { /* There was an error with the heartbeat operation, handle here. */ }
    }
}

Initialization

To include PubNub SDK in your project you need to use CocoaPods.

Install CocoaPods gem by following the procedure defined under How to Get It To add the PubNub SDK to your project with CocoaPods, there are four basic tasks to complete which are covered below:

Create a new Xcode project.

Create a Podfile in a new Xcode project root folder

pod init

platform :ios, '9.0'

target 'application-target-name' do
    use_frameworks!

    pod "PubNub", "~> 4"
end

If you have any other pods you'd like to include, or if you have other targets you'd to add (like a test target) add those entries to this Podfile as well. See the CocoaPods documentation for more information on Podfile configuration.

Install your pods by running pod install via the command line from the directory that contains your Podfile.

Note

After installing your Pods, you should only be working within the workspace generated by CocoaPods or specified by you in Podfile. Always open the newly generated workspace file, not the original project file!

To be able to use PubNub SDK within your application code you need to import it. Import PubNub SDK headers in implementation files for classes where you need to use it using this import statement:

#import <PubNub/PubNub.h>

Complete application delegate configuration

Add the PNObjectEventListener protocol to AppDelegate in implementation file to anonymous category:

Note

#import <PubNub/PubNub.h>

@interface AppDelegate () <PNObjectEventListener>

// Stores reference on PubNub client to make sure what it won't be released.
@property (nonatomic, strong) PubNub *client;

@end

Description

This function is used for initializing the PubNub Client API context. This function must be called before attempting to utilize any API functionality in order to establish account level credentials such as publishKey and subscribeKey.

Method(s)

To Initialize PubNub you can use the following method(s) in the Objective-C SDK:

```
+ (instancetype)clientWithConfiguration:(PNConfiguration *)configuration;
```
Parameter Type Required Description

configuration PNConfiguration Yes Reference on instance which store all user-provided information about how client should operate and handle events.

+ (instancetype)clientWithConfiguration:(PNConfiguration *)configuration callbackQueue:(dispatch_queue_t)callbackQueue;

Parameter	Type	Required	Description
`configuration`	PNConfiguration	Yes	Reference on instance which store all user-provided information about how client should operate and handle events.
`callbackQueue`	dispatch_queue_t	No	Reference on queue which should be used by client for completion block and delegate calls.

Basic Usage

Initialize the PubNub client API:

Note

PNConfiguration *configuration = [PNConfiguration configurationWithPublishKey:@"demo"
                                                                 subscribeKey:@"demo"];
configuration.TLSEnabled = YES;
configuration.uuid = @"myUniqueUUID";
self.client = [PubNub clientWithConfiguration:configuration];

Returns

It returns the PubNub instance for invoking PubNub APIs like publish, subscribeToChannels, historyForChannel, hereNowForChannel, etc.

Other Examples

Initialize the client:

Note

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. Not setting the UUID can significantly impact your billing if your account uses the Monthly Active Users (MAUs) based pricing model, and can also lead to unexpected behavior if you have Presence enabled.
```
PNConfiguration *configuration = [PNConfiguration configurationWithPublishKey:@"demo"
                                                                 subscribeKey:@"demo"];
configuration.uuid = @"myUniqueUUID";
self.client = [PubNub clientWithConfiguration:configuration];
```
Initialization for a Read-Only client:

In the case where a client will only read messages and never publish to a channel, you can simply omit the publishKey when initializing the client:

Note

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. Not setting the UUID can significantly impact your billing if your account uses the Monthly Active Users (MAUs) based pricing model, and can also lead to unexpected behavior if you have Presence enabled.
```
PNConfiguration *configuration = [PNConfiguration configurationWithPublishKey:@""
                                                                 subscribeKey:@"demo"];
self.client = [PubNub clientWithConfiguration:configuration];
```
Use a custom UUID

Set a custom UUID to identify your users.

Note

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. Not setting the UUID can significantly impact your billing if your account uses the Monthly Active Users (MAUs) based pricing model, and can also lead to unexpected behavior if you have Presence enabled.
```
PNConfiguration *configuration = [PNConfiguration configurationWithPublishKey:@"myPublishKey"
                                                                 subscribeKey:@"mySubscribeKey"];
configuration.uuid = @"myUniqueUUID";
self.client = [PubNub clientWithConfiguration:configuration];
```

Event Listeners

Description

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

Listeners should be added before calling the method.

Adding Listeners

Listener's class should conform to PNEventsListener protocol to have access to available callbacks.

// Adding listener.
[pubnub addListener:self];

// Callbacks listed below.

