懂HTTP的人进来看一下

asert · 发表于 2007-2-18 17:45:03

下面是一个发送http请求的程序;

httpclient:

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <string.h>
#include <sys/socket.h>
#include <netdb.h>
#define MAXBUF 1024
int main(int Count, char *Strings[])
{
int sockfd, bytes_read, socklen = sizeof(struct sockaddr);
struct sockaddr_in dest, peer;
struct hostent * hptr;
char buffer[MAXBUF];
char straddr[100];
/*---Make sure we have the right number of parameters---*/
if ( Count != 3 )
printf("usage: httpclient <domain> <page>\n");
if ( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0 )
{
perror("socket error");
abort();
}
if((hptr = gethostbyname(Strings[1])) == NULL)
{
fprintf(stderr, "gethostbyname error\n");
exit(1);
}
/*---Initialize server address/port struct---*/
bzero(&dest, sizeof(dest));
dest.sin_family = AF_INET;
dest.sin_port = htons(80); /*default HTTP Server port */
//dest.sin_addr.s_addr = inet_addr(Strings[1]);
memcpy(&dest.sin_addr, hptr->h_addr, sizeof(struct in_addr));
/*---Connect to server---*/
if (connect(sockfd, (struct sockaddr*)&dest, sizeof(dest)) != 0 )
{
perror("connect error");
abort();
}
getpeername(sockfd, &peer, &socklen);
inet_ntop(AF_INET, &peer.sin_addr, straddr, sizeof(straddr));
printf("peer addr : %s, port : %d\n", straddr, ntohs(peer.sin_port));
sprintf(buffer, "GET %s HTTP/1.0\r\nCache-Control: no cache\r\n\r\n", Strings[2]);
//send(sockfd, buffer, strlen(buffer), 0);
write(sockfd, buffer, strlen(buffer));
/*---While there's data, read and print it---*/
do
{
bzero(buffer, sizeof(buffer));
//bytes_read = recv(sockfd, buffer, sizeof(buffer), 0);
bytes_read = read(sockfd, buffer, sizeof(buffer));
if ( bytes_read > 0 )
printf("%s", buffer);
}
while ( bytes_read > 0 );
/*---Clean up---*/
close(sockfd);
return 0;
}

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编译上面的代码:
gcc httpclient.c -o httpclient
然后输入下面的命令
./httpclient news.sina.com.cn /
请求news.sina.com.cn的页面,但是返回的却是:

peer addr : 61.172.201.194, port : 80
HTTP/1.0 403 Forbidden
Server: CachePower/1.3.1.dev
Mime-Version: 1.0
Date: Sun, 18 Feb 2007 09:36:14 GMT
Content-Type: text/html
Content-Length: 1064
Expires: Sun, 18 Feb 2007 09:36:14 GMT
X-Squid-Error: ERR_ACCESS_DENIED 0
X-Cache: MISS from sh-17.sina.com.cn
Connection: close
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<HTML><HEAD><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<TITLE>ERROR: The requested URL could not be retrieved</TITLE>
<STYLE type="text/css"></STYLE>
</HEAD><BODY>
<H1>ERROR</H1>
<H2>The requested URL could not be retrieved</H2>
<HR noshade size="1px">
<P>
While trying to retrieve the URL:
<A HREF="http://61.172.201.194/">http://61.172.201.194/</A>
<P>
The following error was encountered:
<UL>
<LI>
<STRONG>
Access Denied.
</STRONG>
<P>
Access control configuration prevents your request from
being allowed at this time. Please contact your service provider if
you feel this is incorrect.
</UL>
<P>Your cache administrator is <A HREF="mailto:webmaster">webmaster</A>.
<BR clear="all">
<HR noshade size="1px">
<ADDRESS>
Generated Sun, 18 Feb 2007 09:36:14 GMT by sh-17.sina.com.cn (CachePower/1.3.1.dev)
</ADDRESS>
</BODY></HTML>

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有谁知道原因吗?

