Source code for mezzanine.boot

An app that is forced to the top of the list in ``INSTALLED_APPS``
for the purpose of hooking into Django's ``class_prepared`` signal
and adding custom fields as defined by the ``EXTRA_MODEL_FIELDS``
setting. Also patches ```` to use
``LazyAdminSite`` that defers certains register/unregister calls
until ``admin.autodiscover`` to avoid some timing issues around
custom fields not being available when custom admin classes are
from __future__ import unicode_literals

from collections import defaultdict

from django import VERSION as DJANGO_VERSION
from django.apps import apps
from django.conf import settings
from django.contrib import admin
from django.core.exceptions import ImproperlyConfigured
from django.db.models.signals import class_prepared

from mezzanine.boot.lazy_admin import LazyAdminSite
from mezzanine.utils.importing import import_dotted_path

[docs]def parse_field_path(field_path): """ Take a path to a field like "mezzanine.pages.models.Page.feature_image" and return a model key, which is a tuple of the form ('pages', 'page'), and a field name, e.g. "feature_image". """ model_path, field_name = field_path.rsplit(".", 1) app_name, model_name = model_path.split('.models.') _, app_label = app_name.rsplit('.', 1) return (app_label, model_name.lower()), field_name
[docs]def import_field(field_classpath): """ Imports a field by its dotted class path, prepending "django.db.models" to raw class names and raising an exception if the import fails. """ if '.' in field_classpath: fully_qualified = field_classpath else: fully_qualified = "django.db.models.%s" % field_classpath try: return import_dotted_path(fully_qualified) except ImportError: raise ImproperlyConfigured("The EXTRA_MODEL_FIELDS setting contains " "the field '%s' which could not be " "imported." % field_classpath)
[docs]def parse_extra_model_fields(extra_model_fields): """ Parses the value of EXTRA_MODEL_FIELDS, grouping the entries by model and instantiating the extra fields. Returns a sequence of tuples of the form (model_key, fields) where model_key is a pair of app_label, model_name and fields is a list of (field_name, field_instance) pairs. """ fields = defaultdict(list) for entry in extra_model_fields: model_key, field_name = parse_field_path(entry[0]) field_class = import_field(entry[1]) field_args, field_kwargs = entry[2:] try: field = field_class(*field_args, **field_kwargs) except TypeError as e: raise ImproperlyConfigured( "The EXTRA_MODEL_FIELDS setting contains arguments for the " "field '%s' which could not be applied: %s" % (entry[1], e)) fields[model_key].append((field_name, field)) return fields
fields = parse_extra_model_fields(getattr(settings, "EXTRA_MODEL_FIELDS", []))
[docs]def add_extra_model_fields(sender, **kwargs): """ Injects custom fields onto the given sender model as defined by the ``EXTRA_MODEL_FIELDS`` setting. This is a closure over the "fields" variable. """ model_key = sender._meta.app_label, sender._meta.model_name for field_name, field in fields.get(model_key, {}): field.contribute_to_class(sender, field_name)
if DJANGO_VERSION < (1, 9): if fields: class_prepared.connect(add_extra_model_fields, dispatch_uid="FQFEQ#rfq3r") else: for model_key in fields: apps.lazy_model_operation(add_extra_model_fields, model_key) # Override with LazyAdminSite. It must # be bound to a separate name (admin_site) for access in autodiscover # below. admin_site = LazyAdminSite() = admin_site django_autodiscover = admin.autodiscover
[docs]def autodiscover(*args, **kwargs): """ Replaces django's original autodiscover to add a call to LazyAdminSite's lazy_registration. """ django_autodiscover(*args, **kwargs) admin_site.lazy_registration()
admin.autodiscover = autodiscover