- (void)client:(PubNub *)pubnub didReceiveMessage:(PNMessageResult *)message {
    NSString *channel = message.data.channel; // Channel on which the message has been published
    NSString *subscription = message.data.subscription; // Wild-card channel or channel on which PubNub client actually subscribed
    NSNumber *timetoken = message.data.timetoken; // Publish timetoken
    id msg = message.data.message; // Message payload
    NSString *publisher = message.data.publisher; // Message publisher
}

- (void)client:(PubNub *)pubnub didReceiveSignal:(PNSignalResult *)signal {
    NSString *channel = message.data.channel; // Channel on which the signal has been published
    NSString *subscription = message.data.subscription; // Wild-card channel or channel on which PubNub client actually subscribed
    NSNumber *timetoken = message.data.timetoken; // Signal timetoken
    id msg = message.data.message; // Signal payload
    NSString *publisher = message.data.publisher; // Signal publisher
}

- (void)client:(PubNub *)pubnub didReceiveMessageAction:(PNMessageActionResult *)action {
    NSString *channel = action.data.channel; // Channel on which the message has been published
    NSString *subscription = action.data.subscription; // Wild-card channel or channel on which PubNub client actually subscribed
    NSString *event = action.data.event; // Can be: added or removed
    NSString *type = action.data.action.type; // Message action type
    NSString *value = action.data.action.value; // Message action value
    NSNumber *messageTimetoken = action.data.action.messageTimetoken; // Timetoken of the original message
    NSNumber *actionTimetoken = action.data.action.actionTimetoken; // Timetoken of the message action
    NSString *uuid = action.data.action.uuid; // UUID of user which added / removed message action
}

- (void)client:(PubNub *)pubnub didReceivePresenceEvent:(PNPresenceEventResult *)event {
    NSString *channel = message.data.channel; // Channel on which presence changes
    NSString *subscription = message.data.subscription; // Wild-card channel or channel on which PubNub client actually subscribed
    NSString *presenceEvent = event.data.presenceEvent; // Can be: join, leave, state-change, timeout or interval
    NSNumber *occupancy = event.data.presence.occupancy; // Number of users subscribed to the channel (not available for state-change event)
    NSNumber *timetoken = event.data.presence.timetoken; // Presence change timetoken
    NSString *uuid = event.data.presence.uuid; // UUID of user for which presence change happened

    // Only for 'state-change' event
    NSDictionary *state = event.data.presence.state; // User state (only for state-change event)

    // Only for 'interval' event
    NSArray<NSString *> *join = event.data.presence.join; // UUID of users which recently joined channel
    NSArray<NSString *> *leave = event.data.presence.leave; // UUID of users which recently leaved channel
    NSArray<NSString *> *timeout = event.data.presence.timeout; // UUID of users which recently timed out on channel
}

- (void)client:(PubNub *)pubnub didReceiveObjectEvent:(PNObjectEventResult *)event {
    NSString *channel = event.data.channel; // Channel to which the event belongs
    NSString *subscription = event.data.subscription; // Wild-card channel or channel on which PubNub client actually subscribed
    NSString *event = event.data.event; // Can be: set or delete
    NSString *type = event.data.type; // Entity type: channel, uuid or membership
    NSNumber *timestamp = event.data.timestamp; // Event timestamp

    PNChannelMetadata *channelMetadata = event.data.channelMetadata; // Updated channel metadata (only for channel entity type)
    PNUUIDMetadata *uuidMetadata = event.data.uuidMetadata; // Updated channel metadata (only for uuid entity type)
    PNMembership *membership = event.data.membership; // Updated channel metadata (only for membership entity type)
}

- (void)client:(PubNub *)pubnub didReceiveFileEvent:(PNFileEventResult *)event {
    NSString *channel = event.data.channel; // Channel to which file has been uploaded
    NSString *subscription = event.data.subscription; // Wild-card channel or channel on which PubNub client actually subscribed
    id message = event.data.message; // Message added for uploaded file
    NSString *publisher = event.data.publisher; // UUID of file uploader
    NSURL *fileDownloadURL = event.data.file.downloadURL; // URL which can be used to download file
    NSString *fileIdentifier = event.data.file.identifier; // Unique file identifier
    NSString *fileName = event.data.file.name; // Name with which file has been stored remotely
}

- (void)client:(PubNub *)pubnub didReceiveStatus:(PNStatus *)status {
    PNStatusCategory category = status.category; // One of PNStatusCategory fields to identify status of operation processing
    PNOperationType operation = status.operation; // One of PNOperationType fields to identify for which operation status received
    BOOL isError = status.isError; // Whether any kind of error happened.
    NSInteger statusCode = status.statusCode; // Related request processing status code
    BOOL isTLSEnabled = status.isTLSEnabled; // Whether secured connection enabled
    NSString *uuid = status.uuid; // UUID which configured for passed client
    NSString *authKey = status.authKey; // Auth key configured for passed client
    NSString *origin = status.origin; // Origin against which request has been sent
    NSURLRequest *clientRequest = status.clientRequest; // Request which has been used to send last request (may be nil)
    BOOL willAutomaticallyRetry = status.willAutomaticallyRetry; // Whether client will try to perform automatic retry

