Create message drafts

MessageDraft represents an unpublished message. Use it to:

• Edit text before publishing
• Add channel references, user mentions, and links

Display message elements (mentions, references, links) in your UI by binding the OnMessageDraftUpdatedWithSuggestions delegate.

note

CreateMessageDraft is always synchronous

CreateMessageDraft() is a local, in-memory operation — it does not perform any network requests. It returns a UPubnubChatMessageDraft* directly and has no Async variant. The async/sync split applies to network methods (Send(), SendAsync(), etc.) called on the draft after it is created.

1UPubnubChatMessageDraft* Draft = Channel->CreateMessageDraft(MessageDraftConfig);

Basics

Message drafts consist of FPubnubChatMessageElement structs, each containing a Text field (the display text) and optionally a MentionTarget field (for user mentions, channel references, or URLs). Each element also tracks its Start position and Length in the draft.

The FPubnubChatMentionTarget struct has a MentionTargetType enum property. Available types:

• EPubnubChatMentionTargetType::PCMTT_User
• EPubnubChatMentionTargetType::PCMTT_Channel
• EPubnubChatMentionTargetType::PCMTT_Url
• EPubnubChatMentionTargetType::PCMTT_None (plain text, no mention)

Store draft messages locally

Unreal Chat SDK does not persist drafts. Implement your own local storage to save drafts across channel switches.

Safe mutations

The SDK validates all draft mutations (InsertText, RemoveText, AppendText, AddMention, RemoveMention). Operations that would corrupt an existing mention or link offset return an error in FPubnubChatOperationResult instead of silently breaking the draft's element structure.

Class diagram

Example

Consider the message Hey, I sent Alex this link on the #offtopic channel. where:

• Alex is a reference to the user with the ID of alex_d
• link is a URL of the www.pubnub.com website
• #offtopic is a reference to the channel with the ID of group.offtopic

The list of MessageElement objects returned by the MessageDraftChangeListener is as follows:

Part of Message	Element Type	Code Used to Create
Hey, I sent	Text	MessageDraft->Update("Hey, I sent Alex this link on the #offtopic channel.");
Alex	MentionTarget	MessageDraft->AddMention(12, 4, UPubnubChatMessageDraftUtilities::CreateUserMentionTarget("alex_d"));
this	Text	MessageDraft->Update("Hey, I sent Alex this link on the #offtopic channel.")
link	MentionTarget	MessageDraft->AddMention(22, 4, UPubnubChatMessageDraftUtilities::CreateUrlMentionTarget("https://www.pubnub.com"));
on the	Text	MessageDraft->Update("Hey, I sent Alex this link on the #offtopic channel.");
#offtopic	MentionTarget	MessageDraft->AddMention(34, 9, UPubnubChatMessageDraftUtilities::CreateChannelMentionTarget("group.offtopic"));
channel.	Text	MessageDraft->Update("Hey, I sent Alex this link on the #offtopic channel.");

Internal mention format

The message draft format uses Markdown-like syntax internally, integrating links with the pattern [link text](link target).

Mention Type	Example
user	[John Doe](pn-user://john_doe)
channel	[General Chat](pn-channel://group.chat.123)
url	[PubNub](https://www.pubnub.com)

Custom schemas like pn-user:// and pn-channel:// are used to identify user and channel mentions, while traditional URLs are supported as-is.

Adding message elements

This syntax is internal only. To add elements, use AddMention().

Create a draft message

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

• Plain text
• Mentioned users
• Referenced channels
• Links

Method signature

C++ / Input parameters

1Channel->CreateMessageDraft(FPubnubChatMessageDraftConfig MessageDraftConfig = FPubnubChatMessageDraftConfig())

* required

Parameter	Description
MessageDraftConfig Type: FPubnubChatMessageDraftConfig Default: FPubnubChatMessageDraftConfig()	Configuration for the message draft, including settings such as initial content and metadata.

