Automatic class loading: Difference between revisions
(Added direct to namespace rules) |
(MDLSITE-6087 - namespaced classes are not the default - make it clear here.) |
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==Class naming== | ==Class naming== | ||
To be discoverable by the Moodle automatic classloader, classes must adhere to | To be discoverable by the Moodle automatic classloader, classes must adhere to some class naming and location rules: | ||
* Sit under the '''classes''' directory of every component: | |||
** '''/lib/classes/''' for core component (core). | |||
** '''SUBSYSTEMDIR/classes/''' for subsystem (core_sybsystem). | |||
** '''PLUGINDIR/classes/''' for plugins (plugintype_plugin). | |||
:::Note: The list of valid subsystems and plugin types with their corresponding directories [https://github.com/moodle/moodle/blob/master/lib/components.json can be found in code]. | |||
* One class file for each class. | |||
* Autoloading is always [[Frankenstyle|Frankenstyle-based]] and it will be important part of the discovery. | |||
* It provides autoloading of both: | |||
** '''Frankenstyle namespaced classes''', where the component name is the namespace ('''\core_user\example''' or '''\mod_forum\example'''). This is the [[Coding style#Namespaces|actual way]] to add new classes to Moodle. | |||
** '''Frankenstyle prefixed classes''', where the component name is the prefix of the class ('''core_user_example''' or '''mod_forum_example'''). This is now considered deprecated and only should be used for existing code or APIs not supporting autoloading. | |||
:::Note: Since June 2020 the later is deprecated, see MDLSITE-6087 for more information. | |||
== Frankenstyle namespaced classes == | |||
PHP namespaces are designed to improve code organisation in your projects. Directory structure in classes/ is matching the namespace structure. Main details about their implementation: | |||
* Actual, preferred. | |||
* [[Frankenstyle]] Namespaces: | |||
** Core classes must use the '''namespace core'''. | |||
** Subsystem classes must use the '''namespace core_subsystem'''. | |||
** Plugin classes must use the '''namespace plugintype_pluginname''' | |||
** File names will be the class names '''without the prefix''' | |||
** e.g. Class '''\mod_forum\some_class''' is stored in file '''mod/forum/classes/some_class.php''' | |||
** e.g. Class '''\core\frankenstyle''' class is stored in '''lib/classes/frankenstyle.php''' | |||
** For more details about valid first and second level namespaces see [[Coding_style#Rules_for_level1]]. | |||
=== Code examples (namespaced) === | |||
<code php> | <code php> | ||
<?php | <?php | ||
namespace core\event; | |||
// file lib/classes/event/base.php | |||
class base { | |||
} | } | ||
</code> | </code> | ||
Line 41: | Line 48: | ||
<code php> | <code php> | ||
<?php | <?php | ||
// | namespace mod_forum\event; | ||
// file mod/forum/classes/event/post_read.php | |||
class post_read extends \core\event\base { | |||
} | |||
</code> | </code> | ||
<code php> | <code php> | ||
<?php | <?php | ||
// in any file | // in any file | ||
\mod_forum\event\post_read::create($post->id, ...)->trigger(); | |||
</code> | </code> | ||
== | == Frankenstyle prefixed classes (deprecated)== | ||
Main details about their implementation: | |||
* Deprecated, only for BC and not autoloaded stuff. | |||
* [[Frankenstyle]] Prefixes: | |||
** Core classes must start with the prefix '''core_'''. | |||
** Subsystem classes must start with the prefix '''core_subsystem'''. | |||
** Plugin classes must start with the prefix '''plugintype_pluginname''' | |||
** File names will be the class names '''without the prefix''' | |||
** e.g. Class '''mod_forum_some_class''' is stored in file '''mod/forum/classes/some_class.php''' | |||
** e.g. Class '''core_frankenstyle''' class is stored in '''lib/classes/frankenstyle.php''' | |||
Example: | === Code Examples (prefixed)=== | ||
Example of autoloaded class in forum module: | |||
<code php> | <code php> | ||
<?php | <?php | ||
// file mod/forum/classes/some_class.php | |||
class mod_forum_some_class { | |||
} | } | ||
</code> | </code> | ||
Line 80: | Line 95: | ||
<code php> | <code php> | ||
<?php | <?php | ||
// file mod/forum/lib.php | |||
// no require_once() necessary here | |||
$instance = new mod_forum_some_class(); | |||
</code> | </code> | ||
<code php> | <code php> | ||
<?php | <?php | ||
// in any file | // in any file | ||
if (class_exists('mod_forum_some_class')) { | |||
// do something | |||
} | |||
</code> | </code> | ||
== Backwards compatibility == | |||
There are no know issues that could cause backwards incompatibility, however it is strongly recommended to use the classes subdirectory only for classes that are included automatically. | There are no know issues that could cause backwards incompatibility, however it is strongly recommended to use the classes subdirectory only for classes that are included automatically. | ||
==Performance and developer mode== | == Performance and developer mode == | ||
Class autoloading improves performance and reduces memory footprint. Location of all classes is automatically stored in class map cache, the cache is updated automatically before upgrade or installation, during cache reset and in developer mode. | Class autoloading improves performance and reduces memory footprint. Location of all classes is automatically stored in class map cache, the cache is updated automatically before upgrade or installation, during cache reset and in developer mode. | ||
Line 115: | Line 129: | ||
Otherwise the new class would not be found. | Otherwise the new class would not be found. | ||
==See also== | == See also == | ||
* [[Frankenstyle]] | * [[Frankenstyle]] |
Revision as of 17:04, 19 June 2020
Moodle 2.6
This document describes how to use the functionality of the automatic classloader provided by Moodle.