    // Following information available when operation == PNSubscribeOperation, because status is PNSubscribeStatus instance in this case
    PNSubscribeStatus *subscribeStatus = (PNSubscribeStatus *)status;
    NSNumber *currentTimetoken = subscribeStatus.currentTimetoken; // Timetoken which has been used for current subscribe request
    NSNumber *lastTimeToken = subscribeStatus.lastTimeToken; // Timetoken which has been used for previous subscribe request
    NSArray<NSString *> *subscribedChannels = subscribeStatus.subscribedChannels; // List of channels on which client currently subscribed
    NSArray<NSString *> *subscribedChannelGroups = subscribeStatus.subscribedChannelGroups; // List of channel groups on which client currently subscribed
    NSString *channel = subscribeStatus.data.channel; // Name of channel for which status has been received
    NSString *subscription = subscribeStatus.data.subscription; // Wild-card channel or channel on which PubNub client actually subscribed
    NSNumber *timetoken = subscribeStatus.data.timetoken; // Timetoken at which event arrived
    NSDictionary *userMetadata = subscribeStatus.data.userMetadata; // Metadata / envelope which has been passed along with event

    // Following information available when isError == YES, because status is PNErrorStatus instance in this case
    PNErrorStatus *errorStatus = (PNErrorStatus *)status;
    id associatedObject = errorStatus.associatedObject; // Data which may contain related information (not decrypted message for example)
    NSArray<NSString *> *erroredChannels = errorStatus.errorData.channels; // List of channels for which error reported (mostly because of PAM)
    NSArray<NSString *> *erroredChannelGroups = errorStatus.errorData.channelGroups; // List of channel groups for which error reported (mostly because of PAM)
    NSString *errorInformation = errorStatus.errorData.information; // Stringified information about error
    id errorData = errorStatus.errorData.data; // Additional error information from PubNub service
}

Removing Listeners

[pubnub removeListener:self]

Handling Disconnects

SDK performs automated re-connections and call status handler to report back. This will happen forever, but user may decide to stop it.

- (void)client:(PubNub *)pubnub didReceiveStatus:(PNStatus *)status {
  if (status.isError && status.willAutomaticallyRetry) {
    // Stop automatic retry attempts.
    [status cancelAutomaticRetry];
  }
}

Listener status events

Category	Description
`PNAcknowledgmentCategory`	Reported operation request acknowledgment status.
`PNAccessDeniedCategory`	PAM permission failure.
`PNTimeoutCategory`	Server didn't respond in time for reported operation request.
`PNNetworkIssuesCategory`	No connection to Internet.
`PNRequestMessageCountExceededCategory`	The SDK announces this error if `requestMessageCountThreshold` is set, and the number of messages received from PubNub (in-memory cache messages) exceeds the threshold.
`PNConnectedCategory`	The SDK subscribed to new channels / channel groups.
`PNReconnectedCategory`	The SDK was able to reconnect to PubNub.
`PNDisconnectedCategory`	The SDK unsubscribed from channels / channel groups.
`PNUnexpectedDisconnectCategory`	The SDK unexpectedly lost ability to receive live updated from PubNub.
`PNRequestURITooLongCategory`	Reported operation request URI too long (too many channels / channel groups).
`PNMalformedFilterExpressionCategory`	The SDK has been configured with malformed filtering expression.
`PNMalformedResponseCategory`	The SDK received unexpected PubNub service response.
`PNDecryptionErrorCategory`	The SDK unable to decrypt received message using configured `cipherKey`.
`PNTLSConnectionFailedCategory`	The SDK unable to establish secured connection.
`PNTLSUntrustedCertificateCategory`	The SDK unable to check certificates trust chain.

UUID

Description

This function is used to set a user ID on the fly.

Method(s)

To set UUID you can use the following method(s) in Objective-C SDK:

@property (nonatomic, copy, setter = setUUID:) NSString *uuid;

Basic Usage

Note

// User authorized and we need to update used UUID
PNConfiguration *configuration = self.client.currentConfiguration;
configuration.uuid = @"myUniqueUUID";

__weak __typeof(self) weakSelf = self;
[self.client copyWithConfiguration:configuration completion:^(PubNub *client) {

    weakSelf.client = client;
}];

Other Examples

Creating a function to subscribe a unique channel name:

/**
 Subscription process results arrive to listener which should adopt to
 PNObjectEventListener protocol and registered using:
 */
[self.client addListener:self];
[self.client subscribeToChannels:@[[NSUUID UUID].UUIDString] withPresence:NO];

// Handle new message from one of channels on which client has been subscribed.
- (void)client:(PubNub *)client didReceiveMessage:(PNMessageResult *)message {

