lino.core.inject¶

Functions

`check_pending_injects`(sender[, models_list])
`do_when_prepared`(todo, *model_specs)	Execute the specified function todo on all specified models as soon as they are prepared.
`fix_field_cache`(model)	Remove duplicate entries in the field cache of the specified model in order to fix Django issue #10808
`fmt`(func_caller)
`inject_action`(model_spec, **actions)	Add the specified action(s) to the specified model.
`inject_field`(model_spec, name, field[, doc, ...])	Add the given field to the given model.
`inject_quick_add_buttons`(model, name, target)	Injects a virtual display field name into the specified model.
`on_class_prepared`(sender, **kw)	This is Lino's general class_prepared handler.
`update_field`(model_spec, name, **kw)	Update some attribute of the specified existing field. For example `Human` defines a field first_name, which may not be blank. If you inherit from this mixin but want first_name to be optional::.
`update_model`(model_spec, **actions)	Replace the specified attributes in the specified model.
`when_prepared`(*model_specs)	Decorator to declare a function which will automatically run when the specified models has been prepared.

lino.core.inject.fix_field_cache(model)¶: Remove duplicate entries in the field cache of the specified model in order to fix Django issue #10808

lino.core.inject.on_class_prepared(sender, **kw)¶

This is Lino's general class_prepared handler. It does two things:

Run pending calls to inject_field() and update_field().
Apply a workaround for Django's ticket 10808. In a diamond inheritance pattern, _meta._field_cache contains certain fields twice. So we remove these duplicate fields from _meta._field_cache. (A better solution would be of course to not collect them.)

lino.core.inject.do_when_prepared(todo, *model_specs)¶

Execute the specified function todo on all specified models as soon as they are prepared. If a specified model hasn't yet been prepared, add the call to a queue and execute it later.

If a model_spec is not a string, the function todo is called immediately.

lino.core.inject.when_prepared(*model_specs)¶: Decorator to declare a function which will automatically run when the specified models has been prepared. If the model has already been prepared, the function is executed immediately.

lino.core.inject.inject_action(model_spec, **actions)¶

Add the specified action(s) to the specified model.

This can also be used to inject any other class attribute on a model, e.g. choosers.

lino.core.inject.update_model(model_spec, **actions)¶: Replace the specified attributes in the specified model.

lino.core.inject.inject_field(model_spec, name, field, doc=None, active=False)¶

Add the given field to the given model.

The following code:

class Foo(dd.Model):
   field1 = dd.ForeignKey(...)

dd.inject_field(Foo, 'field2', models.CharField(max_length=20))

is functionally equivalent to this code:

class Foo(dd.Model):
   field1 = dd.ForeignKey(Bar)
   field2 = models.CharField(max_length=20)

Because inject_field is usually called at the global level of models modules, it cannot know whether the given model_spec has already been imported (and its class prepared) or not. That's why it uses Django's class_prepared signal to maintain its own list of models.

Note that inject_field() causes problems when the modified model has subclasses and is not abstract (i.e., is an MTI parent). Subclasses will have only some part of the injected field's definition.

lino.core.inject.update_field(model_spec, name, **kw)¶

Update some attribute of the specified existing field. For example Human defines a field first_name, which may not be blank. If you inherit from this mixin but want first_name to be optional:

class MyPerson(mixins.Human):
    ...
dd.update_field(MyPerson, 'first_name', blank=True)

Or you want to change the label of a field defined in an inherited mixin, as done in lino_xl.lib.outbox:

dd.update_field(Mail, 'user', verbose_name=_("Sender"))

Note that you can update only certain attributes: verbose_name, blank, null, the precision and length of character or decimal fields, ...

You cannot, for example, update the related_model of a ForeignKey field because this property causes a myriad of other things to happen during field initialization.

lino.core.inject.inject_quick_add_buttons(model, name, target)¶: Injects a virtual display field name into the specified model. This field will show up to three buttons [New] [Show last] [Show all]. target is the table that will run these actions. It must be a slave of model.