ue 5.5 c++ mqtt 订阅/发布 json

测试可以发送，接收长度小于100的字符串消息，长消息，会崩溃。

cpp 复制代码

        PublicDependencyModuleNames.AddRange(new string[] { "Core", "CoreUObject", "Engine", "InputCore",
            "EnhancedInput",
            "WebSockets",
            "Json",
            "JsonUtilities", "MQTTCore",
            "AudioMixer"});

MyObject类代码：

MyObject.h

cpp 复制代码

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "UObject/NoExportTypes.h"
#include "IMQTTClient.h"
#include "Json.h"
#include "JsonUtilities.h"
#include "Misc/Base64.h"
#include "Misc/FileHelper.h"

#include "MyObject.generated.h"


UCLASS(BlueprintType, Blueprintable)
class METAHUMANCHARACTERHEIXI_API UMyObject : public UObject
{
	GENERATED_BODY()
public:

	//UPROPERTY()
	TSharedPtr<IMQTTClient, ESPMode::ThreadSafe> MQTTClient;

	UFUNCTION(BlueprintCallable, Category = "Demo")
	void HelloWorld();
	void SaveWav(const FString& FilePath, const TArray<uint8>& AudioBytes, int32 SampleRate, int32 NumChannels);
	void AppendAudioChunk(const TArray<uint8>& Chunk);

	TArray<uint8> ReceivedAudioBuffer;

protected:
	virtual void BeginDestroy() override;
};

MyObject.cpp

cpp 复制代码

// Fill out your copyright notice in the Description page of Project Settings.


#include "MyObject.h"

#include "MQTTSubsystem.h"
#include "IMQTTCoreModule.h"
#include "MQTTClientSettings.h"
#include "Async/Async.h"
#include "MQTTShared.h"
#include "Engine/Engine.h"

//TSharedPtr<IMQTTClient, ESPMode::ThreadSafe> UMyObject::MQTTClient = nullptr;

void UMyObject::SaveWav(const FString& FilePath, const TArray<uint8>& AudioBytes, int32 SampleRate, int32 NumChannels)
{
	if (AudioBytes.Num() == 0) return;

	const int32 BitsPerSample = 16;
	const int32 BlockAlign = NumChannels * BitsPerSample / 8;
	const int32 ByteRate = SampleRate * BlockAlign;
	const int32 DataSize = AudioBytes.Num();
	const int32 ChunkSize = 36 + DataSize;

	TArray<uint8> Wav;
	Wav.Reserve(44 + DataSize); // 头44字节 + PCM数据

	auto AppendInt32 = [&Wav](int32 V)
		{
			Wav.Append(reinterpret_cast<uint8*>(&V), sizeof(int32));
		};

	auto AppendInt16 = [&Wav](int16 V)
		{
			Wav.Append(reinterpret_cast<uint8*>(&V), sizeof(int16));
		};

	// --- WAV Header ---
	Wav.Append(reinterpret_cast<const uint8*>("RIFF"), 4);
	AppendInt32(ChunkSize);
	Wav.Append(reinterpret_cast<const uint8*>("WAVE"), 4);

	Wav.Append(reinterpret_cast<const uint8*>("fmt "), 4);
	AppendInt32(16);           // fmt chunk size
	AppendInt16(1);            // PCM format
	AppendInt16(NumChannels);
	AppendInt32(SampleRate);
	AppendInt32(ByteRate);
	AppendInt16(BlockAlign);
	AppendInt16(BitsPerSample);

	Wav.Append(reinterpret_cast<const uint8*>("data"), 4);
	AppendInt32(DataSize);

	// --- PCM Data ---
	Wav.Append(AudioBytes);

	FFileHelper::SaveArrayToFile(Wav, *FilePath);
}


void UMyObject::AppendAudioChunk(const TArray<uint8>& Chunk)
{
	ReceivedAudioBuffer.Append(Chunk);
}

void UMyObject::HelloWorld()
{
	UE_LOG(LogTemp, Warning, TEXT("Hello World from UMyObject!"));

	if (GEngine)
	{
		GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Green, TEXT("Hello World from UMyObject!"));
	}

	IMQTTCoreModule& MQTTModule = FModuleManager::LoadModuleChecked<IMQTTCoreModule>("MQTTCore");
	FMQTTURL URL;
	URL.Host = TEXT("127.0.0.1");
	URL.Port = 1883;
	MQTTClient = MQTTModule.GetOrCreateClient(URL);

	if (!MQTTClient.IsValid())
	{
		UE_LOG(LogTemp, Error, TEXT("MQTTClient 无效！"));
		return;
	}

