使用WinINet和WinHTTP实现Http访问
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，在这个例程中我使用POST方式，提交数据value1与value2，并从服务器得到他们的和（value1 + value2）。

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。这两套API包含了很多相似的函数与宏定义，呵呵，详细对比请查阅msdn中的文章“Porting WinINet Applications to WinHTTP”，在线MSDN连接：http://msdn2.microsoft.com/en-us/library/aa384068.aspx。在这个例程中，通过一个宏的设置来决定是使用WinHttp还是WinINet。代码如下:

#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。



在这个例程中以上各个流程都进行了简单封装，以便对比两套API函数的些许差异。下面让源代码说话，原工程是一个windows控制台工程，你可以很容易通过拷贝代码重建工程。



另：如果你从服务器得到的返回数据是utf8格式的文本数据，你将需要对返回的数据进行转换才能正确显示中文，日文等。仅供参考，转换为ATL CStringW的函数见下：

#include "stdafx.h"#include <windows.h>#include <stdio.h>#include <stdlib.h>#define _ATL_CSTRING_EXPLICIT_CONSTRUCTORS#include <atlbase.h>#include <atlstr.h>#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#define BUF_SIZE    (1024)// CrackedUrlclass CrackedUrl {    int m_scheme;    CStringW m_host;    int m_port;    CStringW 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)) {            printf("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;    }    int GetPort() const    {        return m_port;    }    LPCWSTR GetPath() const    {        return m_path;    }    static CStringA UrlEncode(const char* p)    {        if (p == 0) {            return CStringA();        }        CStringA 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;    }};// CrackedUrlHINTERNET 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    }}int PostToSite(const LPCWSTR url, const char *form_data, char* &szBuf){ HINTERNET hSession = 0;    HINTERNET hConnect = 0;    HINTERNET hRequest = 0;    CStringW strHeader(L"Content-type: application/x-www-form-urlencoded\r\n");    // Test data    CrackedUrl crackedUrl(url);    CStringA strPostData(form_data);    // Open session.    hSession = OpenSession(L"HttpPost by alien");    if (hSession == NULL) {        //printf("Error:Open session!\n");        return -1;    }    // Connect.    hConnect = Connect(hSession, crackedUrl.GetHostName(), crackedUrl.GetPort());    if (hConnect == NULL) {        //printf("Error:Connect failed!\n");        return -1;    }    // Open request.    hRequest = OpenRequest(hConnect, L"POST", crackedUrl.GetPath(), crackedUrl.GetScheme());    if (hRequest == NULL) {        //printf("Error:OpenRequest failed!\n");        return -1;    }    // Add request header.    if (!AddRequestHeaders(hRequest, strHeader)) {        //printf("Error:AddRequestHeaders failed!\n");        return -1;    }    // Send post data.    if (!SendRequest(hRequest, (const char*)strPostData, strPostData.GetLength())) {        //printf("Error:SendRequest failed!\n");        return -1;    }    // End request    if (!EndRequest(hRequest)) {        //printf("Error:EndRequest failed!\n");        return -1;    }    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;        //printf("Content length:[%s]\n", szBuf);    }    dwSize = BUF_SIZE;    if (QueryInfo(hRequest, statusCodeId, szBuf, &dwSize)) {        szBuf[dwSize] = 0;        //printf("Status code:[%s]\n", szBuf);    }    dwSize = BUF_SIZE;    if (QueryInfo(hRequest, statusTextId, szBuf, &dwSize)) {        szBuf[dwSize] = 0;        //printf("Status text:[%s]\n", szBuf);    }dwSize = BUF_SIZE;ZeroMemory(szBuf, dwSize);if (ReadData(hRequest, szBuf, dwSize, &dwSize)) {szBuf[dwSize] = 0;}    // read data.    /*for (;;) {        dwSize = BUF_SIZE;        if (ReadData(hRequest, szBuf, dwSize, &dwSize) == FALSE) {            break;        }        if (dwSize <= 0) {            break;        }        szBuf[dwSize] = 0;        printf("%s\n", szBuf);    //Output value = value1 + value2    }*/    CloseInternetHandle(hRequest);    CloseInternetHandle(hConnect);    CloseInternetHandle(hSession);    return 0;}DWORD WINAPI ServerThread(LPVOID data){int nRet = 0;WSADATA wsaData;if( (nRet = WSAStartup(0x202, &wsaData)) != 0 ) {printf("WSAStartup() failed: %d\n",nRet);return 0;}SOCKET saccept;SOCKET slisten=socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);if(slisten == INVALID_SOCKET){printf("socket failed:%d\n",WSAGetLastError());return 0;}struct sockaddr_in serv, client;serv.sin_family = AF_INET;serv.sin_port = htons(20000);serv.sin_addr.s_addr = inet_addr("127.0.0.1");if(bind(slisten, (LPSOCKADDR)&serv, sizeof(serv))){printf("bind() failed!");return 0;}if(listen(slisten, 5) == SOCKET_ERROR){printf("listen failed!");return 0;}int len = sizeof(client), size;char buf[1024];while(1){saccept = accept(slisten, (struct sockaddr*)&client, &len);printf("accept client IP:%s port:%d\n", inet_ntoa(client.sin_addr), ntohs(client.sin_port));ZeroMemory(buf, 1024);if((size = recv(saccept, buf, 1024, 0))){printf("buf: %s %d\n", buf, size);}closesocket(saccept);}closesocket(slisten);WSACleanup();}int _tmain(int argc, _TCHAR* argv[]){HANDLE serverThread;char *buffer = new char[BUF_SIZE];serverThread = CreateThread(NULL, 0, ServerThread, NULL, 0, 0);PostToSite(L"http://localhost/chess/login.php","name=alien&pwd=alienchang", buffer);printf("%s\n", buffer);PostToSite(L"http://localhost/chess/chooseRoom.php","uid=1&sid=4", buffer);printf("%s\n", buffer);WaitForSingleObject(serverThread, 1000);return 0;}