Presence API for Cocoa Objective-C SDK
Presence enables you to track the online and offline status of users and devices in real time and store custom state information. Presence provides authoritative information on:
- When a user has joined or left a channel
- Who, and how many, users are subscribed to a particular channel
- Which channel(s) an individual user is subscribed to
- Associated state information for these users
Learn more about our Presence feature here.
Here Now
Requires Presence
This method requires that the Presence add-on is enabled for your key in the Admin Portal.
You can obtain information about the current state of a channel including a list of unique user-ids currently subscribed to the channel and the total occupancy count of the channel by calling the hereNowForChannel function in your application.
Cache
This method has a 3 second response cache time.
Method(s)
To call Here Now you can use the following method(s) in the Cocoa SDK:
Here Now with block
- (void)hereNowForChannel:(NSString *)channel
withCompletion:(PNHereNowCompletionBlock)block;
* required
| Parameter | Description |
|---|---|
channel *Type: NSString | Reference on channel for which here now information should be received. |
block *Type: PNHereNowCompletionBlock | Here now processing completion block which pass two arguments: result - in case of successful request processing \c data field will contain results of here now operation; \c status - in case if error occurred during request processing. |
Here Now with verbosity level and block
- (void)hereNowForChannel:(NSString *)channel
withVerbosity:(PNHereNowVerbosityLevel)level
completion:(PNHereNowCompletionBlock)block;
* required
| Parameter | Description |
|---|---|
channel *Type: NSString | Reference on channel for which here now information should be received. |
level *Type: PNHereNowVerbosityLevel | Reference on one of PNHereNowVerbosityLevel fields to instruct what exactly data it expected in response. |
block *Type: PNHereNowCompletionBlock | Here now processing completion block which pass two arguments: result - in case of successful request processing \c data field will contain results of here now operation; \c status - in case if error occurred during request processing. |
Basic Usage
Get a list of UUIDs subscribed to channel
// With PNHereNowUUID client will pull out list of unique identifiers and occupancy information.
[self.client hereNowForChannel: @"my_channel" withVerbosity:PNHereNowUUID
completion:^(PNPresenceChannelHereNowResult *result,
PNErrorStatus *status) {
// Check whether request successfully completed or not.
if (!status) {
/**
Handle downloaded presence information using:
result.data.uuids - list of uuids.
result.data.occupancy - total number of active subscribers.
*/
}
else {
Response
Response objects which is returned by client when Here Now API for channel used:
@interface PNPresenceGlobalHereNowData : PNServiceData
// Active channels list.
@property (nonatomic, readonly, strong) NSDictionary$lt;NSString *, NSDictionary *> *channels;
// Total number of active channels.
@property (nonatomic, readonly, strong) NSNumber *totalChannels;
// Total number of subscribers.
@property (nonatomic, readonly, strong) NSNumber *totalOccupancy;
@end
@interface PNPresenceChannelGroupHereNowData : PNPresenceGlobalHereNowData
@end
Other Examples
Returning State
Requires Presence
This method requires that the Presence add-on is enabled for your key in the Admin Portal.
/**
With PNHereNowState client aside from occupancy and unique identifiers will will pull out
state information associated with them.
*/
[self.client hereNowForChannel: @"my_channel" withVerbosity:PNHereNowState
completion:^(PNPresenceChannelHereNowResult *result,
PNErrorStatus *status) {
if (!status) {
/**
Handle downloaded presence information using:
result.data.uuids - list of uuids. Each uuid entry will have next
fields: "uuid" - identifier and "state" if it
has been provided.
Example Response
{
"status" : 200,
"message" : "OK",
"service" : "Presence",
"uuids" : [
{
"uuid" : "myUUID0"
},
{
"state" : {
"abcd" : {
"age" : 15
}
},
"uuid" : "myUUID1"
Return Occupancy Only
Requires Presence
This method requires that the Presence add-on is enabled for your key in the Admin Portal.
You can return only the occupancy information for a single channel by specifying the channel and setting UUIDs to false:
// With PNHereNowOccupancy client will pull out only occupancy information.
[self.client hereNowForChannel: @"my_channel" withVerbosity:PNHereNowOccupancy
completion:^(PNPresenceChannelHereNowResult *result,
PNErrorStatus *status) {
if (!status) {
/**
Handle downloaded presence information using:
result.data.occupancy - total number of active subscribers.