yyccrasher · 发表于 2007-2-18 18:33:08

你试试www.baidu.com行不行？

如果可以的话，就说明sina是虚拟主机，不能直接用ip访问的，要在http头里包含正确的url（比如news.sina.con.cn）才可以

njkzkj · 发表于 2007-2-18 18:51:28

yyccrasher is right.
同时要考虑一些常见的HTTP RETURN CODE如HTTP的重定向之类的
另外请用CODE方式上传代码，没有缩进的代码很难看懂

asert · 发表于 2007-2-18 20:07:34

./httpclient news.sina.com.cn / 会连接sina主机的ip然后发送:
GET / HTTP/1.0\r\nCache-Control: no cache\r\n\r\n
但是返回的还是上面的Forbidden

./httpclient news.sina.com.cn http://news.sina.com.cn/也试过了,它会发送
GET http://news.sina.com.cn/ HTTP/1.0\r\nCache-Control: no cache\r\n\r\n
但还是Forbidden

应该发送什么样的http请求才可以呢?

realtang · 发表于 2007-2-18 20:32:33

GET %s HTTP/1.0\r\nCache-Control: no cache\r\n\r\n
就凭这行东西就可以打天下啦??
还是看看RFC的HTTP的协议以后再尝试吧.

asert · 发表于 2007-2-18 20:46:36

Post by realtang
GET %s HTTP/1.0\r\nCache-Control: no cache\r\n\r\n
就凭这行东西就可以打天下啦??
还是看看RFC的HTTP的协议以后再尝试吧.

拜托!我这个菜鸟什么时候说过要"打天下"?
我现在只想知道的是我的http请求到底缺少哪一个header field才导致sina发送Forbidden给我的?

希望好心人来帮帮忙
新年快乐

yyccrasher · 发表于 2007-2-18 20:49:17

http request里的Host字段

asert · 发表于 2007-2-18 21:47:08

to Lain:
还是不行,这次我把http请求GET http://news.sina.com.cn/ HTTP/1.1\r\nHost: news.sina.com.cn\r\n\r\n写死在了代码里:

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <string.h>
#include <sys/socket.h>
#include <netdb.h>
#define MAXBUF 1024
int main(int Count, char *Strings[]) {
int sockfd, bytes_read;
struct sockaddr_in dest;
struct hostent * hptr;
char buffer[MAXBUF];
if ( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0 ) {
perror("socket");
exit(1);
}
if((hptr = gethostbyname("news.sina.com.cn")) == NULL) {
fprintf(stderr, "gethostbyname error\n");
exit(1);
}
/*---Initialize server address/port struct---*/
bzero(&dest, sizeof(dest));
dest.sin_family = AF_INET;
dest.sin_port = htons(80); /*default HTTP Server port */
memcpy(&dest.sin_addr, hptr->h_addr, sizeof(struct in_addr));
/*---Connect to server---*/
if (connect(sockfd, (struct sockaddr*)&dest, sizeof(dest)) != 0 ) {
perror("connect");
exit(1);
}
sprintf(buffer, "GET http://news.sina.com.cn/ HTTP/1.1\r\nHost: news.sina.com.cn\r\n\r\n");
write(sockfd, buffer, strlen(buffer));
/*---While there's data, read and print it---*/
do {
bytes_read = read(sockfd, buffer, sizeof(buffer) - 1);
*(buffer + bytes_read) = 0;
if ( bytes_read > 0 )
printf("%s", buffer);
} while ( bytes_read > 0 );
/*---Clean up---*/
close(sockfd);
return 0;
}

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ideawu · 发表于 2007-2-19 17:52:58

GET http://news.sina.com.cn/ HTTP/1.1\r\nHost: news.sina.com.cn\r\n\r\n

改为=>

GET / HTTP/1.1\r\nHost: news.sina.com.cn\r\n\r\n

都叫你看http的rfc了, 你老是不听话.

njkzkj · 发表于 2007-2-19 20:20:29

可以先用ethereal 之类的软件的来拾取一下用FIREFOX 返问SINA之网络报文

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