mirror of
https://github.com/encode/django-rest-framework.git
synced 2024-11-26 03:23:59 +03:00
503 lines
18 KiB
Python
503 lines
18 KiB
Python
from django import forms
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from django.core.urlresolvers import reverse, get_urlconf, get_resolver, NoReverseMatch
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from django.db import models
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from django.db.models.query import QuerySet
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from django.db.models.fields.related import RelatedField
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from django.utils.encoding import smart_unicode
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from djangorestframework.response import ErrorResponse
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from djangorestframework.utils import as_tuple
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import decimal
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import inspect
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import re
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# TODO: _IgnoreFieldException
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# Map model classes to resource classes
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#_model_to_resource = {}
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def _model_to_dict(instance, resource=None):
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"""
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Given a model instance, return a ``dict`` representing the model.
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The implementation is similar to Django's ``django.forms.model_to_dict``, except:
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* It doesn't coerce related objects into primary keys.
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* It doesn't drop ``editable=False`` fields.
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* It also supports attribute or method fields on the instance or resource.
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"""
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opts = instance._meta
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data = {}
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#print [rel.name for rel in opts.get_all_related_objects()]
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#related = [rel.get_accessor_name() for rel in opts.get_all_related_objects()]
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#print [getattr(instance, rel) for rel in related]
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#if resource.fields:
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# fields = resource.fields
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#else:
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# fields = set(opts.fields + opts.many_to_many)
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fields = resource and resource.fields or ()
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include = resource and resource.include or ()
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exclude = resource and resource.exclude or ()
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extra_fields = fields and list(fields) or list(include)
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# Model fields
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for f in opts.fields + opts.many_to_many:
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if fields and not f.name in fields:
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continue
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if exclude and f.name in exclude:
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continue
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if isinstance(f, models.ForeignKey):
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data[f.name] = getattr(instance, f.name)
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else:
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data[f.name] = f.value_from_object(instance)
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if extra_fields and f.name in extra_fields:
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extra_fields.remove(f.name)
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# Method fields
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for fname in extra_fields:
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try:
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if hasattr(resource, fname):
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# check the resource first, to allow it to override fields
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obj = getattr(resource, fname)
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# if it's a method like foo(self, instance), then call it
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if inspect.ismethod(obj) and len(inspect.getargspec(obj)[0]) == 2:
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obj = obj(instance)
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elif hasattr(instance, fname):
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# now check the object instance
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obj = getattr(instance, fname)
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else:
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continue
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# TODO: It would be nicer if this didn't recurse here.
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# Let's keep _model_to_dict flat, and _object_to_data recursive.
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data[fname] = _object_to_data(obj)
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except NoReverseMatch:
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# Ug, bit of a hack for now
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pass
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return data
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def _object_to_data(obj, resource=None):
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"""
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Convert an object into a serializable representation.
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"""
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if isinstance(obj, dict):
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# dictionaries
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# TODO: apply same _model_to_dict logic fields/exclude here
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return dict([ (key, _object_to_data(val)) for key, val in obj.iteritems() ])
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if isinstance(obj, (tuple, list, set, QuerySet)):
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# basic iterables
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return [_object_to_data(item, resource) for item in obj]
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if isinstance(obj, models.Manager):
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# Manager objects
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return [_object_to_data(item, resource) for item in obj.all()]
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if isinstance(obj, models.Model):
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# Model instances
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return _object_to_data(_model_to_dict(obj, resource))
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if isinstance(obj, decimal.Decimal):
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# Decimals (force to string representation)
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return str(obj)
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if inspect.isfunction(obj) and not inspect.getargspec(obj)[0]:
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# function with no args
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return _object_to_data(obj(), resource)
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if inspect.ismethod(obj) and len(inspect.getargspec(obj)[0]) <= 1:
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# bound method
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return _object_to_data(obj(), resource)
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return smart_unicode(obj, strings_only=True)
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class BaseResource(object):
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"""
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Base class for all Resource classes, which simply defines the interface they provide.
