nginxで404の時だけ別サーバから取得してくる ref: http://qiita.com/items/812c028888c1b460f426

file0.txt

server {
    listen 8888;
    server_name  localhost;

    location / {
        root /tmp/data;
        error_page 404 = @data;
    }   

    location @data {
        internal;

        proxy_pass http://localhost:4567;
        proxy_store on;
        proxy_store_access user:rw group:r all:r;
        proxy_temp_path /tmp/data/temp;

        root /tmp/data;
    }
}

file1.txt

#!/usr/bin/ruby
require 'sinatra'

get '/*' do
  "Generated at #{Time.now.to_s}\n"
end

delete '/:path' do
  path = "/tmp/data/#{params[:path]}"
  File.unlink path
  "delete #{path}\n"
end

file2.txt

$ curl http://localhost:8888/hoge
Generated at 2012-08-02 23:03:25 +0900
$ date
2012年 8月 2日 木曜日 23時03分27秒 JST
$ curl http://localhost:8888/hoge
Generated at 2012-08-02 23:03:25 +0900
$ cat /tmp/data/hoge
Generated at 2012-08-02 23:03:25 +0900

file3.txt

$ curl --request DELETE http://localhost:4567/hoge
delete /tmp/data/hoge
$ curl http://localhost:8888/hoge
Generated at 2012-08-02 23:03:40 +0900