HTML::Mason::Interp(3)User Contributed Perl DocumentatioHTML::Mason::Interp(3)NAMEHTML::Mason::Interp - Mason Component Interpreter
VERSION
version 1.54
SYNOPSIS
my $i = HTML::Mason::Interp->new (data_dir=>'/usr/local/mason',
comp_root=>'/usr/local/www/htdocs/',
...other params...);
DESCRIPTION
Interp is the Mason workhorse, executing components and routing their
output and errors to all the right places. In a mod_perl environment,
Interp objects are handed off immediately to an ApacheHandler object
which internally calls the Interp implementation methods. In that case
the only user method is the new() constructor.
PARAMETERS TO THE new() CONSTRUCTOR
autohandler_name
File name used for autohandlers. Default is "autohandler". If this
is set to an empty string ("") then autohandlers are turned off
entirely.
buffer_preallocate_size
Number of bytes to preallocate in the output buffer for each
request. Defaults to 0. Setting this to, say, your maximum page
size (or close to it) can reduce the number of reallocations Perl
performs as components add to the output buffer.
code_cache_max_size
Specifies the maximum number of components that should be held in
the in-memory code cache. The default is 'unlimited', meaning no
components will ever be discarded; Mason can perform certain
optimizations in this mode. Setting this to zero disables the code
cache entirely. See the code cache section of the administrator's
manual for further details.
comp_root
The component root marks the top of your component hierarchy and
defines how component paths are translated into real file paths.
For example, if your component root is /usr/local/httpd/docs, a
component path of /products/index.html translates to the file
/usr/local/httpd/docs/products/index.html.
Under Apache and CGI, comp_root defaults to the server's document
root. In standalone mode comp_root defaults to the current working
directory.
This parameter may be either a scalar or an array reference. If it
is a scalar, it should be a filesystem path indicating the
component root. If it is an array reference, it should be of the
following form:
[ [ foo => '/usr/local/foo' ],
[ bar => '/usr/local/bar' ] ]
This is an array of two-element array references, not a hash. The
"keys" for each path must be unique and their "values" must be
filesystem paths. These paths will be searched in the provided
order whenever a component path is resolved. For example, given the
above component roots and a component path of /products/index.html,
Mason would search first for /usr/local/foo/products/index.html,
then for /usr/local/bar/products/index.html.
The keys are used in several ways. They help to distinguish
component caches and object files between different component
roots, and they appear in the "title()" of a component.
When you specify a single path for a component root, this is
actually translated into
[ [ MAIN => path ] ]
If you have turned on dynamic_comp_root, you may modify the
component root(s) of an interpreter between requests by calling
"$interp->comp_root" with a value. However, the path associated
with any given key may not change between requests. For example, if
the initial component root is
[ [ foo => '/usr/local/foo' ],
[ bar => '/usr/local/bar' ], ]
then it may not be changed to
[ [ foo => '/usr/local/bar' ],
[ bar => '/usr/local/baz' ],
but it may be changed to
[ [ foo => '/usr/local/foo' ],
[ blarg => '/usr/local/blarg' ] ]
In other words, you may add or remove key/path pairs but not modify
an already-used key/path pair. The reason for this restriction is
that the interpreter maintains a component cache per key that would
become invalid if the associated paths were to change.
compiler
The Compiler object to associate with this Interpreter. By default
a new object of class compiler_class will be created.
compiler_class
The class to use when creating a compiler. Defaults to
HTML::Mason::Compiler.
data_dir
The data directory is a writable directory that Mason uses for
various features and optimizations: for example, component object
files and data cache files. Mason will create the directory on
startup, if necessary, and set its permissions according to the web
server User/Group.
Under Apache, data_dir defaults to a directory called "mason" under
the Apache server root. You will need to change this on certain
systems that assign a high-level server root such as /usr!
In non-Apache environments, data_dir has no default. If it is left
unspecified, Mason will not use object files, and the default data
cache class will be "MemoryCache" instead of "FileCache".
dynamic_comp_root
True or false, defaults to false. Indicates whether the comp_root
can be modified on this interpreter between requests. Mason can
perform a few optimizations with a fixed component root, so you
should only set this to true if you actually need it.
escape_flags
A hash reference of escape flags to set for this object. See the
section on the set_escape method for more details.
ignore_warnings_expr
Regular expression indicating which warnings to ignore when loading
components. Any warning that is not ignored will prevent the
component from being loaded and executed. For example:
ignore_warnings_expr =>
'Global symbol.*requires explicit package'
If set to undef, all warnings are heeded. If set to '.', warnings
are turned off completely as a specially optimized case.
By default, this is set to 'Subroutine .* redefined'. This allows
you to declare global subroutines inside <%once> sections and not
receive an error when the component is reloaded.
object_file_extension
Extension to add to the end of object files. Default is ".obj".
preloads
A list of component paths, optionally with glob wildcards, to load
when the interpreter initializes. e.g.
preloads => ['/foo/index.html','/bar/*.pl']
Default is the empty list. For maximum performance, this should
only be used for components that are frequently viewed and rarely
updated. See the preloading components section of the
administrator's manual for further details.
As mentioned in the developer's manual, a component's "<%once>"
section is executed when it is loaded. For preloaded components,
this means that this section will be executed before a Mason or
Apache request exist, so preloading a component that uses $m or $r
in a "<%once>" section will fail.
request_class
The class to use when creating requests. Defaults to
HTML::Mason::Request.
resolver
The Resolver object to associate with this Compiler. By default a
new object of class resolver_class will be created.
resolver_class
The class to use when creating a resolver. Defaults to
HTML::Mason::Resolver::File.
static_source
True or false, default is false. When false, Mason checks the
timestamp of the component source file each time the component is
used to see if it has changed. This provides the instant feedback
for source changes that is expected for development. However it
does entail a file stat for each component executed.
