C++ http

Http访问有两种方式，GET和POST，就编程来说GET方式相对简单点，它不用向服务器提交数据，程序中使用POST方式，
提交数据并从服务器获取返回值。

为实现Http访问，微软提供了二套API：WinINet, WinHTTP。WinHTTP比WinINet更加安全和健壮，可以这么认为WinHTTP是WinINet的升级版本。
程序中，通过一个宏的设置来决定是使用WinHttp还是WinINet。

#define USE_WINHTTP      //Comment this line to user wininet.

下面来说说实现Http访问的流程（两套API都一样的流程）：

1， 首先我们打开一个Session获得一个HINTERNET session句柄；

2， 然后我们使用这个session句柄与服务器连接得到一个HINTERNET connect句柄；

3， 然后我们使用这个connect句柄来打开Http 请求得到一个HINTERNET request句柄；

4， 这时我们就可以使用这个request句柄来发送数据与读取从服务器返回的数据；

5， 最后依次关闭request，connect，session句柄。

/***********************定义HTTP发送所用方法***********************************/
HINTERNET OpenSession(LPCWSTR userAgent = 0)
{
#ifdef USE_WINHTTP
    return WinHttpOpen(userAgent, NULL, NULL, NULL, NULL);;
#else
    return InternetOpen(userAgent, INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
#endif
}

HINTERNET Connect(HINTERNET hSession, LPCWSTR serverAddr, int portNo)
{
#ifdef USE_WINHTTP
    return WinHttpConnect(hSession, serverAddr, (INTERNET_PORT) portNo, 0);
#else
    return InternetConnect(hSession, serverAddr, portNo, NULL, NULL, INTERNET_SERVICE_HTTP, 0, 0);
#endif
}

HINTERNET OpenRequest(HINTERNET hConnect, LPCWSTR verb, LPCWSTR objectName, int scheme)
{
    DWORD flags = 0;
#ifdef USE_WINHTTP
    if (scheme == INTERNET_SCHEME_HTTPS) {
        flags |= WINHTTP_FLAG_SECURE;
    }

    return WinHttpOpenRequest(hConnect, verb, objectName, NULL, NULL, NULL, flags);

#else
    if (scheme == INTERNET_SCHEME_HTTPS) {
        flags |= INTERNET_FLAG_SECURE;
    }

    return HttpOpenRequest(hConnect, verb, objectName, NULL, NULL, NULL, flags, 0);
#endif
}

BOOL AddRequestHeaders(HINTERNET hRequest, LPCWSTR header)
{
    SIZE_T len = lstrlenW(header);
#ifdef USE_WINHTTP
    return WinHttpAddRequestHeaders(hRequest, header, DWORD(len), WINHTTP_ADDREQ_FLAG_ADD);
#else
    return HttpAddRequestHeaders(hRequest, header, DWORD(len), HTTP_ADDREQ_FLAG_ADD);
#endif
}

BOOL SendRequest(HINTERNET hRequest, const void* body, DWORD size)
{
#ifdef USE_WINHTTP
    return WinHttpSendRequest(hRequest, 0, 0, const_cast<void*>(body), size, size, 0);
#else
    return HttpSendRequest(hRequest, 0, 0, const_cast<void*>(body), size);
#endif
}

BOOL EndRequest(HINTERNET hRequest)
{
#ifdef USE_WINHTTP
    return WinHttpReceiveResponse(hRequest, 0);
#else
    // if you use HttpSendRequestEx to send request then use HttpEndRequest in here!
    return TRUE;
#endif
}

BOOL QueryInfo(HINTERNET hRequest, int queryId, char* szBuf, DWORD* pdwSize)
{
#ifdef USE_WINHTTP
    return WinHttpQueryHeaders(hRequest, (DWORD) queryId, 0, szBuf, pdwSize, 0);
#else
    return HttpQueryInfo(hRequest, queryId, szBuf, pdwSize, 0);
#endif
}

BOOL ReadData(HINTERNET hRequest, void* buffer, DWORD length, DWORD* cbRead)
{
#ifdef USE_WINHTTP
    return WinHttpReadData(hRequest, buffer, length, cbRead);
#else
    return InternetReadFile(hRequest, buffer, length, cbRead);
#endif
}

void CloseInternetHandle(HINTERNET hInternet)
{
    if (hInternet)
{
#ifdef USE_WINHTTP
        WinHttpCloseHandle(hInternet);
#else
        InternetCloseHandle(hInternet);
#endif
    }
}

/**********************************************************/
///通过Http方式发送短信
string SendSMS_HTTP(const long ececcid,const string & password ,const string & msisdn, const string &smsContent)
{
 string rtnStr ="-1";
    HINTERNET hSession = 0;
    HINTERNET hConnect = 0;
    HINTERNET hRequest = 0;
    wstring strHeader(L"Content-type: application/x-www-form-urlencoded\r\n");

    // Test data
    CrackedUrl crackedUrl(L"http://pi.f3.cn/SendSMS.aspx");
 string StrPostData = "ececcid=600000&password="+password+"&msisdn="+msisdn+"&smscontent="+smsContent+"&msgtype=5&longcode=";
 
 StrPostData = string_To_UTF8(StrPostData);

    // Open session.
    hSession = OpenSession(L"HttpPost by lyz_sea@163.com");
    if (hSession == NULL) {
        cout<<"Error:Open session!\n";
        return "-1";
    }

