Message threading

Message threading is a feature that allows users to ask questions, give feedback or add context to a specific message without disrupting the conversation flow. A message thread refers to a collection of messages grouped together, consisting of a parent message and its replies. It can have the following elements:

• A message can have a thread of replies.
• A message that has a thread of replies is a parent message.
• A parent message and its threaded replies are collectively called a message thread.
• Every message within a thread, whether it's parent or reply, is a threaded message.
• A message that doesn't have any replies is an unthreaded message.

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Message threading can be widely used to help conversations flow smoothly while keeping users engaged. Message replies in a thread are common among popular messaging platforms, such as Slack and iMessage.

• Conversation flow: Without message threading, it's hard to specify which message a channel member is responding to. Users would have to explain the context of their response, potentially confusing other channel members and distracting them from reading new messages. Message threads can help everyone stay engaged and carry on their conversation without any interferences.

• In-depth discussions: By allowing users to reply to each other's messages in a thread, they can have more in-depth conversations on one topic. They're able to ask follow-up questions or provide more detailed explanations to a specific message without interrupting others in the channel. Message threads can encourage users to start topic-specific discussions separate from the main channel conversation.

Refer to the following limitations before using the message threading feature:

• Message threading doesn't integrate with SyncManager.
• SDK only supports 1-depth threads, meaning you can only add reply messages to non-reply messages. You can't add a reply to a reply message.
• You can only reply to text and file messages, not admin messages. However, you can add admin type messages as a reply to another message.

You can retrieve messages and their replies.

The loadPreviousMessagesWithLimit:reverse:completionHandler: method of a SBDPreviousMessageListQuery instance returns a list of SBDBaseMessage objects. With this method, you can retrieve previous messages in a specific channel.

The following table lists the properties of this class.

let listQuery = channel!.createPreviousMessageListQuery()
listQuery!.replyType = REPLY_TYPE
listQuery!.includeThreadInfo = INCLUDE_THREAD_INFO
listQuery!.includeParentMessageInfo = INCLUDE_PARENT_MESSAGE_INFO

The following table lists the parameters that this method supports.

// Retrieving previous messages.
listQuery?.loadPreviousMessages(withLimit: LIMIT, reverse: REVERSE, completionHandler: { (messages, error) in
    if error != nil {
        // Handle error.
    }

})

The getMessagesByTimestamp:params:completionHandler: and getMessagesByMessageId:params:completionHandler: methods of a SBDBaseChannel instance return a list of SBDBaseMessage objects. By using these methods, you can retrieve messages in a specific channel according to a SBDMessageListParams object.

The following table lists the properties of this class.

let params = SBDMessageListParams()
params.previousResultSize = PREV_RESULT_SIZE
params.nextResultSize = NEXT_RESULT_SIZE
params.isInclusive = INCLUSIVE
params.reverse = REVERSE
params.replyType = REPLY_TYPE
params.includeThreadInfo = INCLUDE_THREAD_INFO
params.includeParentMessageInfo = INCLUDE_PARENT_MESSAGE_INFO

By using the getMessagesByTimestamp:params:completionHandler: method, you can retrieve a set number of messages of previous and next messages on both sides of a specific timestamp in a channel.

channel?.getMessagesByTimestamp(TIMESTAMP, params: params, completionHandler: { (messages, error) in
    if error != nil {
        // Handle error.
    }

    // A list of previous and next messages on both sides of a specified timestamp is successfully retrieved.
    // Through the "messages" parameter of the callback method,
    // you can access and display the data of each message from the result list that Sendbird server has passed to the callback method.
    self.messages += messages!
})

By using the getMessagesByMessageId:params:completionHandler: method, you can retrieve a set number of previous and next messages on both sides of a specific message ID in a channel.

channel?.getMessagesByMessageId(MESSAGE_ID, params: params, completionHandler: { (messages, error) in
    if error != nil {
        // Handle error.
    }

    // A list of previous and next messages on both sides of a specified message ID is successfully retrieved.
    // Through the "messages" parameter of the callback method,
    // you can access and display the data of each message from the result list that Sendbird server has passed to the callback method.
    self.messages += messages!
})

You can retrieve replies of a parent message if you can specify the parent message like the following. First, create an SBDThreadedMessageListParams object and set properties related to the thread where the target replies belong to.

let params = SBDThreadedMessageListParams()
params.previousResultSize = PREV_RESULT_SIZE
params.nextResultSize = NEXT_RESULT_SIZE
params.isInclusive = INCLUSIVE
params.reverse = REVERSE
params.includeParentMessageInfo = INCLUDE_PARENT_MESSAGE_INFO

