Ruby V4 Presence API Reference for Realtime Apps

Presence enables you to track the online and offline status of users and devices in real time, as well as 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 add-onRequires that the Presence 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

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 here_now() function in your application.

Method(s)

To call Here Now you can use the following method(s) in the Ruby V4 SDK:

here_now(channels: channels, channel_groups: channel_groups, http_sync: http_sync, callback: callback)

Parameter	Type	Required	Description
`channels`	String, Symbol	Optional	Specify the `channels` name to return occupancy results. If `channels` is not provided, `here_now` will return data for all channels (global `here_now`).
`channel_groups`	String, Symbol	Optional	Specify the `channel_groups` name to return occupancy results.
`http_sync`	Boolean	Optional	Default `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.
`callback`	Lambda accepting one parameter	Optional	`Callback` 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

Get a list of uuids subscribed to channel:

pubnub.here_now(
    channel: 'my_channel',
) do |envelope|
    puts envelope
end

Response

#<Pubnub::Envelope
    @result = {
        :data => {
            :uuids => ["2d588b75-0451-4bde-8952-13128c10e952"],
            :occupancy => 1
        }
    },
    @status = {
        :code => 200
    }
>

Other Examples

Return Occupancy for all channels:

You can return only the occupancy information (Global Here Now) by omitting the channel name

pubnub.here_now() do |envelope|
    puts envelope
end

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" ],
                "occupancy": 1
            }
        },
        "total_channels": 3,
        "total_occupancy": 3
    },
    "service": "Presence"
}

Where Now

Description

You can obtain information about the current list of channels to which a UUID is subscribed to by calling the where_now() function in your application.

Note

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 where_now() you can use the following method(s) in the Ruby V4 SDK:

where_now(uuid: uuid, http_sync: http_sync, callback: callback)

Parameter	Type	Required	Description
`uuid`	String	Yes	`UUID` we are looking for.
`http_sync`	Boolean	Optional	Default `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.
`callback`	Lambda accepting one parameter	Optional	`Callback` 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

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:

pubnub.where_now(
    uuid: "my_uuid"
) do |envelope|
    puts envelope.result[:data]
end

Response

#<Pubnub::Envelope:0x007fd38584c168
    @result = {
        :data => {
        "channels" => ["whatever"]
        }
    },
    @status = {
        :code =>200
    }
>

User State

Description

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(channels: channels, state: state, http_sync: http_sync, callback: callback)

Parameter	Type	Required	Description
`channels`	String, Symbol	Yes	Specify `channels` name to set `state` for.
`state`	Hash	Yes	The `state` to set.
`http_sync`	Boolean	Optional	Default `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.
`callback`	Lambda accepting one parameter	Optional	`Callback` 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).

get_state(channels: channels, uuid: uuid, http_sync: http_sync, callback: callback)

Parameter	Type	Required	Description
`channels`	String, Symbol	Yes	Specify `channels` name to get `state` from.
`uuid`	String	Optional	Specifies `UUID`.
`http_sync`	Boolean	Optional	Default `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.
`callback`	Lambda accepting one parameter	Optional	`Callback` 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

Set State :

pubnub.set_state(channel: 'my_channel', state: { key: 'value' }) do |envelope|
    puts envelope.status
end

Get State :

pubnub.state(channel: :my_channel, uuid: 'some-uuid') do |envelope|
    puts envelope.result[:data][:state]
end

Response

#<Pubnub::Envelope:0x007fd3851b5cc8
    @result = {
        :data => {
            :state => {
                "age"=>59,
                "first" => "Robert",
                "last" => "Plant"
            },
            :channel=>"whatever"
        }
    },
    @status = {
        :code => 200
    }
>