trusty (3) Catalyst::Upgrading.3pm.gz
NAME
Catalyst::Upgrading - Instructions for upgrading to the latest Catalyst
Upgrading to Catalyst 5.90040
Catalyst::Plugin::Unicode::Encoding is now core
The previously stand alone Unicode support module Catalyst::Plugin::Unicode::Encoding has been brought
into core as a default plugin. Going forward, all you need is to add a configuration setting for the
encoding type. For example:
package Myapp::Web;
use Catalyst;
__PACKAGE__->config( encoding => 'UTF-8' );
Please note that this is different from the old stand alone plugin which applied "UTF-8" encoding by
default (that is, if you did not set an explicit "encoding" configuration value, it assumed you wanted
UTF-8). In order to preserve backwards compatibility you will need to explicitly turn it on via the
configuration setting. THIS MIGHT CHANGE IN THE FUTURE, so please consider starting to test your
application with proper UTF-8 support and remove all those crappy hacks you munged into the code because
you didn't know the Plugin existed :)
For people that are using the Plugin, you will note a startup warning suggesting that you can remove it
from the plugin list. When you do so, please remember to add the configuration setting, since you can no
longer rely on the default being UTF-8. We'll add it for you if you continue to use the stand alone
plugin and we detect this, but this backwards compatibility shim will likely be removed in a few releases
(trying to clean up the codebase after all).
If you have trouble with any of this, please bring it to the attention of the Catalyst maintainer group.
basic async and event loop support
This version of Catalyst offers some support for using AnyEvent and IO::Async event loops in your
application. These changes should work fine for most applications however if you are already trying to
perform some streaming, minor changes in this area of the code might affect your functionality. Please
see Catalyst::Response\write_fh for more and for a basic example.
We consider this feature experimental. We will try not to break it, but we reserve the right to make
necessary changes to fix major issues that people run into when the use this functionality in the wild.
Upgrading to Catalyst 5.90030
Regex dispatch type is deprecated.
The Regex dispatchtype (Catalyst::DispatchType::Regex) has been deprecated.
You are encouraged to move your application to Chained dispatch (Catalyst::DispatchType::Chained).
If you cannot do so, please add a dependency to Catalyst::DispatchType::Regex to your application's
Makefile.PL
Upgrading to Catalyst 5.9
The major change is that Plack, a toolkit for using the PSGI specification, now replaces most of the
subclasses of Catalyst::Engine. If you are using one of the standard subclasses of Catalyst::Engine this
should be a straightforward upgrade for you. It was a design goal for this release to preserve as much
backwards compatibility as possible. However, since Plack is different from Catalyst::Engine, it is
possible that differences exist for edge cases. Therefore, we recommend that care be taken with this
upgrade and that testing should be greater than would be the case with a minor point update. Please
inform the Catalyst developers of any problems so that we can fix them and incorporate tests.
It is highly recommended that you become familiar with the Plack ecosystem and documentation. Being able
to take advantage of Plack development and middleware is a major bonus to this upgrade. Documentation
about how to take advantage of Plack::Middleware by writing your own ".psgi" file is contained in
Catalyst::PSGI.
If you have created a custom subclass of <Catalyst:Engine>, you will need to convert it to be a subclass
of Plack::Handler.
If you are using the Plack engine, Catalyst::Engine::PSGI, this new release supersedes that code.
If you are using a subclass of Catalyst::Engine that is aimed at nonstandard or internal/testing uses,
such as Catalyst::Engine::Embeddable, you should still be able to continue using that engine.
Advice for specific subclasses of Catalyst::Engine follows:
Upgrading the FastCGI Engine
No upgrade is needed if your myapp_fastcgi.pl script is already upgraded to use
Catalyst::Script::FastCGI.
Upgrading the mod_perl / Apache Engines
The engines that are built upon the various iterations of mod_perl, Catalyst::Engine::Apache::MP13 (for
mod_perl 1, and Apache 1.x) and Catalyst::Engine::Apache2::MP20 (for mod_perl 2, and Apache 2.x), should
be seamless upgrades and will work using Plack::Handler::Apache1 or Plack::Handler::Apache2 as required.
