plack::middleware::conditional(3pm) [debian man page]

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)

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

NAME

       Plack::Middleware::StackTrace - Displays stack trace when your app dies

SYNOPSIS

	 enable "StackTrace";

DESCRIPTION

       This middleware catches exceptions (run-time errors) happening in your application and displays nice stack trace screen. The stack trace is
       also stored in the environment as a plaintext and HTML under the key "plack.stacktrace.text" and "plack.stacktrace.html" respectively, so
       that middleware futher up the stack can reference it.

       This middleware is enabled by default when you run plackup in the default development mode.

       You're recommended to use this middleware during the development and use Plack::Middleware::HTTPExceptions in the deployment mode as a
       replacement, so that all the exceptions thrown from your application still get caught and rendered as a 500 error response, rather than
       crashing the web server.

       Catching errors in streaming response is not supported.

CONFIGURATION

       force
	     enable "StackTrace", force => 1;

	   Force display the stack trace when an error occurs within your application and the response code from your application is 500. Defaults
	   to off.

	   The use case of this option is that when your framework catches all the exceptions in the main handler and returns all failures in your
	   code as a normal 500 PSGI error response. In such cases, this middleware would never have a chance to display errors because it can't
	   tell if it's an application error or just random "eval" in your code. This option enforces the middleware to display stack trace even
	   if it's not the direct error thrown by the application.

       no_print_errors
	     enable "StackTrace", no_print_errors => 1;

	   Skips printing the text stacktrace to console ("psgi.errors"). Defaults to 0, which means the text version of the stack trace error is
	   printed to the errors handle, which usually is a standard error.

AUTHOR

       Tokuhiro Matsuno

       Tatsuhiko Miyagawa

SEE ALSO

       Devel::StackTrace::AsHTML Plack::Middleware Plack::Middleware::HTTPExceptions

perl v5.14.2							    2011-07-08					Plack::Middleware::StackTrace(3pm)