[C++] Linux C++ 实现 http请求 (未验证)

Copy From: http://blog.sina.com.cn/s/blog_5cf4a61d0100y1ut.html

使用linux c++实现了http的get请求
传入参数：传入参数是要请求的url
传出参数：请求到的网页
为了方便说明，这里假定url = "http://search.360buy.com/Search?keyword=?Ь&page=67&ev=";
std::string chttpget::run(std::string url)
{
string page;
int sockfd, ret, i, h;
struct sockaddr_in servaddr;
char str[4096],buf[BUFSIZE];
socklen_t len;
fd_set t_set1;
fd_set mask;
struct timeval tv;

if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0 )
{
printf("创建网络连接失败,本线程即将终止---socket error!\n");
exit(0);
};

bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(PORT);
//将域名转为ip地址
struct hostent *host = gethostbyname(search.360buy.com);

char* ipstr = (char *)inet_ntoa(*(struct in_addr *)(host->h_addr));
if (inet_pton(AF_INET, ipstr, &servaddr.sin_addr) <= 0 )
{
printf("创建网络连接失败,本线程即将终止--inet_pton error!\n");
exit(0);
};

// 非阻塞connect
int flags=fcntl(sockfd,F_GETFL,0);
fcntl(sockfd,F_SETFL,flags|O_NONBLOCK);
ret = connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
if (-1 == ret)
{
printf("与远端建立了连接\n");
if(errno != EINPROGRESS)
{
perror("connect");
close(sockfd);
}

FD_ZERO(&mask);
FD_SET(sockfd,&mask);
tv.tv_sec = 1;
tv.tv_usec = 0;

switch(select(sockfd+1,NULL,&mask,NULL,&tv))
{

case -1:
close(sockfd);
case 0:
close(sockfd);

default:
int error=0;
socklen_t len = sizeof(int);
if(getsockopt(sockfd,SOL_SOCKET,SO_ERROR,&error,&len))
{
if(0 == error)
{
printf("has connect");
}
}
}
}else if(0==ret)
{
printf("has connect\n");
}
memset(str, 0, 4096);
// http协议请求字符串，每一行的后面一定要加\n隔开
strcat(str,"GET /Search?keyword=?Ь&page=68&ev= HTTP/1.1\n");
strcat(str, "Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, application/x-ms-application, application/x-ms-xbap, application/vnd.ms-xpsdocument, application/xaml+xml, */* \n");
strcat(str, "Accept-Language: zh-cn\n");
strcat(str,"User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; (R1 1.6); .NET CLR 2.0.50727; .NET CLR 3.0.04506.648; .NET CLR 3.5.21022; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)\n");
strcat(str,"Host:search.360buy.com\n");
strcat(str,"Connection: Keep-Alive");
strcat(str, "\r\n\r\n");
ret = write(sockfd,str,strlen(str));

if (ret < 0)
{
printf("发送失败！错误代码是%d，错误信息是'%s'\n",errno, strerror(errno));
exit(0);
}
else
{
printf("消息发送成功，共发送了%d个字节！\n\n", ret);
}

FD_ZERO(&t_set1);
FD_SET(sockfd, &t_set1);
while(1)
{
//设置超时为1秒，如果1秒还没有反应直接返回
tv.tv_sec= 1;
tv.tv_usec= 0;
h= 0;
memset(buf, 0, sizeof(buf));
h= select(sockfd +1, &t_set1, NULL, NULL, &tv);
if (h == 0)
{
close(sockfd);
return page;
}
if (h < 0) {
close(sockfd);
printf("在读取数据报文时SELECT检测到异常，该异常导致线程终止！\n");
return "";
};
if (h > 0){
memset(buf, 0, sizeof(buf));

i= read(sockfd, buf, sizeof(buf));

if(i>0)
{
page = page + buf;

}else
{
close(sockfd);
return page;
}

}
}
close(sockfd);
return page;
}
这样就完成了一个http请求。