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"""
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fields = None
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include = None
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exclude = None
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def __init__(self, view):
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self.view = view
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def validate_request(self, data, files=None):
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"""
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Given the request content return the cleaned, validated content.
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Typically raises a :exc:`response.ErrorResponse` with status code 400 (Bad Request) on failure.
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"""
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return data
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def filter_response(self, obj):
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"""
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Given the response content, filter it into a serializable object.
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"""
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return _object_to_data(obj, self)
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class Resource(BaseResource):
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"""
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A Resource determines how a python object maps to some serializable data.
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Objects that a resource can act on include plain Python object instances, Django Models, and Django QuerySets.
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"""
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# The model attribute refers to the Django Model which this Resource maps to.
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# (The Model's class, rather than an instance of the Model)
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model = None
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# By default the set of returned fields will be the set of:
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#
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# 0. All the fields on the model, excluding 'id'.
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# 1. All the properties on the model.
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# 2. The absolute_url of the model, if a get_absolute_url method exists for the model.
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#
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# If you wish to override this behaviour,
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# you should explicitly set the fields attribute on your class.
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fields = None
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class FormResource(Resource):
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"""
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Resource class that uses forms for validation.
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Also provides a :meth:`get_bound_form` method which may be used by some renderers.
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On calling :meth:`validate_request` this validator may set a :attr:`bound_form_instance` attribute on the
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view, which may be used by some renderers.
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"""
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"""
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The :class:`Form` class that should be used for request validation.
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This can be overridden by a :attr:`form` attribute on the :class:`views.View`.
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"""
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form = None
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def validate_request(self, data, files=None):
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"""
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Given some content as input return some cleaned, validated content.
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Raises a :exc:`response.ErrorResponse` with status code 400 (Bad Request) on failure.
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Validation is standard form validation, with an additional constraint that *no extra unknown fields* may be supplied.
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On failure the :exc:`response.ErrorResponse` content is a dict which may contain :obj:`'errors'` and :obj:`'field-errors'` keys.
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If the :obj:`'errors'` key exists it is a list of strings of non-field errors.
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If the :obj:`'field-errors'` key exists it is a dict of ``{'field name as string': ['errors as strings', ...]}``.
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"""
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return self._validate(data, files)
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def _validate(self, data, files, allowed_extra_fields=(), fake_data=None):
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"""
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Wrapped by validate to hide the extra flags that are used in the implementation.
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allowed_extra_fields is a list of fields which are not defined by the form, but which we still
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expect to see on the input.
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fake_data is a string that should be used as an extra key, as a kludge to force .errors
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to be populated when an empty dict is supplied in `data`
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"""
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# We'd like nice error messages even if no content is supplied.
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# Typically if an empty dict is given to a form Django will
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# return .is_valid() == False, but .errors == {}
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#
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# To get around this case we revalidate with some fake data.
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if fake_data:
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data[fake_data] = '_fake_data'
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allowed_extra_fields = allowed_extra_fields + ('_fake_data',)
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bound_form = self.get_bound_form(data, files)
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if bound_form is None:
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return data
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self.view.bound_form_instance = bound_form
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data = data and data or {}
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files = files and files or {}
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seen_fields_set = set(data.keys())
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form_fields_set = set(bound_form.fields.keys())
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allowed_extra_fields_set = set(allowed_extra_fields)
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# In addition to regular validation we also ensure no additional fields are being passed in...
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unknown_fields = seen_fields_set - (form_fields_set | allowed_extra_fields_set)
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unknown_fields = unknown_fields - set(('csrfmiddlewaretoken', '_accept', '_method')) # TODO: Ugh.
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# Check using both regular validation, and our stricter no additional fields rule
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if bound_form.is_valid() and not unknown_fields:
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# Validation succeeded...
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cleaned_data = bound_form.cleaned_data
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cleaned_data.update(bound_form.files)
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# Add in any extra fields to the cleaned content...
