13 messages in ru.sysoev.nginxRe: Trouble with a complex rewrite
FromSent OnAttachments
Wilson BilkovichApr 2, 2007 4:40 am 
Igor SysoevApr 2, 2007 5:25 am 
Wilson BilkovichApr 2, 2007 12:14 pm 
Igor SysoevApr 2, 2007 12:46 pm 
Wilson BilkovichApr 2, 2007 12:54 pm 
Igor SysoevApr 2, 2007 1:19 pm 
Wilson BilkovichApr 2, 2007 2:10 pm 
Igor SysoevApr 2, 2007 2:26 pm 
Wilson BilkovichApr 2, 2007 4:27 pm 
Boris BartsytsApr 10, 2007 8:07 am 
Igor SysoevApr 10, 2007 12:59 pm 
Boris BartsytsApr 11, 2007 3:42 am 
Igor SysoevApr 12, 2007 1:28 pm 
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Subject:Re: Trouble with a complex rewriteActions...
From:Igor Sysoev (is-G@public.gmane.org)
Date:Apr 2, 2007 2:26:16 pm
List:ru.sysoev.nginx

On Mon, Apr 02, 2007 at 05:11:21PM -0400, Wilson Bilkovich wrote:

On 4/2/07, Igor Sysoev <is-G@public.gmane.org> wrote:

On Mon, Apr 02, 2007 at 03:55:20PM -0400, Wilson Bilkovich wrote:

I have two more questions about this: 1. I can use any regular expression supported by PCRE, anywhere in my nginx config, correct?

The regexp engine is PCRE.

The regexp are supported in some directives only: "if", "rewrite", and "location".

2. When I have nested locations, such as: location / { location /api/receive { break; } some_config_option on; }

Configuration options in the outer scope (location /, in this case) are always evaluated, despite the break command? In other words, break only 'breaks' from the location / rewrite loop, not from the rest of the configuration?

If the "rewrite" directive has rewritten URI, then nginx search the new location configuration. The "break" stops this rewrite cycle.

The nested locations are not fully supported, you should use

location / { ... }

location /api/receive { ... }

Sorry to belabor the point, but this is really helping me understand.

location / { set $once = "once"; if ($once) { set $once = ""; rewrite ^ /once break; } set $once = "twice"; rewrite /once /twice break; }

Given that code (assuming it is valid.. if not, let's pretend I wrote it correctly).

I would expect that a request for example.com/ would be rewritten to example.com/once, and that the value of $once would be 'twice'.

This configuration will run as following: 1) $once is "once" so "set $once = "", then URI became "/once" and rewrite stops ("break").

Am I correct about that? My understanding is that break cancels any further rewrites, but has no effect on the other configuration statements that come after it.

nginx has three type of configuration directives:

1) static: the most directives, 2) partially dynamic: the directives with $variable paramters, 3) and dynamic: if/rewrite/set/break/return.

The static directives are compiled into binary structures for each server and locations and they are usually availabe via three and so memory accesses.

The partially dynamic directives are also compiled into binary structures and besides the dynamic parts are compiled into some code that run at request processing stage.

The dynamic directives are compiled into some code that run at request processing stage. They can not be used to choose configuration parts.

The order of directive is mostly important for dynamic directives. So the following configuration are the same:

--------------------

location / { set ...; rewrite ...; if (...) { rewrite ...; break; }

root ...; }

--------------------

location / { root ...;

set ...; rewrite ...; if (...) { rewrite ...; break; } }

--------------------

location / {

set ...; rewrite ...; if (...) { rewrite ...; break; } }

root ...;

--------------------

root ...;

location / {

set ...; rewrite ...; if (...) { rewrite ...; break; } }

--------------------

The place of the "root" directive is not important (in two last configuration it's inherited inside "location /".

-- Igor Sysoev http://sysoev.ru/en/