[UE4] 製作UDP Plugin

產生一個UE4 Plugin

1. 開啟UE4專案
2. Edit -> Plugins -> New Plugin
3. 選擇 "Blank"，建立一個plugin空殼

編輯 [PluginName].Build.cs，新增UDP所需Module

// 新增Json是因為提供了一個可以外部載入檔案來初始化UDP Sender的方法 (StartUDPSenderViaJson)

以下是插件原始碼

	// Fill out your copyright notice in the Description page of Project Settings.
	#include "UDPReceiver.h"
	// Sets default values
	AUDPReceiver::AUDPReceiver(const FObjectInitializer& ObjectInitializer) : Super(ObjectInitializer)
	{
	// Set this actor to call Tick() every frame. You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;
	ListenSocket = NULL;
	}
	// Called when the game starts or when spawned
	void AUDPReceiver::BeginPlay()
	{
	Super::BeginPlay();
	StartUDPReceiver(TEXT("SocketName"), "127.0.0.1", 8890);
	}
	// Called every frame
	void AUDPReceiver::Tick(float DeltaTime)
	{
	Super::Tick(DeltaTime);
	}
	void AUDPReceiver::EndPlay(const EEndPlayReason::Type EndPlayReason)
	{
	Super::EndPlay(EndPlayReason);
	UDPReceiver->Stop();
	delete UDPReceiver;
	UDPReceiver = nullptr;
	// Clear all sockets!
	// Makes sure repeat plays in Editor dont hold on to old sockets!
	if (ListenSocket)
	{
	ListenSocket->Close();
	ISocketSubsystem::Get(PLATFORM_SOCKETSUBSYSTEM)->DestroySocket(ListenSocket);
	}
	}
	bool AUDPReceiver::StartUDPReceiver(
	const FString& YourChosenSocketName,
	const FString& TheIP,
	const int32 ThePort)
	{
	ScreenMsg("RECEIVER INIT");
	FIPv4Address Addr;
	FIPv4Address::Parse(TheIP, Addr);
	//Create Socket
	FIPv4Endpoint Endpoint(Addr, ThePort);
	//BUFFER SIZE
	int32 BufferSize = 2 * 1024 * 1024;
	ListenSocket = FUdpSocketBuilder(*YourChosenSocketName)
	.AsNonBlocking()
	.AsReusable()
	.BoundToEndpoint(Endpoint)
	.WithReceiveBufferSize(BufferSize);
	FTimespan ThreadWaitTime = FTimespan::FromMilliseconds(100);
	UDPReceiver = new FUdpSocketReceiver(ListenSocket, ThreadWaitTime, TEXT("UDP RECEIVER"));
	UDPReceiver->OnDataReceived().BindUObject(this, &AUDPReceiver::Recv);
	UDPReceiver->Start();
	return true;
	}
	void AUDPReceiver::Recv(const FArrayReaderPtr& ArrayReaderPtr, const FIPv4Endpoint& EndPt)
	{
	ScreenMsg("Received bytes", ArrayReaderPtr->Num());
	TArray<FString> Data;
	*ArrayReaderPtr << Data;
	BPEvent_DataReceived(Data);
	}
	float AUDPReceiver::UDPSender_GetFloatData(UPARAM(ref) TArray<FString>& packet)
	{
	if (packet.Num() == 0) return -1;
	FString s = packet[0];
	packet.RemoveAt(0);
	float result = FCString::Atof(*s);
	return result;
	}

view raw UDPReceiver.cpp hosted with ❤ by GitHub

	// Fill out your copyright notice in the Description page of Project Settings.
	#pragma once
	#include "CoreMinimal.h"
	#include "Networking.h"
	#include "Engine.h"
	#include "GameFramework/Actor.h"
	#include "UDPReceiver.generated.h"
	UCLASS()
	class UDPPLUGIN_API AUDPReceiver : public AActor
	{
	GENERATED_BODY()
	public:
	/** Data has been received!! */
	UFUNCTION(BlueprintImplementableEvent)
	void BPEvent_DataReceived(const TArray<FString>& ReceivedData);
	UFUNCTION(BlueprintCallable, Category = "UDReceiver")
	float UDPSender_GetFloatData(UPARAM(ref) TArray<FString>& packet);
	public:
	FSocket* ListenSocket;
	FUdpSocketReceiver* UDPReceiver = nullptr;
	virtual void Recv(const FArrayReaderPtr& ArrayReaderPtr, const FIPv4Endpoint& EndPt);
	bool StartUDPReceiver(
	const FString& YourChosenSocketName,
	const FString& TheIP,
	const int32 ThePort
	);
	public:
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "UDPReceiver")
	bool ShowOnScreenDebugMessages;
	//ScreenMsg
	FORCEINLINE void ScreenMsg(const FString& Msg)
	{
	UE_LOG(LogTemp, Log, TEXT("%s"), *Msg);
	if (!ShowOnScreenDebugMessages) return;
	GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, *Msg);
	}
	FORCEINLINE void ScreenMsg(const FString& Msg, const float Value)
	{
	UE_LOG(LogTemp, Log, TEXT("%s %f"), *Msg, Value);
	if (!ShowOnScreenDebugMessages) return;
	GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, FString::Printf(TEXT("%s %f"), *Msg, Value));
	}
	FORCEINLINE void ScreenMsg(const FString& Msg, const FString& Msg2)
	{
	UE_LOG(LogTemp, Log, TEXT("%s %s"), *Msg, *Msg2);
	if (!ShowOnScreenDebugMessages) return;
	GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, FString::Printf(TEXT("%s %s"), *Msg, *Msg2));
	}
	public:
	// Sets default values for this actor's properties
	AUDPReceiver(const FObjectInitializer& ObjectInitializer);
	protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;
	public:
	// Called every frame
	virtual void Tick(float DeltaTime) override;
	/** Called whenever this actor is being removed from a level */
	virtual void EndPlay(const EEndPlayReason::Type EndPlayReason) override;
	};

