1HTML::Mason::Interp(3)User Contributed Perl DocumentationHTML::Mason::Interp(3)
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6 HTML::Mason::Interp - Mason Component Interpreter
7
9 my $i = HTML::Mason::Interp->new (data_dir=>'/usr/local/mason',
10 comp_root=>'/usr/local/www/htdocs/',
11 ...other params...);
12
14 Interp is the Mason workhorse, executing components and routing their
15 output and errors to all the right places. In a mod_perl environment,
16 Interp objects are handed off immediately to an ApacheHandler object
17 which internally calls the Interp implementation methods. In that case
18 the only user method is the new() constructor.
19
21 autohandler_name
22 File name used for autohandlers. Default is "autohandler". If this
23 is set to an empty string ("") then autohandlers are turned off
24 entirely.
25 buffer_preallocate_size
27 Number of bytes to preallocate in the output buffer for each
28 request. Defaults to 0. Setting this to, say, your maximum page
29 size (or close to it) can reduce the number of reallocations Perl
30 performs as components add to the output buffer.
31 code_cache_max_size
33 Specifies the maximum number of components that should be held in
34 the in-memory code cache. The default is 'unlimited', meaning no
35 components will ever be discarded; Mason can perform certain
36 optimizations in this mode. Setting this to zero disables the code
37 cache entirely. See the code cache section of the administrator's
38 manual for further details.
39 comp_root
41 The component root marks the top of your component hierarchy and
42 defines how component paths are translated into real file paths.
43 For example, if your component root is /usr/local/httpd/docs, a
44 component path of /products/index.html translates to the file
45 /usr/local/httpd/docs/products/index.html.
46 Under Apache and CGI, comp_root defaults to the server's document
48 root. In standalone mode comp_root defaults to the current working
49 directory.
50 This parameter may be either a scalar or an array reference. If it
52 is a scalar, it should be a filesystem path indicating the
53 component root. If it is an array reference, it should be of the
54 following form:
55 [ [ foo => '/usr/local/foo' ],
57 [ bar => '/usr/local/bar' ] ]
58 This is an array of two-element array references, not a hash. The
60 "keys" for each path must be unique and their "values" must be
61 filesystem paths. These paths will be searched in the provided
62 order whenever a component path is resolved. For example, given the
63 above component roots and a component path of /products/index.html,
64 Mason would search first for /usr/local/foo/products/index.html,
65 then for /usr/local/bar/products/index.html.
66 The keys are used in several ways. They help to distinguish
68 component caches and object files between different component
69 roots, and they appear in the "title()" of a component.
70 When you specify a single path for a component root, this is
72 actually translated into
73 [ [ MAIN => path ] ]
75 If you have turned on dynamic_comp_root, you may modify the
77 component root(s) of an interpreter between requests by calling
78 "$interp->comp_root" with a value. However, the path associated
79 with any given key may not change between requests. For example, if
80 the initial component root is
81 [ [ foo => '/usr/local/foo' ],
83 [ bar => '/usr/local/bar' ], ]
84 then it may not be changed to
86 [ [ foo => '/usr/local/bar' ],
88 [ bar => '/usr/local/baz' ],
89 but it may be changed to
91 [ [ foo => '/usr/local/foo' ],
93 [ blarg => '/usr/local/blarg' ] ]
94 In other words, you may add or remove key/path pairs but not modify
96 an already-used key/path pair. The reason for this restriction is
97 that the interpreter maintains a component cache per key that would
98 become invalid if the associated paths were to change.
99 compiler
101 The Compiler object to associate with this Interpreter. By default
102 a new object of class compiler_class will be created.
103 compiler_class
105 The class to use when creating a compiler. Defaults to
106 HTML::Mason::Compiler.
107 data_dir
109 The data directory is a writable directory that Mason uses for
110 various features and optimizations: for example, component object
111 files and data cache files. Mason will create the directory on
112 startup, if necessary, and set its permissions according to the web
113 server User/Group.
114 Under Apache, data_dir defaults to a directory called "mason" under
116 the Apache server root. You will need to change this on certain
117 systems that assign a high-level server root such as /usr!
