Publish/Subscribe API for PubNub Angular2 SDK

Publish

Description

The publish() function is used to send a message to all subscribers of a channel. To publish a message you must first specify a valid publishKey at initialization. A successfully published message is replicated across the PubNub Real-Time Network and sent simultaneously to all subscribed clients on a channel.

Messages in transit can be secured from potential eavesdroppers with SSL/TLS by setting ssl to true during initialization.

Publish Anytime

It's not required to be subscribed to a channel in order to publish to that channel.

Message Data:

The message argument can contain any JSON serializable data, including: Objects, Arrays, Ints and Strings. data should not contain special Angular2 V4 classes or functions as these will not serialize. String content can include any single-byte or multi-byte UTF-8 character.

Don't Use JSON.stringify!

It is important to note that you should not use JSON.stringify() when sending signals/messages via PubNub. Why? Because the serialization is done for you automatically. Instead just pass the full object as the message payload. PubNub takes care of everything for you.

Message Size:

The maximum number of characters per message is 32 KiB by default. The maximum message size is based on the final escaped character count, including the channel name. An ideal message size is under 1800 bytes which allows a message to be compressed and sent using single IP datagram (1.5 KiB) providing optimal network performance.

If the message you publish exceeds the configured size, you will receive the following message:

Message Too Large Error
["PUBLISHED",[0,"Message Too Large","13524237335750949"]]

For further details, check Calculating Message Payload Size Before Publish.

Message Publish Rate:

Messages can be published as fast as bandwidth conditions will allow. There is a soft limit based on max throughput since messages will be discarded if the subscriber can't keep pace with the publisher.

For example, if 200 messages are published simultaneously before a subscriber has had a chance to receive any messages, the subscriber may not receive the first 100 messages because the message queue has a limit of only 100 messages stored in memory.

Publishing to Multiple Channels:

It is not possible to publish a message to multiple channels simultaneously. The message must be published to one channel at a time.

Publishing Messages Reliably:

There are some best practices to ensure messages are delivered when publishing to a channel:

  • Publish to any given channel in a serial manner (not concurrently).
  • Check that the return code is success (e.g. [1,"Sent","136074940..."])
  • Publish the next message only after receiving a success return code.
  • If a failure code is returned ([0,"blah","<timetoken>"]), retry the publish.
  • Avoid exceeding the in-memory queue's capacity of 100 messages. An overflow situation (aka missed messages) can occur if slow subscribers fail to keep up with the publish pace in a given period of time.
  • Throttle publish bursts in accordance with your app's latency needs e.g. Publish no faster than 5 msgs per second to any one channel.

Method(s)

To Publish a message you can use the following method(s) in the Angular2 V4 SDK:

publish( {Object message, String channel, Boolean storeInHistory, Boolean sendByPost, Object meta, Number ttl }, Function callback )
ParameterTypeRequiredDefaultDescription
Operation ArgumentsHashYesA hash of arguments.
messageObjectYesThe message may be any valid JSON type including objects, arrays, strings, and numbers.
channelStringYesSpecifies channel name to publish messages to.
storeInHistoryBooleanOptionaltrueIf true the messages are stored in history.
If storeInHistory is not specified, then the history configuration on the key is used.
sendByPostBooleanOptionalfalseWhen true, the SDK uses HTTP POST to publish the messages. The message is sent in the BODY of the request, instead of the query string when HTTP GET is used. Also the messages are compressed thus reducing the size of the messages. Using HTTP POST to publish messages adheres to RESTful API best practices.
metaObjectOptionalPublish extra meta with the request.
ttlNumberOptionalSet a per message time to live in storage.
  1. If storeInHistory = true, and ttl = 0, the message is stored with no expiry time.
  2. If storeInHistory = true and ttl = X (X is an Integer value), the message is stored with an expiry time of X hours.
  3. If storeInHistory = false, the ttl parameter is ignored.
  4. If ttl is not specified, then expiration of the message defaults back to the expiry value for the key.
callbackFunctionOptionalExecutes on a successful/unsuccessful publish.

