NAME¶
Mason::Manual::UpgradingFromMason1 - Summary of differences between Mason 1 and
Mason 2
DESCRIPTION¶
Mason 2.x comes ten years after Mason 1.0 (known as HTML::Mason) and twelve
years after the original Mason release. It has been rearchitected and
reimplemented from the ground up.
That said, the philosophy and core syntax are similar enough that it should
still be recognizable and "feel like Mason" to existing users.
This manual attempts to summarize the differences between Mason 1 and 2, to help
existing users decide if they are interested and, if so, migrate their
projects.
There is currently no automated way to convert a Mason 1 to a Mason 2 site, but
there hopefully will be someday. (Contributions welcome. :))
ARCHITECTURE¶
- •
- In Mason 1, each component was an instance of a common Component class. In
Mason 2, each component is its own Moose class, with a class name
generated from the component path.
- •
- The main component body - the content and the inline Perl sections - are
placed into a "main" method.
- •
- Calling a component (via "<& &>" or
"$m->comp" ) entails creating a new instance of the component
class, and calling its "main" method. Component call parameters
are passed to the constructor and placed in attributes.
MAJOR FEATURES¶
- •
- Plugins now utilize Moose roles and are much more powerful and
flexible than in Mason 1. Some features that were (or would have been) in
the core of Mason 1 are now in plugins. See Mason::Manual::Plugins.
- •
- Web integration in Mason 1 was centered around mod_perl and was
part of the core. In Mason 2 all web integration has been split out into a
companion web framework, Poet, which in turn uses PSGI to integrate with
any server backend. You can also use Mason as the templating layer in
popular web frameworks such as Catalyst and Dancer. There is no longer
anything web-specific in the Mason core.
- •
- Subcomponents have been eliminated, replaced with class
methods.
- •
- Error processing/formatting has been eliminated. Mason now simply
throws fatal errors to the caller. In a Plack environment,
Plack::Middleware::StackTrace will catch the error and format it
nicely.
- •
- Resolvers and Anonymous components have been eliminated.
Components need to be in files. If your components live in another data
source, you could use FUSE <http://fuse.sourceforge.net/> or a
custom plugin to keep a file hierarchy up to date with the data
source.
- •
- Caching support has been simplified. "$m->cache"
simply returns a CHI object with an appropriate namespace for the
component.
SYNTAX¶
- •
- "<%once>" has been replaced with
"<%class>".
- •
- "<%cleanup>" has been eliminated; it was not very useful
anyway, since it was not guaranteed to run after an exception. You can use
add_cleanup to add cleanup code for the end of the request, which is good
enough in most cases, or you can add a "DEMOLISH" method to the
component.
- •
- Single blank lines between blocks are now removed, so you can space blocks
out for readability without generating a ton of newlines.
- •
- Whitespace is required after a %-line and around the expression in a
"<% %>" tag. This improves readability and leaves open the
possibility of additional syntax.
- •
- "<%args>" and "<%shared>" are gone. Use
Moose attributes instead.
- •
- The "<%ARGS>" hash is gone, you can instead use
"$.args" or "$self->args" to get all the parameters
passed to a component.
- •
- "<%method>" and "<%def>" have been
replaced with just "<%method>", which creates a true class
method rather than a subcomponent.
- •
- The "<%filter>" tag is now used to define filters, instead
of automatically applying a filter to the current component.
- •
- "Components with content" syntax has been eliminated; use the
CompCall filter instead.
- •
- "Escape flags" in substitution tags now utilize filters.
MISC PARAMETER CHANGES¶
Interp parameters¶
- •
- "buffer_preallocate_size", "code_cache_max_size" and
"use_object_files" have been deemed unnecessary and
eliminated.
- •
- "escape_flags" has been eliminated; define filters instead.
- •
- "data_dir" now defaults to a directory created with
tempdir.
- •
- "preloads" has been eliminated; this code does roughly the same:
$interp->load($_) for (grep { /some_condition/ } $interp->all_paths);
Request parameters¶
- •
- "autoflush" and "max_recurse" have been eliminated
because they are too difficult to implement efficiently.
Compiler parameters¶
- •
- "preprocess", "postprocess_perl", and
"postprocess_text" have been eliminated; similar effects can be
achieved with plugins targeting Mason::Compilation.
- •
- "default_escape_flags" has been eliminated, but see
Mason::Plugin::DefaultFilter for a third-party substitute.
MISC METHOD CHANGES¶
Interp methods¶
- •
- "exec" has been renamed to run.
Request methods¶
- •
- "cache_self" has been eliminated; use the Cache filter
instead.
- •
- "callers", "caller" and "caller_args" have
been eliminated; now that component calls are simply method calls
underneath, they are too difficult to implement efficiently.
- •
- "call_next" has been replaced with Moose's
"inner".
- •
- "call_self" has been eliminated; use filters instead.
- •
- "current_comp" has been eliminated. Within a component, use
$self; outside a component you can call current_comp_class, which will at
least get you the class.
- •
- "dhandler_arg" has been renamed to path_info.
- •
- "exec" has been renamed to run.
- •
- "fetch_comp" has been renamed to load.
- •
- "subexec" has been replaced with visit and go.
SEE ALSO¶
Mason
AUTHOR¶
Jonathan Swartz <swartz@pobox.com>
COPYRIGHT AND LICENSE¶
This software is copyright (c) 2012 by Jonathan Swartz.
This is free software; you can redistribute it and/or modify it under the same
terms as the Perl 5 programming language system itself.