Listen and handle different AGS events

Last updated on October 23, 2024

Overview

This guide provides information on how to modify the Extend Event Handler app template to listen and handle different events from AccelByte Gaming Services (AGS).

Prerequisites

Clone an Extend Event Handler app template.

Go

git clone https://github.com/AccelByte/extend-event-handler-go.git

C#

git clone https://github.com/AccelByte/extend-event-handler-csharp.git

Java

git clone https://github.com/AccelByte/extend-event-handler-java.git

Python

git clone https://github.com/AccelByte/extend-event-handler-python.git

Identify and download specific event descriptors

Here is how you can get the protobuf event descriptor for the AGS event you are looking for.

• Identify your AGS event: Go to the API Events page and find the AGS event you are looking for.

• Locate the Protobuf event descriptor: After finding the AGS event, get the URL to the protobuf (*.proto) file on the same page.

• Download the protobuf event descriptor: As an example for this guide, we need the userLoggedIn event. Therefore, we need to download the IAM directory which contains the userLoggedIn event.

Generate stub from event descriptor

Go

Put the iam directory you have downloaded in pkg/proto/accelbyte-asyncapi directory in your Extend Event Handler project.

...
|__ main.go
|__ pkg
    ...
    ├── proto
    │   └── accelbyte-asyncapi
    │       └── iam              # Directory structure containing protobuf files
    ├── pb
    ...
...

Next, in the top-level directory of your Extend Event Handler project, run the following command.

make proto

You will see your stub generated at pkg/pb/accelbyte-asyncapi.

...
|__ main.go
|__ pkg
    ...
    ├── proto
    │   └── accelbyte-asyncapi
    │       └── iam              # Directory containing protobuf files
    ├── pb
    │   └── accelbyte-asyncapi
    │       └── iam              # Directory containing "stub" generated code
    ...
...

C#

Put the iam directory you have downloaded in src/AccelByte.PluginArch.EventHandler.Demo.Server/Protos directory in your Extend Event Handler project.

Then, you need to include the specific protobuf file to be generated by .NET gRPC Tool. Modify src/AccelByte.PluginArch.EventHandler.Demo.Server/AccelByte.PluginArch.EventHandler.Demo.Server.csproj file and add or update the following section.

<ItemGroup>
    <Protobuf Include="Protos\iam\account\v1\account.proto" GrpcServices="Server" />
</ItemGroup>

tips

You can include more than one protobuf file. Just add more <Protobuf> lines inside <ItemGroup>.

Next, use the following command to generate code from the included protobuf files.

dotnet build

Java

Put the iam directory you have downloaded in src/main/proto/accelbyte-asyncapi directory in your Extend Event Handler project.

...

├── src
│   ├── main
│   │   ├── proto                    
│   │   │   └── accelbyte-asyncapi  
|   |   │       └── iam              # Directory containing protobuf files   
...   

Next, use the following command to generate code from the included protobuf files.

make build

Python

Put the iam directory structure you have downloaded in src/app/proto directory in your Extend Event Handler project.

...

├── src
│   ├── app
│   │   ├── proto

Next, use the following command to generate code from the included protobuf files.

make build

Creating your callback implementation

Go

• Create a New Go File: Go to directory pkg/service and create a new Go file. For example loginHandler.go.

• Embed the Generated Stub: In the new Go file, define a struct type that embeds the stub type. For example, if your event is userLoggedIn you will see UnimplementedUserAuthenticationUserLoggedInServiceServer stub and your struct declaration might look something like the following.

  import pb "extend-event-handler/pkg/pb/accelbyte-asyncapi/iam/account/v1"
  
  type LoginHandler struct {
    pb.UnimplementedUserAuthenticationUserLoggedInServiceServer
    // your fields here
  }

• Define OnMessage Methods: Define a method on your new struct named OnMessage. This method should have the same signature as the OnMessage method in the stub, but with your own implementation. This is the method that will be invoked when the AGS event is received.

  import pb "extend-event-handler/pkg/pb/accelbyte-asyncapi/iam/account/v1"
  
  func (o *LoginHandler) OnMessage(ctxt context.Context, msg *pb.UserLoggedIn) (*emptypb.Empty, error) {
    
    // your event handling code here
   
    return &emptypb.Empty{}, nil
  }

C#

• Create a New C# File: Go to directory src/AccelByte.PluginArch.EventHandler.Demo.Server/Services and create a new C# file. For example UserLoggedInService.cs.

