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 != -1)
   {
       strUrl = strUrl.substr(7);
   }
   else
       return "";
   int indexSlash = strUrl.find("/");
   if(indexSlash != -1)
   {
       return strUrl.substr(0, indexSlash);
   }
   else
       return strUrl;
   return "";
}
string GetRequestStr(string strUrl)
{
   int indexHttp = strUrl.find("http://");
   if(indexHttp != -1)
   {
       strUrl = strUrl.substr(7);
   }
   else
       return "";
   int indexSlash = strUrl.find("/");
   if(indexSlash == -1)
   {
       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 = 0;
   DWORD dwDownloaded = 0;
   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, 0);
 // Specify an HTTP server.
   if (hSession)
       hConnect = WinHttpConnect(hSession, host,
       INTERNET_DEFAULT_HTTP_PORT, 0);
 // 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,
       0, WINHTTP_NO_REQUEST_DATA, 0,
       0, 0);
// End the request.
   if (bResults)
       bResults = WinHttpReceiveResponse(hRequest, NULL);

//obtain the html source code       
   if (bResults)
       do
       {
         // Check for available data.
           dwSize = 0;
           if (!WinHttpQueryDataAvailable( hRequest, &dwSize))
               printf( "Error %u in WinHttpQueryDataAvailable.
",
               GetLastError());
         // Allocate space for the buffer.
           pszOutBuffer = new char[dwSize+1];
           if (!pszOutBuffer)
           {
               printf("Out of memory
");
               dwSize=0;
           }
           else
           {
               // Read the Data.
               ZeroMemory(pszOutBuffer, dwSize+1);
             if (!WinHttpReadData( hRequest, (LPVOID)pszOutBuffer,
                   dwSize, &dwDownloaded))
               {
                   printf( "Error %u in WinHttpReadData.
",
                       GetLastError());
               }
               else
               {
                    //printf("%s", pszOutBuffer);
                   // Data in vFileContent
                    vFileContent.push_back(pszOutBuffer);
                    
               }
             // Free the memory allocated to the buffer.
               delete [] pszOutBuffer;
           }
     } while (dwSize>0);
    // Keep checking for data until there is nothing left.
   // Report any errors.
       if (!bResults)
           printf("Error %d has occurred.
",GetLastError());
     // Close any open handles.
       if (hRequest) WinHttpCloseHandle(hRequest);
       if (hConnect) WinHttpCloseHandle(hConnect);
       if (hSession) WinHttpCloseHandle(hSession);
       
       for(int i=0;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 0;
}

 

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。。