Presence API for Go 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.

For information on how to receive presence events and what those events are, refer to Presence Events.

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.

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 Go SDK:

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

* required

Parameter	Description
Channels Type: []string Default: n/a	The Channels to get the here now details.
ChannelGroups Type: []string Default: n/a	The Channel groups to get the here now details.
IncludeState Type: bool Default: False	If true, the response will include the presence states of the users for channels/channelGroups.
IncludeUUIDs Type: bool Default: True	If true, the response will include the UUIDs of the connected clients
QueryParam Type: map[string]string Default: 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

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

Get a list of UUIDs subscribed to channel

package main

import (
	"fmt"
	"log"

	pubnub "github.com/pubnub/go/v7"
)

func main() {
	// Configure the PubNub instance with demo keys
	config := pubnub.NewConfigWithUserId("myUniqueUserId")
	config.SubscribeKey = "demo"
	config.PublishKey = "demo"

show all 44 lines

Rest Response from Server

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

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

HereNowChannelData

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

HereNowOccupantsData

Method	Description
UUID Type: string	UUID of the user
State Type: map[string]interface	State of the user.

Other Examples

Returning State

Requires Presence

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

For information on how to receive presence events and what those events are, refer to Presence Events.

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

Requires Presence

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

For information on how to receive presence events and what those events are, refer to Presence Events.

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
}

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

Requires Presence

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

For information on how to receive presence events and what those events are, refer to Presence Events.

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.

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 WhereNow() you can use the following method(s) in the Go SDK:

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

* required

Parameter	Description
UUID Type: string Default: n/a	UUID to get info on.
QueryParam Type: map[string]string Default: 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	Description
Channels Type: []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

Requires Presence

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

For information on how to receive presence events and what those events are, refer to Presence Events.

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

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

* required

Parameter	Description
Channels Type: []string	channels to set state.
ChannelGroups Type: []string	channel groups to set state.
State Type: map[string]interface	state to set.
UUID Type: string	Set the Presence state info for a given UUID.
QueryParam Type: map[string]string	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()

* required

Parameter	Description
Channels Type: []string	channels to get state.
ChannelGroups Type: []string	channel groups to get state.
UUID Type: string	Get the Presence state info for a given UUID.
QueryParam Type: map[string]string	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

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	Description
State Type: interface	map of UUIDs and the user states.

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

Method	Description
State Type: 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

Requires Presence

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

For information on how to receive presence events and what those events are, refer to Presence Events.

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 SDK:

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

* required

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