Check for existing remote files

[Mikhail Mazursky]

2011/1/13 mignev <nginx-forum at nginx.us>:
> First thanks for the critique. Such types of solutions are many, but I
> don't want such solution. In my case i have over a million images of
> which i don't know the name or their existence. I want to try for
> existence of requested file and if he is found then return to me. If the
> requested file is not exist go to my proxy_pass $mybackend; and  he will
> generate and upload it. WIth this idea i want to skip database layer. I
> have some ideas how i can do that but firstly i want to hear your
> feedback about that.

server {
....

  location ~ ^/remote/(?<remote_url>.+)$ {
    proxy_intercept_errors on;
    error_page 404 = @mybackend;
    proxy_pass http://$remote_url;
  }

  location @mybackend {
    proxy_pass http://mybackend_upstream;
  }
}

This shows the general idea about how to do this, but i haven't tested
so there may be syntax errors.