Basic Usage

Publish a message to a channel:

pubnub.publish(
{
message:{
such: 'Hello from the PubNub Angular2 SDK!'
},
channel: 'my_channel'
},
function (status, response) {
if (status.error) {
console.log(status);
} else {
console.log("message Published w/ timetoken", response.timetoken);
}
}
);
Note

Before running the above publish example, either using the Debug Console or in a separate script running in a separate terminal window, subscribe to the same channel that is being published to.

Response

type PublishResponse = {
timetoken: number
}

Other Examples

Publish a JSON serialized message

var newMessage = {
text: 'Hi There!'
}
pubnub.publish(
{
message: newMessage,
channel: 'my_channel'
},
function(status, response) {
if (status.error) {
console.log("publishing failed w/ status: ", status);
} else {
console.log("message published w/ server response: ", response);
}
}
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Store the published message for 10 hours

pubnub.publish(
{
message: {
such: 'Hello from the PubNub Angular2 SDK!'
},
channel: 'my_channel',
storeInHistory: true,
ttl: 10
},
function (status, response) {
if (status.error) {
console.log(status);
} else {
console.log("message Published w/ timetoken", response.timetoken);
}
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Basic usage using Promises

pubnub.publish({
message:{
such: 'Hello from the PubNub Angular2 SDK!'
},
channel: 'my_channel'
}).then((response) => {
console.log(response)
}).catch((error) => {
console.log(error)
});

Publish a JSON serialized message using Promises

var newMessage = {
text: 'Hi There!'
}
pubnub.publish({
message: newMessage,
channel: 'my_channel'
}).then((response) => {
console.log(response)
}).catch((error) => {
console.log(error)
});

Store the published message for 10 hours using Promises

pubnub.publish({
message: {
such: 'Hello from the PubNub Angular2 SDK!'
},
channel: 'my_channel',
storeInHistory: true,
ttl: 10
}).then((response) => {
console.log(response)
}).catch((error) => {
console.log(error)
});

Fire

Description

The fire endpoint allows the client to send a message to PubNub Functions Event Handlers. These messages will go directly to any Event Handlers registered on the channel that you fire to and will trigger their execution. The content of the fired request will be available for processing within the Event Handler. The message sent via fire() isn't replicated, and so won't be received by any subscribers to the channel. The message is also not stored in history.

Method(s)

To Fire a message you can use the following method(s) in the Angular2 V4 SDK:

fire( {Object message, String channel, Boolean sendByPost, Object meta}, Function callback )
ParameterTypeRequiredDefaultDescription
Operation ArgumentsHashYesA hash of arguments.
messageObjectYesThe message may be any valid JSON type including objects, arrays, strings, and numbers.
channelStringYesSpecifies channel name to publish messages to.
sendByPostBooleanOptionalfalseIf true the messages sent via POST.
metaObjectOptionalPublish extra meta with the request.
callbackFunctionOptionalExecutes on a successful/unsuccessful publish.

Basic Usage

Fire a message to a channel:

pubnub.fire(
{
message: {
such: 'Hello from the PubNub Angular2 SDK!'
},
channel: 'my_channel'
},
function (status, response) {
if (status.error) {
console.log(status);
} else {
console.log("message fired w/ timetoken", response.timetoken);
}
}
);

Subscribe

Description

This function causes the client to create an open TCP socket to the PubNub Real-Time Network and begin listening for messages on a specified channel. To subscribe to a channel the client must send the appropriate subscribeKey at initialization. By default a newly subscribed client will only receive messages published to the channel after the subscribe() call completes.

Tip

You can be notified of connectivity via the listener, on establishing connection the statusEvent.category returns PNConnectedCategory.

By waiting for the connect event to return before attempting to publish, you can avoid a potential race condition on clients that subscribe and immediately publish messages before the subscribe has completed.

Warning

Unsubscribing from all channels, and then subscribing to a new channel Y is not the same as subscribing to channel Y and then unsubscribing from the previously-subscribed channel(s). Unsubscribing from all channels resets the last-received timetoken and thus, there could be some gaps in the subscription that may lead to message loss.

