Create message drafts

A MessageDraft object is an abstraction for composing a message that has not yet been published. You can use it to:

You can display user mentions, channel references, and links (collectively called "message elements") to the user on the front end of your application by adding a message draft state listener.

Message drafts consist of MessageElement objects, which can be either instances of Text or MentionTarget.

Text are simple strings, while MentionTarget elements are used for user mentions, channel references, and URLs. They contain a text and a reference to the linked element regardless if it's a user, a channel, or a URL.

Each MentionTarget has a MentionType enum property, which defines the type of mention. Available targets include:

  • MentionTarget::user
  • MentionTarget::channel
  • MentionTarget::url
Store draft messages locally

Unreal Chat SDK does not provide a method for storing the drafted message on the client, so whenever a user drafts a message in a chat app, changes a channel, and goes back to that channel, the drafted message gets lost.

To save drafted messages before they are published on channels, implement your own local storage mechanism suitable for the platform you use.

Create a draft message​

CreateMessageDraft() creates a (MessageDraft object) that can consist of:

Method signature​

Output​

ParameterTypeDescription
UPubnubMessageDraft*UPubnubMessageDraft*Pointer to the created MessageDraft object, which can be used to edit the draft, insert mentions, and eventually send the message.

Basic usage​

Create a draft message containing just plain text.

// Assuming you have a valid UPubnubChannel* pointer named Channel

// Define a configuration for the message draft if needed (using default configuration here)
FPubnubMessageDraftConfig DraftConfig; // This might include settings like initial content or behaviors

// Create a message draft from the channel with the specified configuration
UPubnubMessageDraft* MyMessageDraft = Channel->CreateMessageDraft(DraftConfig);

// Now MyMessageDraft can be used to build and send messages
MyMessageDraft->InsertText(0, "Hello there! Please review and confirm.");
MyMessageDraft->Send();

Add message draft change listener​

Add a callback to listen for changes to the message draft along with receiving suggestions for user mentions, links, and channel references.

AddChangeListener() returns all links referenced in the draft message that match the provided 3-letter string from your app's keyset.

icon

Single listener


Method signature​

Output​

This method doesn't return any data.

Basic usage​

Add the listener to your message draft.

// Assuming you have a UPubnubMessageDraft pointer named MyMessageDraft

// Define your callback function to handle updates 
void AMyActor::OnMessageDraftUpdate(const TArray<UPubnubMessageElement*>& MessageElements)
{
    // Iterate through the current message elements and handle updates
    for (const UPubnubMessageElement* Element : MessageElements)
    {
        // Process each element as needed
        // Example: Output the text of each element to the log
        UE_LOG(LogTemp, Log, TEXT("Draft Element Text: %s"), *Element->GetText());
    }
}

// Set up the delegate to bind your callback
show all 23 lines

Add message draft change listener (with suggestions)​

Add a callback to listen for changes to the message draft along with receiving suggestions for user mentions, links, and channel references.

AddChangeListenerWithSuggestions() returns all links referenced in the draft message that match the provided 3-letter string from your app's keyset.

icon

Single listener


For example, if you type #Sup, you will get the list of channels starting with Sup like Support or Support-Agents. The default number of returned suggested channel names is 10, configurable to a maximum value of 100.

Method signature​

Output​

This method doesn't return any data.

Basic usage​

Add the listener to your message draft.

// Assuming you have a UPubnubMessageDraft pointer named MyMessageDraft

// Define your callback function to handle updates with suggestions
void AMyActor::OnMessageDraftUpdateWithSuggestions(const TArray<UPubnubMessageElement*>& MessageElements, const TArray<FPubnubSuggestedMention>& SuggestedMentions)
{
    // Iterate through the current message elements and handle updates
    for (const UPubnubMessageElement* Element : MessageElements)
    {
        // Process each element as needed
        UE_LOG(LogTemp, Log, TEXT("Draft Element Text: %s"), *Element->GetText());
    }

    // Process suggested mentions
    for (const FPubnubSuggestedMention& Suggestion : SuggestedMentions)
    {
show all 29 lines

Add message element​

AddMention() adds a user mention, channel reference or a link specified by a mention target at a given position.

Method signature​

Output​

This method returns no output data.

Basic usage​

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

// Create a message draft
UPubnubMessageDraft* MyMessageDraft = Channel->CreateMessageDraft();

// Insert greeting text before the mention of Alex
MyMessageDraft->InsertText(0, "Hello Alex! I have sent you this link on the #offtopic channel.");

// Create a user mention target for Alex
FString UserName = "Alex";
UPubnubMentionTarget* UserMentionTarget = UPubnubMentionTarget::CreateUserMentionTarget(UserName);

// Add the user mention for Alex
MyMessageDraft->AddMention(6, UserName.Len(), UserMentionTarget); // 'Hello ' is 6 characters long

// Create a URL mention target for the link
FString Url = "https://www.example.com";
show all 31 lines

Remove message element​

RemoveMention() removes a user mention, channel reference, or a link at a given position.