FPubnubChatMessageDraftConfig

* required

Parameter	Description
UserSuggestionSource Type: EPubnubChatMessageDraftSuggestionSource Default: PCMDSS_Global	Source for user mention suggestions. PCMDSS_Channel limits suggestions to channel members; PCMDSS_Global searches all app users.
IsTypingIndicatorTriggered Type: bool Default: false	When true, the draft triggers typing indicator events on the channel when text is edited.
UserLimit Type: int Default: 10	Maximum number of user mention suggestions to return (max: 100).
ChannelLimit Type: int Default: 10	Maximum number of channel reference suggestions to return (max: 100).

Output

Parameter	Description
UPubnubChatMessageDraft* Type: UPubnubChatMessageDraft*	Pointer to the created MessageDraft object, which can be used to edit the draft, insert mentions, and eventually send the message.

Blueprint

Sample code

Reference code

This example is a self-contained code snippet ready to be run. Set up your Unreal project and follow the instructions in the lines marked with ACTION REQUIRED before running the code. Use it as a reference when working with other examples in this document.

Create a message draft on a channel.

C++

Actor.h

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Actor.cpp

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Blueprint

Listen for message draft changes

Bind to delegates on the MessageDraft object to receive notifications when the draft content changes.

OnMessageDraftUpdated delegate:

• Fires when the draft content changes (after InsertText, RemoveText, AddMention, RemoveMention, Update, or InsertSuggestedMention)
• Provides the current list of message elements (TArray<FPubnubChatMessageElement>)
• Does not include suggestions (use OnMessageDraftUpdatedWithSuggestions for that)

Details

Delegate signature

Delegate	Parameter
FOnPubnubChatMessageDraftUpdated Type: TArray<FPubnubChatMessageElement>	MessageElements

Sample code

Reference code

This example is a self-contained code snippet ready to be run. Set up your Unreal project and follow the instructions in the lines marked with ACTION REQUIRED before running the code. Use it as a reference when working with other examples in this document.

Bind the delegate to your message draft.

Actor.h

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Actor.cpp

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Listen for message draft changes (with suggestions)

Bind the OnMessageDraftUpdatedWithSuggestions delegate to receive draft changes along with suggestions for user mentions, links, and channel references.

OnMessageDraftUpdatedWithSuggestions delegate:

• Fires when the draft content changes
• Provides the current state of message elements (TArray<FPubnubChatMessageElement>)
• Offers FPubnubChatSuggestedMention items suggesting user mentions, links, or channel references

Unlike OnMessageDraftUpdated, which only delivers content changes, this delegate also includes suggestion data for dynamic draft updates.

Details

Example: typing #Sup returns channels like Support or Support-Agents. Default: 10 suggestions (max: 100).

Delegate signature

Delegate	Parameter
FOnPubnubChatMessageDraftUpdatedWithSuggestions Type: TArray<FPubnubChatMessageElement>	MessageElements
Type: TArray<FPubnubChatSuggestedMention>	SuggestedMentions

Sample code

Reference code

This example is a self-contained code snippet ready to be run. Set up your Unreal project and follow the instructions in the lines marked with ACTION REQUIRED before running the code. Use it as a reference when working with other examples in this document.

Bind the delegate to your message draft.

Actor.h

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Actor.cpp

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Add message element

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

Method signature

1MessageDraft->AddMention(int Position, int Length, const FPubnubChatMentionTarget MentionTarget)

* required

Parameter	Description
Position * Type: int Default: n/a	Position of a character in a message where the message element you want to insert starts. It's counted from the beginning of the message (including spaces), with 0 as the first character.
Length * Type: int Default: n/a	Number of characters the message element should occupy in the draft message's text.
MentionTarget * Type: FPubnubChatMentionTarget Default: n/a	Mention target struct. Create using UPubnubChatMessageDraftUtilities factory methods. Available mention types (EPubnubChatMentionTargetType): PCMTT_User PCMTT_Channel PCMTT_Url

Output

Type	Description
FPubnubChatOperationResult	Operation result with Error (bool) and ErrorMessage (FString).

Sample code

Reference code

This example is a self-contained code snippet ready to be run. Set up your Unreal project and follow the instructions in the lines marked with ACTION REQUIRED before running the code. Use it as a reference when working with other examples in this document.

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.

