Go 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 HereNow() function in your application.

Method(s)

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

pn.HereNow().Channels([]string).ChannelGroups([]string).IncludeState(bool).IncludeUUIDs(bool).QueryParam(queryParam).Execute()

Parameter	Type	Required	Default	Description
`Channels`	[]string	Optional		The `Channels` to get the here now details.
`ChannelGroups`	[]string	Optional		The `Channel groups` to get the here now details.
`IncludeState`	bool	Optional	False	If `true`, the response will include the presence states of the users for `channels`/`channelGroups`.
`IncludeUUIDs`	bool	Optional	True	If `true`, the response will include the `UUIDs` of the connected clients
`QueryParam`	map[string]string	Optional	`nil`	QueryParam accepts a map, the keys and values of the map are passed as the query string parameters of the URL called by the API.

Basic Usage

Get a list of UUIDs subscribed to channel:

res, status, err := pn.HereNow().
    Channels([]string{"my-channel-1"}).
    IncludeUUIDs(true).
    Execute()

for _, v := range res.Channels {
    fmt.Println("---")
    fmt.Println("Channel: ", v.ChannelName)
    fmt.Println("Occupancy: ", v.Occupancy)
    fmt.Println("Occupants")

    for _, v := range v.Occupants {
        fmt.Println("UUID: ", v.UUID, ", state: ", v.State)
    }
}

fmt.Println(status, err)

Rest Response from Server

The HereNow() operation returns a. PNHereNowResult which contains the following fields:

Method	Type	Description
`TotalChannels`	int	Total `Channels`
`TotalOccupancy`	int	Total `Occupancy`
`Channels`	[]HereNowChannelData

HereNowChannelData:

Method	Type	Description
`ChannelName`	string	`Channel` name
`Occupancy`	int	`Occupancy` of the `Channel`
`Occupants`	[]HereNowOccupantsData

HereNowOccupantsData:

Method	Type	Description
`UUID`	string	`UUID` of the user
`State`	map[string]interface{}	`State` of the user.

Other Examples

Returning State:

res, status, err := pn.HereNow().
    Channels([]string{"my-channel-1"}). // who is present on those channels?
    IncludeUUIDs(true). // if false, only shows occupancy count
    IncludeState(true). // include state with request (false by default)
    Execute()

Example Response:

for _, v := range res.Channels {
    fmt.Println(v.ChannelName) // my_channel
    fmt.Println(v.Occupancy) // 3
    fmt.Println(v.Occupants) // members of a channel

    for _, v := range v.Occupants {
        fmt.Println(v.UUID) // some_uuid;
        fmt.Println(v.State) // channel member state, if applicable
    }
}

Return Occupancy Only:

You can return only the occupancy information for a single channel by specifying the channel and setting UUIDs to false:

res, status, err := pn.HereNow().
    Channels([]string{"my-channel-1"}). // who is present on those channels?
    IncludeUUIDs(false). // if false, only shows occupancy count
    IncludeState(false). // include state with request (false by default)
    Execute()

Example Response:

for _, v := range res.Channels {
    fmt.Println(v.ChannelName) // my_channel
    fmt.Println(v.Occupancy) // 3
}

Returning UUIDs and occupancy for all channels:

You can return the list of UUIDs and occupancy for all channels by omitting the channel:

res, status, err := pn.HereNow().
    IncludeUUIDs(true). // if false, only shows occupancy count
    IncludeState(false). // include state with request (false by default)
    Execute()

Example Response:

res.TotalChannels // 4
res.TotalOccupancy // 12

for _, v := range res.Channels {
    fmt.Println(v.ChannelName) // my_channel
    fmt.Println(v.Occupancy) // 3
    fmt.Println(v.Occupants) // members of a channel

    for _, v := range v.Occupants {
        fmt.Println(v.UUID) // some_uuid;
    }
}

Return Occupancy for all channels:

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

res, status, err := pn.HereNow().
    IncludeUUIDs(true). // if false, only shows occupancy count
    IncludeState(true). // include state with request (false by default)
    Execute()

Example Response:

res.TotalChannels // 4
res.TotalOccupancy // 12

for _, v := range res.Channels {
    fmt.Println(v.Occupancy) // 3
    fmt.Println(v.Occupants) // members of a channel

    for _, v := range v.Occupants {
        fmt.Println(v.UUID) // some_uuid;
    }
}

Here Now for Channel Groups:

res, status, err := pn.HereNow().
    ChannelGroups([]string{"cg1", "cg2", "cg3"}). // who is present on channel groups?
    IncludeUUIDs(true). // if false, only shows occupancy count
    IncludeState(true). // include state with request (false by default)
    Execute()

Example Response:

res.TotalOccupancy // 12

Where Now

Description

You can obtain information about the current list of channels to which a UUID is subscribed to by calling the WhereNow() 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 WhereNow() you can use the following method(s) in the Go V4 SDK:

pn.WhereNow().UUID(string).QueryParam(queryParam).Execute()

Parameter	Type	Required	Default	Description
`UUID`	string	Optional		`UUID` to get info on.
`QueryParam`	map[string]string	Optional	`nil`	QueryParam accepts a map, the keys and values of the map are passed as the query string parameters of the URL called by the API.