	TSharedPtr<IMQTTClient> LocalClient = MQTTClient;

	MQTTClient->OnMessage().AddLambda([](const FMQTTClientMessage& Msg)
		{
			// 拷贝数据
			FString TopicCopy = Msg.Topic;
			TArray<uint8> PayloadCopy = Msg.Payload;

			// 切回 GameThread，显式 Move 捕获
			AsyncTask(ENamedThreads::GameThread,
				[TopicCopy = MoveTemp(TopicCopy), PayloadCopy = MoveTemp(PayloadCopy)]()
				{
					if (TopicCopy == "ue/audio")
					{
						FString FilePath = FPaths::ProjectSavedDir() / TEXT("received.wav");

						if (PayloadCopy.Num() > 0)
						{
							UE_LOG(LogTemp, Error, TEXT("[MQTT] start Saved audio "));
							const int32 SampleRate = 44100;
							const int32 NumChannels = 1;
							const int32 BitsPerSample = 16;
							const int32 BlockAlign = NumChannels * BitsPerSample / 8;
							const int32 ByteRate = SampleRate * BlockAlign;
							const int32 DataSize = PayloadCopy.Num();
							const int32 ChunkSize = 36 + DataSize;

							TArray<uint8> Wav;
							Wav.Reserve(44 + DataSize);

							auto AppendInt32 = [&Wav](int32 V) { Wav.Append(reinterpret_cast<uint8*>(&V), sizeof(int32)); };
							auto AppendInt16 = [&Wav](int16 V) { Wav.Append(reinterpret_cast<uint8*>(&V), sizeof(int16)); };

							// WAV header
							Wav.Append(reinterpret_cast<const uint8*>("RIFF"), 4);
							AppendInt32(ChunkSize);
							Wav.Append(reinterpret_cast<const uint8*>("WAVE"), 4);
							Wav.Append(reinterpret_cast<const uint8*>("fmt "), 4);
							AppendInt32(16);
							AppendInt16(1);
							AppendInt16(NumChannels);
							AppendInt32(SampleRate);
							AppendInt32(ByteRate);
							AppendInt16(BlockAlign);
							AppendInt16(BitsPerSample);
							Wav.Append(reinterpret_cast<const uint8*>("data"), 4);
							AppendInt32(DataSize);

							// PCM 数据
							Wav.Append(PayloadCopy);

							FFileHelper::SaveArrayToFile(Wav, *FilePath);
							UE_LOG(LogTemp, Error, TEXT("[MQTT] Saved audio, size=%d bytes"), DataSize);
						}
					}
					else if (TopicCopy == "ue/messages")
					{
						//FString PayloadStr(UTF8_TO_TCHAR(PayloadCopy.GetData()));

						const uint8* DataPtr = PayloadCopy.GetData();
						int32 DataSize = PayloadCopy.Num();

						FString PayloadStr(DataSize, UTF8_TO_TCHAR((const char*)DataPtr));

						TSharedPtr<FJsonObject> JsonObject;
						TSharedRef<TJsonReader<>> Reader = TJsonReaderFactory<>::Create(PayloadStr);

						if (FJsonSerializer::Deserialize(Reader, JsonObject) && JsonObject.IsValid())
						{
							FString Type = JsonObject->GetStringField("type");
							if (Type == "command")
							{
								FString CommandData = JsonObject->GetStringField("data");
								UE_LOG(LogTemp, Log, TEXT("[MQTT] Command: %s"), *CommandData);

								if (GEngine)
								{
									GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Yellow,
										FString::Printf(TEXT("MQTT Command: %s"), *CommandData));
								}
							}
							else {
								UE_LOG(LogTemp, Error, TEXT("[MQTT] DataSize: %d"), DataSize);
							}
						}
					}
				});
		});

	MQTTClient->OnConnect().AddLambda([LocalClient](EMQTTConnectReturnCode ReturnCode)
		{
			// 后台线程回调
			AsyncTask(ENamedThreads::GameThread, [ReturnCode, LocalClient]()
				{
					if (ReturnCode == EMQTTConnectReturnCode::Accepted)
					{
						UE_LOG(LogTemp, Warning, TEXT("MQTT Connected!"));
						if (GEngine) {
							GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Green, TEXT("conn ok"));
						}