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for key in (allowed_extra_fields_set & seen_fields_set) - set(cleaned_data.keys()):
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cleaned_data[key] = data[key]
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return cleaned_data
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# Validation failed...
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detail = {}
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if not bound_form.errors and not unknown_fields:
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# is_valid() was False, but errors was empty.
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# If we havn't already done so attempt revalidation with some fake data
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# to force django to give us an errors dict.
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if fake_data is None:
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return self._validate(data, files, allowed_extra_fields, '_fake_data')
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# If we've already set fake_dict and we're still here, fallback gracefully.
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detail = {u'errors': [u'No content was supplied.']}
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else:
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# Add any non-field errors
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if bound_form.non_field_errors():
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detail[u'errors'] = bound_form.non_field_errors()
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# Add standard field errors
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field_errors = dict(
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(key, map(unicode, val))
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for (key, val)
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in bound_form.errors.iteritems()
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if not key.startswith('__')
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)
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# Add any unknown field errors
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for key in unknown_fields:
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field_errors[key] = [u'This field does not exist.']
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if field_errors:
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detail[u'field-errors'] = field_errors
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# Return HTTP 400 response (BAD REQUEST)
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raise ErrorResponse(400, detail)
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def get_bound_form(self, data=None, files=None, method=None):
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"""
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Given some content return a Django form bound to that content.
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If form validation is turned off (:attr:`form` class attribute is :const:`None`) then returns :const:`None`.
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"""
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# A form on the view overrides a form on the resource.
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form = getattr(self.view, 'form', self.form)
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# Use the requested method or determine the request method
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if method is None and hasattr(self.view, 'request') and hasattr(self.view, 'method'):
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method = self.view.method
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elif method is None and hasattr(self.view, 'request'):
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method = self.view.request.method
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# A method form on the view or resource overrides the general case.
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# Method forms are attributes like `get_form` `post_form` `put_form`.
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if method:
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form = getattr(self, '%s_form' % method.lower(), form)
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form = getattr(self.view, '%s_form' % method.lower(), form)
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if not form:
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return None
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if data is not None:
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return form(data, files)
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return form()
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#class _RegisterModelResource(type):
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# """
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# Auto register new ModelResource classes into ``_model_to_resource``
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# """
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# def __new__(cls, name, bases, dct):
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# resource_cls = type.__new__(cls, name, bases, dct)
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# model_cls = dct.get('model', None)
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# if model_cls:
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# _model_to_resource[model_cls] = resource_cls
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# return resource_cls
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class ModelResource(FormResource):
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"""
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Resource class that uses forms for validation and otherwise falls back to a model form if no form is set.
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Also provides a :meth:`get_bound_form` method which may be used by some renderers.
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"""
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# Auto-register new ModelResource classes into _model_to_resource
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#__metaclass__ = _RegisterModelResource
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"""
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The form class that should be used for request validation.
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If set to :const:`None` then the default model form validation will be used.
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This can be overridden by a :attr:`form` attribute on the :class:`views.View`.
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"""
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form = None
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"""
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The model class which this resource maps to.
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This can be overridden by a :attr:`model` attribute on the :class:`views.View`.
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"""
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model = None
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"""
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The list of fields to use on the output.
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May be any of:
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The name of a model field.
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The name of an attribute on the model.
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The name of an attribute on the resource.
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The name of a method on the model, with a signature like ``func(self)``.
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The name of a method on the resource, with a signature like ``func(self, instance)``.
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"""
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fields = None
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"""
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The list of fields to exclude. This is only used if :attr:`fields` is not set.
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"""
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exclude = ('id', 'pk')
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"""
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The list of extra fields to include. This is only used if :attr:`fields` is not set.
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"""
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include = ('url',)
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def __init__(self, view):
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"""
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Allow :attr:`form` and :attr:`model` attributes set on the
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:class:`View` to override the :attr:`form` and :attr:`model`
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attributes set on the :class:`Resource`.
