Using error_page to a named location - possible?

[Max]

06 марта 2012, 21:47 от Maxim Dounin <mdounin at mdounin.ru>:
> Hello!
> 
> On Tue, Mar 06, 2012 at 04:37:41PM +0000, Ed W wrote:
> 
> > Hi, as part of a larger problem I have a captive portal which grabs
> > all incoming URLs and after evaluating a bunch of logic redirects
> > the caller somewhere else.  I use proxy_pass to pass the request to
> > my cgi code.
> >
> > However, I would like to customise the error message in the event
> > that the upstream daemon is unavailable.  I can't figure out how to
> > do that affecting part of the incoming URLs.  Is it possible to do
> > something like "error_page @502_error" in conjunction with
> > proxy_pass?
> 
> Yes, see below.
> 
> >
> > So, I have
> >
> > server {
> >   listen 8000 default_server;
> >
> >   root /var/www/cp/htdocs/public;
> >
> >   location / {
> >     proxy_read_timeout 5;
> >     proxy_pass http://127.0.0.1:3000;
> >     error_page 502 /502.html;
> >     proxy_set_header Host $http_host;
> >     proxy_set_header X-Server-Addr $server_addr;
> >     proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
> >     proxy_set_header X-Forwarded-HTTPS 0;
> >     proxy_set_header X-Captive-Portal-Redirect 1;
> > }
> >   location /502.html {
> >     internal;
> >   }
> > }
> >
> >
> > However, if I visit "http://somewhere/502.html" I get a 404 response
> > (presumably matching the location /502.html and the 404 is due to
> > the "internal"?)
> 
> Yes.
> 
> > I can't see that it's possible to use something like:
> >
> >   location / {
> >     proxy_pass http://127.0.0.1:3000;
> >     error_page 502 @502;
> >   }

It is possible, you should use the proxy_intercept_errors directive:

location / {
    proxy_pass http://127.0.0.1:3000;
    proxy_intercept_errors on;
    error_page 502 @502;
}

location @502 {
    # all named locations are internal by default, hence no "internal;"
    return 502 "Gateway error while servicing $request_uri!\n";
}
 
Max