Mention users

The Mentions feature lets users tag specific individuals within a chat or conversation.

Kotlin Chat SDK lets one user tag another user by adding @ and typing at least three first letters of the username they want to mention. As a result, they get a list of suggested usernames when typing such a suggestion, like @Mar.

Generic referencing

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

The list of returned users depends on your app configuration - these can be either all members in the channel where you write a message or all users of your app (user data taken from the Admin Portal keyset for your app). The number of returned suggested users for the mention also depends on your app configuration and can show up to 100 suggestions. The names of the suggested users can consist of multiple words and contain up to 200 characters.

You can configure your app to let users mention up to 100 users in a single message (default value is 10).

You can implement mentions in your app in a similar way you would implement 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

You can let users mention other users in a draft message by adding @ and manually typing at least three first letters of the username they want to mention, like @Mar.

Whenever you mention a user, this user is added to the list of all mentioned users inside the MessageDraft object. This draft contains the text content and all mentioned users and their names from the selected user metadata source (all channel members or all users on the app's keyset). Once you send this message (send()), that information gets stored in the 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() lets you remove a previously added 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

If you don't provide the position of the first character of the message element to remove, it isn't 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

The message elements listener returns all users mentioned in the draft message that match the provided 3-letter string from a selected data source (channel members or global users on your app's keyset).

Single listener

The message elements listener returns suggested mentions for channel references, user mentions, and links.

For example, if you type Sam, you will get the list of users starting with Sam like Samantha or Samir. The default number of returned suggested usernames is 10 which is configurable to a maximum value of 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

The getCurrentUserMentions() method lets you collect in one place all instances when a specific user was mentioned by someone - either in channels or threads. You can use this info to create a channel with all user-related mentions.

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

You can monitor all events emitted when you are mentioned in a parent or thread channel you are a member of using the listenForEvents() method. You can use this method to create pop-up notifications for the users.

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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