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"""
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super(ModelResource, self).__init__(view)
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if getattr(view, 'model', None):
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self.model = view.model
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def validate_request(self, data, files=None):
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"""
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Given some content as input return some cleaned, validated content.
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Raises a :exc:`response.ErrorResponse` with status code 400 (Bad Request) on failure.
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Validation is standard form or model form validation,
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with an additional constraint that no extra unknown fields may be supplied,
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and that all fields specified by the fields class attribute must be supplied,
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even if they are not validated by the form/model form.
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On failure the ErrorResponse content is a dict which may contain :obj:`'errors'` and :obj:`'field-errors'` keys.
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If the :obj:`'errors'` key exists it is a list of strings of non-field errors.
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If the ''field-errors'` key exists it is a dict of {field name as string: list of errors as strings}.
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"""
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return self._validate(data, files, allowed_extra_fields=self._property_fields_set)
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def get_bound_form(self, data=None, files=None, method=None):
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"""
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Given some content return a ``Form`` instance bound to that content.
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If the :attr:`form` class attribute has been explicitly set then that class will be used
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to create the Form, otherwise the model will be used to create a ModelForm.
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"""
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form = super(ModelResource, self).get_bound_form(data, files, method=method)
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# Use an explict Form if it exists
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if form:
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return form
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elif self.model:
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# Fall back to ModelForm which we create on the fly
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class OnTheFlyModelForm(forms.ModelForm):
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class Meta:
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model = self.model
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#fields = tuple(self._model_fields_set)
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# Instantiate the ModelForm as appropriate
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if data and isinstance(data, models.Model):
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# Bound to an existing model instance
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return OnTheFlyModelForm(instance=content)
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elif data is not None:
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return OnTheFlyModelForm(data, files)
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return OnTheFlyModelForm()
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# Both form and model not set? Okay bruv, whatevs...
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return None
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def url(self, instance):
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"""
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Attempts to reverse resolve the url of the given model *instance* for this resource.
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Requires a ``View`` with :class:`mixins.InstanceMixin` to have been created for this resource.
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This method can be overridden if you need to set the resource url reversing explicitly.
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"""
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if not hasattr(self, 'view_callable'):
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raise NoReverseMatch
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# dis does teh magicks...
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urlconf = get_urlconf()
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resolver = get_resolver(urlconf)
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possibilities = resolver.reverse_dict.getlist(self.view_callable[0])
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for tuple_item in possibilities:
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possibility = tuple_item[0]
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# pattern = tuple_item[1]
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# Note: defaults = tuple_item[2] for django >= 1.3
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for result, params in possibility:
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#instance_attrs = dict([ (param, getattr(instance, param)) for param in params if hasattr(instance, param) ])
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instance_attrs = {}
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for param in params:
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if not hasattr(instance, param):
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continue
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attr = getattr(instance, param)
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if isinstance(attr, models.Model):
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instance_attrs[param] = attr.pk
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else:
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instance_attrs[param] = attr
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try:
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return reverse(self.view_callable[0], kwargs=instance_attrs)
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except NoReverseMatch:
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pass
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raise NoReverseMatch
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@property
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def _model_fields_set(self):
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"""
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Return a set containing the names of validated fields on the model.
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"""
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model_fields = set(field.name for field in self.model._meta.fields)
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if fields:
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return model_fields & set(as_tuple(self.fields))
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return model_fields - set(as_tuple(self.exclude))
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@property
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def _property_fields_set(self):
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"""
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Returns a set containing the names of validated properties on the model.
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"""
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property_fields = set(attr for attr in dir(self.model) if
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isinstance(getattr(self.model, attr, None), property)
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and not attr.startswith('_'))
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if self.fields:
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return property_fields & set(as_tuple(self.fields))
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return property_fields.union(set(as_tuple(self.include))) - set(as_tuple(self.exclude))
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