Message history

PubNub APIs let you effectively fetch historical messages from direct, group, or public conversations.

While App Context API lets you manage metadata and relationships between users and channels, enabling efficient tracking of which channels are associated with a given user, Message Persistence API lets you retrieve messages from those channels. Together, these APIs enable you to gather all conversations involving a user and easily fetch specific message histories for any interactions between users.

Use GetHistory() to fetch past messages from a channel.

API limitation

Results cannot be filtered by message type. All messages within the specified timeframe are returned.

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

• In Blueprints, you can access PubNub from any Widget or Actor. Start by initializing chat using InitChat on UPubnubChatSubsystem. Afterwards, you can use the returned UPubnubChat object reference to call all Chat SDK functions.

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 UPubnubChatSubsystem as any other Game Instance Subsystem.

  1
  

  Chat now allows you to call all Chat SDK functions, for example, Chat->GetChannel("my_channel").

Usage in Blueprints and C++

Asynchronous and synchronous method execution

Most PubNub Unreal SDK methods are available in both asynchronous and synchronous variants.

• Asynchronous methods (Async suffix) return void and take an optional delegate parameter that fires when the operation completes.

  1Channel->GetHistoryAsync(StartTimetoken, EndTimetoken, OnGetHistoryResponseDelegate);

  You can also use native callbacks that accept lambdas instead of dynamic delegates. Native callback types have the Native suffix (for example, FOnPubnubChatGetHistoryResponseNative).

• Synchronous methods (no suffix) block the main game thread until the operation completes and return a result struct directly.

  1FPubnubChatGetHistoryResult Result = Channel->GetHistory(StartTimetoken, EndTimetoken);

Method signature

C++ / Input parameters

1Channel->GetHistory(
2    FString StartTimetoken,
3    FString EndTimetoken,
4    int Count = 25
5);

Blueprint

Input parameters

* required

Parameter	Description
StartTimetoken * Type: FString Default: n/a	Timetoken delimiting the start of a time slice (exclusive) to pull messages from. For details, refer to the Fetch History section.
EndTimetoken * Type: FString Default: n/a	Timetoken delimiting the end of a time slice (inclusive) to pull messages from. For details, refer to the Fetch History section.
Count Type: int Default: 25	Number of historical messages to return for the channel in a single call. Default is 25. Since each call returns all attached message reactions by default, it is recommended to keep this value low; the server supports up to 100 messages per request.

Output

Field	Type	Description
Result	FPubnubChatOperationResult	Operation result with Error and ErrorMessage.
Messages	TArray<UPubnubChatMessage*>	Array listing the requested number of historical Message objects.
IsMore	bool	Indicates if more messages exist beyond the returned range.

By default, each call returns all message reactions and metadata attached to the retrieved messages.

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.

Retrieve message history for a channel asynchronously.

C++

Actor.h

1

Actor.cpp

1

Blueprint