Catalyst::Engine::Apache2::MP19, however, is no longer supported, as Plack does not support mod_perl
version 1.99. This is unlikely to be a problem for anyone, as 1.99 was a brief beta-test release for
mod_perl 2, and all users of mod_perl 1.99 are encouraged to upgrade to a supported release of Apache 2
and mod_perl 2.
Upgrading the HTTP Engine
The default development server that comes with the Catalyst distribution should continue to work as
expected with no changes as long as your "myapp_server" script is upgraded to use Catalyst::Script::HTTP.
Upgrading the CGI Engine
If you were using Catalyst::Engine::CGI there is no upgrade needed if your myapp_cgi.pl script is already
upgraded to use Catalyst::Script::CGI.
Upgrading Catalyst::Engine::HTTP::Prefork
If you were using Catalyst::Engine::HTTP::Prefork then Starman is automatically loaded. You should (at
least) change your "Makefile.PL" to depend on Starman.
You can regenerate your "myapp_server.pl" script with "catalyst.pl" and implement a
"MyApp::Script::Server" class that looks like this:
package MyApp::Script::Server;
use Moose;
use namespace::autoclean;
extends 'CatalystX::Script::Server::Starman';
1;
This takes advantage of the new script system, and will add a number of options to the standard server
script as extra options are added by Starman.
More information about these options can be seen at "SYNOPSIS" in CatalystX::Script::Server::Starman.
An alternate route to implement this functionality is to write a simple .psgi file for your application,
and then use the plackup utility to start the server.
Upgrading the PSGI Engine
If you were using Catalyst::Engine::PSGI, this new release supersedes this engine in supporting Plack. By
default the Engine is now always Plack. As a result, you can remove the dependency on
Catalyst::Engine::PSGI in your "Makefile.PL".
Applications that were using Catalyst::Engine::PSGI previously should entirely continue to work in this
release with no changes.
However, if you have an "app.psgi" script, then you no longer need to specify the PSGI engine. Instead,
the Catalyst application class now has a new method "psgi_app" which returns a PSGI compatible coderef
which you can wrap in the middleware of your choice.
Catalyst will use the .psgi for your application if it is located in the "home" directory of the
application.
For example, if you were using Catalyst::Engine::PSGI in the past, you will have written (or generated) a
"script/myapp.psgi" file similar to this one:
use Plack::Builder;
use MyCatalytApp;
MyCatalystApp->setup_engine('PSGI');
builder {
enable ... # enable your desired middleware
sub { MyCatalystApp->run(@_) };
};
Instead, you now say:
use Plack::Builder;
use MyCatalystApp;
builder {
enable ... #enable your desired middleware
MyCatalystApp->psgi_app;
};
In the simplest case:
MyCatalystApp->setup_engine('PSGI');
my $app = sub { MyCatalystApp->run(@_) }
becomes
my $app = MyCatalystApp->psgi_app(@_);
NOT:
my $app = sub { MyCatalystApp->psgi_app(@_) };
# If you make ^^ this mistake, your app won't work, and will confuse the hell out of you!
You can now move "script/myapp.psgi" to "myapp.psgi", and the built-in Catalyst scripts and your test
suite will start using your .psgi file.
NOTE: If you rename your .psgi file without these modifications, then any tests run via Catalyst::Test
will not be compatible with the new release, and will result in the development server starting, rather
than the expected test running.
NOTE: If you are directly accessing "$c->req->env" to get the PSGI environment then this accessor is
moved to "$c->engine->env", you will need to update your code.
Engines which are known to be broken
The following engines DO NOT work as of Catalyst version 5.9. The core team will be happy to work with
the developers and/or users of these engines to help them port to the new Plack/Engine system, but for
now, applications which are currently using these engines WILL NOT run without modification to the engine
code.