view raw UDPReceiver.h hosted with ❤ by GitHub

	// Fill out your copyright notice in the Description page of Project Settings.
	#include "UDPSender.h"
	// Sets default values
	AUDPSender::AUDPSender(const FObjectInitializer& ObjectInitializer) : Super(ObjectInitializer)
	{
	// Set this actor to call Tick() every frame. You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;
	SenderSocket = NULL;
	}
	// Called when the game starts or when spawned
	void AUDPSender::BeginPlay()
	{
	Super::BeginPlay();
	}
	// Called every frame
	void AUDPSender::Tick(float DeltaTime)
	{
	Super::Tick(DeltaTime);
	}
	// Called whenever this actor is being removed from a level
	void AUDPSender::EndPlay(const EEndPlayReason::Type EndPlayReason)
	{
	Super::EndPlay(EndPlayReason);
	if (SenderSocket)
	{
	SenderSocket->Close();
	ISocketSubsystem::Get(PLATFORM_SOCKETSUBSYSTEM)->DestroySocket(SenderSocket);
	}
	}
	bool AUDPSender::StartUDPSender(const FString& YourChosenSocketName, FString RemoteIP /*= "127.0.0.1"*/, int32 RemotePort /*= 8890*/)
	{
	//Create Remote Address.
	RemoteAddr = ISocketSubsystem::Get(PLATFORM_SOCKETSUBSYSTEM)->CreateInternetAddr();
	bool bIsValid;
	RemoteAddr->SetIp(*RemoteIP, bIsValid);
	RemoteAddr->SetPort(RemotePort);
	if (!bIsValid)
	{
	ScreenMsg("IP address was not valid!" + RemoteIP);
	return false;
	}
	SenderSocket = FUdpSocketBuilder(*YourChosenSocketName)
	.AsReusable()
	.WithBroadcast()
	;
	//Set Send Buffer Size
	int32 SendSize = 2 * 1024 * 1024;
	SenderSocket->SetSendBufferSize(SendSize, SendSize);
	SenderSocket->SetReceiveBufferSize(SendSize, SendSize);
	ScreenMsg("UDP Sender Initialized Successfully!!!");
	return true;
	}
	bool AUDPSender::StartUDPSenderViaJson(FString filePath)
	{
	// Load JSON
	FString loadPath = FPaths::ProjectContentDir() + filePath;
	if (!FPlatformFileManager::Get().GetPlatformFile().FileExists(*loadPath))
	{
	UE_LOG(LogTemp, Warning, TEXT("FILE NOT FOUND %s"), *loadPath);
	return false;
	}
	FString fileData;
	FFileHelper::LoadFileToString(fileData, *loadPath);
	TSharedPtr<FJsonObject> JsonParsed;
	TSharedRef<TJsonReader<TCHAR>> JsonReader = TJsonReaderFactory<TCHAR>::Create(fileData);
	FString IPFromJSON = TEXT("");
	int32 PortFromJSON = 0;
	if (FJsonSerializer::Deserialize(JsonReader, JsonParsed))
	{
	TSharedPtr<FJsonObject> section = JsonParsed->GetObjectField("General");
	IPFromJSON = section->GetStringField("IP");
	PortFromJSON = section->GetIntegerField("Port");
	ScreenMsg("RemoteAddress From JSON: [MyUDP] IP=" + IPFromJSON + ", Port=", PortFromJSON);
	}
	else
	{
	UE_LOG(LogTemp, Warning, TEXT("JSON deserialize failed"));
	return false;
	}
	// Load JSON END
	if (!IPFromJSON.IsEmpty() && PortFromJSON != 0)
	{
	}
	else
	{
	UE_LOG(LogTemp, Warning, TEXT("JSON parsing failed"));
	return false;
	}
	//Create Remote Address.
	RemoteAddr = ISocketSubsystem::Get(PLATFORM_SOCKETSUBSYSTEM)->CreateInternetAddr();
	bool bIsValid;
	RemoteAddr->SetIp(*IPFromJSON, bIsValid);
	RemoteAddr->SetPort(PortFromJSON);
	if (!bIsValid)
	{
	ScreenMsg("IP address was not valid!" + IPFromJSON);
	return false;
	}
	SenderSocket = FUdpSocketBuilder(TEXT("") /* YourChosenSocketName */)
	.AsReusable()
	.WithBroadcast()
	;
	//Set Send Buffer Size
	int32 SendSize = 2 * 1024 * 1024;
	SenderSocket->SetSendBufferSize(SendSize, SendSize);
	SenderSocket->SetReceiveBufferSize(SendSize, SendSize);
	ScreenMsg("UDP Sender Initialized Successfully!!!");
	return true;
	}
	TArray<FString> AUDPSender::UDPSender_AddFloatData(UPARAM(ref) TArray<FString>& packet, float data)
	{
	packet.Add(FString::SanitizeFloat(data));
	return packet;
	}
	bool AUDPSender::UDPSender_SendPacket(TArray<FString> packet)
	{
	if (!SenderSocket)
	{
	ScreenMsg("No sender socket");
	return false;
	}
	int32 BytesSent = 0;
	FArrayWriter Writer;
	Writer << packet;
	SenderSocket->SendTo(Writer.GetData(), Writer.Num(), BytesSent, *RemoteAddr);
	if (BytesSent <= 0)
	{
	const FString Str = "Socket is valid but the sender sent 0 bytes.";
	UE_LOG(LogTemp, Error, TEXT("%s"), *Str);
	ScreenMsg(Str);
	return false;
	}
	ScreenMsg("UDP~ Send Succcess! Bytes Sent = ", BytesSent);
	return true;
	}