*/
}
else {
/**
Handle presence audit error. Check 'category' property
Example Response
{
"status": 200,
"message": "OK",
"payload": {
"channels": {
"81d8d989-b95f-443c-a726-04fac323b331": {
"uuids": [ "70fc1140-22b5-4abc-85b2-ff8c17b24d59" ],
"occupancy": 1
},
"81b7a746-d153-49e2-ab70-3037a75cec7e": {
"uuids": [ "91363e7f-584b-49cc-822c-52c2c01e5928" ],
"occupancy": 1
},
"c068d15e-772a-4bcd-aa27-f920b7a4eaa8": {
"uuids": [ "ccfac1dd-b3a5-4afd-9fd9-db11aeb65395" ],
Here Now for Channel Groups
Request information about subscribers on specific channel group. This API method will retrieve the list of UUIDs along with their state for each remote data object and the number of subscribers.
Method(s)
To do Here Now for Channel Groups you can use the following method(s) in the Cocoa SDK:
Here Now for channel groups with block
- (void)hereNowForChannelGroup:(NSString *)group
withCompletion:(PNChannelGroupHereNowCompletionBlock)block;
* required
| Parameter | Description |
|---|---|
group *Type: NSString | Reference on channel group for which here now information should be received. |
block *Type: PNChannelGroupHereNowCompletionBlock | Here now processing completion block which pass two arguments: result - in case of successful request processing data field will contain results of here now operation; status - in case if error occurred during request processing. |
Here Now for channel groups with verbosity level and block
- (void)hereNowForChannelGroup:(NSString *)group
withVerbosity:(PNHereNowVerbosityLevel)level
completion:(PNChannelGroupHereNowCompletionBlock)block;
* required
| Parameter | Description |
|---|---|
group *Type: NSString | Reference on channel group for which here now information should be received. |
level *Type: PNHereNowVerbosityLevel | Reference on one of PNHereNowVerbosityLevel fields to instruct what exactly data it expected in response. |
block *Type: PNChannelGroupHereNowCompletionBlock | Here now processing completion block which pass two arguments: result - in case of successful request processing data field will contain results of here now operation; status - in case if error occurred during request processing. |
Basic Usage
Here Now for channel groups
[self.client hereNowForChannelGroup:@"my_group"
withCompletion:^(PNPresenceChannelGroupHereNowResult *result,
PNErrorStatus *status) {
if (!status) {
/**
Handle downloaded presence information using:
result.data.channels - dictionary with active channels and presence information on
each. Each channel will have next fields: "uuids" - list of
subscribers; occupancy - number of active subscribers.
Each uuids entry has next fields: "uuid" - identifier and
"state" if it has been provided.
result.data.totalChannels - total number of active channels.
result.data.totalOccupancy - total number of active subscribers.
Response
Response objects which is returned by client when Here Now API for channel group used:
@interface PNPresenceGlobalHereNowData : PNServiceData
// Active channels list.
@property (nonatomic, readonly, strong) NSDictionary$lt;NSString *, NSDictionary *> *channels;
// Total number of active channels.
@property (nonatomic, readonly, strong) NSNumber *totalChannels;
// Total number of subscribers.
@property (nonatomic, readonly, strong) NSNumber *totalOccupancy;
@end
@interface PNPresenceChannelGroupHereNowData : PNPresenceGlobalHereNowData
@end
Where Now
Requires Presence
This method requires that the Presence add-on is enabled for your key in the Admin Portal.
You can obtain information about the current list of channels to which a UUID is subscribed to by calling the whereNowUUID function in your application.
Timeout events
If the app is killed/crashes and restarted (or the page containing the PubNub instance is refreshed on the browser) within the heartbeat window no timeout event is generated.
Method(s)
To call whereNowUUID you can use the following method(s) in the Cocoa SDK:
- (void)whereNowUUID:(NSString *)uuid
withCompletion:(PNWhereNowCompletionBlock)block;
* required
| Parameter | Description |
|---|---|
uuid *Type: NSString | Reference on UUID for which request should be performed. |
block *Type: PNWhereNowCompletionBlock | Where now processing completion block which pass two arguments: result - in case of successful request processing data field will contain results of where now operation; status - in case if error occurred during request processing. |
Basic Usage
You simply need to define the uuid and the callback function to be used to send the data to as in the example below.