Basic Usage

You simply need to define the UUID to be used to send the data to as in the example below.

Get a list of channels a UUID is subscribed to:

res, status, err := pn.WhereNow().
    UUID("username-uuid"). // uuid of the user we want to spy on
    Execute()

Rest Response from Server

Method	Type	Description
`Channels`	[]string	The list of `channels` where the `UUID` is present.

Other Examples

In the case you omit UUID field in WhereNow() request, the UUID of a current PubNub instance will be used.

res, status, err := pn.WhereNow().Execute()

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:

pn.SetState().Channels([]string).ChannelGroups([]string).State(map[string]interface{}).UUID(string).QueryParam(queryParam).Execute()

Parameter	Type	Required	Description
`Channels`	[]string	Optional	`channels` to set `state`.
`ChannelGroups`	[]string	Optional	`channel groups` to set `state`.
`State`	map[string]interface{}	Optional	`state` to set.
`UUID`	string	Optional	Set the Presence state info for a given `UUID`.
`QueryParam`	map[string]string	Optional	QueryParam accepts a map, the keys and values of the map are passed as the query string parameters of the URL called by the API.

Get State:

pn.GetState().Channels([]string).ChannelGroups([]string).UUID(string).QueryParam(queryParam).Execute()

Basic Usage

Set State :

res, status, err := pn.SetState().
    Channels([]string{"ch"}).
    State(map[string]interface{}{
        "is_typing": true,
    }).
    Execute()

fmt.Println(res, status, err)

Get State :

res, status, err := pn.GetState().
    Channels([]string{"ch1", "ch2", "ch3"}).
    ChannelGroups([]string{"cg1", "cg2", "cg3"}).
    UUID("suchUUID").
    Execute()

fmt.Println(res, status, err)

Response

The SetState() operation returns a PNSetStateResult which contains the following fields:

Method	Type	Description
`State`	interface{}	map of `UUIDs` and the user states.

The GetState() operation returns a PNGetStateResult which contains the following fields:

Method	Type	Description
`State`	map[string]interface{}	map of `UUIDs` and the user states.

Other Examples

Set state for channels in a channel group:

myState := map[string]interface{}{
    "age": 20,
}

pn.SetState().
    ChannelGroups([]string{"cg1", "cg2", "cg3"}).
    Channels([]string{"ch1", "ch2", "ch3"}).
    State(myState).
    Execute()

if presence.Event == "state-change" {
    res, status, err := pn.GetState().
        Channels([]string{"ch1"}).
        UUID("is_typing").
        Execute()
    fmt.Println(res, status, err)
}

Heartbeat without subscription

Description

You can send presence heartbeat notifications without subscribing to a channel. These notifications are sent periodically and indicate whether a client is connected or not. Make sure to correctly set the presence timeout and interval properties during Configuration This feature requires the Presence add-on.

Method(s)

To send heartbeat notifications without subscribing to a channel, you can use the following method(s) in the Go V4 SDK:

pn.Presence().Connected(bool).Channels([]‌string).ChannelGroups([]string).Execute()

Parameter	Type	Required	Description
`Connected`	bool	Yes	Whether client's presence should be changed to connected (`true` to join) or off-line (`false` to leave).
`Channels`	[]string	Optional	List of channel names for which client's presence state should be changed according to passed connected value.
`ChannelGroups`	[]string	Optional	List of channel groups names for which client's presence state should be changed according to passed connected value.

Basic Usage

pn.Presence().
    Connected(true).
    Channels([]‌string{"my-channel"}).
    ChannelGroups([]string{"my-channel-group"}).
    Execute()

Other Examples

To start heartbeating without subscription to channel or channel group

pn.Presence().
    Connected(true).
    Channels([]‌string{"my-channel"}).
    ChannelGroups([]string{"my-channel-group"}).
    Execute()

To stop heartbeating without subscription to channel or channel group

pn.Presence().
    Connected(false).
    Channels([]‌string{"my-channel"}).
    ChannelGroups([]string{"my-channel-group"}).
    Execute()