VS2008 C++ 利用WinHttp API获取任意Http网址的源码

最近一直在看有关Http的知识，对其基本的理论知识已经有所掌握，想通过一个C++具体的例子进行实际操作。。于是上网查找了很多资料，发现在Windows系统上，可以通过WinHttp API接口开啊Http，于是仿照网上例子编写一个获取网页源码的C++程序。其中的代码基本是copy网友，主要是自己对代码的理解，并以此作为入门。

例子代码如下：

 // WinHttpTest.cpp : 定义控制台应用程序的入口点。
 //
 //#include <stdafx.h>
 #include <vector>
 #include <winsock2.h>
 #include <Winhttp.h>
 //#include <urlmon.h>
 #include <windows.h>
 #include <iostream>
 #include <fstream>
 #include <string>
 #include "AtlBase.h"
 #include "AtlConv.h"
 using namespace std;
 #pragma comment(lib, "winhttp")//这一句不能省略
 string GetHost(string strUrl)
 {
    int indexHttp = strUrl.find("http://");
    if(indexHttp != -)
    {
        strUrl = strUrl.substr();
    }
    else
        return "";
    int indexSlash = strUrl.find("/");
    if(indexSlash != -)
    {
        return strUrl.substr(, indexSlash);
    }
    else
        return strUrl;
    return "";
 }
 string GetRequestStr(string strUrl)
 {
    int indexHttp = strUrl.find("http://");
    if(indexHttp != -)
    {
        strUrl = strUrl.substr();
    }
    else
        return "";
    int indexSlash = strUrl.find("/");
    if(indexSlash == -)
    {
        return "";
    }
    else
        return strUrl.substr(indexSlash);
 }
 string GetHtml(string strUrl)
 {
    string strHost = GetHost(strUrl);//获取Host
    string strRequestStr = GetRequestStr(strUrl);//获取请求路径
    USES_CONVERSION;
     //2014年7月9日10:02:29
     //LPCWSTR的定义 typedef const wchar_t* LPCWSTR;
     //LPSTR的定义   typedef char* LPCWSTR;
     //LPWSTR的定义  typedef wchar_t* LPWSTR;
    LPCWSTR host = A2CW(strHost.c_str());//string转换为常量指针类型
    LPCWSTR requestStr = A2CW(strRequestStr.c_str());
    //Variables
    DWORD dwSize = ;
    DWORD dwDownloaded = ;
    LPSTR pszOutBuffer;
    vector <string>  vFileContent;
    BOOL  bResults = FALSE;

    //Note the definition of HINTERNET
    HINTERNET  hSession = NULL,
        hConnect = NULL,
        hRequest = NULL;
        string strHtml = "";// store the html code
        string str;//temporary variables
        ofstream out("test.html",ios::binary);//output the html code to a html text;
    //2014年7月9日10:39:33
    //Search the WinHttp API
    //what to do when call the function WinHttpOpen？
    // Use WinHttpOpen to obtain a session handle.
    hSession = WinHttpOpen(L"WinHTTP Example/1.0",
        WINHTTP_ACCESS_TYPE_DEFAULT_PROXY,
        WINHTTP_NO_PROXY_NAME,
        WINHTTP_NO_PROXY_BYPASS, );
  // Specify an HTTP server.
    if (hSession)
        hConnect = WinHttpConnect(hSession, host,
        INTERNET_DEFAULT_HTTP_PORT, );
  // Create an HTTP request handle.
    if (hConnect)
        hRequest = WinHttpOpenRequest(hConnect, L"GET", requestStr,
        NULL, WINHTTP_NO_REFERER,
        NULL,
        NULL);
  // Send a request.
    if (hRequest)
        bResults = WinHttpSendRequest(hRequest,
        WINHTTP_NO_ADDITIONAL_HEADERS,
        , WINHTTP_NO_REQUEST_DATA, ,
        , );
 // End the request.
    if (bResults)
        bResults = WinHttpReceiveResponse(hRequest, NULL);

 //obtain the html source code
    if (bResults)
        do
        {
          // Check for available data.
            dwSize = ;
            if (!WinHttpQueryDataAvailable( hRequest, &dwSize))
                printf( "Error %u in WinHttpQueryDataAvailable.\n",
                GetLastError());
          // Allocate space for the buffer.
            pszOutBuffer = new char[dwSize+];
            if (!pszOutBuffer)
            {
                printf("Out of memory\n");
                dwSize=;
            }
            else
            {
                // Read the Data.
                ZeroMemory(pszOutBuffer, dwSize+);
              if (!WinHttpReadData( hRequest, (LPVOID)pszOutBuffer,
                    dwSize, &dwDownloaded))
                {
                    printf( "Error %u in WinHttpReadData.\n",
                        GetLastError());
                }
                else
                {
                     //printf("%s", pszOutBuffer);
                    // Data in vFileContent
                     vFileContent.push_back(pszOutBuffer);

                }
              // Free the memory allocated to the buffer.
                delete [] pszOutBuffer;
            }
      } while (dwSize>);
     // Keep checking for data until there is nothing left.
    // Report any errors.
        if (!bResults)
            printf("Error %d has occurred.\n",GetLastError());
      // Close any open handles.
        if (hRequest) WinHttpCloseHandle(hRequest);
        if (hConnect) WinHttpCloseHandle(hConnect);
        if (hSession) WinHttpCloseHandle(hSession);

        for(int i=;i<(int)vFileContent.size();i++)
        {
            str=vFileContent[i];
            out<<str;
            strHtml += vFileContent[i];
        }
        out.close();
        return strHtml;
 }
 int _tmain(int argc, _TCHAR* argv[])
 {

    string str = GetHtml("http://bbs.bccn.net/thread-294526-1-1.html");
    //output the html code
    //cout << str << endl;
    system("pause");
    return ;
 }

执行后，可以双击tes.html文件运行，也可打开这个文件与通过浏览器打开的网页源码就行对比。。