118 In non-Apache environments, data_dir has no default. If it is left
120 unspecified, Mason will not use object files, and the default data
121 cache class will be "MemoryCache" instead of "FileCache".
122 dynamic_comp_root
124 True or false, defaults to false. Indicates whether the comp_root
125 can be modified on this interpreter between requests. Mason can
126 perform a few optimizations with a fixed component root, so you
127 should only set this to true if you actually need it.
128 escape_flags
130 A hash reference of escape flags to set for this object. See the
131 section on the set_escape method for more details.
132 ignore_warnings_expr
134 Regular expression indicating which warnings to ignore when loading
135 components. Any warning that is not ignored will prevent the
136 component from being loaded and executed. For example:
137 ignore_warnings_expr =>
139 'Global symbol.*requires explicit package'
140 If set to undef, all warnings are heeded. If set to '.', warnings
142 are turned off completely as a specially optimized case.
143 By default, this is set to 'Subroutine .* redefined'. This allows
145 you to declare global subroutines inside <%once> sections and not
146 receive an error when the component is reloaded.
147 object_file_extension
149 Extension to add to the end of object files. Default is ".obj".
150 preloads
152 A list of component paths, optionally with glob wildcards, to load
153 when the interpreter initializes. e.g.
154 preloads => ['/foo/index.html','/bar/*.pl']
156 Default is the empty list. For maximum performance, this should
158 only be used for components that are frequently viewed and rarely
159 updated. See the preloading components section of the
160 administrator's manual for further details.
161 As mentioned in the developer's manual, a component's "<%once>"
163 section is executed when it is loaded. For preloaded components,
164 this means that this section will be executed before a Mason or
165 Apache request exist, so preloading a component that uses $m or $r
166 in a "<%once>" section will fail.
167 request_class
169 The class to use when creating requests. Defaults to
170 HTML::Mason::Request.
171 resolver
173 The Resolver object to associate with this Compiler. By default a
174 new object of class resolver_class will be created.
175 resolver_class
177 The class to use when creating a resolver. Defaults to
178 HTML::Mason::Resolver::File.
179 static_source
181 True or false, default is false. When false, Mason checks the
182 timestamp of the component source file each time the component is
183 used to see if it has changed. This provides the instant feedback
184 for source changes that is expected for development. However it
185 does entail a file stat for each component executed.
186 When true, Mason assumes that the component source tree is
188 unchanging: it will not check component source files to determine
189 if the memory cache or object file has expired. This can save many
190 file stats per request. However, in order to get Mason to recognize
191 a component source change, you must flush the memory cache and
192 remove object files. See static_source_touch_file for one easy way
193 to arrange this.
194 We recommend turning this mode on in your production sites if
196 possible, if performance is of any concern.
197 static_source_touch_file
199 Specifies a filename that Mason will check once at the beginning of
200 of every request. When the file timestamp changes, Mason will (1)
201 clear its in-memory component cache, and (2) remove object files if
202 they have not already been deleted by another process.
203 This provides a convenient way to implement static_source mode.
205 All you need to do is make sure that a single file gets touched
206 whenever components change. For Mason's part, checking a single
207 file at the beginning of a request is much cheaper than checking
208 every component file when static_source=0.
209 use_object_files
211 True or false, default is true. Specifies whether Mason creates
212 object files to save the results of component parsing. You may want
213 to turn off object files for disk space reasons, but otherwise this
214 should be left alone.
215
217 All of the above properties have standard accessor methods of the same
218 name. Only comp_root and ignore_warnings_expr can be modified in an
219 existing interpreter; the rest are read-only.
220
222 apply_escapes ($text, $flags, [more flags...])
223 This method applies a one or more escapes to a piece of text. The
224 escapes are specified by giving their flag. Each escape is applied
225 to the text in turn, after which the now-modified text is returned.
226 remove_escape ($name)
228 Given an escape name, this removes that escape from the
229 interpreter's known escapes. If the name is not recognized, it is
230 simply ignored.
231 set_escape ($name => see below])
233 This method is called to add an escape flag to the list of known
234 escapes for the interpreter. The flag may only consist of the
235 characters matching "\w" and the dash (-). It must start with an
236 alpha character or an underscore (_).