Actor.h

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Actor.cpp

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Remove message element

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

Method signature

1MessageDraft->RemoveMention(int Position)

* required

Parameter	Description
Position * Type: int Default: n/a	Position of the first character of the message element you want to remove.

Position value

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

Output

Type	Description
FPubnubChatOperationResult	Operation result with Error (bool) and ErrorMessage (FString).

Sample code

Reference code

This example is a self-contained code snippet ready to be run. Set up your Unreal project and follow the instructions in the lines marked with ACTION REQUIRED before running the code. Use it as a reference when working with other examples in this document.

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

Actor.h

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Actor.cpp

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Update message text

Update() replaces the text of a draft message with new content.

Removing message elements

The SDK preserves message elements when possible. If element text is modified, that element is removed.

Method signature

1MessageDraft->Update(const FString& NewText)

* required

Parameter	Description
NewText * Type: FString Default: n/a	The new full draft text.

Output

Type	Description
FPubnubChatOperationResult	Operation result with Error (bool) and ErrorMessage (FString).

Sample code

Reference code

This example is a self-contained code snippet ready to be run. Set up your Unreal project and follow the instructions in the lines marked with ACTION REQUIRED before running the code. Use it as a reference when working with other examples in this document.

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

Actor.h

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Actor.cpp

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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 OnMessageDraftUpdatedWithSuggestions delegate 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

1MessageDraft->InsertSuggestedMention(const FPubnubChatSuggestedMention SuggestedMention)

* required

Parameter	Description
SuggestedMention * Type: FPubnubChatSuggestedMention Default: n/a	A user, channel, or URL suggestion obtained from the OnMessageDraftUpdatedWithSuggestions delegate. The ReplaceFrom text must match the current draft text at Offset.

Output

Type	Description
FPubnubChatOperationResult	Operation result with Error (bool) and ErrorMessage (FString).

Sample code

Reference code

This example is a self-contained code snippet ready to be run. Set up your Unreal project and follow the instructions in the lines marked with ACTION REQUIRED before running the code. Use it as a reference when working with other examples in this document.

Bind the delegate and insert a suggested element.

Actor.h

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Actor.cpp

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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

Inserting text strictly inside a mention span (not at its start or end position) removes the mention and converts its text to plain text. Inserting at the exact start or end boundary of a mention preserves the mention.

Method signature

1MessageDraft->InsertText(int Position, FString Text)

* required

Parameter	Description
Position * Type: int Default: n/a	Position of a character in a message where the text you want to insert starts. It's counted from the beginning of the message (including spaces), with 0 as the first character.
Text * Type: FString Default: n/a	Text that you want to insert.

Output

Type	Description
FPubnubChatOperationResult	Operation result with Error (bool) and ErrorMessage (FString).

Sample code

Reference code

This example is a self-contained code snippet ready to be run. Set up your Unreal project and follow the instructions in the lines marked with ACTION REQUIRED before running the code. Use it as a reference when working with other examples in this document.

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

Actor.h

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Actor.cpp

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Append text

AppendText() adds text at the end of the draft message. Equivalent to calling InsertText() at position GetCurrentText().Len().

Method signature

1MessageDraft->AppendText(const FString Text)

* required

Parameter	Description
Text * Type: FString Default: n/a	Text to append to the end of the draft. Must be non-empty.

Output

Type	Description
FPubnubChatOperationResult	Operation result with Error (bool) and ErrorMessage (FString).

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 range overlaps an existing mention or link element, the operation returns an error (FPubnubChatOperationResult.Error = true). Use RemoveMention() to explicitly remove a mention element.

Method signature

1MessageDraft->RemoveText(int Position, int Length)

* required

Parameter	Description
Position * Type: int Default: n/a	Position of a character in a message where the text you want to insert starts. It's counted from the beginning of the message (including spaces), with 0 as the first character.
Length * Type: int Default: n/a	How many characters to remove, starting at the given Position.

Output

Type	Description
FPubnubChatOperationResult	Operation result with Error (bool) and ErrorMessage (FString).