						//TArray<TPair<FString, EMQTTQualityOfService>> TopicsToSubscribe;
						//TopicsToSubscribe.Add(MakeTuple(FString("ue/messages"), EMQTTQualityOfService::Once));
						//TopicsToSubscribe.Add(MakeTuple(FString("ue/audio"), EMQTTQualityOfService::Once));

						//// 订阅 topic
						//if (UMyObject::MQTTClient.IsValid())
						//{
						//	UMyObject::MQTTClient->Subscribe(TopicsToSubscribe);

						//	if (GEngine)
						//	{
						//		GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Green, TEXT("MQTT TopicsToSubscribe ok"));
						//	}
						//}

						TArray<TPair<FString, EMQTTQualityOfService>> TopicsToSubscribe;
						TopicsToSubscribe.Add(MakeTuple(FString("ue/messages"), EMQTTQualityOfService::Once));
						TopicsToSubscribe.Add(MakeTuple(FString("ue/audio"), EMQTTQualityOfService::Once));

						LocalClient->Subscribe(TopicsToSubscribe);

						UE_LOG(LogTemp, Error, TEXT("MQTT TopicsToSubscribe ok"));

						if (GEngine) {
							GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Green, TEXT("MQTT TopicsToSubscribe ok"));
						}

					/*	if (LocalClient.IsValid()) {
							FTimerHandle TimerHandle;
							GWorld->GetTimerManager().SetTimer(TimerHandle, [LocalClient]() {
								if (LocalClient.IsValid()) {
									TArray<TPair<FString, EMQTTQualityOfService>> TopicsToSubscribe;
									TopicsToSubscribe.Add(MakeTuple(FString("ue/messages"), EMQTTQualityOfService::Once));
									TopicsToSubscribe.Add(MakeTuple(FString("ue/audio"), EMQTTQualityOfService::Once));

									LocalClient->Subscribe(TopicsToSubscribe);

									UE_LOG(LogTemp, Error, TEXT("MQTT TopicsToSubscribe ok"));

									if (GEngine) {
										GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Green, TEXT("MQTT TopicsToSubscribe ok"));
									}
								}
								}, 0.1f, false);
						}*/
					}
					else
					{
						UE_LOG(LogTemp, Error, TEXT("MQTT con failed，ReturnCode=%d"), static_cast<int32>(ReturnCode));
					}
				});
		});

	/*MQTTClient->OnConnect().AddLambda([LocalClient](EMQTTConnectReturnCode ReturnCode)
		{
			if (ReturnCode == EMQTTConnectReturnCode::Accepted)
			{
				UE_LOG(LogTemp, Error, TEXT("MQTT conn ok"));

				TArray<TPair<FString, EMQTTQualityOfService>> TopicsToSubscribe;
				TopicsToSubscribe.Add(MakeTuple(FString("ue/messages"), EMQTTQualityOfService::Once));
				TopicsToSubscribe.Add(MakeTuple(FString("ue/audio"), EMQTTQualityOfService::Once));

				LocalClient->Subscribe(TopicsToSubscribe);
				UE_LOG(LogTemp, Error, TEXT("MQTT TopicsToSubscribe ok"));
				if (GEngine)
				{
					GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Green, TEXT("MQTT TopicsToSubscribe ok"));
				}
			}
			else
			{
				UE_LOG(LogTemp, Warning, TEXT("MQTT con failed，ReturnCode=%d"), static_cast<int32>(ReturnCode));
			}
		});*/
	/*FTimerHandle TimerHandle;
	GetWorld()->GetTimerManager().SetTimer(TimerHandle, [this]()
		{
			if (MQTTClient.IsValid())
			{
				MQTTClient->Connect();
			}
		}, 0.1f, false);*/

	MQTTClient->Connect();
	if (GEngine)
	{
		GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Green, TEXT("IMQTTCoreModule 127.0.0.1----------!"));
	}
}

void UMyObject::BeginDestroy()
{
	// 确保后台线程不再访问 MQTTClient
	if (MQTTClient.IsValid())
	{
		// 断开连接
		MQTTClient->Disconnect();

		UE_LOG(LogTemp, Error, TEXT("MQTT Disconnect"));
		MQTTClient.Reset();
	}

	Super::BeginDestroy();
}