    // Handle new message stored in message.data.message
    if (![message.data.channel isEqualToString:message.data.subscription]) {

        // Message has been received on channel group stored in message.data.subscription.
    }
    else {

        // Message has been received on channel stored in message.data.channel.
    }

    NSLog(@"Received message: %@ on channel %@ at %@", message.data.message,
          message.data.channel, message.data.timetoken);
}

// Handle subscription status change.
- (void)client:(PubNub *)client didReceiveStatus:(PNStatus *)status {

    if (status.operation == PNSubscribeOperation) {

        // Check whether received information about successful subscription or restore.
        if (status.category == PNConnectedCategory || status.category == PNReconnectedCategory) {

            // Status object for those categories can be casted to `PNSubscribeStatus` for use below.
            PNSubscribeStatus *subscribeStatus = (PNSubscribeStatus *)status;
            if (subscribeStatus.category == PNConnectedCategory) {

                // This is expected for a subscribe, this means there is no error or issue whatsoever.
            }
            else {

                /**
                 This usually occurs if subscribe temporarily fails but reconnects. This means there was
                 an error but there is no longer any issue.
                 */
            }
        }
        else if (status.category == PNUnexpectedDisconnectCategory) {

            /**
             This is usually an issue with the internet connection, this is an error, handle
             appropriately retry will be called automatically.
             */
        }
        // Looks like some kind of issues happened while client tried to subscribe or disconnected from
        // network.
        else {

            PNErrorStatus *errorStatus = (PNErrorStatus *)status;
            if (errorStatus.category == PNAccessDeniedCategory) {

                /**
                 This means that PAM does allow this client to subscribe to this channel and channel group
                 configuration. This is another explicit error.
                 */
            }
            else {

                /**
                 More errors can be directly specified by creating explicit cases for other error categories
                 of `PNStatusCategory` such as: `PNDecryptionErrorCategory`,
                 `PNMalformedFilterExpressionCategory`, `PNMalformedResponseCategory`, `PNTimeoutCategory`
                 or `PNNetworkIssuesCategory`
                 */
            }
        }
    }
}

Initializing with a custom uuid:

Note

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. Not setting the UUID can significantly impact your billing if your account uses the Monthly Active Users (MAUs) based pricing model, and can also lead to unexpected behavior if you have Presence enabled.
```
PNConfiguration *configuration = self.client.currentConfiguration;
configuration.uuid = @"myUniqueUUID";

__weak __typeof(self) weakSelf = self;
[self.client copyWithConfiguration:configuration completion:^(PubNub *client) {

    // Store reference on new client with updated configuration.
    weakSelf.client = client;
}];
```

Creating a unique auth_key for PAM on initialization:

PNConfiguration *configuration = self.client.currentConfiguration;
configuration.authKey = [NSUUID UUID].UUIDString.lowercaseString;

__weak __typeof(self) weakSelf = self;
[self.client copyWithConfiguration:configuration completion:^(PubNub *client) {

    // Store reference on new client with updated configuration.
    weakSelf.client = client;
}];

Authentication Key

Description

Setter and getter for users auth key.

Method(s)

@property (nonatomic, nullable, copy) NSString *authKey;

@property (nonatomic, copy, setter = setUUID:) NSString *uuid;

Basic Usage

Set Auth Key

PNConfiguration *configuration = self.client.currentConfiguration;
configuration.authKey = @"my_new_authkey";

__weak __typeof(self) weakSelf = self;
[self.client copyWithConfiguration:configuration completion:^(PubNub *client) {

    // Store reference on new client with updated configuration.
    weakSelf.client = client;
}];

Get Auth Key

// Request current client configuration and pull out authorisation key from it.
NSString *authorizationKey = self.client.currentConfiguration.authKey;

Returns

Get Auth key returns the current authentication key.

Filter Expression

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

Stream filtering allows a subscriber to apply a filter to only receive messages that satisfy the conditions of the filter. The message filter is set by the subscribing client(s) but it is applied on the server side thus preventing unwanted messages (those that do not meet the conditions of the filter) from reaching the subscriber.

To set/get filters you can use the following property. To learn more about filtering, refer to the Publish Messages documentation.

Method(s)

@property (nonatomic, nullable, copy) NSString *filterExpression;

Basic Usage

Set Filter Expression

Note

PNConfiguration *configuration = [PNConfiguration configurationWithPublishKey:@"demo"
                                                                 subscribeKey:@"demo"];
self.client = [PubNub clientWithConfiguration:configuration];
self.client.filterExpression = @"(senderID=='PubNub')";

Get Filter Expression

NSLog(@"Filtering expression: %@", self.client.filterExpression);

Returns

Get Filter Expression returns the Current filtering expression.
Set Filter Expression:

Warning

If filter expression is malformed, PNObjectEventListener won't receive any messages and presence events from service (only error status).