我正在构建一个程序来读取网页。我尝试阅读
http://en.wikipedia.org/wiki/France
但后来我得到了回复：
HTTP/1.0 301 Moved Permanently.
我无法理解的是，新链接（在位置字段中）与我给出的相同......那么重定向页面的新链接在哪里？
这是回应：
HTTP/1.0 301 Moved Permanently
Date: Wed, 16 Jan 2013 22:26:03 GMT
Server: Apache
X-Content-Type-Options: nosniff
Cache-Control: private, s-maxage=0, max-age=0, must-revalidate
Vary: Accept-Encoding,X-Forwarded-Proto,Cookie
Last-Modified: Wed, 16 Jan 2013 22:26:03 GMT
Location: http://en.wikipedia.org/wiki/France
Content-Length: 0
Content-Type: text/html; charset=utf-8
X-Cache: MISS from sq64.wikimedia.org
X-Cache-Lookup: HIT from sq64.wikimedia.org:3128
Age: 45
X-Cache: HIT from amssq32.esams.wikimedia.org
X-Cache-Lookup: HIT from amssq32.esams.wikimedia.org:3128
X-Cache: MISS from amssq35.esams.wikimedia.org
X-Cache-Lookup: MISS from amssq35.esams.wikimedia.org:80
Connection: close
谢谢
根据Eric的回答，我再次测试了我的程序。
我发送了以下命令：
GET http://www.wikipedia.org/wiki/france HTTP/1.1
回应是：
HTTP/1.0 301 Moved Permanently
Date: Thu, 17 Jan 2013 22:36:04 GMT
Server: Apache
Location: http://en.wikipedia.org/wiki/france
Content-Length: 243
Content-Type: text/html; charset=iso-8859-1
X-Cache: MISS from sq64.wikimedia.org
X-Cache-Lookup: MISS from sq64.wikimedia.org:3128
X-Cache: MISS from amssq45.esams.wikimedia.org
X-Cache-Lookup: MISS from amssq45.esams.wikimedia.org:3128
X-Cache: MISS from knsq26.knams.wikimedia.org
X-Cache-Lookup: MISS from knsq26.knams.wikimedia.org:80
Connection: close
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>301 Moved Permanently</title>
</head><body>
<h1>Moved Permanently</h1>
<p>The document has moved <a href="http://en.wikipedia.org/wiki/france">here</a>.</p>
</body></html>
这当然是预料之中的。现在我发送：
GET http://en.wikipedia.org/wiki/france HTTP/1.1
得到的回应是：
HTTP/1.0 301 Moved Permanently
Date: Wed, 16 Jan 2013 22:26:03 GMT
Server: Apache
X-Content-Type-Options: nosniff
Cache-Control: private, s-maxage=0, max-age=0, must-revalidate
Vary: Accept-Encoding,X-Forwarded-Proto,Cookie
Last-Modified: Wed, 16 Jan 2013 22:26:03 GMT
Location: http://en.wikipedia.org/wiki/France
Content-Length: 0
Content-Type: text/html; charset=utf-8
X-Cache: MISS from sq64.wikimedia.org
X-Cache-Lookup: HIT from sq64.wikimedia.org:3128
Age: 45
X-Cache: HIT from amssq32.esams.wikimedia.org
X-Cache-Lookup: HIT from amssq32.esams.wikimedia.org:3128
X-Cache: MISS from amssq35.esams.wikimedia.org
X-Cache-Lookup: MISS from amssq35.esams.wikimedia.org:80
Connection: close
我尝试使用 wget：
wget.exe http://en.wikipedia.org/wiki/france
没关系！页面已加载：
wget.exe http://en.wikipedia.org/wiki/france
--2013-01-18 00:43:06-- http://en.wikipedia.org/wiki/france
Resolving en.wikipedia.org... 91.198.174.225
Connecting to en.wikipedia.org|91.198.174.225|:80... connected.
HTTP request sent, awaiting response... 301 Moved Permanently
Location: http://en.wikipedia.org/wiki/France [following]
--2013-01-18 00:43:06-- http://en.wikipedia.org/wiki/France
Reusing existing connection to en.wikipedia.org:80.
HTTP request sent, awaiting response... 200 OK
Length: 854896 (835K) [text/html]
Saving to: `France'
100%[======================================>] 854,896 573K/s in 1.5s
2013-01-18 00:43:08 (573 KB/s) - `France' saved [854896/854896]
那么我的程序有什么问题吗？
问题是我的程序在内部将给定地址更改为小写。这导致链接中的“france”为小写“f”，而不是 301 响应所需的大写“F”。
我以为 URL 不区分大小写，但现在我知道了：
“虽然域名不区分大小写，但 URL 的其余部分可能会区分大小写”(http://www.wisegeek.com/are-urls-case-sensitive.htm)