Catalyst::Engine::Wx
Catalyst::Engine::Zeus
Catalyst::Engine::JobQueue::POE
Catalyst::Engine::XMPP2
Catalyst::Engine::SCGI
Engines with unknown status
The following engines are untested or have unknown compatibility. Reports are highly encouraged:
Catalyst::Engine::Mojo
Catalyst::Engine::Server (marked as Deprecated)
Catalyst::Engine::HTTP::POE (marked as Deprecated)
Plack functionality
See Catalyst::PSGI.
Tests in 5.9
Tests should generally work the same in Catalyst 5.9, but there are some differences.
Previously, if using Catalyst::Test and doing local requests (against a local server), if the application
threw an exception then this exception propagated into the test.
This behavior has been removed, and now a 500 response will be returned to the test. This change
standardizes behavior, so that local test requests behave similarly to remote requests.
Upgrading to Catalyst 5.80
Most applications and plugins should run unaltered on Catalyst 5.80.
However, a lot of refactoring work has taken place, and several changes have been made which could cause
incompatibilities. If your application or plugin is using deprecated code, or relying on side effects,
then you could have issues upgrading to this release.
Most issues found with existing components have been easy to solve. This document provides a complete
description of behavior changes which may cause compatibility issues, and of new Catalyst warnings which
might be unclear.
If you think you have found an upgrade-related issue which is not covered in this document, please email
the Catalyst list to discuss the problem.
Moose features
Application class roles
You can only apply method modifiers after the application's "->setup" method has been called. This means
that modifiers will not work with methods run during the call to "->setup".
See Catalyst::Manual::ExtendingCatalyst for more information about using Moose in your applications.
Controller actions in Moose roles
You can use MooseX::MethodAttributes::Role if you want to declare actions inside Moose roles.
Using Moose in Components
The correct way to use Moose in a component in a both forward and backwards compatible way is:
package TestApp::Controller::Root;
use Moose;
BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
See "Components which inherit from Moose::Object before Catalyst::Component".
Known backwards compatibility breakages
Applications in a single file
Applications must be in their own file, and loaded at compile time. This issue generally only affects the
tests of CPAN distributions. Your application will fail if you try to define an application inline in a
block, and use plugins which supply a " new " method, then use that application latter in tests within
the same file.
This is due to the fact that Catalyst is inlining a new method on your application class allowing it to
be compatible with Moose. The method used to do this changed in 5.80004 to avoid the possibility of
reporting an 'Unknown Error' if your application failed to compile.
Issues with Class::C3
Catalyst 5.80 uses the Algorithm::C3 method dispatch order. This is built into Perl 5.10, and comes via
Class::C3 for Perl 5.8. This replaces NEXT with Class::C3::Adopt::NEXT, forcing all components to resolve
methods using C3, rather than the unpredictable dispatch order of NEXT.
This issue manifests itself by your application failing to start due to an error message about having a
non-linear @ISA.
The Catalyst plugin most often causing this is Catalyst::Plugin::Session::Store::FastMmap - if you are
using this plugin and see issues, then please upgrade your plugins, as it has been fixed. Note that
Makefile.PL in the distribution will warn about known incompatible components.
This issue can, however, be found in your own application - the only solution is to go through each base
class of the class the error was reported against, until you identify the ones in conflict, and resolve
them.
To be able to generate a linear @ISA, the list of superclasses for each class must be resolvable using
the C3 algorithm. Unfortunately, when superclasses are being used as mixins (to add functionality used in
your class), and with multiple inheritance, it is easy to get this wrong.
Most common is the case of:
package Component1; # Note, this is the common case
use base qw/Class::Accessor::Fast Class::Data::Inheritable/;
package Component2; # Accidentally saying it this way causes a failure
use base qw/Class::Data::Inheritable Class::Accessor::Fast/;
package GoesBang;
use base qw/Component1 Component2/;
Any situation like this will cause your application to fail to start.
For additional documentation about this issue, and how to resolve it, see Class::C3::Adopt::NEXT.
Components which inherit from Moose::Object before Catalyst::Component
Moose components which say:
package TestApp::Controller::Example;
use Moose;
extends qw/Moose::Object Catalyst::Component/;
to use the constructor provided by Moose, while working (if you do some hacks with the " BUILDARGS "
method), will not work with Catalyst 5.80 as "Catalyst::Component" inherits from "Moose::Object", and so
@ISA fails to linearize.
