Plack::Middleware::Conditional(3pm)			User Contributed Perl Documentation		       Plack::Middleware::Conditional(3pm)

NAME

       Plack::Middleware::Conditional - Conditional wrapper for Plack middleware

SYNOPSIS

	 use Plack::Builder;

	 builder {
	     enable_if { $_[0]->{REMOTE_ADDR} eq '127.0.0.1' } 'StackTrace', force => 1;
	     $app;
	 };

	 # or using the OO interface:
	 $app = Plack::Middleware::Conditional->wrap(
	     $app,
	     condition	=> sub { $_[0]->{REMOTE_ADDR} eq '127.0.0.1' },
	     builder => sub { Plack::Middleware::StackTrace->wrap($_[0], force => 1) },
	 );

DESCRIPTION

       Plack::Middleware::Conditional is a piece of meta-middleware, to run a specific middleware component under runtime conditions. The goal of
       this middleware is to avoid baking runtime configuration options in individual middleware components, and rather share them as another
       middleware component.

EXAMPLES

       Note that some of the middleware component names are just made up for the explanation and might not exist.

	 # Minify JavaScript if the browser is Firefox
	 enable_if { $_[0]->{HTTP_USER_AGENT} =~ /Firefox/ } 'JavaScriptMinifier';

	 # Enable Stacktrace when being accessed from the local network
	 enable_if { $_[0]->{REMOTE_ADDR} =~ /^10.0.1.*/ } 'StackTrace';

	 # Work with other conditional setter middleware:
	 # Transcode Jpeg on the fly for mobile clients
	 builder {
	     enable 'MobileDetector';
	     enable_if { $_[0]->{'plack.mobile_detected'} }
	       'TranscodeJpeg', max_size => 30_000;
	     $app;
	 };

       Note that in the last example MobileDetector should come first because the conditional check runs in pre-run conditions, which is from
       outer to inner: that is, from the top to the bottom in the Builder DSL code.

AUTHOR

       Tatsuhiko Miyagawa

       Steve Cook

SEE ALSO

       Plack::Builder

perl v5.14.2							    2012-04-14				       Plack::Middleware::Conditional(3pm)