WinSock C++编程获取网页

使用WinSock。

#include 
#include 
#include 
#include "winsock2.h"
#include 

#pragma comment(lib, "ws2_32.lib") 

using namespace std;

#define DEFAULT_PAGE_BUF_SIZE 1048576

void main()
{
    WSADATA wsaData;
    int err;
    err = WSAStartup(MAKEWORD(2,2), &wsaData);
    if( err != 0 )
    {
        return;
    }

    // timer is start

    clock_t start, finish;
    double duration;
    start = clock();

    char host[] = "www.baidu.com";
    char *request = "GET / HTTP/1.0\r\nHost: www.baidu.com\r\nConnection: Close\r\n\r\n";

    struct hostent *hp;
    hp = gethostbyname(host);
    if(hp == NULL)
    { 
        cout << "gethostbyname() error in GetIpByHost: " << host << endl;
        return;
    }
    
    // 获取域名对应的IP

    struct in_addr inAddr;
    LPSTR lpAddr;
    lpAddr = hp->h_addr;
    memmove(&inAddr,lpAddr,4);

    int sock, ret = 0, optval = 1;
    struct sockaddr_in sa;
    sa.sin_family = AF_INET;        
    sa.sin_port = htons(80);
    sa.sin_addr.s_addr = inet_addr(inet_ntoa(inAddr));
    
    sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    connect(sock, (SOCKADDR*)&sa, sizeof(sa));
    if(sock == -1)
    {
        return;
    }
    if(sock == -2)
    {
        return;
    }

    // send the "GET" data

    ret = send(sock, request, strlen(request), 0);

    // 网页内容长度。可以从http头部数据中获取 "Content-Length:"

    int m_nContentLength = DEFAULT_PAGE_BUF_SIZE;
    
    char *pageBuf;
    pageBuf = (char *)malloc(m_nContentLength);
    memset(pageBuf, 0, m_nContentLength);

    int bytesRead = 0;
    while(ret > 0)
    {
        ret = recv(sock, pageBuf + bytesRead, m_nContentLength - bytesRead, 0);
        
        if(ret > 0)
        {
            bytesRead += ret;
        }
    }
    pageBuf[bytesRead] = '\0';

    cout << bytesRead << endl;

    // write the html content to the file

    ofstream ofs;
    ofs.open("ofs.txt");
    ofs << pageBuf << endl;

    ofs.close();
    free(pageBuf);
    closesocket(sock);
    WSACleanup();

    // timer is finish

    finish = clock();
    duration = (double)(finish - start) / CLOCKS_PER_SEC;
    cout << "have cost " << duration << " seconds\n";
    
    return;
}