Compare and rewrite URL with mod_rewrite based on path and query string

问题

I have URLs in a scheme

/([0-9]*)/some/path/script.jsf?someId=([0-9]*)

and I'd like to redirect to $2 the user if $1 doesn't match $2. So for example if the user requests

/1/some/path/script.jsf?someId=1

everthing is fine and the user shouldn't be redirected but if the user requests

/1/some/path/script.jsf?someId=2

the user should be redirected to

/2/some/path/script.jsf?someId=2

I've tried this rule:

RewriteCond %{REQUEST_URI} ^/([0-9]*)/
RewriteCond %{QUERY_STRING} someId=([0-9]*)
RewriteCond %1 !%2
RewriteRule (.*) /%2/some/path/script.jsf?someId=%2 [R]

but %2 seems always empty. So I've tried this rule:

RewriteCond %{REQUEST_URI} ^/([0-9]*)/some/path/script.jsf?someId=([0-9]*)
RewriteCond %1 !%2
RewriteRule (.*) /%2/)/some/path/script.jsf?someId=%2 [R]

回答1:

%n only accesses backreferences from

the last matched RewriteCond in the current set of conditions.

That's why your %2 always seems empty in your first set of rules.

Your second attempt gets around this problem for the RewriteCond %1 !%2, but you can't refer to %2 in your RewriteRule, as it refers to, again, the last matched RewriteCond.

If you're running Apache 2, there's a very simple way to do this using a negative lookahead assertion:

RewriteRule ^/([0-9]*)/some/path/script.jsf?someId=(?!$1(?:$|[^0-9]))([0-9]*) /$2/some/path/script.jsf?someId=$2 [R]

The important part is

(?!$1(?:$|[^0-9]))

which asserts that the next sequence of characters cannot be exactly the number in $1. (The $|[^0-9] bit assures that trailing numbers are considered.)

来源：https://stackoverflow.com/questions/13289007/compare-and-rewrite-url-with-mod-rewrite-based-on-path-and-query-string