Publish/Subscribe API for PubNub Ruby SDK

The foundation of the PubNub service is the ability to send a message and have it delivered anywhere in less than 30ms. Send a message to just one other person, or broadcast to thousands of subscribers at once.

For higher-level conceptual details on publishing and subscribing, refer to Connection Management and to Publish Messages.

Publish​

publish() sends a message to all channel subscribers. A successfully published message is replicated across PubNub's points of presence and sent simultaneously to all subscribed clients on a channel.

ObjectNode

The new Jackson parser does not recognize JSONObject. Use ObjectNode instead.

  • You must initialize PubNub with the publishKey.
  • You don't have to be subscribed to a channel to publish to it.
  • You cannot publish to multiple channels simultaneously.

Method(s)​

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

publish(
    channel: String,
    message: Object,
    store: Boolean,
    compressed: Boolean,
    publish_key: String,
    http_sync: Boolean,
    custom_message_type: String
    callback: Lambda
)
ParameterTypeRequiredDescription
channelStringYesSpecify the channel name to publish the messages.
messageObjectYesSerializable object that has defined #to_json method.
storeBooleanOptionalSpecifies if message should be stored for history.Default true.
compressedBooleanOptionalSpecifies if message should be compressed.Default false.
publish_keyStringOptionalSpecifies the required publish_key to use to send messages to a channel.
http_syncBooleanOptionalDefault false. Method will be executed asynchronously and will return future, to get it's value you can use value method. If set to true, method will return array of envelopes (even if there's only one envelope).
For sync methods Envelope object will be returned.
custom_message_typeStringOptionalA case-sensitive, alphanumeric string from 3 to 50 characters describing the business-specific label or category of the message. Dashes - and underscores _ are allowed. The value cannot start with special characters or the string pn_ or pn-.

Examples: text, action, poll.
callbackLambda accepting one parameterOptionalCallback that will be called for each envelope.
For async methods future will be returned, to retrieve value Envelope object you have to call value method (thread will be locked until the value is returned).

Basic Usage​

Publish a message to a channel​

pubnub.publish(
    channel: 'my_channel',
    message: { text: 'Hi!' },
    custom_message_type: 'text-message'
) do |envelope|
    puts envelope.status
end
Subscribe to the channel

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.

Rest Response from Server​

The function returns the following formatted response:

[1, "Sent", "13769558699541401"]

Other Examples​

Publish a JSON serialized message​

pubnub.publish(
    message:  {
        key: {
            inner_key: :value
        }
    },
    custom_message_type: 'text-message',
    channel:   :whatever
)

Skip message from storage​

pubnub.publish(message: 'Not gonna store that', store: false)

Fire​

The fire endpoint allows the client to send a message to Functions Event Handlers and Illuminate. 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 Ruby SDK:

fire(
    channel: channel,
    message: message,
    compressed: compressed,
    publish_key: publish_key,
    http_sync: http_sync,
    callback: callback
)
ParameterTypeRequiredDescription
channelStringYesSpecify the channel name to publish the messages.
messageObjectYesSerializable object that has defined #to_json method.
compressedBooleanOptionalSpecifies if message should be compressed.Default false.
publish_keyStringOptionalSpecifies the required publish_key to use to send messages to a channel.
http_syncBooleanOptionalDefault false. Method will be executed asynchronously and will return future, to get it's value you can use value method. If set to true, method will return array of envelopes (even if there's only one envelope).
For sync methods Envelope object will be returned.
callbackLambda accepting one parameterOptionalCallback that will be called for each envelope.
For async methods future will be returned, to retrieve value Envelope object you have to call value method (thread will be locked until the value is returned).

Basic Usage​

Fire a message to a channel​

pubnub.fire(
    channel: 'my_channel',
    message: {
        text: 'Hi!'
    }
) do |envelope|
    puts envelope.status
end

Signal​

The signal() function is used to send a signal to all subscribers of a channel.

By default, signals are limited to a message payload size of 64 bytes. This limit applies only to the payload, and not to the URI or headers. If you require a larger payload size, please contact support.

Method(s)​

To Signal a message you can use the following method(s) in the Ruby SDK:

pubnub.signal(
    message: Object,
    channel: String,
    compressed: Boolean,
    custom_message_type: String
)
ParameterTypeRequiredDescription
messageObjectYesSerializable object that has defined #to_json method.
channelStringYesSpecify the channel name to send the messages.
compressedBooleanOptionalSpecifies if message should be compressed. Default false.
custom_message_typeStringOptionalA case-sensitive, alphanumeric string from 3 to 50 characters describing the business-specific label or category of the message. Dashes - and underscores _ are allowed. The value cannot start with special characters or the string pn_ or pn-.

