Mention users

Tag users in chat messages with @ mentions. Type @ followed by at least three letters to see username suggestions.

Generic referencing

Channel references, user mentions, and links are MessageElement instances with different MentionTarget values.

Configuration options:

• User source: channel members or all app users
• Suggestions: up to 100 usernames (default: 10)
• Username length: up to 200 characters
• Mentions per message: up to 100 (default: 10)

Implementation follows similar patterns to channel referencing and links.

Requires App Context

To mention users from a keyset, you must enable App Context for your app's keyset in the Admin Portal.

Add user mentions

Add user mentions with @ followed by at least three letters (e.g., @Mar).

Mentioned users are stored in the MessageDraft object. When sent with send(), mention data is saved to message metadata.

Method signature

You can add a user reference by calling the addMention() method with the target of MentionTarget.User.

Refer to the addMention() method for details.

Sample code

Create the Hello Alex! I have sent you this link on the #offtopic channel. message where Alex is a user mention.

1// create an empty message draft
2val messageDraft = channel.createMessageDraft(isTypingIndicatorTriggered = channel.type != ChannelType.PUBLIC)
3

4// change the text
5messageDraft.update(text = "Hello Alex! I have sent you this link on the #offtopic channel.")
6

7// add a user mention to the string 'Alex'
8messageDraft.addMention(offset = 6, length = 4, target = MentionTarget.User(userId = "alex_d"))

Remove user mentions

removeMention() removes a user mention from a draft message.

Method signature

You can remove user mentions from a draft message by calling the removeMention() method at the exact offset where the user mention starts.

Refer to the removeMention() method for details.

Offset value

Provide the exact offset position where the mention starts; otherwise, it won't be removed.

Sample code

Remove the user mention from the Hello Alex! I have sent you this link on the #offtopic channel. message where Alex is a user mention.

1// assume the message reads
2// Hello Alex! I have sent you this link on the #offtopic channel.`
3

4// remove the channel reference
5messageDraft.removeMention(offset = 6)

Get user suggestions

getUserSuggestions() returns users matching a 3-letter string from channel members or global users.

Example: typing Sam returns Samantha, Samir, etc. Default limit: 10 users (max: 100).

Method signature

You must add a message elements listener to receive user suggestions.

Refer to the addChangeListener() method for details.

Sample code

1// create a message draft
2val messageDraft = channel.createMessageDraft(isTypingIndicatorTriggered = channel.type != ChannelType.PUBLIC)
3

4// add the listener
5val listener = { elements: List<MessageElement>, suggestedMentions: PNFuture<List<SuggestedMention>> ->
6        updateUI(elements) // updateUI is your own function for updating UI
7        suggestedMentions.async { result ->
8            result.onSuccess { updateSuggestions(it) } // updateSuggestions is your own function for displaying suggestions
9        }
10    }
11messageDraft.addChangeListener(listener)

Get mentioned users

To return all users mentioned in a message, use the getMessageElements() method.

Method signature

This method has the following signature:

1message.getMessageElements(): List<MessageElement>

Input

This method doesn't take any parameters.

Output

Type	Description
List<MessageElement>	A list of message elements representing parsed components of the input text, including processed user mentions, links, and referenced channels based on the available data.

Each MessageElement on the returned list can be of one of these types:

• data class PlainText(override val text: String) : MessageElement
• data class Link(override val text: String, val target: MentionTarget) : MessageElement

If a MessageElement is of type Link, its target depends on the returned item:

// Mentioned user identified by [userId].
data class User(val userId: String) : MentionTarget


// Referenced channel identified by [channelId].
data class Channel(val channelId: String) : MentionTarget


// Link to [url].
data class Url(val url: String) : MentionTarget

MessageElement details

Sample code

Check if the message with the 16200000000000000 timetoken contains any mentions.

1chat.getChannel("incident-management").async { channelResult ->
2    channelResult.onSuccess { channel ->
3        // Successfully retrieved the channel
4        channel?.getMessage(16200000000000000L)?.async { messageResult ->
5            messageResult.onSuccess { message ->
6                // Handle success
7                val elements = message?.getMessageElements()
8

9                // Check if any elements represent user mentions
10                val hasMentions = elements?.any { element ->
11                    // Assuming there's a specific type or condition for mentions
12                    element is Link && element.target is User
13                } ?: false
14

15                if (hasMentions) {
16                    println("The message contains mentions.")
17                } else {
18                    println("The message does not contain any mentions.")
19                }
20            }.onFailure { error ->
21                // Handle failure
22                println("Failed to retrieve the message: ${error.message}")
23            }
24        }
25    }.onFailure { error ->
26        // Failed to retrieve the channel
27        println("Failed to retrieve the channel: ${error.message}")
28    }
29}

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Collect all user-related mentions

getCurrentUserMentions() retrieves all instances where the current user was mentioned in channels or threads. Use this to build a mentions feed.

