error_page

[Igor Sysoev]

On Wed, Oct 20, 2010 at 09:35:20PM +0400, Maxim Dounin wrote:

> Hello!
> 
> On Wed, Oct 20, 2010 at 07:03:37PM +0200, Witold Filipczyk wrote:
> 
> > On Wed, Oct 20, 2010 at 08:25:42PM +0400, Maxim Dounin wrote:
> > > Hello!
> > > 
> > > On Wed, Oct 20, 2010 at 05:58:09PM +0200, witekfl at gazeta.pl wrote:
> > > 
> > > > On Wed, Oct 20, 2010 at 07:21:19PM +0400, Igor Sysoev wrote:
> > > > > On Wed, Oct 20, 2010 at 05:10:59PM +0200, witekfl Gazeta.pl wrote:
> > > > > 
> > > > > > Hi,
> > > > > > probably better place for these questions would be nginx-users, but I ask
> > > > > > here.
> > > > > > I want to serve static pages as error codes but without changing the error
> > > > > > code.
> > > > > > 
> > > > > > Now if:
> > > > > > error_page 404 http://blablabla.com/404.html
> > > > > > There is 302 and next 200 OK
> > > > > > I want 404.
> > > > > > 
> > > > > > error_page 404 /404.html
> > > > > > it works, but:
> > > > > > if there is:
> > > > > > location = /404.html {
> > > > > > internal;
> > > > > > }
> > > > > > then cannot be a normal location
> > > > > > location = /404.html {
> > > > > > },
> > > > > > so request such as http://blabla1.com/404.html won't work.
> > > > > > 
> > > > > > error_page 404 @404;
> > > > > > location @404 {
> > > > > >    root /blabla;
> > > > > >    index 404.html;
> > > > > > }
> > > > > > doesn't work either
> > > > > > 
> > > > > > There must be some way to achieve it.
> > > > > > How?
> > > > > 
> > > > > I do not understand the problem. With this configuration
> > > > > 
> > > > > error_page  404 /404.html;
> > > > > locaiton = /404.html {
> > > > >     internal;
> > > > >     root /path/to/page;
> > > > > }
> > > > > 
> > > > > you will get 404 code with /404.html body for both requests:
> > > > > 
> > > > > http://blabla1.com/non-existant.html
> > > > > http://blabla1.com/404.html
> > > > 
> > > > Yes, but I want:
> > > > http://blabla1.com/404.html to be 200 OK and serve http://blabla1.com/404.html
> > > > not /path/to/page/404.html
> > > 
> > > Something like this:
> > > 
> > >     error_page 404 @notfound;
> > > 
> > >     location @notfound {
> > >         rewrite ^ /404.html break;
> > >         root /path/to/page;
> > >     }
> > > 
> > > should do the trick.
> > 
> > Yes, it works. Thanks!
> > Could you explain, why it works.
> > Why this rewrite is required?
> > Does it mean that for 404 by default /404.html is requested or not?
> 
> Short answer:
> 
> You have to use rewrite to map request to correct file.
> 
> Long answer:
> 
> Normally nginx uses error pages in the same URI namespace as the 
> site itself (i.e. error_page 404 /404.html; will use the same file 
> as available though normal /404.html request).  Note that 
> "internal" doesn't introduce another namespace, it's only protects 
> some part of the namespace from direct outside access.
> 
> If you want for some reason to introduce another namespace which 
> won't interfere with site's one - you have to use named locations.
> 
> On the other hand, redirect to named location doesn't change URI, 
> so request to "/something-not-here" with
> 
>     error_page 404 @notfound;
> 
> will result in request to "/something-not-here" being processed in 
> location @notfound.  This will map to <root> + <uri> file, i.e. 
> "/path/to/page/something-not-here".  To map request to correct 
> file one have to use "rewrite".  With
> 
>     location @notfound {
>         rewrite ^ /404.html break;
>         root /path/to/page;
>     }
> 
> any request in location @notfound will be mapped to 
> "/path/to/page/404.html" file.
> 
> [...here should be explanation why "alias" won't work instead of 
> root + rewrite, but I'm bored...]
> 
> Note well: I don't recommend this aproach as I consider having 
> error pages in site's namespace is a good practice.  Additionally, 
> this aproach is less efficient than normal error pages.  I've just 
> outlined how to do what you're asked for.

This configuraion

error_page  404 /404.html;
locaiton = /404.html {
    internal;
    root /path/to/page;
}

does the same for outside observer: it always returns 404 with /404.html body.


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