Get a list of channels a UUID is subscribed to
[self.client whereNowUUID:self.client.uuid withCompletion:^(PNPresenceWhereNowResult *result,
PNErrorStatus *status) {
if (!status) {
// Handle downloaded presence 'where now' information using: result.data.channels
}
else {
/**
Handle presence audit 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.
Response
Response objects which is returned by client when Where Now API is used:
@interface PNPresenceWhereNowData : PNServiceData
// List of channels on which client subscribed.
@property (nonatomic, readonly, strong) NSArray<NSString *> *channels;
@end
@interface PNPresenceWhereNowResult : PNResult
// Stores reference on client presence request processing information.
@property (nonatomic, readonly, strong) PNPresenceWhereNowData *data;
@end
User State
Requires Presence
This method requires that the Presence add-on is enabled for your key in the Admin Portal.
Clients can set a dynamic custom state (score, game state, location) for their users on one or more channels and store it on a channel as long as the user stays subscribed.
The state is not persisted, and when the client disconnects, the state data is lost. For more information, refer to Presence State.
Method(s)
Set State
Set state on channels
- (void)setState:(nullable NSDictionary<NSString *, id> *)state
forUUID:(NSString *)uuid
onChannel:(NSString *)channel
withCompletion:(nullable PNSetStateCompletionBlock)block;
* required
| Parameter | Description |
|---|---|
stateType: NSDictionary | Reference on dictionary which should be bound to uuid on specified channel.If value is nil, state will be removed for uuid on channel. |
uuid *Type: NSString | Reference on unique user identifier for which state should be bound. |
channel *Type: NSString | Name of the channel which will store provided state information for uuid. |
blockType: PNSetStateCompletionBlock | State modification for user on channel processing completion block which pass only one argument - request processing status to report about how data pushing was successful or not. |
Set state on channel groups
- (void)setState:(nullable NSDictionary<NSString *, id> *)state
forUUID:(NSString *)uuid
onChannelGroup:(NSString *)group
withCompletion:(nullable PNSetStateCompletionBlock)block;
* required
| Parameter | Description |
|---|---|
stateType: NSDictionary | Reference on dictionary which should be bound to uuid on specified channel group.If value is nil, state will be removed for uuid on group. |
uuid *Type: NSString | Reference on unique user identifier for which state should be bound. |
group *Type: NSString | Name of channel group which will store provided state information for uuid. |
blockType: PNSetStateCompletionBlock | State modification for user on channel processing completion block which pass only one argument - request processing status to report about how data pushing was successful or not. |
Get State
Get state from channels
- (void)stateForUUID:(NSString *)uuid
onChannel:(NSString *)channel
withCompletion:(PNChannelStateCompletionBlock)block;
* required
| Parameter | Description |
|---|---|
uuid *Type: NSString | Reference on unique user identifier for which state should be retrieved. |
channel *Type: NSString | Name of channel from which state information for uuid will be pulled out. |
block *Type: PNChannelStateCompletionBlock | State audition for user on cahnnel processing completion block which pass two arguments: result - in case of successful request processing data field will contain results of client state retrieve operation; status - in case if error occurred during request processing. |
Get state from channel groups
- (void)stateForUUID:(NSString *)uuid
onChannelGroup:(NSString *)group
withCompletion:(PNChannelGroupStateCompletionBlock)block;
* required
| Parameter | Description |
|---|---|
uuid *Type: NSString | Reference on unique user identifier for which state should be retrieved. |
group *Type: NSString | Name of channel group from which state information for uuid will be pulled out. |
block *Type: PNChannelGroupStateCompletionBlock | State audition for user on cahnnel group processing completion block which pass two arguments: result - in case of successful request processing data field will contain results of client state retrieve operation; status - in case if error occurred during request processing. |
Basic Usage
Set State
[self.client setState: @{@"Key": @"Value"} forUUID:self.client.uuid onChannel: @"my_channel"
withCompletion:^(PNClientStateUpdateStatus *status) {
if (!status.isError) {
// Client state successfully modified on specified channel.
}
else {
/**
Handle client state modification 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.
Get State
[self.client stateForUUID:self.client.uuid onChannel:@"chat"
withCompletion:^(PNChannelClientStateResult *result, PNErrorStatus *status) {
if (!status) {
// Handle downloaded state information using: result.data.state
}
else{
/**
Handle client state audit 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.