The correct way to use Moose in a component in a both forward and backwards compatible way is:
package TestApp::Controller::Root;
use Moose;
BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
Note that the " extends " declaration needs to occur in a begin block for attributes to operate
correctly.
This way you do not inherit directly from "Moose::Object" yourself. Having components which do not
inherit their constructor from "Catalyst::Component" is unsupported, and has never been recommended,
therefore you're on your own if you're using this technique. You'll need to detect the version of
Catalyst your application is running, and deal with it appropriately.
You also don't get the Moose::Object constructor, and therefore attribute initialization will not work as
normally expected. If you want to use Moose attributes, then they need to be made lazy to correctly
initialize.
Note that this only applies if your component needs to maintain component backwards compatibility for
Catalyst versions before 5.71001 - in 5.71001 attributes work as expected, and the BUILD method is called
normally (although BUILDARGS is not).
If you depend on Catalyst 5.8, then all Moose features work as expected.
You will also see this issue if you do the following:
package TestApp::Controller::Example;
use Moose;
use base 'Catalyst::Controller';
as " use base " appends to @ISA.
use Moose in MyApp
Similar to the above, this will also fail:
package MyApp;
use Moose;
use Catalyst qw/
ConfigLoader
/;
__PACKAGE__->setup;
If you need to use Moose in your application class (e.g. for method modifiers etc.) then the correct
technique is:
package MyApp;
use Moose;
use Catalyst;
extends 'Catalyst';
__PACKAGE__->config( name => 'MyApp' );
__PACKAGE__->setup(qw/
ConfigLoader
/);
Anonymous closures installed directly into the symbol table
If you have any code which installs anonymous subroutine references directly into the symbol table, you
may encounter breakages. The simplest solution is to use Sub::Name to name the subroutine. Example:
# Original code, likely to break:
my $full_method_name = join('::', $package_name, $method_name);
*$full_method_name = sub { ... };
# Fixed Code
use Sub::Name 'subname';
my $full_method_name = join('::',$package_name, $method_name);
*$full_method_name = subname $full_method_name, sub { ... };
Additionally, you can take advantage of Catalyst's use of Class::MOP and install the closure using the
appropriate metaclass. Example:
use Class::MOP;
my $metaclass = Moose::Meta::Class->initialize($package_name);
$metaclass->add_method($method_name => sub { ... });
Hooking into application setup
To execute code during application start-up, the following snippet in MyApp.pm used to work:
sub setup {
my ($class, @args) = @_;
$class->NEXT::setup(@args);
... # things to do after the actual setup
}
With Catalyst 5.80 this won't work anymore, because Catalyst no longer uses NEXT.pm for method
resolution. The functionality was only ever originally operational as NEXT remembers what methods have
already been called, and will not call them again.
Using this now causes infinite recursion between MyApp::setup and Catalyst::setup, due to other backwards
compatibility issues related to how plugin setup works. Moose method modifiers like "before|after|around
setup => sub { ... };" also will not operate correctly on the setup method.
The right way to do it is this:
after setup_finalize => sub {
... # things to do after the actual setup
};
The setup_finalize hook was introduced as a way to avoid this issue.
Components with a new method which returns false
Previously, if you had a component which inherited from Catalyst::COMPONENT, but overrode the new method
to return false, then your class's configuration would be blessed into a hash on your behalf, and this
would be returned from the COMPONENT method.
This behavior makes no sense, and so has been removed. Implementing your own " new " method in components
is highly discouraged. Instead, you should inherit the new method from Catalyst::Component, and use
Moose's BUILD functionality and/or Moose attributes to perform any construction work necessary for your
class.
__PACKAGE__->mk_accessor('meta');
Won't work due to a limitation of Moose. This is currently being fixed inside Moose.
Class::Data::Inheritable side effects
Previously, writing to a class data accessor would copy the accessor method down into your package.
This behavior has been removed. While the class data is still stored per-class, it is stored on the
metaclass of the class defining the accessor.
