Manage message updates

Edit messages and receive events whenever someone edits them.

You can use PubNub's functionality via Blueprints or directly in C++ code.

• In Blueprints, the whole SDK is managed by a subsystem, so start by initalizing the PubnubChatSubsystem node. Afterwards, you can use the Pubnub Chat object reference.

Blueprint functions

The Blueprints provided in the documentation show how you can structure your application and may contain utility methods and elements like buttons that are not part of the Unreal Chat SDK and are meant to serve as guidance.

• In C++, you can use the PubNub SDK as any other Game Instance Subsystem.

  #include "Kismet/GameplayStatics.h"
  #include "PubnubChatSubsystem.h"
  
  UGameInstance* GameInstance = UGameplayStatics::GetGameInstance(this);
  UPubnubChatSubsystem* PubnubChatSubsystem = GameInstance->GetSubsystem<UPubnubChatSubsystem>();
  
  UPubnubChat* Chat = PubnubChatSubsystem ->InitChat("demo", "demo", "my_user") // config optional

  Chat now allows you to call all Chat SDK functions, for example:

  Chat->DeleteUser("SomeUserID");

Usage in Blueprints and C++

Requires Message Persistence

To manage messages in PubNub storage, you must enable Message Persistence for your app's keyset in the Admin Portal.

Edit messages

Change the content of the existing message to a new one using the EditText() method.

Method signature

Blueprint

C++ / Input parameters

Message->EditText(FString NewText);

* required

Parameter	Description
newText * Type: string Default: n/a	New/updated text that you want to add in place of the existing message.

Output

This method doesn't return anything.

Sample code

Correct the number of the support ticket you sent to 78398.

#include "Kismet/GameplayStatics.h"
#include "PubnubChatSubsystem.h"

UGameInstance* GameInstance = UGameplayStatics::GetGameInstance(this);
UPubnubChatSubsystem* PubnubChatSubsystem = GameInstance->GetSubsystem<UPubnubChatSubsystem>();

UPubnubChat* Chat = PubnubChatSubsystem ->InitChat("demo", "demo", "my_user");

UPubnubChannel* Channel = Chat->GetChannel("support");

FString Timetoken = "16200000000000001";

// Fetch the message
UPubnubMessage* Message = Channel->GetMessage(Timetoken);

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Get message updates

You can receive updates when specific messages and related message reactions are added, edited, or removed on other clients using the following methods:

• StreamUpdates() checks message and message reaction-related updates on a single Message object.
• StreamUpdatesOn() checks message and message reaction-related updates on a list of Message objects.

Both methods accept a callback function as an argument. The Unreal Chat SDK invokes this callback whenever someone adds, edits or deletes a message, or adds or removes a message reaction to/from the specific message(s).

Underneath, these methods subscribe the current user to a channel and add a message reactions event listener to receive all messageAction events of type added or removed. These methods also return the unsubscribe function you can invoke to stop receiving messageAction events and unsubscribe from the channel.

Method signature

Blueprint

C++ / Input parameters

• StreamUpdates()

  Message->StreamUpdates(FOnPubnubMessageStreamUpdateReceived MessageUpdateCallback);

• StreamUpdatesOn()

  Message->StreamUpdatesOn(
      TArray<UPubnubMessage*> Messages, 
      FOnPubnubMessageStreamUpdateReceived MessageUpdateCallback
  );

Parameter	Required in StreamUpdates()	Required in StreamUpdatesOn()	Description
Messages Type: TArray<UPubnubMessage*> Default: n/a	No	Yes	Array of Message objects for which you want to get updates.
MessageUpdateCallback Type: FOnPubnubMessageStreamUpdateReceived Default: n/a	Yes	Yes	Callback function passed as a parameter to both methods. It defines the custom behavior to be executed when detecting channel metadata changes.

Each function in the Unreal Chat SDK that takes a callback as a parameter requires you to handle the response type accordingly.

For example, you can bind a callback function for the Channel->StreamPresence method to its handler in the following way:

// Create a pubnub response delegate
// you MUST implement your own callback function to handle the response
FOnPubnubChannelStreamPresenceReceived PresenceResponse;
PresenceResponse.BindDynamic(this, &AMyActor::OnPresenceResponseReceived);

Channel->StreamPresence(PresenceResponse);

You can implement the callback function to handle the response as follows:

AMyActor.h

UFUNCTION()
void OnPresenceResponseReceived(const TArray<FString> &PresentUsersIDs);

AMyActor.cpp

void AMyActor::OnPresenceResponseReceived(const TArray<FString> &PresentUsersIDs)
{
	for(auto PresentUser : PresentUsersIDs)
	{
		UE_LOG(LogTemp, Log, TEXT("Present User ID: "), *PresentUser);
	}
}

Handle the response

Output

Type	Description
UPubnubCallbackStop*	Object on which you can call Stop() to stop receiving updates.

Sample code

• StreamUpdates()

  Get message and message reaction-related updates for the message with the timetoken 16200000000000000 published on the support channel.

  #include "Kismet/GameplayStatics.h"
  #include "PubnubChatSubsystem.h"
  
  UGameInstance* GameInstance = UGameplayStatics::GetGameInstance(this);
  UPubnubChatSubsystem* PubnubChatSubsystem = GameInstance->GetSubsystem<UPubnubChatSubsystem>();
  
  UPubnubChat* Chat = PubnubChatSubsystem ->InitChat("demo", "demo", "my_user");
  
  UPubnubChannel* Channel = Chat->GetChannel("support");
  
  FString Timetoken = "16200000000000000";
  
  // Fetch the message
  UPubnubMessage* Message = Channel->GetMessage(Timetoken);
  

  show all 21 lines

• StreamUpdatesOn()

  Get message and message reaction-related updates for several messages published on the support channel.

  #include "Kismet/GameplayStatics.h"
  #include "PubnubChatSubsystem.h"
  
  UGameInstance* GameInstance = UGameplayStatics::GetGameInstance(this);
  UPubnubChatSubsystem* PubnubChatSubsystem = GameInstance->GetSubsystem<UPubnubChatSubsystem>();
  
  UPubnubChat* Chat = PubnubChatSubsystem ->InitChat("demo", "demo", "my_user");
  
  UPubnubChannel* Channel = Chat->GetChannel("support");
   // Get the channels and save the reference
  UPubnubMessage* Message1 = Channel->GetMessage("16200000000000000");
  UPubnubMessage* Message2 = Channel->GetMessage("16200000000000001");
  
  TArray<UPubnubMessage*> Messages;
  Messages.Add(Message1);

  show all 23 lines

Other examples

• StreamUpdates()

  Stop listening to updates for the message with the timetoken 16200000000000000 published on the support channel.

  auto StopUpdates = Message->StreamUpdates(StreamUpdatesResponse);
  
  StopUpdates->Stop();

• StreamUpdatesOn()

  Stop listening to updates for the last ten messages published on the support channel.

  auto StopUpdates = Message->StreamUpdatesOn(Messages, MessagesStreamUpdatesResponse);
  
  StopUpdates->Stop();