预备工作

1. 添加依赖
   

   Copy 1PrivateDependencyModuleNames.AddRange(
    2    new string[]
    3    {
    4        "CoreUObject",
    5        "Engine",
    6        "Slate",
    7        "SlateCore",
    8        // ... add private dependencies that you statically link with here ...	
    9        "HTTP",
   10    }
   11    );

2. 头文件
   

   Copy1#include "HTTP.h"

FHttpRequestPtr，FHttpResponsePtr，FHttpRequestRef和FHttpResponseRef的定义在Intefaces/IHttpRequest.h中

发送请求

Copy 1FString Token = TEXT("<token string>");
 2
 3FString Auth = FString::Printf(TEXT("Bearer %s"), *Token);
 4FString Url = FString::Printf(TEXT("<url string>"));
 5
 6FHttpRequestRef Req = FHttpModule::Get().CreateRequest();
 7Req->SetTimeout(1050);
 8Req->SetURL(Url);
 9Req->SetVerb(TEXT("GET"));
10Req->SetHeader(TEXT("Authorization"), Auth);
11
12// Req->SetHeader(TEXT("content-Type"), TEXT("application/json"));
13// Req->SetContentAsString(TEXT("<content string>"));
14
15// 此处添加绑定
16
17Req->ProcessRequest();

绑定回调函数

Copy1Req->OnProcessRequestComplete().BindUObject(this, &UFirstGISubsystem::OnHttpResponse);

Copy 1void UFirstGISubsystem::OnHttpResponse(FHttpRequestPtr Request, FHttpResponsePtr Response, bool bSuccess)
 2{
 3    if (bSuccess && Response.IsValid())
 4    {
 5        int32 ResponseCode = Response->GetResponseCode();
 6        FString ResponseContent = Response->GetContentAsString();
 7
 8        UE_LOG(LogTemp, Display, TEXT("[%s][%d]Response Content: %s"), *FString(__FUNCTION__), __LINE__, *ResponseContent);
 9    }
10    else { UE_LOG(LogTemp, Warning, TEXT("[%s][%d]Invalid response"), *FString(__FUNCTION__), __LINE__); }
11}

绑定lambda

Copy 1Req->OnProcessRequestComplete().BindLambda(
 2    [](FHttpRequestPtr Request, FHttpResponsePtr Response, bool bSuccess)
 3    {
 4        if (bSuccess && Response.IsValid())
 5        {
 6            int32 ResponseCode = Response->GetResponseCode();
 7            FString ResponseContent = Response->GetContentAsString();
 8            // TArray<uint8> ResponseContent = Response->GetContent();
 9
10            UE_LOG(LogTemp, Display, TEXT("[%s][%d]Response Content: %s"), *FString(__FUNCTION__), __LINE__, *ResponseContent);
11        }
12        else { UE_LOG(LogTemp, Warning, TEXT("[%s][%d]Invalid response"), *FString(__FUNCTION__), __LINE__); }
13    });

注意

1. Http的请求与回复默认异步，很合理。但如果本身就由另外的线程发送请求，在发送Http请求后等待回复，更易管理
   
   使用FEvent可以实现同步
   

2. 默认在主线程发送Http请求，可设置为子线程发送
   
   5.1 不支持， 5.3 可以
   

   Copy1Req->SetDelegateThreadPolicy(EHttpRequestDelegateThreadPolicy::CompleteOnHttpThread);

POST提交格式

Content Type		写内容方法	取内容方法
application/json	FString	SetContentAsString	GetContentAsString
multipart/form-data	TArray<uint8>	SetContent	GetContent

定义边界

文本内容任意，需要特殊的开始和结束界定

1. 边界字符串
   
   可以使用时间戳，也可以使用GUID
   

   Copy1FString Boundary = TEXT("-----") + FString::FromInt(FDataTime::Now().ToUnixTimestamp());

2. 开始边界和结束边界
   
   以 \r\n 开始和结束
   

   Copy1FString BeginBoundary = TEXT("\r\n--") + Boundary + TEXT("\r\n");
   2FString EndBoundary = TEXT("\r\n--") + Boundary + TEXT("--\r\n");

携带参数

1. 头部说明
   

   Copy1FString ParamHeader = TEXT("Content-Disposition: form-data; name=\"<param name>\"; \r\n");

2. 参数类型
   

   Copy1FString ParamContentType = TEXT("Content-Type: text/plain\r\n\r\n");

3. 参数文本格式
   

   Content-Disposition: form-data; name="<param name>"; \r\n
   Content-Type: text/plain\r\n\r\n
   <参数值>

特例：文件类型参数

1. 头部说明
   

   Copy1FString ParamHeader = TEXT("Content-Disposition: form-data; name=\"file\"; filename=\"<file name>\" \r\n");

2. 参数类型
   

   Copy1FString ParamContentType = TEXT("Content-Type: application/octet-stream\r\n\r\n");

3. 参数文本格式
   

   Content-Disposition: form-data; name="file"; filename="<file name>" \r\n
   Content-Type: application/octet-stream\r\n\r\n
   <文本内容>

完整文本

<BeginBoundary>
<参数1>
<BeginBoundary>
<参数2>
<EndBoundary>

设置Http请求头部参数

1. 长度
   

   Copy1Req->SetHeader(TEXT("Content-Length"), TEXT("<Content length>"));

2. 负载类型和边界
   

   Copy1FString ContentType = FString::Printf(TEXT("multipart/form-data; boundary=%s"), *Boundary);