Method signature​

Output​

This method returns no output data.

Basic usage​

Remove the URL element from the word link in the Hello Alex! I have sent you this link on the #offtopic channel. message.

// Assume the message reads:
// Hello Alex! I have sent you this link on the #offtopic channel.

// Remove the link mention
MessageDraft->RemoveMention(33);

Update message text​

Update() lets you replace the text of a draft message with new content.

Removing message elements

As a best effort, the optimal set of insertions and removals that converts the current text to the provided text is calculated to preserve any message elements.

If any message element text is found to be modified in the updated text, the message element is removed.

Method signature​

Output​

This method returns no output data.

Basic usage​

Change the message I sent Alex this picture. to I did not send Alex this picture. where Alex is a user mention.

// the message reads:
// I sent [Alex] this picture.
// where [Alex] is a user mention
MessageDraft->Update("I did not send Alex this picture.");
// the message now reads: 
// I did not send [Alex] this picture.
// the mention is preserved because its text wasn't changed
Mention text changes

If you decided to change the name Alex to some other name, the mention would be removed because your updated text's index coincided with an existing mention.

For more manual control over inserting and removing parts of a message, refer to Insert message text and Remove message text.

Insert suggested message element​

Inserts a message element returned by the MessageDraft change listener into the MessageDraft.

Text must match

The SuggestedMention must be up to date with the message text, that is, SuggestedMention.ReplaceFrom must match the message draft at position SuggestedMention.ReplaceFrom, otherwise an exception is thrown.

Method signature​

Output​

This method returns no output data.

Basic usage​

Register a listener and insert a suggested element.

// Assuming you have a UPubnubMessageDraft pointer named MyMessageDraft

// Define your callback function that handles draft updates with suggestions
void AMyActor::OnMessageDraftUpdateWithSuggestions(const TArray<UPubnubMessageElement*>& MessageElements, const TArray<FPubnubSuggestedMention>& SuggestedMentions)
{
    // Check if there are any suggested mentions
    if (SuggestedMentions.Num() > 0) 
    {
        // Insert the first suggested mention into the draft
        const FPubnubSuggestedMention& FirstSuggestion = SuggestedMentions[0];
        MyMessageDraft->InsertSuggestedMention(FirstSuggestion, FirstSuggestion.ReplaceTo);
        
        // Log the action for debugging purposes
        UE_LOG(LogTemp, Log, TEXT("Inserted suggested mention: %s"), *FirstSuggestion.ReplaceTo);
    }
show all 26 lines

Insert message text​

InsertText() lets you insert plain text in the draft message at a given position from the beginning of the message.

Removing message elements

If the position of the text you want to insert corresponds to an existing message element, this element is removed.

Method signature​

Output​

This method returns no output data.

Basic usage​

In the message Check this support article https://www.support-article.com/., add the word out between the words Check and this.

// Assuming you have a UPubnubMessageDraft pointer named MyMessageDraft

// Start by setting the initial text in the message draft
MyMessageDraft->Update(TEXT("Check this support article https://www.support-article.com/."));

// Find the position to insert "out"
// "Check " is 6 characters long, so "out" should be inserted at position 6
int InsertPosition = 6;

// Use InsertText to add the word "out" at the specified position
MyMessageDraft->InsertText(InsertPosition, TEXT("out "));

// At this point, the draft should read: "Check out this support article https://www.support-article.com/."

// You may Log the resulting draft for clarity
show all 16 lines

Remove message text​

RemoveText() lets you remove plain text from the draft message at a given position from the beginning of the message.

Removing message elements

If the position of the text you want to remove corresponds to an existing message element, this element is removed.

Method signature​

Output​

This method returns no output data.

Basic usage​

In the message Check out this support article https://www.support-article.com/., remove the word out.

// Assuming you have a UPubnubMessageDraft pointer named MyMessageDraft

// Start by setting the initial text in the message draft
MyMessageDraft->Update(TEXT("Check out this support article https://www.support-article.com/."));

// Determine the position and length of the text to remove
// "Check " is 6 characters long, so "out" starts at position 6 and has a length of 4 (including the trailing space)
int RemovePosition = 6;
int RemoveLength = 4;

// Use RemoveText to delete the word "out " from the draft
MyMessageDraft->RemoveText(RemovePosition, RemoveLength);

// At this point, the draft should read: "Check this support article https://www.support-article.com/."

show all 17 lines

Send a draft message​

Send() publishes the draft text message with all mentioned users, links, and referenced channels.

Whenever you mention any users, Send() also emits events of type mention.

Method signature​

Output​

This method returns no output data.

Basic usage​

Send a draft message containing just plain text.

// Create a message draft
var messageDraft = Channel->CreateMessageDraft();

// Add initial text
MessageDraft->Update("Hello Alex!");

// Send the message
MessageDraft->Send();
Last updated on
On this page