mirror of
https://github.com/encode/django-rest-framework.git
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296 lines
10 KiB
Python
296 lines
10 KiB
Python
"""
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Helper functions for mapping model fields to a dictionary of default
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keyword arguments that should be used for their equivelent serializer fields.
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"""
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import inspect
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from django.core import validators
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from django.db import models
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from django.utils.text import capfirst
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from rest_framework.validators import UniqueValidator
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NUMERIC_FIELD_TYPES = (
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models.IntegerField, models.FloatField, models.DecimalField
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)
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class ClassLookupDict(object):
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"""
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Takes a dictionary with classes as keys.
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Lookups against this object will traverses the object's inheritance
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hierarchy in method resolution order, and returns the first matching value
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from the dictionary or raises a KeyError if nothing matches.
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"""
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def __init__(self, mapping):
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self.mapping = mapping
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def __getitem__(self, key):
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if hasattr(key, '_proxy_class'):
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# Deal with proxy classes. Ie. BoundField behaves as if it
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# is a Field instance when using ClassLookupDict.
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base_class = key._proxy_class
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else:
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base_class = key.__class__
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for cls in inspect.getmro(base_class):
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if cls in self.mapping:
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return self.mapping[cls]
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raise KeyError('Class %s not found in lookup.' % base_class.__name__)
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def __setitem__(self, key, value):
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self.mapping[key] = value
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def needs_label(model_field, field_name):
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"""
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Returns `True` if the label based on the model's verbose name
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is not equal to the default label it would have based on it's field name.
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"""
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default_label = field_name.replace('_', ' ').capitalize()
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return capfirst(model_field.verbose_name) != default_label
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def get_detail_view_name(model):
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"""
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Given a model class, return the view name to use for URL relationships
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that refer to instances of the model.
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"""
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return '%(model_name)s-detail' % {
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'app_label': model._meta.app_label,
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'model_name': model._meta.object_name.lower()
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}
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def get_field_kwargs(field_name, model_field):
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"""
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Creates a default instance of a basic non-relational field.
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"""
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kwargs = {}
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validator_kwarg = list(model_field.validators)
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# The following will only be used by ModelField classes.
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# Gets removed for everything else.
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kwargs['model_field'] = model_field
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if model_field.verbose_name and needs_label(model_field, field_name):
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kwargs['label'] = capfirst(model_field.verbose_name)
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if model_field.help_text:
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kwargs['help_text'] = model_field.help_text
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max_digits = getattr(model_field, 'max_digits', None)
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if max_digits is not None:
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kwargs['max_digits'] = max_digits
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decimal_places = getattr(model_field, 'decimal_places', None)
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if decimal_places is not None:
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kwargs['decimal_places'] = decimal_places
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if isinstance(model_field, models.TextField):
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kwargs['style'] = {'base_template': 'textarea.html'}
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if isinstance(model_field, models.AutoField) or not model_field.editable:
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# If this field is read-only, then return early.
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# Further keyword arguments are not valid.
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kwargs['read_only'] = True
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return kwargs
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if model_field.has_default() or model_field.blank or model_field.null:
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kwargs['required'] = False
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if model_field.null and not isinstance(model_field, models.NullBooleanField):
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kwargs['allow_null'] = True
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if model_field.blank and (isinstance(model_field, models.CharField) or
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isinstance(model_field, models.TextField)):
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kwargs['allow_blank'] = True
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if isinstance(model_field, models.FilePathField):
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kwargs['path'] = model_field.path
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if model_field.match is not None:
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kwargs['match'] = model_field.match
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if model_field.recursive is not False:
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kwargs['recursive'] = model_field.recursive
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if model_field.allow_files is not True:
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kwargs['allow_files'] = model_field.allow_files
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if model_field.allow_folders is not False:
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kwargs['allow_folders'] = model_field.allow_folders
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if model_field.choices:
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# If this model field contains choices, then return early.
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# Further keyword arguments are not valid.
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kwargs['choices'] = model_field.choices
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return kwargs
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# Our decimal validation is handled in the field code, not validator code.
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# (In Django 1.9+ this differs from previous style)
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if isinstance(model_field, models.DecimalField):
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validator_kwarg = [
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validator for validator in validator_kwarg
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if not isinstance(validator, validators.DecimalValidator)
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]
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# Ensure that max_length is passed explicitly as a keyword arg,
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# rather than as a validator.
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max_length = getattr(model_field, 'max_length', None)
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if max_length is not None and (isinstance(model_field, models.CharField) or
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isinstance(model_field, models.TextField)):
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kwargs['max_length'] = max_length
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validator_kwarg = [
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validator for validator in validator_kwarg
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if not isinstance(validator, validators.MaxLengthValidator)
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]
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# Ensure that min_length is passed explicitly as a keyword arg,
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# rather than as a validator.