When true, Mason assumes that the component source tree is
unchanging: it will not check component source files to determine
if the memory cache or object file has expired. This can save many
file stats per request. However, in order to get Mason to recognize
a component source change, you must flush the memory cache and
remove object files. See static_source_touch_file for one easy way
to arrange this.
We recommend turning this mode on in your production sites if
possible, if performance is of any concern.
static_source_touch_file
Specifies a filename that Mason will check once at the beginning of
of every request. When the file timestamp changes, Mason will (1)
clear its in-memory component cache, and (2) remove object files if
they have not already been deleted by another process.
This provides a convenient way to implement static_source mode.
All you need to do is make sure that a single file gets touched
whenever components change. For Mason's part, checking a single
file at the beginning of a request is much cheaper than checking
every component file when static_source=0.
use_object_files
True or false, default is true. Specifies whether Mason creates
object files to save the results of component parsing. You may want
to turn off object files for disk space reasons, but otherwise this
should be left alone.
ACCESSOR METHODS
All of the above properties have standard accessor methods of the same
name. Only comp_root and ignore_warnings_expr can be modified in an
existing interpreter; the rest are read-only.
ESCAPE FLAG METHODS
apply_escapes ($text, $flags, [more flags...])
This method applies a one or more escapes to a piece of text. The
escapes are specified by giving their flag. Each escape is applied
to the text in turn, after which the now-modified text is returned.
remove_escape ($name)
Given an escape name, this removes that escape from the
interpreter's known escapes. If the name is not recognized, it is
simply ignored.
set_escape ($name => see below])
This method is called to add an escape flag to the list of known
escapes for the interpreter. The flag may only consist of the
characters matching "\w" and the dash (-). It must start with an
alpha character or an underscore (_).
The right hand side may be one of several things. It can be a
subroutine reference. It can also be a string match "/^\w+$/", in
which case it is assumed to be the name of a subroutine in the
"HTML::Mason::Escapes" module. Finally, if it is a string that
does not match the above regex, then it is assumed to be "eval"able
code, which will return a subroutine reference.
When setting these with "PerlSetVar" directives in an Apache
configuration file, you can set them like this:
PerlSetVar MasonEscapeFlags "h => \&HTML::Mason::Escapes::basic_html_escape"
PerlSetVar MasonEscapeFlags "flag => \&subroutine"
PerlSetVar MasonEscapeFlags "uc => sub { ${$_[0]} = uc ${$_[0]}; }"
PerlAddVar MasonEscapeFlags "thing => other_thing"
OTHER METHODS
comp_exists (path)
Given an absolute component path, this method returns a boolean
value indicating whether or not a component exists for that path.
exec (comp, args...)
Creates a new HTML::Mason::Request object for the given comp and
args, and executes it. The return value is the return value of
comp, if any.
This is useful for running Mason outside of a web environment. See
"using Mason from a standalone script" in HTML::Mason::Admin for
examples.
This method isn't generally useful in a mod_perl environment; see
subrequests instead.
flush_code_cache
Empties the component cache. When using Perl 5.00503 or earlier,
you should call this when finished with an interpreter, in order to
remove circular references that would prevent the interpreter from
being destroyed.
load (path)
Returns the component object corresponding to an absolute component
"path", or undef if none exists. Dies with an error if the
component fails to load because of a syntax error.
make_component (comp_source => ... )
make_component (comp_file => ... )
This method compiles Mason component source code and returns a
Component object. The source may be passed in as a string in
"comp_source", or as a filename in "comp_file". When using
"comp_file", the filename is specified as a path on the file
system, not as a path relative to Mason's component root (see
$m->fetch_comp for that).
If Mason encounters an error during processing, an exception will
be thrown.
Example of usage:
# Make an anonymous component
my $anon_comp =
eval { $interp->make_component
( comp_source => '<%perl>my $name = "World";</%perl>Hello <% $name %>!' ) };
die $@ if $@;
$m->comp($anon_comp);
make_request (@request_params)
This method creates a Mason request object. The arguments to be
passed are the same as those for the "HTML::Mason::Request->new"
constructor or its relevant subclass. This method will likely only
be of interest to those attempting to write new handlers or to
subclass "HTML::Mason::Interp". If you want to create a
subrequest, see subrequests instead.
purge_code_cache ()
Called during request execution in order to clear out the code
cache. Mainly useful to subclasses that may want to take some
custom action upon clearing the cache.
set_global ($varname, [values...])
This method sets a global to be used in components. "varname" is a
variable name, optionally preceded with a prefix ("$", "@", or
"%"); if the prefix is omitted then "$" is assumed. "varname" is
followed by a value, in the case of a scalar, or by one or more
values in the case of a list or hash. For example:
# Set a global variable $dbh containing the database handle
$interp->set_global(dbh => DBI->connect(...));
# Set a global hash %session from a local hash
$interp->set_global('%session', %s);
The global is set in the package that components run in: usually
"HTML::Mason::Commands", although this can be overridden via the
in_package parameter. The lines above, for example, are equivalent
to:
$HTML::Mason::Commands::dbh = DBI->connect(...);
%HTML::Mason::Commands::session = %s;
assuming that in_package has not been changed.
Any global that you set should also be registered with the
allow_globals parameter; otherwise you'll get warnings from
"strict".
SEE ALSO
Mason
AUTHORS
· Jonathan Swartz <swartz@pobox.com>
· Dave Rolsky <autarch@urth.org>
· Ken Williams <ken@mathforum.org>
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.
perl v5.18.2 2014-01-19 HTML::Mason::Interp(3)