view raw UDPSender.cpp hosted with ❤ by GitHub

	// Fill out your copyright notice in the Description page of Project Settings.
	#pragma once
	#include "CoreMinimal.h"
	#include "Networking.h"
	#include "Engine.h"
	#include "GameFramework/Actor.h"
	#include "UDPSender.generated.h"
	UCLASS()
	class UDPPLUGIN_API AUDPSender : public AActor
	{
	GENERATED_BODY()
	public:
	TSharedPtr<FInternetAddr> RemoteAddr;
	FSocket* SenderSocket;
	public:
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "UDPSender")
	bool ShowOnScreenDebugMessages;
	UFUNCTION(BlueprintCallable, Category = "UDPSender")
	bool StartUDPSender(const FString& YourChosenSocketName, FString RemoteIP = "127.0.0.1", int32 RemotePort = 8890);
	/** ProjectContentDir + filePath */
	UFUNCTION(BlueprintCallable, Category = "UDPSender")
	bool StartUDPSenderViaJson(FString filePath);
	UFUNCTION(BlueprintCallable, Category = "UDPSender")
	TArray<FString> UDPSender_AddFloatData(UPARAM(ref) TArray<FString>& packet, float data);
	UFUNCTION(BlueprintCallable, Category = "UDPSender")
	bool UDPSender_SendPacket(TArray<FString> packet);
	//ScreenMsg
	FORCEINLINE void ScreenMsg(const FString& Msg)
	{
	UE_LOG(LogTemp, Log, TEXT("%s"), *Msg);
	if (!ShowOnScreenDebugMessages) return;
	GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, *Msg);
	}
	FORCEINLINE void ScreenMsg(const FString& Msg, const float Value)
	{
	UE_LOG(LogTemp, Log, TEXT("%s %f"), *Msg, Value);
	if (!ShowOnScreenDebugMessages) return;
	GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, FString::Printf(TEXT("%s %f"), *Msg, Value));
	}
	FORCEINLINE void ScreenMsg(const FString& Msg, const FString& Msg2)
	{
	UE_LOG(LogTemp, Log, TEXT("%s %s"), *Msg, *Msg2);
	if (!ShowOnScreenDebugMessages) return;
	GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, FString::Printf(TEXT("%s %s"), *Msg, *Msg2));
	}
	public:
	// Sets default values for this actor's properties
	AUDPSender(const FObjectInitializer& ObjectInitializer);
	protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;
	public:
	// Called every frame
	virtual void Tick(float DeltaTime) override;
	// Called whenever this actor is being removed from a level
	virtual void EndPlay(const EEndPlayReason::Type EndPlayReason) override;
	};

view raw UDPSender.h hosted with ❤ by GitHub

參考資料

• UDP Socket Sender Receiver From One UE4 Instance To Another
• UE4修改自Rama的UDP通信蓝图插件
• JSON Parsed
• JSON Editor Online