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min_length = next((
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validator.limit_value for validator in validator_kwarg
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if isinstance(validator, validators.MinLengthValidator)
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), None)
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if min_length is not None and isinstance(model_field, models.CharField):
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kwargs['min_length'] = min_length
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validator_kwarg = [
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validator for validator in validator_kwarg
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if not isinstance(validator, validators.MinLengthValidator)
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]
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# Ensure that max_value is passed explicitly as a keyword arg,
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# rather than as a validator.
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max_value = next((
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validator.limit_value for validator in validator_kwarg
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if isinstance(validator, validators.MaxValueValidator)
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), None)
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if max_value is not None and isinstance(model_field, NUMERIC_FIELD_TYPES):
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kwargs['max_value'] = max_value
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validator_kwarg = [
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validator for validator in validator_kwarg
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if not isinstance(validator, validators.MaxValueValidator)
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]
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# Ensure that max_value is passed explicitly as a keyword arg,
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# rather than as a validator.
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min_value = next((
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validator.limit_value for validator in validator_kwarg
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if isinstance(validator, validators.MinValueValidator)
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), None)
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if min_value is not None and isinstance(model_field, NUMERIC_FIELD_TYPES):
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kwargs['min_value'] = min_value
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validator_kwarg = [
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validator for validator in validator_kwarg
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if not isinstance(validator, validators.MinValueValidator)
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]
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# URLField does not need to include the URLValidator argument,
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# as it is explicitly added in.
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if isinstance(model_field, models.URLField):
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validator_kwarg = [
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validator for validator in validator_kwarg
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if not isinstance(validator, validators.URLValidator)
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]
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# EmailField does not need to include the validate_email argument,
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# as it is explicitly added in.
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if isinstance(model_field, models.EmailField):
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validator_kwarg = [
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validator for validator in validator_kwarg
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if validator is not validators.validate_email
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]
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# SlugField do not need to include the 'validate_slug' argument,
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if isinstance(model_field, models.SlugField):
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validator_kwarg = [
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validator for validator in validator_kwarg
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if validator is not validators.validate_slug
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]
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# IPAddressField do not need to include the 'validate_ipv46_address' argument,
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if isinstance(model_field, models.GenericIPAddressField):
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validator_kwarg = [
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validator for validator in validator_kwarg
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if validator is not validators.validate_ipv46_address
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]
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if getattr(model_field, 'unique', False):
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unique_error_message = model_field.error_messages.get('unique', None)
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if unique_error_message:
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unique_error_message = unique_error_message % {
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'model_name': model_field.model._meta.object_name,
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'field_label': model_field.verbose_name
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}
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validator = UniqueValidator(
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queryset=model_field.model._default_manager,
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message=unique_error_message)
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validator_kwarg.append(validator)
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if validator_kwarg:
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kwargs['validators'] = validator_kwarg
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return kwargs
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def get_relation_kwargs(field_name, relation_info):
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"""
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Creates a default instance of a flat relational field.
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"""
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model_field, related_model, to_many, to_field, has_through_model = relation_info
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kwargs = {
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'queryset': related_model._default_manager,
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'view_name': get_detail_view_name(related_model)
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}
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if to_many:
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kwargs['many'] = True
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if to_field:
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kwargs['to_field'] = to_field
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if has_through_model:
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kwargs['read_only'] = True
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kwargs.pop('queryset', None)
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if model_field:
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if model_field.verbose_name and needs_label(model_field, field_name):
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kwargs['label'] = capfirst(model_field.verbose_name)
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help_text = model_field.help_text
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if help_text:
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kwargs['help_text'] = help_text
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if not model_field.editable:
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kwargs['read_only'] = True
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kwargs.pop('queryset', None)
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if kwargs.get('read_only', False):
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# If this field is read-only, then return early.
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# No further keyword arguments are valid.
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return kwargs
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if model_field.has_default() or model_field.blank or model_field.null:
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kwargs['required'] = False
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if model_field.null:
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kwargs['allow_null'] = True
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if model_field.validators:
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kwargs['validators'] = model_field.validators
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if getattr(model_field, 'unique', False):
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validator = UniqueValidator(queryset=model_field.model._default_manager)
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kwargs['validators'] = kwargs.get('validators', []) + [validator]
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if to_many and not model_field.blank:
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kwargs['allow_empty'] = False
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return kwargs
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def get_nested_relation_kwargs(relation_info):
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kwargs = {'read_only': True}
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if relation_info.to_many:
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kwargs['many'] = True
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return kwargs
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def get_url_kwargs(model_field):
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return {
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'view_name': get_detail_view_name(model_field)
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}
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