diff options
| -rw-r--r-- | djangorestframework/mixins.py | 127 |
1 files changed, 87 insertions, 40 deletions
diff --git a/djangorestframework/mixins.py b/djangorestframework/mixins.py index e01de3fc..8e6b1ed8 100644 --- a/djangorestframework/mixins.py +++ b/djangorestframework/mixins.py @@ -6,6 +6,7 @@ classes that can be added to a `View`. from django.contrib.auth.models import AnonymousUser from django.core.paginator import Paginator from django.db.models.fields.related import ForeignKey +from django.db.models.query import Q from django.http import HttpResponse from urlobject import URLObject @@ -482,7 +483,75 @@ class InstanceMixin(object): ########## Model Mixins ########## -class ReadModelMixin(object): +class ModelMixin(object): + """ Implements mechanisms used by other classes (like *ModelMixin group) to + define a query that represents Model instances the Mixin is working with. + + If a *ModelMixin is going to retrive an instance (or queryset) using args and kwargs + passed by as URL arguments, it should provied arguments to objects.get and objects.filter + methods wrapped in by `build_query` + + If a *ModelMixin is going to create/update an instance get_instance_data handles the instance + data creation/preaparation. + + """ + + def build_query(self, *args, **kwargs): + """ Returns django.db.models.Q object to be used for the objects retrival. + + Arguments: + - args: unnamed URL arguments + - kwargs: named URL arguments + + If a URL passes any arguments to the view being the QueryMixin subclass + build_query manages the arguments and provides the Q object that will be + used for the objects retrival with filter/get queryset methods. + + Technically, neither args nor kwargs have to be provided, however the default + behaviour is to map all kwargs as the query constructors so that if this + method is not overriden only kwargs keys being model fields are valid. + + If args are provided, the last one (args[-1) is understood as instance pk. This + should be removed in the future, though. + + """ + + tmp = dict(kwargs) + if args: + # If we have any none kwargs then assume the last represents the primrary key + # Otherwise assume the kwargs uniquely identify the model + tmp.update({'pk': args[-1]}) + return Q(**tmp) + + + def get_instance_data(self, model, content, **kwargs): + """ Returns the dict with the data for model instance creation/update query. + + Arguments: + - model: model class (django.db.models.Model subclass) to work with + - content: a dictionary with instance data + - kwargs: a dict of URL provided keyword arguments + + The create/update queries are created basicly with the contet provided + with POST/PUT HTML methods and kwargs passed in the URL. This methods simply merges + the URL data and the content preaparing the ready-to-use data dictionary. + + """ + + tmp = dict(kwargs) + + for field in model._meta.fields: + if isinstance(field, ForeignKey) and tmp.has_key(field.name): + # translate 'related_field' kwargs into 'related_field_id' + tmp[field.name + '_id'] = tmp[field.name] + del tmp[field.name] + + all_kw_args = dict(content.items() + tmp.items()) + + return all_kw_args + + +class ReadModelMixin(ModelMixin): """ Behavior to read a `model` instance on GET requests """ @@ -490,22 +559,21 @@ class ReadModelMixin(object): model = self.resource.model try: - if args: - # If we have any none kwargs then assume the last represents the primrary key - self.model_instance = model.objects.get(pk=args[-1], **kwargs) - else: - # Otherwise assume the kwargs uniquely identify the model - filtered_keywords = kwargs.copy() - if BaseRenderer._FORMAT_QUERY_PARAM in filtered_keywords: - del filtered_keywords[BaseRenderer._FORMAT_QUERY_PARAM] - self.model_instance = model.objects.get(**filtered_keywords) + self.model_instance = model.objects.get(self.build_query(*args, **kwargs)) except model.DoesNotExist: raise ErrorResponse(status.HTTP_404_NOT_FOUND) return self.model_instance + def build_query(self, *args, **kwargs): + # Build query is overriden to filter the kwargs priori + # to use them as build_query argument + filtered_keywords = kwargs.copy() + if BaseRenderer._FORMAT_QUERY_PARAM in filtered_keywords: + del filtered_keywords[BaseRenderer._FORMAT_QUERY_PARAM] + return super(ReadModelMixin, self).build_query(*args, **filtered_keywords) -class CreateModelMixin(object): +class CreateModelMixin(ModelMixin): """ Behavior to create a `model` instance on POST requests """ @@ -516,11 +584,6 @@ class CreateModelMixin(object): content = dict(self.CONTENT) m2m_data = {} - for field in model._meta.fields: - if isinstance(field, ForeignKey) and kwargs.has_key(field.name): - # translate 'related_field' kwargs into 'related_field_id' - kwargs[field.name + '_id'] = kwargs[field.name] - del kwargs[field.name] for field in model._meta.many_to_many: if content.has_key(field.name): @@ -529,12 +592,8 @@ class CreateModelMixin(object): ) del content[field.name] - all_kw_args = dict(content.items() + kwargs.items()) - if args: - instance = model(pk=args[-1], **all_kw_args) - else: - instance = model(**all_kw_args) + instance = model(**self.get_instance_data(model, content, *args, **kwargs)) instance.save() for fieldname in m2m_data: @@ -556,7 +615,7 @@ class CreateModelMixin(object): return Response(status.HTTP_201_CREATED, instance, headers) -class UpdateModelMixin(object): +class UpdateModelMixin(ModelMixin): """ Behavior to update a `model` instance on PUT requests """ @@ -565,24 +624,17 @@ class UpdateModelMixin(object): # TODO: update on the url of a non-existing resource url doesn't work correctly at the moment - will end up with a new url try: - if args: - # If we have any none kwargs then assume the last represents the primary key - self.model_instance = model.objects.get(pk=args[-1], **kwargs) - else: - # Otherwise assume the kwargs uniquely identify the model - self.model_instance = model.objects.get(**kwargs) + self.model_instance = model.objects.get(self.build_query(*args, **kwargs)) for (key, val) in self.CONTENT.items(): setattr(self.model_instance, key, val) except model.DoesNotExist: - self.model_instance = model(**self.CONTENT) - self.model_instance.save() - + self.model_instance = model(**self.get_instance_data(model, self.CONTENT, *args, **kwargs)) self.model_instance.save() return self.model_instance -class DeleteModelMixin(object): +class DeleteModelMixin(ModelMixin): """ Behavior to delete a `model` instance on DELETE requests """ @@ -590,12 +642,7 @@ class DeleteModelMixin(object): model = self.resource.model try: - if args: - # If we have any none kwargs then assume the last represents the primrary key - instance = model.objects.get(pk=args[-1], **kwargs) - else: - # Otherwise assume the kwargs uniquely identify the model - instance = model.objects.get(**kwargs) + instance = model.objects.get(self.build_query(*args, **kwargs)) except model.DoesNotExist: raise ErrorResponse(status.HTTP_404_NOT_FOUND, None, {}) @@ -603,7 +650,7 @@ class DeleteModelMixin(object): return -class ListModelMixin(object): +class ListModelMixin(ModelMixin): """ Behavior to list a set of `model` instances on GET requests """ @@ -635,7 +682,7 @@ class ListModelMixin(object): if ordering: args = as_tuple(ordering) queryset = queryset.order_by(*args) - return queryset.filter(**kwargs) + return queryset.filter(self.build_query(**kwargs)) ########## Pagination Mixins ########## |