Method(s)

To Subscribe to a channel you can use the following method(s) in the Angular2 V4 SDK:

subscribe({Array channels, Array channelGroups, Boolean withPresence, Array/Boolean triggerEvents, Number autoload, Number timetoken})
ParameterTypeRequiredDefaultDescription
Operation ArgumentsHashYesA hash of arguments.
channelsArraySpecifying either channels or channelGroups is mandatorySpecifies the channels to subscribe to. It is possible to specify multiple channels as a list or as an array.
channelGroupsArraySpecifying either channels or channelGroups is mandatorySpecifies the channelGroups to subscribe to.
withPresenceBooleanOptionalfalseIf true it also subscribes to presence instances.
triggerEventsArray/BooleanOptionalIf true, all events will be invoked without adding listeners to receive real-time messages, presences and status of the channel subscribed.
If this is an array, this has to contain the events to delegate like message, presence, status.
autoloadNumberOptionalSpecifies a number of messages to pull from history between 1 to 100.
timetokenNumberOptionalSpecifies timetoken from which to start returning any available cached messages. Message retrieval with timetoken is not guaranteed and should only be considered a best-effort service.

Basic Usage

Subscribe to a channel:

pubnub.subscribe({
channels: ['my_channel'],
withPresence: true
});

Returns

ObjectDescription
categoryPNConnectedCategory
operationPNSubscribeOperation
affectedChannelsThe channels affected in the operation, of type array.
subscribedChannelsAll the current subscribed channels, of type array.
affectedChannelGroupsThe channel groups affected in the operation, of type array.
lastTimetokenThe last timetoken used in the subscribe request, of type long.
currentTimetokenThe current timetoken fetched in the subscribe response, which is going to be used in the next request, of type long.
{
category: 'PNConnectedCategory',
operation: 'PNSubscribeOperation',
affectedChannels: ['my_channel_1'],
subscribedChannels: ['my_channel_1'],
affectedChannelGroups: [],
lastTimetoken: '14974492380756600',
currentTimetoken: '14974492384874375'
}

Subscribe Message Response

ObjectDescription
channelThe channel for which the message belongs.
subscriptionThe channel group or wildcard subscription match (if exists).
timetokenPublish timetoken.
messageThe payload.
actualChannelDeprecated. Use property channel.
subscribedChannelDeprecated. Use property subscription.
{
actualChannel: null,
channel: "my_channel_1",
message: "Hello World!",
publisher: "pn-58e1a647-3e8a-4c7f-bfa4-e007ea4b2073",
subscribedChannel: "my_channel_1",
subscription: null,
timetoken: "14966804541029440"
}

Presence Response

ObjectDescription
actionCan be join, leave, state-change or timeout.
channelThe channel for which the message belongs.
occupancyNo. of users connected with the channel.
stateUser State.
subscriptionThe channel group or wildcard subscription match (if exists)
timestampCurrent timetoken.
timetokenPublish timetoken.
uuidUUIDs of users who are connected with the channel.
{
category: 'PNConnectedCategory',
operation: 'PNSubscribeOperation',
affectedChannels: ['my_channel_1'],
subscribedChannels: ['my_channel_1'],
affectedChannelGroups: [],
lastTimetoken: '14974492380756600',
currentTimetoken: '14974492384874375'
}

Other Examples

Subscribing to multiple channels

It's possible to subscribe to more than one channel using the Multiplexing feature. The example shows how to do that using an array to specify the channel names.

Alternative subscription methods

You can also use Wildcard Subscribe and Channel Groups to subscribe to multiple channels at a time. To use these features, the Stream Controller add-on must be enabled on your keyset in the Admin Portal.

pubnub.subscribe({
channels: ['my_channel1', 'my_channel2', 'my_channel3']
});

Subscribing to a Presence channel

Requires Presence add-on

This method requires that the Presence add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

For any given channel there is an associated Presence channel. You can subscribe directly to the channel by appending -pnpres to the channel name. For example the channel named my_channel would have the presence channel named my_channel-pnpres.

pubnub.addListener({
presence: function(m) {
console.log(m);
},
message: function(message) {
console.log(message)
}
});

pubnub.subscribe({
channels: ["my_channel"],
withPresence: true
});