Examples: text, action, poll.

Basic Usage​

Signal a message to a channel​

pubnub.signal(
    channel: 'foo',
    message: {
        msg: 'Hello Signals'
    },
    custom_message_type: 'text-message'
);

Rest Response from Server​

The function returns the following formatted response:

[1, "Sent", "13769558699541401"]

Subscribe​

Receive messages​

Your app receives messages and events via event listeners. The event listener is a single point through which your app receives all the messages, signals, and events that are sent in any channel you are subscribed to.

For more information about adding a listener, refer to the Event Listeners section.

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 subscribe_key at initialization. By default a newly subscribed client will only receive messages published to the channel after the subscribe() call completes.

Connectivity notification

You can be notified of connectivity via the envelope.status. By waiting for the envelope.status 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.

Using Ruby SDK, if a client becomes disconnected from a channel, it can automatically attempt to reconnect to that channel and retrieve any available messages that were missed during that period by setting restore to true. By default a client will attempt to reconnect after exceeding a 320 second connection timeout.

Unsubscribing from all channels

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 Ruby SDK:

subscribe(
    channels: channels,
    channel_groups: group,
    presence: presence,
    presence_callback: presence_callback,
    with_presence: with_presence,
    http_sync: http_sync,
    callback: callback
)
ParameterTypeRequiredDescription
channelsString, Symbol, ArrayOptionalSpecify the channels to subscribe to. It is possible to specify multiple channels as an array. It is possible to subscribe to wildcard channels.
channel_groupsString, Symbol, ArrayOptionalSpecifies the group to subscribe to. It is possible to specify multiple groups as an array.
presenceString, Symbol, ArrayOptionalSpecifies the channel to presence subscribe to. It is possible to specify multiple channels as an array.
presence_callbackLambda accepting one argumentOptionalCallback that is called for each presence event from wildcard subscribe. Works only with http_sync set to true.
with_presenceBooleanOptionalSubscribes to all presence channels of channels listed in channels parameter.
http_syncBooleanOptionalDefault false. Method will be executed asynchronously and will return future, to get it's value you can use value method. If set to true, method will return array of envelopes (even if there's only one envelope).
For sync methods they will return array of Envelopes - envelope object for each message.
callbackLambda accepting one parameterOptionalCallback that is called for each retrieved message. Works only with http_sync set to true.
Event listeners

The response of the subscription is handled by Listener. Please see the Listeners section for more details.

Basic Usage​

Subscribe to a channel:

# Subscribe to channel 'my_channel'.
pubnub.subscribe(
    channels: :my_channel
)

Rest Response from Server​

The output below demonstrates the response format to a successful call:

[[], "Time Token"]

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.

# Subscribe to channels (with presence) and groups
pubnub.subscribe(
    channels: ['debug', 'info', 'warn'],
    channel_groups: ['ruby_group', 'jruby_group', 'rbx_group'],
    presence: ['debug', 'info', 'warn']
)
# You will be subscribed to channels: debug, info, warn, debug-pnpres, info-pnpres and warn-pnpres
# and to groups: ruby_group, jruby_group, rbx_group.

Subscribing to a Presence channel​

Requires Presence

This method requires that the Presence add-on is enabled for your key in the Admin Portal.

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.

# Subscribes to room0, room0-pnpres, room1, room1-pnpres, room2, room2-pnpres
pubnub.subscribe(
    channels: ['room0', 'room1', 'room2'],
    with_presence: true
)

Sample Responses​

Join Event​

{
    "action": "join",
    "timestamp": 1345546797,
    "uuid": "175c2c67-b2a9-470d-8f4b-1db94f90e39e",
    "occupancy": 2
}
Leave Event​
{
    "action" : "leave",
    "timestamp" : 1345549797,
    "uuid" : "175c2c67-b2a9-470d-8f4b-1db94f90e39e",
    "occupancy" : 1
}
Timeout Event​
{
    "action": "timeout",
    "timestamp": 1345549797,
    "uuid": "76c2c571-9a2b-d074-b4f8-e93e09f49bd",
    "occupancy": 0
}
Custom Presence Event (State Change)​
{
    "action": "state-change",
    "uuid": "76c2c571-9a2b-d074-b4f8-e93e09f49bd",
    "timestamp": 1345549797,
    "data": {
        "isTyping": true
    }
}
Interval Event​
{
    "action":"interval",
    "timestamp":1474396578,
    "occupancy":2
}

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",
    "occupancy" : <# users in channel>,
    "timestamp" : <unix timestamp>,
    "joined" : ["uuid2", "uuid3"],
    "timedout" : ["uuid1"]
}

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.

