C发送http请求

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C语言发送http请求和普通的socket通讯,原理是一样的.无非就三步connect()连上服务器,send()发送数据,recv()接收数据.只不过发送的数据有特定的格式.下面的是简单发送一个http请求的例子

#include <netinet/in.h>#include <sys/socket.h>#include <netdb.h>#include <unistd.h>#include <string.h>#include <stdio.h>int main(int argc, char **argv){    /* 构造查询包 */    const char quary[] =     "GET / HTTP/1.0\r\n"    "Host: blog.csdn.net\r\n"    "\r\n";    const char hostname[] = "blog.csdn.net";    struct sockaddr_in sin;    struct hostent *h;    const char *cp;    int fd;    ssize_t n_written, remaining;    char buf[1024];    /* 查找该域名的地址 */     h = gethostbyname(hostname);    if(h == NULL)    {        fprintf(stderr, "Couldn't lookup %s:%s\n", hostname, hstrerror(h_errno));        return 1;    }    if (h->h_addrtype != AF_INET)    {        fprintf(stderr, "No ipv6 support, sorry.\n");        return 1;    }    /* 创建一个套接字用来连接服务器 */    fd = socket(AF_INET, SOCK_STREAM, 0);    if (fd < 0)    {        perror("socket");        return 1;    }    /* 连接到服务器 */    sin.sin_family = AF_INET;    sin.sin_port = htons(80);    sin.sin_addr = *(struct in_addr*)h->h_addr;    if (connect(fd, (struct sockaddr *)&sin, sizeof(sin)))    {        perror("connect");        close(fd);        return 1;    }    /* 发送请求 */    cp = quary;    remaining = strlen(quary);    while(remaining)    {        n_written = send(fd,cp, remaining, 0);        if (n_written <= 0)        {            perror("send");            return 1;        }        remaining -= n_written;        cp += n_written;    }    /* 获取响应 */    while(1)    {        ssize_t result = recv(fd, buf, sizeof(buf), 0);        if (result == 0)        {            break;        }        else if (result < 0)        {            perror("recv\n");            close(fd);            return 1;        }        fwrite(buf, 1, result, stdout);    }    close(fd);    return 0;}

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