UE5- socket客户端写法

# 实现目标

• ue5 c++ 实现socket客户端，读取服务端数据，并进行解析

#实现步骤

1. {projectName}.Build.cs里增加 "WebSockets","JsonUtilities", "Json"配置信息，最终输出如下：

   using UnrealBuildTool;
   
   public class myue521 : ModuleRules
   {
   	public myue521(ReadOnlyTargetRules Target) : base(Target)
   	{
   		PCHUsage = PCHUsageMode.UseExplicitOrSharedPCHs;
   
   		PublicDependencyModuleNames.AddRange(new string[] { "Core", "CoreUObject", "Engine", "InputCore"
           , "HeadMountedDisplay", "EnhancedInput"
           , "WebSockets","JsonUtilities", "Json"});
   	}
   }

   说明，其中myue521是我的模块名，文件名为myue521.Build.cs。 新增的模块："WebSockets","JsonUtilities", "Json"。

2. 准备实现自己的webscoket_client。具体操作步骤如下：

   1. 在ue5中自定义类，父类设置为UGameInstance,我这命名为UUWebSocketGameInstance

       

   2. 在UUWebSocketGameInstance.h里新增如下方法。

      1. 其中init和 Shutdown方法是在父类UGameInstance中定义的，我们这里覆盖它；

      2. WebSocket用来标识我们代码生成的socket，计划在init里初始化，在Shutdown里销毁

      3. OnConnected、OnConnectionError、OnClosed、OnMessage、OnMessageSent用来处理socket消息，具体看后买你的代码实现。

   3. 在UUWebSocketGameInstance.cpp里实现已经生命的方法。

      // Fill out your copyright notice in the Description page of Project Settings.
      
      
      #include "UWebSocketGameInstance.h"
      #include "WebSockets/Public/WebSocketsModule.h"
      #include "WebSockets/Public/IWebSocket.h"
      #include "Templates/SharedPointer.h"
      
      
      void UUWebSocketGameInstance::Init() {
      	Super::Init();
      
      	if (!FModuleManager::Get().IsModuleLoaded("WebSockets")) {
      		FModuleManager::Get().LoadModule("WebSockets");
      	}
      
      	WebSocket = FWebSocketsModule::Get().CreateWebSocket("ws://127.0.0.1:8081/webSocketServer/ue");
      	 
      	WebSocket->OnConnected().AddUObject(this, &UUWebSocketGameInstance::OnConnected);
      	WebSocket->OnConnectionError().AddUObject(this, &UUWebSocketGameInstance::OnConnectionError);
      	WebSocket->OnClosed().AddUObject(this, &UUWebSocketGameInstance::OnClosed);
      	WebSocket->OnMessage().AddUObject(this, &UUWebSocketGameInstance::OnMessage);
      	WebSocket->OnMessageSent().AddUObject(this, &UUWebSocketGameInstance::OnMessageSent);
      
      	WebSocket->Connect();
      
      }
       
      
      void UUWebSocketGameInstance::Shutdown() {
      
      	if (WebSocket->IsConnected()) {
      		WebSocket->Close();
      	} 
      	Super::Shutdown();
      }
      
      
      
      void UUWebSocketGameInstance::OnConnected()
      {
      	UE_LOG(LogTemp, Warning, TEXT("%s"), *FString(__FUNCTION__));
      
      	GEngine->AddOnScreenDebugMessage(-1, 3.0f, FColor::Green, "Successfully Connected");
      }
      
      void UUWebSocketGameInstance::OnConnectionError(const FString& Error)
      {
      	UE_LOG(LogTemp, Warning, TEXT("%s Error:%s"), *FString(__FUNCTION__), *Error);
      }
      
      void UUWebSocketGameInstance::OnClosed(int32 StatusCode, const FString& Reason, bool bWasClean)
      {
      	UE_LOG(LogTemp, Warning, TEXT("%s StatusCode:%d Reason:%s bWasClean:%d"),
      		*FString(__FUNCTION__), StatusCode, *Reason, bWasClean);
      }
      
      void UUWebSocketGameInstance::OnMessage(const FString& Message)
      {
      	GEngine->AddOnScreenDebugMessage(-1, 3.0f, FColor::Cyan, FString::Printf(TEXT("%s Message:%s"), *FString(__FUNCTION__), *Message) );
      
      	UE_LOG(LogTemp, Warning, TEXT("%s Message:%s"), *FString(__FUNCTION__), *Message);
      
      	TSharedRef< TJsonReader<> > Reader = TJsonReaderFactory<>::Create(Message);
      	TSharedPtr Root;
      
      	if (FJsonSerializer::Deserialize(Reader, Root))
      	{
      		if (Root->HasField(TEXT("Topic"))) {
      			FString Topic = Root->GetStringField(TEXT("Topic"));
      			TSharedPtr Data = Root->GetObjectField(TEXT("Data"));
      
      			// TSharedPtr ObjectField = Object->GetObjectField(TEXT("realtime"));
      			FString KeyField = Data->GetStringField("Key");
      			FString ValueField = Data->GetStringField("Value");
      
      
      			GEngine->AddOnScreenDebugMessage(-1, 3.0f, FColor::Cyan, "Key: " + KeyField + ",Value:" + ValueField);
      		}
      		else {
      			GEngine->AddOnScreenDebugMessage(-1, 3.0f, FColor::Cyan, "解析json异常");
      		}
      	}
      }
      
      void UUWebSocketGameInstance::OnMessageSent(const FString& MessageString)
      {
      	UE_LOG(LogTemp, Warning, TEXT("%s MessageString:%s"), *FString(__FUNCTION__), *MessageString);
      }
      
      

      1. 其中UUWebSocketGameInstance::Init()里初始化了websocket,并配置监听方法

      2. UUWebSocketGameInstance::Shutdown()用来销毁生成的websocket

      3. UUWebSocketGameInstance::OnConnected（），UUWebSocketGameInstance::OnConnectionError，UUWebSocketGameInstance::OnClosed，UUWebSocketGameInstance::OnMessage，UUWebSocketGameInstance::OnMessageSent是用来处理绑定消息的。其中UUWebSocketGameInstance::OnMessage里的消息是json格式，具体格式见下面的备注1.

3. 开始配置使用并调用方法。

   1. 自主调用可以在某个Character里通过如下代码进行调用。可以在自己的类里面调用。比如放到构造方法或者某个动作触发调用。

      void Amyue521Character::NotifyServer() {
      	UUWebSocketGameInstance* GameInstance = Cast(GetGameInstance());
      	if (GameInstance) {
      		if (GameInstance->WebSocket->IsConnected()) {
      			GameInstance->WebSocket->Send("FROM UnrealEngine 5");
      		}
      	}
      }

   2. 通过UE5的项目设置进行修改游戏实例。

       

4. 备注

   1. 约定接收的json数据格式为

      {
          "Topic": "Unreal",
          "Data": {
              "Key": "mood",
              "Value": 1.0
          }
       }

5. 总结

   1.  通过该例子我们学到了websocket,json的应用

   2. 还学到的两种打印log的方法

      GEngine->AddOnScreenDebugMessage(-1, 3.0f, FColor::Cyan, FString::Printf(TEXT("%s Message:%s"), *FString(__FUNCTION__), *Message) );
      
      UE_LOG(LogTemp, Warning, TEXT("%s Message:%s"), *FString(__FUNCTION__), *Message);

6. 待解决的问题

   1. 为什么使用UGameInstance， UGameInstance在UE5中充当什么角色