NAME

Plack::Middleware::Deflater - Compress response body with Gzip or Deflate

SYNOPSIS

  use Plack::Builder;

  builder {
    enable sub {
        my $app = shift;
        sub {
            my $env = shift;
            my $ua = $env->{HTTP_USER_AGENT} || '';
            # Netscape has some problem
            $env->{"psgix.compress-only-text/html"} = 1 if $ua =~ m!^Mozilla/4!;
            # Netscape 4.06-4.08 have some more problems
             $env->{"psgix.no-compress"} = 1 if $ua =~ m!^Mozilla/4\.0[678]!;
            # MSIE (7|8) masquerades as Netscape, but it is fine
            if ( $ua =~ m!\bMSIE (?:7|8)! ) {
                $env->{"psgix.no-compress"} = 0;
                $env->{"psgix.compress-only-text/html"} = 0;
            }
            $app->($env);
        }
    };
    enable "Deflater",
        content_type => ['text/css','text/html','text/javascript','application/javascript'],
        vary_user_agent => 1;
    sub { [200,['Content-Type','text/html'],["OK"]] }
  };

DESCRIPTION

Plack::Middleware::Deflater is a middleware to encode your response body in gzip or deflate, based on "Accept-Encoding" HTTP request header. It would save the bandwidth a little bit but should increase the Plack server load, so ideally you should handle this on the frontend reverse proxy servers.

This middleware removes "Content-Length" and streams encoded content, which means the server should support HTTP/1.1 chunked response or downgrade to HTTP/1.0 and closes the connection.

CONFIGURATIONS

content_type

  content_type => 'text/html',
  content_type => [ 'text/html', 'text/css', 'text/javascript', 'application/javascript', 'application/x-javascript' ]

Content-Type header to apply deflater. if content-type is not defined, Deflater will try to deflate all contents.

vary_user_agent

  vary_user_agent => 1

Add "User-Agent" to Vary header.

ENVIRONMENT VALUE

psgix.no-compress: Do not apply deflater
psgix.compress-only-text/html: Apply deflater only if content_type is "text/html"
plack.skip-deflater: Skip all Deflater features

Compare psgix.no-compress with plack.skip-deflater

If no-compress is true, PM::Deflater skips gzip or deflate. But adds Vary: Accept-Encoding and Vary: User-Agent header. skip-deflater forces to skip all PM::Deflater feature, doesn't allow to add Vary header.

LICENSE

This software is licensed under the same terms as Perl itself.

AUTHOR

Tatsuhiko Miyagawa