With the timestamp of the parent message, you can retrieve its replies by passing an SBDThreadedMessageListParams object as an argument to the parameter in the getThreadedMessagesByTimestamp:params:completionHandler: method.

parentMessage.getThreadedMessages(byTimestamp: TIMESTAMP, params: params) { (parentMessage, threadedReplies, error) in
    if error != nil {
        // Handle error.
    }

    // A list of replies of the specified parent message timestamp is successfully retrieved.
    // Through the "threadedReplies" parameter of the callback method,
    // you can access and display the data of each message from the result list that Sendbird server has passed to the callback method.
}

You can retrieve a specific message by creating and passing the SBDMessageRetrievalParams object as a parameter to the getMessageWithParams:completionHandler: method.

let params = SBDMessageRetrievalParams()
params.messageId = MESSAGE_ID
params.channelType = CHANNEL_TYPE
params.channelUrl = CHANNEL_URL

SBDBaseMessage.getWith(params) { (message, error) in
    if error != nil {
        // Handle error.
    }

    // The specified message is successfully retrieved.
}

You can reply to a specific message in a channel through the sendUserMessageWithParams:completionHandler: or sendFileMessageWithParams:completionHandler: method. To do so, you should create a SBDUserMessageParams or a SBDFileMessageParams object and then specify the parentMessageId property of the object. Sending reply messages works the same way as sending regular messages to a channel except replies have an additional parentMessageId property.

When replying to a message through the sendUserMessageWithParams:completionHandler: method, you should specify and pass a SBDUserMessageParams object to the method as a parameter.

let params = SBDUserMessageParams(message: MESSAGE_TEXT)
params?.parentMessageId = PARENT_MESSAGE_ID

channel?.sendUserMessage(with: params!, completionHandler: { (message, error) in
    if error != nil {
        // Handle error.
    }

    // A reply to a specific message in the form of a text message is successfully sent.
})

When replying with a file message through the sendFileMessageWithParams:completionHandler: method, you should specify and pass a SBDFileMessageParams object to the method as a parameter.

let params = SBDFileMessageParams(file: FILE!)
params?.parentMessageId = PARENT_MESSAGE_ID

channel?.sendFileMessage(with: params!, completionHandler: { (message, error) in
    if error != nil {
        // Handle error.
    }

    // A reply to a specific message in the form of a file message is successfully sent.
})

You can retrieve message changelogs.

Each message changelog has distinct properties such as a timestamp that indicates when a message was updated and a unique ID of a deleted message. Based on these two properties, you can retrieve message changelogs in two different ways: either by timestamp or by token. Both getMessageChangeLogsSinceToken:params:completionHandler: and getMessageChangeLogsSinceTimestamp:params:completionHandler: methods require a parameter SBDMessageChangeLogsParams object to determine what messages to return.

let params = SBDMessageChangeLogsParams()
params.replyType = REPLY_TYPE
params.includeThreadInfo = INCLUDE_THREAD_INFO
params.includeParentMessageInfo = INCLUDE_PARENT_MESSAGE_INFO

The following table lists the properties of this class.

You can retrieve message changelogs by specifying a timestamp. The results will include changelogs that were created after the specified timestamp.

channel?.getMessageChangeLogs(sinceTimestamp: TIMESTAMP, params: params, completionHandler: { (updatedMessages, deletedMessageIds, hasMore, token, error) in
    if error != nil {
        // Handle error.
    }

    // A list of message changelogs created after the specified timestamp is successfully retrieved.
    
})

You can also retrieve message changelogs by specifying a token. The token is an opaque string that marks the starting point of the next page in the result set and it is included in the callback of the previous call. Based on the token, the next page will start with changelogs that were created after the specified token.

channel?.getMessageChangeLogs(sinceToken: TOKEN, params: params, completionHandler: { (updatedMessages, deletedMessageIds, hasMore, token, error) in
    if error != nil {
        // Handle error.
    }

    // A list of message changelogs created after the specified token is successfully retrieved.
})

Once a reply is created or deleted from a thread, the channel:didUpdateThreadInfo: event delegate method is invoked. The method returns a SBDThreadInfoUpdateEvent object that has the latest information about the thread. This object needs to be applied to the parent message object.

Note: Like other messages, when a reply is created in a channel, the onMessageReceived() method of the channel event handler in client apps will be called.

func channel(_ channel: SBDBaseChannel, didUpdateThreadInfo threadInfoUpdateEvent: SBDThreadInfoUpdateEvent) {
    // Look for a message that has threadInfoUpdateEvent.targetMessageId
    // Apply the event to the message.
    message.apply(threadInfoUpdateEvent)
}