Provided by: libhtml-mason-perl_1.60-2_all 
NAME
HTML::Mason::Interp - Mason Component Interpreter
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".
perl v5.38.2 2024-03-05 HTML::Mason::Interp(3pm)