虚幻引擎实现流式Http接口并接入百度文心一言大模型(仅适用于UE5.2之后的版本)

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已于 2025-01-22 11:35:09 修改

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文章标签： 1024程序员节虚幻文心一言 http

于 2024-10-24 11:07:57 首次发布

本文链接：https://blog.youkuaiyun.com/qq_48223371/article/details/143203885

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在UE5.2（不包含5.2）之后，UE的HTTP模块已经实现了对流式接口的支持，我也是偶然间在写流式接接口时发现的，不过没有发现这方面的资料，现在来记录一下，实现流式接口接收百度的文心一言大模型。

注意：5.2之前的版本貌似是没有实现的，5.2之前的版本可能需要自己去扩展引擎的源码或者借助第三方库。

引入模块

首先在代码中引入对应模块，如果是在插件中实现，就在插件的Build.cs文件引入，如果在项目的Source中实现，就在项目的Build.cs文件引入，我这里是插件，所以在插件中引入

插件实现

我们在插件中创建名为AIFunction的文件，文件的类是继承UBlueprintAsyncActionBase

在头文件中，首先我们创建一个结构体，用于我们传入的请求参数，

USTRUCT(BlueprintType)
struct FAIRequest
{
	GENERATED_BODY()


	UPROPERTY(BlueprintReadWrite)
	FString URL;
	UPROPERTY(BlueprintReadWrite)
	TArray<FString> Message;
	UPROPERTY(BlueprintReadWrite)
	FString APIKey;
	UPROPERTY(BlueprintReadWrite)
	FString APISecret;
	UPROPERTY(BlueprintReadWrite)
	FString AppID;
	UPROPERTY(BlueprintReadWrite)
	FString access_token;
	UPROPERTY(BlueprintReadWrite)
	bool stream;
};

接着声明两个枚举类型，用来表示我们请求的AI类型与返回类型，用于蓝图中的多输出节点

UENUM(BlueprintType)
enum class EAIType  : uint8
{
  Baidu UMETA(DisplayName = "百度"),
	Tencent UMETA(DisplayName = "腾讯"),
	Ali UMETA(DisplayName = "阿里"),
	Dianxin UMETA(DisplayName = "电信"),
	XunFei UMETA(DisplayName = "讯飞")
};
UENUM()
enum class EResponseType  : uint8
{
	Completed,
	Failed,
	Stream
};

声明一个多播代理，用于在http返回时将数据传出

DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FAIReceive,FString, Response);

接着我们声明一个SendAI函数，GetBaiduToken函数，BaiduAI函数，来实现调用百度的接口

UCLASS()
class PAASAIMODULE_API UAIFunction: public UBlueprintAsyncActionBase
{
	GENERATED_BODY()


public:


	UPROPERTY(BlueprintAssignable)
	FAIReceive OnCompleted;  //请求完成时
	UPROPERTY(BlueprintAssignable)
	FAIReceive OnFailed;    //请求失败时
	UPROPERTY(BlueprintAssignable)
	FAIReceive OnStream;     //流式请求时


	FHttpRequestStreamDelegate StreamDelegate; //用于http流式请求的代理


	
	UFUNCTION(BlueprintCallable,meta=( BlueprintInternalUseOnly="true" ))
	static  UAIFunction* SendAI( EAIType Type,const FAIRequest& Request);
	UFUNCTION(BlueprintCallable,meta=( BlueprintInternalUseOnly="true" ))
	static  UAIFunction* GetBaiduToken(const FString& apikey, const FString& secretkey);
	
protected:
	
	//自动生成token待完成
	void BaiDuAI(const FAIRequest& Request);


	void DianXinAI(const FAIRequest& Request);
};

我这里使用的异步蓝图节点，非阻塞式的请求http。对于蓝图的异步节点，大家可以自行了解。

完整的.h文件内容为下

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


#pragma once


#include "CoreMinimal.h"
#include "Interfaces/IHttpRequest.h"
#include "Kismet/BlueprintFunctionLibrary.h"
#include "Kismet/BlueprintAsyncActionBase.h"
#include "AIFunction.generated.h"