• Embed the Generated Stub: In the new C# file, create a new class which inherits UserAuthenticationUserLoggedInService.UserAuthenticationUserLoggedInServiceBase. For example, UserLoggedInService.

  namespace AccelByte.PluginArch.EventHandler.Demo.Server.Services
  {
      public class UserLoggedInService : UserAuthenticationUserLoggedInService.UserAuthenticationUserLoggedInServiceBase
      {
         ...
      }
  }

• Define OnMessage Methods: Override the OnMessage method and implement the logic which will be executed when the AGS event is received.

  public override Task<Empty> OnMessage(UserLoggedIn request, ServerCallContext context)
  {
     ...
  }

Java

• Create a New Java File: Go to directory src/main/java/net/accelbyte/service and create a new Java file. For example LoginHandler.java.

• Embed the Generated Stub: In the new Java file, create a new class which inherits UserAuthenticationUserLoggedInServiceGrpc.UserAuthenticationUserLoggedInServiceImplBase. For example, LoginHandler.

  public class LoginHandler extends UserAuthenticationUserLoggedInServiceGrpc.UserAuthenticationUserLoggedInServiceImplBase {
    ...
  }

• Define OnMessage Methods: Override the onMessage method and implement the logic which will be executed when the AGS event is received.

  @Override
  public void onMessage(UserLoggedIn request, StreamObserver<Empty> responseObserver) {
    ...
  }

Python

• Create a New Python File: Go to directory src/app/services and create a new Python file. For example login_handler.py.

• Embed the Generated Stub: In the new Python file, create a new class which inherits UserAuthenticationUserLoggedInServiceServicer. For example, AsyncLoginHandlerService.

  from app.proto.account_pb2_grpc import UserAuthenticationUserLoggedInServiceServicer
  
  class AsyncLoginHandlerService(UserAuthenticationUserLoggedInServiceServicer):
      ...

• Define OnMessage Methods: Override the OnMessage method and implement the logic which will be executed when the AGS event is received.

  async def OnMessage(self, request: UserLoggedIn, context):
      ...

Registering the event handler struct into the service

Go

Go to main.go in the Event Handler project and register the gRPC service we have created as follows.

import "extend-event-handler/pkg/service"

// gRPC server that you already initialized in the service
s := grpc.NewServer(...)

// Register IAM Handler
loginHandler := service.LoginHandler{} // or service.NewLoginHandler() if you created the constructor method
pb.RegisterUserAuthenticationUserLoggedInServiceServer(s, loginHandler)

C#

Go to src/AccelByte.PluginArch.EventHandler.Demo.Server/Program.cs in the Event Handler project and register the gRPC service we have created as follows.

app.MapGrpcService<UserLoggedInService>();

Java

Go to src/main/java/net/accelbyte/serviceLoginHandler.java in the Event Handler project and register the gRPC service we have created by adding @GRpcService annotation.

@GRpcService
public class LoginHandler extends UserAuthenticationUserLoggedInServiceGrpc.UserAuthenticationUserLoggedInServiceImplBase {
    ...

Python

Go to src/app/__main__.py in the Event Handler project and register the gRPC service we have created as follows.

opts.append(
    AppGRPCServiceOpt(
        AsyncLoginHandlerService(
            logger=logger,
            namespace=namespace
        ),
        AsyncLoginHandlerService.full_name,
        add_UserAuthenticationUserLoggedInServiceServicer_to_server,
    )
)