Sample Responses

Join Event

{
"channel": "my_channel",
"subscription": null,
"actualChannel": null,
"subscribedChannel": "my_channel-pnpres",
"action": "join",
"timetoken": "15119466699655811",
"occupancy": 2,
"uuid": "User1",
"timestamp": 1511946669
}

Leave Event

{
"channel": "my_channel",
"subscription": null,
"actualChannel": null,
"subscribedChannel": "my_channel-pnpres",
"action": "leave",
"timetoken": "15119446002445794",
"occupancy": 1,
"uuid": "User1",
"timestamp": 1511944600
}

Timeout Event

{
"channel": "my_channel",
"subscription": null,
"actualChannel": null,
"subscribedChannel": "my_channel-pnpres",
"action": "timeout",
"timetoken": "15119519897494311",
"occupancy": 3,
"uuid": "User2",
"timestamp": 1511951989
}

Custom Presence Event (State Change)

{
"channel": "my_channel",
"subscription": null,
"actualChannel": null,
"subscribedChannel": "my_channel-pnpres",
"action": "state-change",
"state": {
"isTyping": true
},
"timetoken": "15119477895378127",
"occupancy": 5,
"uuid": "User4",
"timestamp": 1511947789
}

Interval Event

{
"action": "interval",
"occupancy": 2,
"timestamp": 1511947739
}

When a channel is in interval mode with presence_deltas pnconfig flag enabled, the interval message may also include the following fields which contain an array of changed UUIDs since the last interval message.

  • joined
  • left
  • timedout

For example, this interval message indicates there were 2 new UUIDs that joined and 1 timed out UUID since the last interval:

{
"action":"interval",
"timestamp":1548340678,
"occupancy":2,
"join":["pn-94bea6d1-2a9e-48d8-9758-f1b7162631ed","pn-cecbfbe3-312f-4928-93a2-5a79c91b10e0"]},
"timedout":["pn-cecbfbe3-312f-4928-93a2-5a79c91b10e0"],
"b":"my-channel-pnpres"
}

If the full interval message is greater than 30KB (since the max publish payload is ∼32KB), none of the extra fields will be present. Instead there will be a here_now_refresh boolean field set to true. This indicates to the user that they should do a hereNow request to get the complete list of users present in the channel.

{
"channel": "my_channel",
"subscription": null,
"actualChannel": null,
"subscribedChannel": "my_channel-pnpres",
"action": "interval",
"timetoken": "15119477396210903",
"occupancy": 4,
"timestamp": 1511947739,
"here_now_refresh" : true
}
  1. Subscribe to a channel with support of triggerEvents:
pubnub.subscribe({
channels : ['my_channel1'],
withPresence: true,
triggerEvents: true
});

pubnub.subscribe({
channels : ['my_channel2'],
withPresence: true,
triggerEvents: ['message', 'presence', 'status']
});
  1. Subscribe to a channel with autoload:
pubnub.subscribe({
channels: ['my_channel'],
triggerEvents: true,
withPresence: true,
autoload: 100
});

Wildcard subscribe to channels

Requires Stream Controller add-on

This method requires that the Stream Controller add-on is enabled for your key in the Admin Portal (with Enable Wildcard Subscribe checked). Read the support page on enabling add-on features on your keys.

Wildcard subscribes allow the client to subscribe to multiple channels using wildcard. For example, if you subscribe to a.* you will get all messages for a.b, a.c, a.x. The wildcarded * portion refers to any portion of the channel string name after the dot (.).

pubnub.subscribe({
channels: ['ab.*']
});
Wildcard grants and revokes

Only one level (a.*) of wildcarding is supported. If you grant on * or a.b.*, the grant will treat * or a.b.* as a single channel named either * or a.b.*. You can also revoke permissions from multiple channels using wildcards but only if you previously granted permissions using the same wildcards. Wildcard revokes, similarly to grants, only work one level deep, like a.*.