USTRUCT(BlueprintType)
struct FAIRequest
{
	GENERATED_BODY()


	UPROPERTY(BlueprintReadWrite)
	FString URL;
	UPROPERTY(BlueprintReadWrite)
	TArray<FString> Message;
	UPROPERTY(BlueprintReadWrite)
	FString APIKey;
	UPROPERTY(BlueprintReadWrite)
	FString APISecret;
	UPROPERTY(BlueprintReadWrite)
	FString AppID;
	UPROPERTY(BlueprintReadWrite)
	FString access_token;
	UPROPERTY(BlueprintReadWrite)
	bool stream;
};


UENUM()
enum class EResponseType  : uint8
{
	Completed,
	Failed,
	Stream
};


UENUM(BlueprintType)
enum class EAIType  : uint8
{
	Baidu UMETA(DisplayName = "百度"),
	Tencent UMETA(DisplayName = "腾讯"),
	Ali UMETA(DisplayName = "阿里"),
	Dianxin UMETA(DisplayName = "电信"),
	XunFei UMETA(DisplayName = "讯飞")
	
};
/**
 * 
 */


DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FAIReceive,FString, Response);






UCLASS()
class PAASAIMODULE_API UAIFunction: public UBlueprintAsyncActionBase
{
	GENERATED_BODY()


public:


    UPROPERTY(BlueprintAssignable)
	FAIReceive OnCompleted;  //请求完成时
	UPROPERTY(BlueprintAssignable)
	FAIReceive OnFailed;    //请求失败时
	UPROPERTY(BlueprintAssignable)
	FAIReceive OnStream;     //流式请求时


	FHttpRequestStreamDelegate StreamDelegate;//用于http流式请求的代理


	
	UFUNCTION(BlueprintCallable,meta=( BlueprintInternalUseOnly="true" ))
	static  UAIFunction* SendAI( EAIType Type,const FAIRequest& Request);
	UFUNCTION(BlueprintCallable,meta=( BlueprintInternalUseOnly="true" ))
	static  UAIFunction* GetBaiduToken(const FString& apikey, const FString& secretkey);
	
protected:
	
	//自动生成token待完成
	void BaiDuAI(const FAIRequest& Request);


};

接着我们在cpp文件中实现相应的函数

//函数根据AI类型去调用相应的AI请求
UAIFunction* UAIFunction::SendAI( EAIType Type,const FAIRequest& Request)
{
	UAIFunction* AIFunction = NewObject<UAIFunction>();
	switch (Type)
	{
	case EAIType::Baidu:
		AIFunction->BaiDuAI(Request);
		break;
	case EAIType::Ali:
		break;
	case EAIType::Tencent:
		break;
	case EAIType::Dianxin:
		break;
	default:
		break;
	}
	
	return AIFunction;
}
//获取Baidu的Token
UAIFunction* UAIFunction::GetBaiduToken(const FString& apikey, const FString& secretkey)
{
	UAIFunction* AIFunction = NewObject<UAIFunction>();
	TSharedRef<IHttpRequest, ESPMode::ThreadSafe> HttpRequest = FHttpModule::Get().CreateRequest();
	FString URL = FString::Printf(TEXT("https://aip.baidubce.com/oauth/2.0/token?grant_type=client_credentials&client_id=%s&client_secret=%s"),*apikey,*secretkey );
	HttpRequest->SetURL(URL);
	HttpRequest->SetVerb(TEXT("POST"));
	HttpRequest->SetHeader(TEXT("Content-Type"), TEXT("application/json"));
	HttpRequest->OnProcessRequestComplete().BindLambda(([AIFunction](FHttpRequestPtr Request, FHttpResponsePtr Response, bool bWasSuccessful)
	{
		if (bWasSuccessful && Response.IsValid())
		{
			FString ResponseContent =Response->GetContentAsString();
			TSharedPtr<FJsonObject> ResultObj;
			TSharedRef<TJsonReader<>> Reader = TJsonReaderFactory<>::Create(ResponseContent);
			FJsonSerializer::Deserialize(Reader,ResultObj);
			FString DataString;
			if (ResultObj->TryGetStringField(TEXT("access_token"),DataString))
			{
				AIFunction->OnCompleted.Broadcast(DataString);
			}
		}
		else
		{
			AIFunction->OnFailed.Broadcast(TEXT("失败"));
		}
		