Response
Set State
Response objects which is returned by client when Set State API for channels used:
@interface PNClientStateUpdateData : PNChannelClientStateData
@end
@interface PNClientStateUpdateStatus : PNErrorStatus
// Stores reference on client state for channel request processing information.
@property (nonatomic, nonnull, readonly, strong) PNClientStateUpdateData *data;
@end
Get State
Response objects which is returned by client when Get State API for channel used:
@interface PNChannelClientStateData : PNServiceData
// User-provided client state information.
@property (nonatomic, readonly, strong) NSDictionary<NSString *, id> *state;
@end
@interface PNChannelClientStateResult : PNResult
// Stores reference on client state for channel request processing information.
@property (nonatomic, readonly, strong) PNChannelClientStateData *data;
@end
Response objects which is returned by client when Get State API for channel group used:
@interface PNChannelGroupClientStateData : PNServiceData
// Multi channel client state information.
@property (nonatomic, readonly, strong) NSDictionary<NSString *, NSDictionary *> *channels;
@end
@interface PNChannelGroupClientStateResult : PNResult
// Stores reference on client state for channel group request processing information.
@property (nonatomic, readonly, strong) PNChannelGroupClientStateData *data;
@end
User State (Builder Pattern)
Requires Presence
This method requires that the Presence add-on is enabled for your key in the Admin Portal.
The state API is used to set/get key/value pairs specific to a subscriber uuid.
State information is supplied as a JSON object of key/value pairs.
Method(s)
Set State
state()
.set()
.uuid(NSString *)
.state(NSDictionary *)
.channels(NSArray<NSString *> *)
.channelGroups(NSArray<NSString *> *)
.performWithCompletion(nullable PNSetStateCompletionBlock);
* required
| Parameter | Description |
|---|---|
uuidType: NSString | Unique user identifier for which state should be bound. Current PubNub user ID will be used by default if not set or set to nil. |
stateType: NSDictionary | Data which should be bound to specified uuid on channels / channelGroups. |
channelsType: NSArray <NSString *> | List of the channel names which will store provided state information for uuid. Not required if channelGroups is set. |
channelGroupsType: NSArray <NSString *> | List of channel group names which will store provided state information for uuid. Not required if channels is set. |
completionType: PNSetStateCompletionBlock | State modification for user on channel / channel group completion block which pass only one argument - request status reports state change was successful or not (errorData contains error information in case of failure). |
Optional arguments
This method uses the builder pattern, you can remove the arguments which are optional.
Get State
state()
.audit()
.uuid(NSString *)
.channels(NSArray<NSString *> *)
.channelGroups(NSArray<NSString *> *)
.performWithCompletion(PNGetStateCompletionBlock);
* required
| Parameter | Description |
|---|---|
uuidType: NSString | Unique user identifier for which state should be retrieved. Current PubNub user ID will be used by default if not set or set to nil. |
channelsType: NSArray<NSString *> | List of the channel names from which state information for uuid will be pulled out. Not required if channelGroups is set. |
channelGroupsType: NSArray<NSString *> | List of channel group names from which state information for uuid will be pulled out. Not required if channels is set. |
completion *Type: PNGetStateCompletionBlock | State audition for user on channel / channel group completion block which pass two arguments: result - in case of successful request processing data field will contain results of client state retrieve operation; status - in case of error occurred during request processing. |
Optional arguments
This method uses the builder pattern, you can remove the arguments which are optional.
Basic Usage
Set State
self.client.state().set().state(@{@"state": @"test"})
.channels(@[@"channel1", @"channel12"])
.channelGroups(@[@"group1", @"group2"])
.performWithCompletion(^(PNClientStateUpdateStatus *status) {
if (!status.isError) {
// Client state successfully modified on specified channels and groups.
} else {
/**
Handle client state modification 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]
Get State
self.client.state().audit().uuid(@"PubNub")
.channels(@[@"channel1", @"channel12"])
.channelGroups(@[@"group1", @"group2"])
.performWithCompletion(^(PNClientStateGetResult *result, PNErrorStatus *status) {
if (!status.isError) {
// Handle downloaded state information using: result.data.channels
} else {
/**
Handle client state audit 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]