Subscribe 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 Admin Portal. Read the support page on enabling add-on features on your keys.

pubnub.subscribe({
channelGroups: ['my_channelGroup']
});

Subscribing to multiple channel groups

Requires Stream Controller add-on

This method requires that the Stream Controller add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

pubnub.subscribe({
channelGroups: ['my_channelGroup1', 'my_channelGroup2', 'my_channelGroup3']
});

Subscribing to a channel and channel group simultaneously

Requires Stream Controller add-on

This method requires that the Stream Controller add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

pubnub.subscribe({
channels: ['my_channel'],
channelGroups: ['my_channelGroup']
});

Unsubscribe

Description

When subscribed to a single channel, this function causes the client to issue a leave from the channel and close any open socket to the PubNub Network. For multiplexed channels, the specified channel(s) will be removed and the socket remains open until there are no more channels remaining in the list.

Warning

Unsubscribing from all channels, and then subscribing to a new channel Y is not the same as subscribing to channel Y and then unsubscribing from the previously-subscribed channel(s). Unsubscribing from all channels resets the last-received timetoken and thus, there could be some gaps in the subscription that may lead to message loss.

Method(s)

To Unsubscribe from a channel you can use the following method(s) in the Angular2 V4 SDK:

unsubscribe({Array channels, Array channelGroups})
ParameterTypeRequiredDescription
Operation ArgumentsHashYesA hash of arguments.
channelsArrayYesSpecifies the channel to unsubscribe from.
channelGroupsArraySpecifying either channels or channelGroups is mandatorySpecifies the channelGroups to unsubscribe from.

Basic Usage

Unsubscribe from a channel:

pubnub.unsubscribe({
channels : ['my_channel']
});

Response

The output below demonstrates the response to a successful call:

{
"action" : "leave"
}

Other Examples

Unsubscribing from multiple channels

Requires Stream Controller add-on

This method requires that the Stream Controller add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

pubnub.unsubscribe({
channels : ['my_channel1', 'my_channel2', 'my_channel3']
});
Response
{
"action" : "leave"
}

Unsubscribing from multiple channel groups.

Requires Stream Controller add-on

This method requires that the Stream Controller add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

pubnub.unsubscribe({
channelGroups : ['my_channelGroup1', 'my_channelGroup2', 'my_channelGroup3']
});

Unsubscribe All

Description

Unsubscribe from all channels and all channel groups

Method(s)

unsubscribeAll()

Basic Usage

pubnub.unsubscribeAll();

Returns

None

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

A listener lets you to catch up real time messages, get presence and status information if you do not want to use the getMessage, getPresence, getStatus methods. Remember add a listener before subscribing a channel.

pubnub.addListener({
status: function(st) {
if (st.category === "PNUnknownCategory") {
var newState = {
new: 'error'
};
pubnub.setState({
state: newState
},
function (status) {
console.log(st.errorData.message);
});
}
},
message: function(message) {
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Removing Listeners

var existingListener = {
message: function () {
},
};

pubnub.removeListener(existingListener);

Listener status events

CategoryDescription
PNNetworkUpCategoryThe SDK detected that the network is online.
PNNetworkDownCategoryThe SDK announces this when a connection isn't available, or when the SDK isn't able to reach the PubNub Data Stream Network.
PNNetworkIssuesCategoryA subscribe event experienced an exception when running. The SDK isn't able to reach the PubNub Data Stream Network. This may be due to many reasons, such as: the machine or device isn't connected to the internet; the internet connection has been lost; your internet service provider is having trouble; or, perhaps the SDK is behind a proxy.
PNReconnectedCategoryThe SDK was able to reconnect to PubNub.
PNConnectedCategorySDK subscribed with a new mix of channels. This is fired every time the channel or channel group mix changes.
PNAccessDeniedCategoryAccess Manager permission failure.
PNMalformedResponseCategoryJSON parsing crashed.
PNBadRequestCategoryThe server responded with a bad response error because the request is malformed.
PNDecryptionErrorCategoryIf using decryption strategies and the decryption fails.
PNTimeoutCategoryFailure to establish a connection to PubNub due to a timeout.
PNRequestMessageCountExceedCategoryThe SDK announces this error if requestMessageCountThreshold is set, and the number of messages received from PubNub (in-memory cache messages) exceeds the threshold.
PNUnknownCategoryReturned when the subscriber gets a non-200 HTTP response code from the server.