	}));
	HttpRequest->ProcessRequest();
	return AIFunction;


}
//发送AI请求
void UAIFunction::BaiDuAI(const FAIRequest& Request)
{
	AddToRoot();
	TSharedRef<IHttpRequest, ESPMode::ThreadSafe> HttpRequest = FHttpModule::Get().CreateRequest();
	FString URL = FString::Printf(TEXT("%s?access_token=%s"), *Request.URL, *Request.access_token);
	HttpRequest->SetURL(URL);
	HttpRequest->SetVerb(TEXT("POST"));
	HttpRequest->SetHeader(TEXT("Content-Type"), TEXT("application/json"));
	FString OutJsonData;
	TSharedRef<TJsonWriter<>> Writer = TJsonWriterFactory<>::Create(&OutJsonData);


	Writer->WriteObjectStart();						// JSON对象开始
	//Writer->WriteValue(L"category", InfoCategory);  // 填充普通字段
	Writer->WriteArrayStart(L"messages");			// Json 数组字段开始	
	for (FString str : Request.Message)
	{
		Writer->WriteObjectStart();
		Writer->WriteValue(L"role", L"user");		// 填充普通字段
		Writer->WriteValue(L"content", str);	// 填充普通字段
		Writer->WriteObjectEnd();
	}
	Writer->WriteArrayEnd();// Json 数组字段结束
	Writer->WriteValue(L"stream", Request.stream); //是否流式
	Writer->WriteObjectEnd();              //JSON对象结束
	Writer->Close();
	HttpRequest->SetContentAsString(OutJsonData); //设置流式请求代理


	if (Request.stream)
	{
		// 流式请求
		StreamDelegate.BindLambda([=,this](void* st,int64 length)
		{
			if (length >0)
			{
				//处理数据 
				FString str = FString(UTF8_TO_TCHAR(static_cast<const char*>(st)));
				str.RemoveAt(0,5); //去掉返回数据的前置字符，因为百度返回的数据前有一个data:的字符，无法解析
				if (!str.IsEmpty())
				{
					str.ReplaceInline(TEXT("\\n"),TEXT(""));
					str.RemoveSpacesInline();
					TSharedPtr<FJsonObject> ResultObj;
					TSharedRef<TJsonReader<>> Reader = TJsonReaderFactory<>::Create(str);
					FString DataString;
					bool success =  FJsonSerializer::Deserialize(Reader,ResultObj);
					FString Meaasge;
					if (!success)
					{
						return true;
					}
					if (ResultObj->TryGetStringField(TEXT("result"),Meaasge))
					{
						if (!Meaasge.IsEmpty())
						{
							//Meaasge.RemoveFromStart(TEXT("\n")); 从开始删除第一个匹配的字符
							this->OnStream.Broadcast(Meaasge);
						}
					}
					else
					{
						return true;
					}
				}
				return true;
			}
			return false;
		});
		HttpRequest->SetResponseBodyReceiveStreamDelegate(StreamDelegate);
	}
	HttpRequest->OnProcessRequestComplete().BindLambda(([=,this](FHttpRequestPtr Request, FHttpResponsePtr Response, bool bWasSuccessful)
	{
		if (bWasSuccessful && Response.IsValid())
		{
			this->StreamDelegate.Unbind();
			FString ResponseContent =Response->GetContentAsString();
			this->OnCompleted.Broadcast(ResponseContent);
			RemoveFromRoot();
		}
		
	}));


	HttpRequest->ProcessRequest();
}

完成后，编译成功后会有下面两个节点。

注意：在选择了流式接口返回后，正常在请求Completed的时候是不会在返回数据的，也就是说Stream和Completed两个只会有一个有数据。

注：对于百度的模型，大家还是去看一下官方文档会对代码有更多的理解，而且需要去申请相应的账号。

文心一言API接入指南-百度开发者中心https://developer.baidu.com/article/detail.html?id=1089328

开局逆风的才是主角。