纯C编写HTTP Client

本文使用纯C在Windows下编写一个简单的HTTP Client，废话不说，直接代码：

#include <stdio.h>#include <winsock2.h>#pragma comment(lib, "ws2_32.lib")char sndBuf[1024] = {0};//发送缓冲char rcvBuf[1<<14] = {0};//接收缓冲int main(int argc, char **argv){    SOCKET sSocket = INVALID_SOCKET;    SOCKADDR_IN stSvrAddrIn = {0}; //服务器端地址    int num = 0;    int nRet = SOCKET_ERROR;    struct hostent *remoteHost;//域名    struct in_addr addr;//ip    //u_long ul = 1;    WSADATA wsaData;    if(argc < 2){        printf("usage: %s <url|IP>\n", argv[0]);        return 1;    }    nRet = WSAStartup(MAKEWORD(2, 0), &wsaData);    if(nRet!=0){        printf("WSAStartup failed!\n");        return 1;    }    remoteHost = gethostbyname(argv[1]); //获取ip地址    if(remoteHost == NULL){        printf("Gethostbyname Error:%d\n",WSAGetLastError());        return 1;    }    addr.s_addr = *(u_long*)remoteHost->h_addr;    //printf("ip: %s\n",inet_ntoa(addr));    //HTTP 消息构造开始，这是程序的关键之处    sprintf(sndBuf, "GET / HTTP/1.1\r\n"        "Host:%s\r\n\r\n",argv[1]);    sSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);    stSvrAddrIn.sin_family = AF_INET;    stSvrAddrIn.sin_port = htons(80);    stSvrAddrIn.sin_addr = addr;    //ioctl(sockfd, FIONBIO, &ul); //设置为非阻塞模式select    nRet = connect(sSocket, (SOCKADDR*)&stSvrAddrIn, sizeof(SOCKADDR));    if (SOCKET_ERROR == nRet){        printf("Connect failed!\n");        return 1;    }    //发送HTTP请求消息    send(sSocket, (char*)sndBuf, sizeof(sndBuf), 0);    //接收HTTP响应消息    while(1)    {        num = recv(sSocket, rcvBuf, sizeof(rcvBuf), 0);        printf("%s\n%d", rcvBuf,num);        if(0>=num){            break;        }    }    return 0;}