cache.psgi

use strict;
use warnings;

use Plack::Request;
use Plack::App::File;
use Plack::App::Proxy;
use File::Basename;
use Path::Class qw/dir/;

my %cache;

my $proxy = Plack::App::Proxy->new->to_app;

return sub {
    my $env = shift;

    my $req = Plack::Request->new($env);
    my $res;

    if ( !defined($cache{$req->request_uri}) ) {

        my $file_path = dir('.', basename($req->path_info) )->absolute->stringify;

        if ( -f $file_path ) {
             $res = Plack::App::File->new( file => $file_path )->call($env);
        }
        else
        {   
            $env->{'plack.proxy.url'} = $req->request_uri;
            $res = $proxy->($env);
        }
        $cache{$req->request_uri} = $res;
    }

    $cache{$req->request_uri};
};

gistfile2.txt

plackup cache.psgi -p 3000 -s Coro