214 lines
8.3 KiB
Python
214 lines
8.3 KiB
Python
"""
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Django Admin support for polymorphic inlines.
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Each row in the inline can correspond with a different subclass.
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"""
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from functools import partial
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from django.contrib.admin.options import InlineModelAdmin
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from django.contrib.admin.utils import flatten_fieldsets
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from django.forms import Media
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from polymorphic.formsets import polymorphic_child_forms_factory, BasePolymorphicInlineFormSet, PolymorphicFormSetChild
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from polymorphic.formsets.utils import add_media
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class PolymorphicParentInlineModelAdmin(InlineModelAdmin):
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"""
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A polymorphic inline, where each formset row can be a different form.
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Note that:
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* Permissions are only checked on the base model.
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* The child inlines can't override the base model fields, only this parent inline can do that.
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"""
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formset = BasePolymorphicInlineFormSet
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#: The extra forms to show
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#: By default there are no 'extra' forms as the desired type is unknown.
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#: Instead, add each new item using JavaScript that first offers a type-selection.
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extra = 0
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#: Inlines for all model sub types that can be displayed in this inline.
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#: Each row is a :class:`PolymorphicChildInlineModelAdmin`
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child_inlines = ()
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def __init__(self, parent_model, admin_site):
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super(PolymorphicParentInlineModelAdmin, self).__init__(parent_model, admin_site)
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# While the inline is created per request, the 'request' object is not known here.
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# Hence, creating all child inlines unconditionally, without checking permissions.
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self.child_inline_instances = self.get_child_inline_instances()
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# Create a lookup table
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self._child_inlines_lookup = {}
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for child_inline in self.child_inline_instances:
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self._child_inlines_lookup[child_inline.model] = child_inline
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def get_child_inline_instances(self):
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"""
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:rtype List[PolymorphicChildInlineModelAdmin]
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"""
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instances = []
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for ChildInlineType in self.child_inlines:
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instances.append(ChildInlineType(parent_inline=self))
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return instances
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def get_child_inline_instance(self, model):
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"""
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Find the child inline for a given model.
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:rtype: PolymorphicChildInlineModelAdmin
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"""
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try:
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return self._child_inlines_lookup[model]
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except KeyError:
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raise ValueError("Model '{0}' not found in child_inlines".format(model.__name__))
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def get_formset(self, request, obj=None, **kwargs):
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"""
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Construct the inline formset class.
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This passes all class attributes to the formset.
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:rtype: type
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"""
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# Construct the FormSet class
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FormSet = super(PolymorphicParentInlineModelAdmin, self).get_formset(request, obj=obj, **kwargs)
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# Instead of completely redefining super().get_formset(), we use
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# the regular inlineformset_factory(), and amend that with our extra bits.
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# This code line is the essence of what polymorphic_inlineformset_factory() does.
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FormSet.child_forms = polymorphic_child_forms_factory(
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formset_children=self.get_formset_children(request, obj=obj)
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)
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return FormSet
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def get_formset_children(self, request, obj=None):
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"""
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The formset 'children' provide the details for all child models that are part of this formset.
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It provides a stripped version of the modelform/formset factory methods.
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"""
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formset_children = []
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for child_inline in self.child_inline_instances:
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# TODO: the children can be limited here per request based on permissions.
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formset_children.append(child_inline.get_formset_child(request, obj=obj))
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return formset_children
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def get_fieldsets(self, request, obj=None):
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"""
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Hook for specifying fieldsets.
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"""
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if self.fieldsets:
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return self.fieldsets
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else:
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return [] # Avoid exposing fields to the child
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def get_fields(self, request, obj=None):
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if self.fields:
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return self.fields
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else:
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return [] # Avoid exposing fields to the child
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@property
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def media(self):
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# The media of the inline focuses on the admin settings,
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# whether to expose the scripts for filter_horizontal etc..
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# The admin helper exposes the inline + formset media.
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base_media = super(PolymorphicParentInlineModelAdmin, self).media
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all_media = Media()
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add_media(all_media, base_media)
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# Add all media of the child inline instances
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for child_instance in self.child_inline_instances:
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child_media = child_instance.media
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# Avoid adding the same media object again and again
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if child_media._css != base_media._css and child_media._js != base_media._js:
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add_media(all_media, child_media)
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return all_media
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class PolymorphicChildInlineModelAdmin(InlineModelAdmin):
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"""
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The child inline; which allows configuring the admin options
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for the child appearance.
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Note that not all options will be honored by the parent, notably the formset options:
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* :attr:`extra`
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* :attr:`min_num`
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* :attr:`max_num`
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The model form options however, will all be read.
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"""
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formset_child = PolymorphicFormSetChild
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extra = 0 # TODO: currently unused for the children.
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def __init__(self, parent_inline):
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self.parent_inline = parent_inline
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super(PolymorphicChildInlineModelAdmin, self).__init__(parent_inline.parent_model, parent_inline.admin_site)
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def get_formset(self, request, obj=None, **kwargs):
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# The child inline is only used to construct the form,
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# and allow to override the form field attributes.
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# The formset is created by the parent inline.
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raise RuntimeError("The child get_formset() is not used.")
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def get_fields(self, request, obj=None):
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if self.fields:
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return self.fields
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# Standard Django logic, use the form to determine the fields.
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# The form needs to pass through all factory logic so all 'excludes' are set as well.
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# Default Django does: form = self.get_formset(request, obj, fields=None).form
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# Use 'fields=None' avoids recursion in the field autodetection.
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form = self.get_formset_child(request, obj, fields=None).get_form()
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return list(form.base_fields) + list(self.get_readonly_fields(request, obj))
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def get_formset_child(self, request, obj=None, **kwargs):
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"""
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Return the formset child that the parent inline can use to represent us.
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:rtype: PolymorphicFormSetChild
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"""
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# Similar to the normal get_formset(), the caller may pass fields to override the defaults settings
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# in the inline. In Django's GenericInlineModelAdmin.get_formset() this is also used in the same way,
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# to make sure the 'exclude' also contains the GFK fields.
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#
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# Hence this code is almost identical to InlineModelAdmin.get_formset()
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# and GenericInlineModelAdmin.get_formset()
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#
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# Transfer the local inline attributes to the formset child,
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# this allows overriding settings.
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if 'fields' in kwargs:
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fields = kwargs.pop('fields')
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else:
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fields = flatten_fieldsets(self.get_fieldsets(request, obj))
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if self.exclude is None:
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exclude = []
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else:
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exclude = list(self.exclude)
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exclude.extend(self.get_readonly_fields(request, obj))
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if self.exclude is None and hasattr(self.form, '_meta') and self.form._meta.exclude:
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# Take the custom ModelForm's Meta.exclude into account only if the
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# InlineModelAdmin doesn't define its own.
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exclude.extend(self.form._meta.exclude)
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#can_delete = self.can_delete and self.has_delete_permission(request, obj)
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defaults = {
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"form": self.form,
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"fields": fields,
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"exclude": exclude or None,
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"formfield_callback": partial(self.formfield_for_dbfield, request=request),
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}
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defaults.update(kwargs)
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# This goes through the same logic that get_formset() calls
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# by passing the inline class attributes to modelform_factory()
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FormSetChildClass = self.formset_child
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return FormSetChildClass(self.model, **defaults)
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