237 The right hand side may be one of several things. It can be a
239 subroutine reference. It can also be a string match "/^\w+$/", in
240 which case it is assumed to be the name of a subroutine in the
241 "HTML::Mason::Escapes" module. Finally, if it is a string that
242 does not match the above regex, then it is assumed to be "eval"able
243 code, which will return a subroutine reference.
244 When setting these with "PerlSetVar" directives in an Apache
246 configuration file, you can set them like this:
247 PerlSetVar MasonEscapeFlags "h => \&HTML::Mason::Escapes::basic_html_escape"
249 PerlSetVar MasonEscapeFlags "flag => \&subroutine"
250 PerlSetVar MasonEscapeFlags "uc => sub { ${$_[0]} = uc ${$_[0]}; }"
251 PerlAddVar MasonEscapeFlags "thing => other_thing"
252
254 comp_exists (path)
255 Given an absolute component path, this method returns a boolean
256 value indicating whether or not a component exists for that path.
257 exec (comp, args...)
259 Creates a new HTML::Mason::Request object for the given comp and
260 args, and executes it. The return value is the return value of
261 comp, if any.
262 This is useful for running Mason outside of a web environment. See
264 "using Mason from a standalone script" in HTML::Mason::Admin for
265 examples.
266 This method isn't generally useful in a mod_perl environment; see
268 subrequests instead.
269 flush_code_cache
271 Empties the component cache. When using Perl 5.00503 or earlier,
272 you should call this when finished with an interpreter, in order to
273 remove circular references that would prevent the interpreter from
274 being destroyed.
275 load (path)
277 Returns the component object corresponding to an absolute component
278 "path", or undef if none exists. Dies with an error if the
279 component fails to load because of a syntax error.
280 make_component (comp_source => ... )
282 make_component (comp_file => ... )
283 This method compiles Mason component source code and returns a
284 Component object. The source may be passed in as a string in
285 "comp_source", or as a filename in "comp_file". When using
286 "comp_file", the filename is specified as a path on the file
287 system, not as a path relative to Mason's component root (see
288 $m->fetch_comp for that).
289 If Mason encounters an error during processing, an exception will
291 be thrown.
292 Example of usage:
294 # Make an anonymous component
296 my $anon_comp =
297 eval { $interp->make_component
298 ( comp_source => '<%perl>my $name = "World";</%perl>Hello <% $name %>!' ) };
299 die $@ if $@;
300 $m->comp($anon_comp);
302 make_request (@request_params)
304 This method creates a Mason request object. The arguments to be
305 passed are the same as those for the "HTML::Mason::Request->new"
306 constructor or its relevant subclass. This method will likely only
307 be of interest to those attempting to write new handlers or to
308 subclass "HTML::Mason::Interp". If you want to create a
309 subrequest, see subrequests instead.
310 purge_code_cache ()
312 Called during request execution in order to clear out the code
313 cache. Mainly useful to subclasses that may want to take some
314 custom action upon clearing the cache.
315 set_global ($varname, [values...])
317 This method sets a global to be used in components. "varname" is a
318 variable name, optionally preceded with a prefix ("$", "@", or
319 "%"); if the prefix is omitted then "$" is assumed. "varname" is
320 followed by a value, in the case of a scalar, or by one or more
321 values in the case of a list or hash. For example:
322 # Set a global variable $dbh containing the database handle
324 $interp->set_global(dbh => DBI->connect(...));
325 # Set a global hash %session from a local hash
327 $interp->set_global('%session', %s);
328 The global is set in the package that components run in: usually
330 "HTML::Mason::Commands", although this can be overridden via the
331 in_package parameter. The lines above, for example, are equivalent
332 to:
333 $HTML::Mason::Commands::dbh = DBI->connect(...);
335 %HTML::Mason::Commands::session = %s;
336 assuming that in_package has not been changed.
338 Any global that you set should also be registered with the
340 allow_globals parameter; otherwise you'll get warnings from
341 "strict".
342perl v5.32.0 2020-07-28 HTML::Mason::Interp(3)