Therefore anything relying on the side effect of the accessor being copied down will be broken.
The following test demonstrates the problem:
{
package BaseClass;
use base qw/Class::Data::Inheritable/;
__PACKAGE__->mk_classdata('foo');
}
{
package Child;
use base qw/BaseClass/;
}
BaseClass->foo('base class');
Child->foo('sub class');
use Test::More;
isnt(BaseClass->can('foo'), Child->can('foo'));
Extending Catalyst::Request or other classes in an ad hoc manner using mk_accessors
Previously, it was possible to add additional accessors to Catalyst::Request (or other classes) by
calling the mk_accessors class method.
This is no longer supported - users should make a subclass of the class whose behavior they would like to
change, rather than globally polluting the Catalyst objects.
Confused multiple inheritance with Catalyst::Component::COMPONENT
Previously, Catalyst's COMPONENT method would delegate to the method on the right hand side, which could
then delegate back again with NEXT. This is poor practice, and in addition, makes no sense with C3 method
dispatch order, and is therefore no longer supported.
If a COMPONENT method is detected in the inheritance hierarchy to the right hand side of
Catalyst::Component::COMPONENT, then the following warning message will be emitted:
There is a COMPONENT method resolving after Catalyst::Component
in ${next_package}.
The correct fix is to re-arrange your class's inheritance hierarchy so that the COMPONENT method you
would like to inherit is the first (left-hand most) COMPONENT method in your @ISA.
Development server relying on environment variables
Previously, the development server would allow propagation of system environment variables into the
request environment, this has changed with the adoption of Plack. You can use Plack::Middleware::ForceEnv
to achieve the same effect.
WARNINGS
Actions in your application class
Having actions in your application class will now emit a warning at application startup as this is
deprecated. It is highly recommended that these actions are moved into a MyApp::Controller::Root (as
demonstrated by the scaffold application generated by catalyst.pl).
This warning, also affects tests. You should move actions in your test, creating a
myTest::Controller::Root, like the following example:
package MyTest::Controller::Root;
use strict;
use warnings;
use parent 'Catalyst::Controller';
__PACKAGE__->config(namespace => '');
sub action : Local {
my ( $self, $c ) = @_;
$c->do_something;
}
1;
::[MVC]:: naming scheme
Having packages called MyApp::[MVC]::XX is deprecated and can no longer be generated by catalyst.pl
This is still supported, but it is recommended that you rename your application components to
Model/View/Controller.
A warning will be issued at application startup if the ::[MVC]:: naming scheme is in use.
Catalyst::Base
Any code using Catalyst::Base will now emit a warning; this module will be removed in a future release.
Methods in Catalyst::Dispatcher
The following methods in Catalyst::Dispatcher are implementation details, which may change in the 5.8X
release series, and therefore their use is highly deprecated.
tree
dispatch_types
registered_dispatch_types
method_action_class
action_hash
container_hash
The first time one of these methods is called, a warning will be emitted:
Class $class is calling the deprecated method Catalyst::Dispatcher::$public_method_name,
this will be removed in Catalyst 5.9
You should NEVER be calling any of these methods from application code.
Plugin authors and maintainers whose plugins currently call these methods should change to using the
public API, or, if you do not feel the public API adequately supports your use case, please email the
development list to discuss what API features you need so that you can be appropriately supported.
Class files with names that don't correspond to the packages they define
In this version of Catalyst, if a component is loaded from disk, but no symbols are defined in that
component's name space after it is loaded, this warning will be issued:
require $class was successful but the package is not defined.
This is to protect against confusing bugs caused by mistyping package names, and will become a fatal
error in a future version.
Please note that 'inner packages' (via Devel::InnerPackage) are still fully supported; this warning is
only issued when component file naming does not map to any of the packages defined within that component.
$c->plugin method
Calling the plugin method is deprecated, and calling it at run time is highly deprecated.
Instead you are recommended to use Catalyst::Model::Adaptor or similar to compose the functionality you
need outside of the main application name space.
Calling the plugin method will not be supported past Catalyst 5.81.