{
    "action" : "interval",
    "occupancy" : <# users in channel>,
    "timestamp" : <unix timestamp>,
    "here_now_refresh" : true
}

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 (.).

# Subscribe to wildcard channel 'ruby.*' (make sure you have wildcard subscribe enabled in your pubnub admin console!)
# specify two different callbacks for messages from channels and presence events in channels.
pubnub.subscribe(
    channels: 'ruby.*'
)
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.*.

Subscribing with State​

Requires Presence

This method requires that the Presence add-on is enabled for your key in the Admin Portal.

Required UserId

Always set the UserId to uniquely identify the user or device that connects to PubNub. This UserId should be persisted, and should remain unchanged for the lifetime of the user or the device. If you don't set the UserId, you won't be able to connect to PubNub.

require 'pubnub'

PUBKEY = 'demo'
SUBKEY = 'demo'

pubnub = Pubnub.new(
    subscribe_key: SUBKEY,
    publish_key: PUBKEY,
    ssl: true
)

callback = Pubnub::SubscribeCallback.new(
    message: ->(envelope) {
        puts "MESSAGE: #{envelope.result[:data]}"
    },
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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.

# Subscribe to group
pubnub.subscribe(
    channel_groups: 'ruby_group'
)

Subscribe to the presence channel of a channel group​

note
Requires Stream Controller and Presence add-ons

This method requires both the Stream Controller and Presence add-ons are enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

pubnub = Pubnub.new(
    subscribe_key: :demo,
    publish_key: :demo
)

callback = Pubnub::SubscribeCallback.new(
    message:  ->(_envelope) {
    },
    presence: ->(envelope) {
        puts "PRESENCE: #{envelope.result[:data]}"
    },
    status:   ->(_envelope) {
    }
)

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Subscribe Sync​
Loop

The loop will exit when there is no subscribed channel left, closing the program in turn.

require 'pubnub'
pubnub = Pubnub.new(
    subscribe_key: :demo,
    publish_key: :demo
)

pubnub.subscribe(channels: :whatever)
while pubnub.subscribed_channels.size > 0 do
    sleep 1
end

Unsubscribe​

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.

Unsubscribing from all channels

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 Ruby SDK:

unsubscribe(
    channels: channels,
    channel_groups: group,
    http_sync: http_sync,
    callback: callback
)
ParameterTypeRequiredDescription
channelsSymbol, StringOptionalSpecify the channels to unsubscribe from. (Required if channel_groups is not specified)
channel_groupsSymbol, StringOptionalSpecify the channel_groups to unsubscribe from. (Required if channels is not specified)
http_syncBooleanOptionalDefault false. Method will be executed asynchronously and will return future, to get it's value you can use value method. If set to true, method will return array of envelopes (even if there's only one envelope).
For sync methods Envelope object will be returned.
callbackLambda accepting one parameterOptionalCallback that will be called for each envelope.
For async methods future will be returned, to retrieve value Envelope object you have to call value method (thread will be locked until the value is returned).

Basic Usage​

Unsubscribe from a channel:

pubnub.unsubscribe(
    channel: 'my_channel'
) do |envelope|
    puts envelope.status
end

Response​

#<Pubnub::Envelope
    @status = {
        :code => 200,
        :operation => :leave,
        :category => :ack,
        :error => false,
        # [...]
    },
    # [...]
>

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(
    channel: ['chan1','chan2','chan3']
) do |envelope|
    puts envelope.status
end
pubnub.unsubscribe(
    channel: ['chan1','chan2','chan3']
) do |envelope|
    puts envelope.result[:data][:messages]
end
Example Response​
{
    "action" : "leave"
}

Unsubscribing from a channel group​

pubnub.leave(channel_group: "cg1") do |envelope|
    puts envelope.status
end

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.leave(group: ["cg1", "cg2"]) do |envelope|
    puts envelope
end
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