lino.core.plugin

This defines the Plugin class.

See Introduction to plugins before reading this.

(This module's source code is available here.)

Classes

Plugin(site, app_label, app_name, ...)

The base class for all plugin descriptors.

class lino.core.plugin.Plugin(site, app_label, app_name, app_module, needed_by)

Bases: object

The base class for all plugin descriptors.

For an introduction, see Introduction to plugins.

Plugin descriptors get defined and configured before Django models start to load. Lino creates one Plugin instance for every installed plugin and makes it globally available in dd.plugins.FOO (where FOO is the app_label of the plugin).

The Plugin class is comparable to Django's AppConfig class which has been added in version 1.7., but there is at least one important difference: in Lino the Plugin instances for all installed plugins are available (in dd.plugins) before Django starts to load the first models.py. This is possible because Plugins are defined in __init__.py files of your plugins. As a consequence, unlike Django's AppConfig, you cannot define a Plugin in your models.py file, you must define it in your plugins's __init__.py.

needs_plugins = []

A list of names of plugins needed by this plugin.

The default implementation of get_required_plugins() returns this list.

extends_models = None

If specified, a list of model names for which this app provides a subclass.

For backwards compatibility this has no effect when override_modlib_models is set.

disables_plugins = []

A list of strings with names of plugins to not install even though they are yeld by get_installed_apps. This is applied as an additional plugin filter even after get_apps_modifiers.

The plugin names can be either the full name or just the app_label.

This list is allowed to contain names of plugins which are not installed at all.

Usage example: The lino.modlib.tinymce works only with ExtJS 3, and we currently believe that we will never need it in ExtJS 6. When switching back and forth between lino.modlib.extjs and lino_extjs6.extjs6, we had to remove it explicitly by also defining a get_apps_modifiers method:

def get_apps_modifiers(self, **kw):
    kw = super(Site, self).get_apps_modifiers(**kw)
    kw.update(tinymce=None)
    return kw

Now lino_extjs6.extjs6 has disables_plugins set to ['tinymce'] and we no longer need above code because Lino now removes it automatically when ExtJS 6 is being used.

ui_handle_attr_name = None

Currently implemented by lino.modlib.extjs, lino.modlib.bootstrap3.

menu_group = None

The name of another plugin to be used as menu group.

See get_menu_group().

media_base_url = None

Remote URL base for media files.

media_root = None

Local path where third-party media files are installed.

Only used if this app has media_base_url empty and media_name non-empty, and if the media directory has no entry named media_name.

media_name = None

Either None (default) or a non-empty string with the name of the subdirectory of your media directory which is expected to contain media files for this app.

None means that there this app has no media files of her own.

Best practice is to set this to the app_label. Will be ignored if media_base_url is nonempty.

url_prefix = None

The url prefix under which this app should ask to install its url patterns.

site_js_snippets = []

List of js snippets to be injected into the lino_*.js file.

renderer = None

The renderer used by this plugin. See Introduction to Front end Renderers.

needed_by = None

If not None, then it is the Plugin instance which caused this plugin to automatically install.

verbose_name = None

The verbose name of this plugin, as shown to the user. This can be a lazily translated string.

short_name = None

The abbreviated name of this plugin, shown to the user in places where shortness is important, e.g. as the label of the tabs of a detail layout. This can be a lazily translated string. Defaults to verbose_name.

configure(**kw)

Set the given parameter(s) of this Plugin instance. Any number of parameters can be specified as keyword arguments.

Raise an exception if caller specified a key that does not have a corresponding attribute.

get_required_plugins()

Return a list of names of plugins needed by this plugin.

The default implementation returns needs_plugins.

Lino will automatically install these plugins if necessary.

Note that Lino will add them before your plugin.

Note that only the app_label (not the whole plugin name) is used when testing whether a plugin is installed. IOW if a plugin says it requires a plugin "stdlib.foo" and an application already has some plugin "mylib.foo" installed, "mylib" satisfies "stdlib.foo".

on_init()

This will be called when the Plugin is being instantiated (i.e. even before the Site instantiation has finished. Used by lino.modlib.users to set user_model.

on_plugins_loaded(site)

Called exactly once on each installed plugin, when the Site has loaded all plugins, but before calling setup_plugins(). All this happens before settings are ready and long before the models modules start to load.

This is used for initializing default values of plugin attributes that (a) depend on other plugins but (b) should be overridable in lino.core.site.Site.setup_plugins().

For example groups uses this to set a default value to the commentable_model for comments plugin.

Or lino.modlib.checkdata uses it to set responsible_user to "robin" when it is a demo site.

on_site_startup(site)

This will be called exactly once, when models are ready.

post_site_startup(site)

This will be called exactly once, when models are ready.

classmethod extends_from()

Return the plugin from which this plugin inherits.

classmethod get_subdir(name)

Get the absolute path of the named subdirectory if it exists.

before_analyze()

This is called during startup, when all models modules have been imported, and before Lino starts to analyze them.

on_ui_init(kernel)

This is called when the kernel is being instantiated.

get_patterns()

Override this to return a list of url patterns to be added to the Site's patterns.

get_requirements(site)

Return an iteration of required Python packages.

These will be installed during install.

Plugins can use quite sophisticated logic to decide which packages they require. For example lino_xl.lib.appypod check whether the appy package is already installed and does not require it then. This is to support the use case when a developer has a clone of the appy sources and uses this version. In this case we don't want to override it. Similar for lino_xl.lib.mailbox and its django_mailbox requirement.

get_head_lines(site, request)

Yield or return a list of textlines to add to the <head> of the html page.

get_menu_group()

Return the plugin (a Plugin instance) into whose menu this plugin should add its menu commands.

This returns self by default, unless

  • this plugin defines an explicit menu_group. In this case return the named plugin.

  • this plugin was automatically installed because some other plugin needs it. In this case return that other plugin.

When a plugin A is automatically being installed because needed by a plugin B which is itself being installed automatically because needed by a third plugin C, then A.get_menu_group returns C (and not B). A case where this happens is lino_welfare.modlib.pcsw which needs lino_xl.lib.coachings which in turn needs lino_xl.lib.clients.

setup_user_prefs(up)

Called when a lino.core.userprefs.UserPrefs get instantiated.

get_dashboard_items(user)

Return or yield a sequence of items to be rendered on the dashboard.

Called by lino.core.site.Site.get_dashboard_items().

Every item is expected to be either an instance of lino.core.dashboard.DashboardItem, or a lino.core.actors.Actor.

Tables are shown with a limit of lino.core.tables.AbstractTable.preview_limit rows.

get_detail_url(ar, actor, pk, *args, **kw)

Return the URL to the given database row.

This is only a relative URL. Get the fully qualified URI by prefixing lino.core.site.Site.server_url.

The extjs frontend overrides this and returns different URIs depending on whether ar.request is set or not.