Sample code

Reference code

This example is a self-contained code snippet ready to be run. Set up your Unreal project and follow the instructions in the lines marked with ACTION REQUIRED before running the code. Use it as a reference when working with other examples in this document.

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

Actor.h

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Actor.cpp

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Send a draft message

Send() publishes the draft message with all mentioned users, links, and referenced channels. Mentioning users also emits mention events.

Method signature

1MessageDraft->Send(FPubnubChatSendTextParams SendTextParams = FPubnubChatSendTextParams())

* required

Parameter	Description
SendTextParams Type: FPubnubChatSendTextParams Default: FPubnubChatSendTextParams()	Struct providing additional parameters.
→ StoreInHistory Type: bool Default: true	If true, the messages are stored in Message Persistence. If not specified, the Message Persistence configuration from the Admin Portal keyset is used.
→ SendByPost Type: bool Default: false	When true, the SDK uses HTTP POST to publish the messages.
→ Meta Type: FString Default: ""	Publish additional metadata with the request.

User mentions, channel references, and links are not passed in SendTextParams. They are added to the MessageDraft object through AddMention() and serialized automatically when Send() is called. To quote another message, use SetQuotedMessage() before calling Send().

Output

Type	Description
FPubnubChatOperationResult	Operation result with Error (bool) and ErrorMessage (FString).

Sample code

Reference code

This example is a self-contained code snippet ready to be run. Set up your Unreal project and follow the instructions in the lines marked with ACTION REQUIRED before running the code. Use it as a reference when working with other examples in this document.

Send a draft message containing just plain text.

Actor.h

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Actor.cpp

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Send a draft message (async)

SendAsync() is the asynchronous variant of Send(). It sends the draft on a background thread and calls the provided delegate when the operation completes.

Method signature

1MessageDraft->SendAsync(FOnPubnubChatOperationResponse OnOperationResponse, FPubnubChatSendTextParams SendTextParams = FPubnubChatSendTextParams())

* required

Parameter	Description
OnOperationResponse Type: FOnPubnubChatOperationResponse	Callback executed when the operation completes.
SendTextParams Type: FPubnubChatSendTextParams	Same parameters as Send().

Get current draft text

GetCurrentText() returns the current full draft text by concatenating all message elements.

Method signature

1MessageDraft->GetCurrentText()

Output

Type	Description
FString	The full draft text string.

Get message elements

GetMessageElements() returns a copy of the current message elements (text segments and mentions with position and target).

Method signature

1MessageDraft->GetMessageElements()

Output

Type	Description
TArray<FPubnubChatMessageElement>	Array of message elements in the draft.

FPubnubChatMessageElement

Field	Type	Description
Text	FString	The display text of this element.
MentionTarget	FPubnubChatMentionTarget	The mention target (user, channel, or URL). MentionTargetType is PCMTT_None for plain text.
Start	int	Start position (0-based) in the draft.
Length	int	Length of this element in the draft.

Get text to send

GetTextToSend() returns the serialized draft text as it would be sent by Send(). Mentions are encoded as markdown links (for example, [Alex](pn-user://alex_d)). Use this to preview or parse the final message format.

Method signature

1MessageDraft->GetTextToSend()

Output

Type	Description
FString	Serialized draft text with mentions as markdown links. Empty if the draft is empty.

Set quoted message

SetQuotedMessage() attaches (or clears) a quoted message on the draft. The quoted message is sent alongside the draft text when Send() is called. Pass nullptr to remove any existing quoted message.

Method signature

1MessageDraft->SetQuotedMessage(UPubnubChatMessage* InQuotedMessage)

* required

Parameter	Description
InQuotedMessage * Type: UPubnubChatMessage* Default: n/a	The message to quote, or nullptr to clear the quoted message.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. Set up your Unreal project and follow the instructions in the lines marked with ACTION REQUIRED before running the code. Use it as a reference when working with other examples in this document.

Quote a message using a message draft.

Actor.h

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Actor.cpp

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Get quoted message

GetQuotedMessage() returns the quoted message attached to the draft, if any.

Method signature

1MessageDraft->GetQuotedMessage()

Output

Type	Description
UPubnubChatMessage*	The quoted message, or nullptr if none is set.