URI redirection (2)

目次

• 1.0.0 Location
• 2.0.0 Description
• 3.0.0 Redirection loop

Location

	$web/etc/rewrite

Description

This file is used to give valid URI to the client.
URI redirection takes two steps. The first is by /sys/lib/httpd.rewrite and the second is by $web/etc/rewrite. The former is managed by the server administrator and the latter, by the document administrator.

The first field is a path from document root, therefore

• first field begins with "/"
  
• first field cannot begin with "/~"
  

The format allowed in second field is one of:

• scheme://hostdom[:port][/path][;params][?query]
  
• /path[;params][?query]
  

where [ ] is meta symbol that denote inside of these symbol can be omitted and

• scheme :: any scheme
  
• hostdom :: full name of host (pegasus.goodwill.com for example)
  
• port :: port number
  
• path :: path to document
  
• params :: argument list for CGI
  
• query :: query string
  

The matched portion is replaced by the string of second field. See also path matching.

Redirection loop

Let's consider about

/private		https://pegasus.goodwill.com/private

that appeared in case study of /sys/lib/httpd.rewrite.
Why bob wrote such a line? He wanted to use https for /private.
Request will come at first time with http://pegasus.goodwill.com/private. The request will then be redirected to https://pegasus.goodwill.com/private. The client will make a second request https://pegasus.goodwill.com/private. What will happen then?
If server redirects the request to https://pegasus.goodwill.com/private, then the redirection will fall into infinite loop! Therefore Pegasus does not redirect the request and simply accept as a request of this URI.
The expression of redirection loop is allowed only in $web/etc/rewrite, not in /sys/lib/httpd.rewrite. And the loop must be closed in a single line.