    // Connect.
    hConnect = Connect(hSession, crackedUrl.GetHostName(), crackedUrl.GetPort());
    if (hConnect == NULL) {
        cout<<"Error:Connect failed!\n";
        return "-1";
    }

    // Open request.
    hRequest = OpenRequest(hConnect, L"POST", crackedUrl.GetPath(), crackedUrl.GetScheme());
    if (hRequest == NULL) {
        cout<<"Error:OpenRequest failed!\n";
        return "-1";
   }

    // Add request header.
 if (!AddRequestHeaders(hRequest, strHeader.c_str())) {
        cout<<"Error:AddRequestHeaders failed!\n";
        return "-1";
    }

    // Send post data.
 if (!SendRequest(hRequest, StrPostData.c_str(), StrPostData.length())) {
        cout<<"Error:SendRequest failed!\n";
        return "-1";
    }

    // End request
    if (!EndRequest(hRequest)) {
        cout<<"Error:EndRequest failed!\n";
        return "-1";
    }

    char szBuf[BUF_SIZE];
    DWORD dwSize = 0;
    szBuf[0] = 0;

    // Query header info.
#ifdef USE_WINHTTP
    int contextLengthId = WINHTTP_QUERY_CONTENT_LENGTH;
    int statusCodeId = WINHTTP_QUERY_STATUS_CODE;
    int statusTextId = WINHTTP_QUERY_STATUS_TEXT;
#else
    int contextLengthId = HTTP_QUERY_CONTENT_LENGTH;
    int statusCodeId = HTTP_QUERY_STATUS_CODE;
    int statusTextId = HTTP_QUERY_STATUS_TEXT;
#endif
    dwSize = BUF_SIZE;
    if (QueryInfo(hRequest, contextLengthId, szBuf, &dwSize)) {
        szBuf[dwSize] = 0;
        cout<<"Content length: "<<szBuf<<endl;
    }
    dwSize = BUF_SIZE;
    if (QueryInfo(hRequest, statusCodeId, szBuf, &dwSize)) {
        szBuf[dwSize] = 0;
        cout<<"Status code: "<< szBuf<<endl;
    }

    dwSize = BUF_SIZE;
    if (QueryInfo(hRequest, statusTextId, szBuf, &dwSize)) {
        szBuf[dwSize] = 0;
        cout<<"Status text:"<<szBuf<<endl;
    }

    // read data.
    for (;;) {
        dwSize = BUF_SIZE;
        if (ReadData(hRequest, szBuf, dwSize, &dwSize) == FALSE) {
           break;
        }

        if (dwSize <= 0) {
            break;
        }

        szBuf[dwSize] = 0;
        
  rtnStr =::UTF8_To_string(string(szBuf));

  cout<<rtnStr<<endl;//Output 返回值
   
    }

    CloseInternetHandle(hRequest);
    CloseInternetHandle(hConnect);
    CloseInternetHandle(hSession);

 return  rtnStr;
}

以上方法中用到的CrackURL方法在以下CrackURL.h文件中：

#pragma once
//#include<iostream>
//using namespace std;

#define USE_WINHTTP    //Comment this line to user wininet.
 #ifdef USE_WINHTTP
     #include <winhttp.h>
     #pragma comment(lib, "winhttp.lib")
 #else
     #include <wininet.h>
     #pragma comment(lib, "wininet.lib")
 #endif

 // CrackedUrl
 class CrackedUrl {
     int m_scheme;
     wstring m_host;
     int m_port;
     wstring m_path;
 public:
     CrackedUrl(LPCWSTR url)
     {
         URL_COMPONENTS uc = { 0};
         uc.dwStructSize = sizeof(uc);
 
         const DWORD BUF_LEN = 256;
 
         WCHAR host[BUF_LEN];
         uc.lpszHostName = host;
         uc.dwHostNameLength = BUF_LEN;
 
         WCHAR path[BUF_LEN];
         uc.lpszUrlPath = path;
         uc.dwUrlPathLength = BUF_LEN;
 
         WCHAR extra[BUF_LEN];
         uc.lpszExtraInfo = extra;
         uc.dwExtraInfoLength = BUF_LEN;
 
 #ifdef USE_WINHTTP
         if (!WinHttpCrackUrl(url, 0, ICU_ESCAPE, &uc)) {
             cout<<"Error:WinHttpCrackUrl failed!\n";
         }
 
 #else
         if (!InternetCrackUrl(url, 0, ICU_ESCAPE, &uc)) {
             printf("Error:InternetCrackUrl failed!\n");
         }
 #endif
         m_scheme = uc.nScheme;
         m_host = host;
         m_port = uc.nPort;
         m_path = path;
     }
 
     int GetScheme() const
     {
         return m_scheme;
     }
 
     LPCWSTR GetHostName() const
     {
   return m_host.c_str();
    }

    int GetPort() const
     {
         return m_port;
     }
 
     LPCWSTR GetPath() const
     {
   return m_path.c_str();
     }
 
     static string UrlEncode(const char* p)
     {
         if (p == 0) {
             return string();
         }
 
         string buf;
 
        for (;;) {
             int ch = (BYTE) (*(p++));
             if (ch == ‘\0‘) {
                 break;
             }
 
             if (isalnum(ch) || ch == ‘_‘ || ch == ‘-‘ || ch == ‘.‘) {
                 buf += (char)ch;
            }
            else if (ch == ‘ ‘) {
                buf += ‘+‘;
            }
            else {
                char c[16];
                wsprintfA(c, "%%%02X", ch);
                buf += c;
            }
        }

        return buf;
    }
};