星外飞客

apache中基于user-agent的rewrite实例

最近在给一个网站增加手机版本访问，碰到个问题，如何区分客户端是电脑还是手机，查询资料有说通过判断request的User-Agent参数，进而产生不同的行为来，觉得可行，记录下资料。

1. 根据不同的 User-Agent 来给出 response出不同的内容出来，比较高级的让我觉得高级的是，这个通常应该是在代码层来完成的，现在可以通过修改Apache的配置，启用 mod_rewrite 来简单实现：

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Browser Dependent Content

Description:

At least for important top-level pages it is sometimes necessary to provide the optimum of browser dependent content, i.e. one has to provide a maximum version for the latest Netscape variants, a minimum version for the Lynx browsers and a average feature version for all others.

Solution: ….

We cannot use content negotiation because the browsers do not provide their type in that form. Instead we have to act on the HTTP header "User-Agent". The following condig does the following: If the HTTP header "User-Agent" begins with "Mozilla/3", the page foo.html is rewritten to foo.NS.html and and the rewriting stops. If the browser is "Lynx" or "Mozilla" of version 1 or 2 the URL becomes foo.20.html. All other browsers receive page foo.32.html. This is done by the following ruleset:

RewriteCond %{HTTP_USER_AGENT}  ^Mozilla/3.*

RewriteRule ^foo\.html$         foo.NS.html          [L]

RewriteCond %{HTTP_USER_AGENT}  ^Lynx/.*            [OR]

RewriteCond %{HTTP_USER_AGENT}  ^Mozilla/[12].*

RewriteRule ^foo\.html$         foo.20.html          [L]

RewriteRule ^foo\.html$         foo.32.html          [L]

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2. 根据User-Agent的不同，动态的修改response出去的Content-Type,这个尤其就更可贵了，不然如果要修改一个 .mp3的content-type为“video”则需要处理程序读出.mp3的内容，然后在stream被output之前设置一下content-type, 而如今通过apache可以在mod_rewrite里轻松实现:

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RewriteCond  ${lowercase:%{HTTP_USER_AGENT}}  ^dopod-s500

RewriteRule ^(.+\.png) – [T=video/png]

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如果将request的User-Agent全部小写后，里面是以dopod-s500开头的话，这样的ua请求.png的文件的时候，其返回的content-type修改为 video/png .