尽管主机名正确，服务器响应 header 状态代码为 301

Question

我用 c 编写了一个简单的客户端套接字，大部分都成功了。

我遇到的问题是我的客户端套接字从 www.w3.org.

接收到 301 状态，具有讽刺意味的是

观察，当我用我的客户端 c 套接字发送以下 GET 时

GET / HTTP/1.1
Host: time.com
Connection: keep-alive
Accept: */*
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2490.80 Safari/537.36
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-US,en;q=0.8

我收到

HTTP/1.1 200 OK
Server: nginx
Date: Thu, 12 Nov 2015 08:44:34 GMT
Content-Type: text/html; charset=UTF-8
Transfer-Encoding: chunked
Connection: keep-alive
Vary: Accept-Encoding
Last-Modified: Thu, 12 Nov 2015 08:40:48 GMT
Cache-Control: max-age=74, must-revalidate
X-nananana: Batcache
Vary: Cookie
X-hacker: If you're reading this, you should visit automattic.com/jobs and apply to join the fun, mention this header.
X-Pingback: http://time.com/xmlrpc.php
X-UA-Compatible: IE=edge,chrome=1
Link: <http://ti.me/nACNOw>; rel=shortlink
Content-Encoding: gzip
X-ac: 4.ord _dca

但是，当我向 www.w3.org.

发送 GET 请求时

GET / HTTP/1.1
Host: www.w3.org
Connection: keep-alive
Accept: */*
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2490.80 Safari/537.36
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-US,en;q=0.8

我收到

HTTP/1.1 301 Moved Permanently
Content-length: 0
Location: http://www.w3.org/
Connection: close

当google chrome 发送类似的 GET 到 www.w3.org

GET / HTTP/1.1
Host: www.w3.org
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-US,en;q=0.8
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2490.86 Safari/537.36

服务器响应

HTTP/1.1 200 OK
Accept-Ranges: bytes
Cache-Control: max-age=600
Content-Length: 39276
Content-Location: Home.html
Content-Type: text/html; charset=utf-8
Date: Sun, 15 Nov 2015 04:40:47 GMT
ETag: "996c-524790d293380;89-3f26bd17a2f00"
Expires: Sun, 15 Nov 2015 04:50:47 GMT
Last-Modified: Sat, 14 Nov 2015 05:00:14 GMT
P3P: policyref="http://www.w3.org/2014/08/p3p.xml"
Server: Apache/2
TCN: choice
Vary: negotiate,accept

Why does my client's GET receive a 301 despite its near equivalence with Chrome's GET?

Do some websites have a strict set of required HTTP header fields?

Is there a bigger picture that I'm missing?

Answer 1

w3.org 使用永久重定向强制规范 URL www.w3.org。仅请求 w3.org 将导致 HTTP 301。规范的 URL 是一个偏好问题，因此不应假设无前缀的 URL 将始终重定向到 www 前缀为 1.

尽管主机名正确，服务器响应 header 状态代码为 301

Server response header states status code 301 despite correct hostname

http

httpresponse

httprequest

http-headers