Class naming
To be discoverable by the Moodle automatic classloader, classes must adhere to some class naming and location rules:
- Sit under the classes directory of every component:
- /lib/classes/ for core component (core).
- SUBSYSTEMDIR/classes/ for subsystem (core_sybsystem).
- PLUGINDIR/classes/ for plugins (plugintype_plugin).
- Note: The list of valid subsystems and plugin types with their corresponding directories can be found in code.
- One class file for each class.
- Autoloading is always Frankenstyle-based and it will be important part of the discovery.
- It provides autoloading of both:
- Frankenstyle namespaced classes, where the component name is the namespace (\core_user\example or \mod_forum\example). This is the actual way to add new classes to Moodle.
- Frankenstyle prefixed classes, where the component name is the prefix of the class (core_user_example or mod_forum_example). This is now considered deprecated and only should be used for existing code or APIs not supporting autoloading.
- Note: Since June 2020 the later is deprecated, see MDLSITE-6087 for more information.
Frankenstyle namespaced classes
PHP namespaces are designed to improve code organisation in your projects. Directory structure in classes/ is matching the namespace structure. Main details about their implementation:
- Actual, preferred.
- Frankenstyle Namespaces:
- Core classes must use the namespace core.
- Subsystem classes must use the namespace core_subsystem.
- Plugin classes must use the namespace plugintype_pluginname
- File names will be the class names without the prefix
- e.g. Class \mod_forum\some_class is stored in file mod/forum/classes/some_class.php
- e.g. Class \core\frankenstyle class is stored in lib/classes/frankenstyle.php
- For more details about valid first and second level namespaces see Coding_style#Rules_for_level1.
Code examples (namespaced)
<?php
namespace core\event;
// file lib/classes/event/base.php
class base {
}
<?php
namespace mod_forum\event;
// file mod/forum/classes/event/post_read.php
class post_read extends \core\event\base {
}
<?php
// in any file
\mod_forum\event\post_read::create($post->id, ...)->trigger();
Frankenstyle prefixed classes (deprecated)
Main details about their implementation:
- Deprecated, only for BC and not autoloaded stuff.
- Frankenstyle Prefixes:
- Core classes must start with the prefix core_.
- Subsystem classes must start with the prefix core_subsystem.
- Plugin classes must start with the prefix plugintype_pluginname
- File names will be the class names without the prefix
- e.g. Class mod_forum_some_class is stored in file mod/forum/classes/some_class.php
- e.g. Class core_frankenstyle class is stored in lib/classes/frankenstyle.php
Code Examples (prefixed)
Example of autoloaded class in forum module:
<?php
// file mod/forum/classes/some_class.php
class mod_forum_some_class {
}
<?php
// file mod/forum/lib.php
// no require_once() necessary here
$instance = new mod_forum_some_class();
<?php
// in any file
if (class_exists('mod_forum_some_class')) {
// do something
}
Backwards compatibility
There are no know issues that could cause backwards incompatibility, however it is strongly recommended to use the classes subdirectory only for classes that are included automatically.
Performance and developer mode
Class autoloading improves performance and reduces memory footprint. Location of all classes is automatically stored in class map cache, the cache is updated automatically before upgrade or installation, during cache reset and in developer mode.
There is only one inconvenience - if you add new class or remove it you need to do one of the following:
- visit yourserver/admin/index.php
- purge caches
- or add $CFG->debug = (E_ALL | E_STRICT); to your config.php
Otherwise the new class would not be found.