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

SEE ALSO

    Plack, http://httpd.apache.org/docs/2.2/en/mod/mod_deflate.html