Method signature

This method has the following signature:

1chat.getCurrentUserMentions(
2    startTimetoken: Long?,
3    endTimetoken: Long?,
4    count: Int?
5): PNFuture<GetCurrentUserMentionsResult>

Input

* required

Parameter	Description
startTimetoken Type: Long Default: n/a	Timetoken delimiting the start of a time slice (exclusive) to pull messages with mentions from. For details, refer to the Batch History section.
endTimetoken Type: Long Default: n/a	Timetoken delimiting the end of a time slice (inclusive) to pull messages with mentions from. For details, refer to the Batch History section.
count Type: Int Default: 100	Number of historical messages with mentions to return in a single call. Since each call returns all attached message actions by default, the maximum number of returned messages is 100. For more details, refer to the description of the includeMessageActions parameter in the Kotlin SDK docs.

Output

Parameter	Description
PNFuture<GetCurrentUserMentionsResult> Type: object	Returned object containing two fields: enhancedMentionsData and isMore.
→ enhancedMentionsData Type: enhancedMentionsData (ChannelMentionData or ThreadMentionData)	Array listing the requested number of historical mention events with a set of information that differ slightly depending on whether you were mentioned in the main (parent) channel or in a thread. For mentions in the parent channel, the returned ChannelMentionData includes these fields: event (of type Event<EventContent.Mention>), channelId where you were mentioned, message that included the mention, userId that mentioned you. For mentions in threads, the returned ThreadMentionData includes similar fields, the only difference is that you'll get parentChannelId and threadChannelId fields instead of just channelId to clearly differentiate the thread that included the mention from the parent channel in which this thread was created.
→ isMore Type: Boolean	Info whether there are more historical events to pull.

Sample code

List the last ten mentions for the current chat user.

1chat.getCurrentUserMentions(count = 10).async { mentionsResult ->
2    mentionsResult.onSuccess { mentions ->
3        // handle success
4        println("Last 10 mentions for the current user:")
5        mentions.data.forEach { mention ->
6            println("Message: ${mention.message.content}, Mentioned At: ${mention.message.timetoken}")
7        }
8    }.onFailure { exception ->
9        // handle failure
10        println("Error getting user mentions")
11    }
12}

Show notifications for mentions

listenForEvents() monitors mention events in channels and threads you're a member of. Use this to trigger pop-up notifications.

Events documentation

To read more about the events of type mention, refer to the Chat events documentation.

Method signature

This method has the following parameters:

1inline fun <reified T : EventContent> listenForEvents(
2    channel: String,
3    customMethod: EmitEventMethod?,
4    noinline callback: (event: Event<T>) -> Unit
5): AutoCloseable {
6    return listenForEvents(T::class, channel, customMethod, callback)
7}

Input

* required

Parameter	Description
T * Type: reified T : EventContent Default: n/a	Reified type parameter bounded by the EventContent interface, allowing access to type information at runtime.
channel * Type: String Default: Mentioned user ID	Channel to listen for new mention events. By default, it's the current (mentioned) user's ID.
customMethod Type: String Default: n/a	An optional custom method for emitting events. If not provided, defaults to null.
callback * Type: noinline (event: Event<T>) -> Unit Default: n/a	A lambda function that is called with an Event<T> as its parameter. It defines the custom behavior to be executed whenever an mention event type is detected on the specified channel.

Output

Type	Description
AutoCloseable	Interface that lets you stop receiving moderation-related updates (moderation events) by invoking the close() method.

Sample code

Print a notification for a mention of the current chat user on the support channel.

1val user = chat.currentUser
2chat.listenForEvents(user.id) { event: Event<EventContent.Mention> ->
3    if (event.payload.channel == "support") {
4        println("${user.id} has been mentioned on the support channel!")
5    }
6}

Get mentioned users (deprecated)

You can access the mentionedUsers property of the Message object to return all users mentioned in a message.

Method signature

This is how you can access the property:

1message.mentionedUsers

Sample code

Check if the message with the 16200000000000000 timetoken contains any mentions.

1channel.getMessage(16200000000000000).async { result ->
2    result.onSuccess { message: Message? ->
3        if (message != null) {
4            // Access the mentionedUsers property
5            val mentionedUsers = message.mentionedUsers
6            
7            if (mentionedUsers.isNotEmpty()) {
8                println("The message contains the following mentioned users:")
9                mentionedUsers.forEach { user ->
10                    println("User: ${user.name}")
11                }
12            } else {
13                println("The message does not contain any mentions.")
14            }
15        } else {
16            println("Message does not exist")
17        }
18    }.onFailure { exception: PubNubException ->
19        println("Exception occurred: ${exception.message}")
20    }
21}

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