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Diffstat (limited to 'djangorestframework/mixins.py')
| -rw-r--r-- | djangorestframework/mixins.py | 388 |
1 files changed, 0 insertions, 388 deletions
diff --git a/djangorestframework/mixins.py b/djangorestframework/mixins.py index 28fa5847..e69de29b 100644 --- a/djangorestframework/mixins.py +++ b/djangorestframework/mixins.py @@ -1,388 +0,0 @@ -""" -The :mod:`mixins` module provides a set of reusable `mixin` -classes that can be added to a `View`. -""" - -from django.core.paginator import Paginator -from django.db.models.fields.related import ForeignKey -from urlobject import URLObject - -from djangorestframework import status -from djangorestframework.renderers import BaseRenderer -from djangorestframework.resources import Resource, FormResource, ModelResource -from djangorestframework.response import Response, ImmediateResponse - - -__all__ = ( - # Base behavior mixins - 'ResourceMixin', - # Model behavior mixins - 'ReadModelMixin', - 'CreateModelMixin', - 'UpdateModelMixin', - 'DeleteModelMixin', - 'ListModelMixin', - 'PaginatorMixin' -) - - -########## Resource Mixin ########## - -class ResourceMixin(object): - """ - Provides request validation and response filtering behavior. - - Should be a class as described in the :mod:`resources` module. - - The :obj:`resource` is an object that maps a view onto it's representation on the server. - - It provides validation on the content of incoming requests, - and filters the object representation into a serializable object for the response. - """ - resource = None - - @property - def CONTENT(self): - """ - Returns the cleaned, validated request content. - - May raise an :class:`response.ImmediateResponse` with status code 400 (Bad Request). - """ - if not hasattr(self, '_content'): - self._content = self.validate_request(self.request.DATA, self.request.FILES) - return self._content - - @property - def PARAMS(self): - """ - Returns the cleaned, validated query parameters. - - May raise an :class:`response.ImmediateResponse` with status code 400 (Bad Request). - """ - return self.validate_request(self.request.GET) - - @property - def _resource(self): - if self.resource: - return self.resource(self) - elif getattr(self, 'model', None): - return ModelResource(self) - elif getattr(self, 'form', None): - return FormResource(self) - elif getattr(self, '%s_form' % self.request.method.lower(), None): - return FormResource(self) - return Resource(self) - - def validate_request(self, data, files=None): - """ - Given the request *data* and optional *files*, return the cleaned, validated content. - May raise an :class:`response.ImmediateResponse` with status code 400 (Bad Request) on failure. - """ - return self._resource.validate_request(data, files) - - def filter_response(self, obj): - """ - Given the response content, filter it into a serializable object. - """ - return self._resource.filter_response(obj) - - def get_bound_form(self, content=None, method=None): - if hasattr(self._resource, 'get_bound_form'): - return self._resource.get_bound_form(content, method=method) - else: - return None - - -########## Model Mixins ########## - -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. - """ - - queryset = None - - def get_query_kwargs(self, *args, **kwargs): - """ - Return a dict of kwargs that will be used to build the - model instance retrieval or to filter querysets. - """ - - kwargs = dict(kwargs) - - # If the URLconf includes a .(?P<format>\w+) pattern to match against - # a .json, .xml suffix, then drop the 'format' kwarg before - # constructing the query. - if BaseRenderer._FORMAT_QUERY_PARAM in kwargs: - del kwargs[BaseRenderer._FORMAT_QUERY_PARAM] - - return kwargs - - def get_instance_data(self, model, content, **kwargs): - """ - Returns the dict with the data for model instance creation/update. - - 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 field.name in tmp: - # 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 - - def get_instance(self, **kwargs): - """ - Get a model instance for read/update/delete requests. - """ - return self.get_queryset().get(**kwargs) - - def get_queryset(self): - """ - Return the queryset for this view. - """ - return getattr(self.resource, 'queryset', - self.resource.model.objects.all()) - - def get_ordering(self): - """ - Return the ordering for this view. - """ - return getattr(self.resource, 'ordering', None) - - -class ReadModelMixin(ModelMixin): - """ - Behavior to read a `model` instance on GET requests - """ - def get(self, request, *args, **kwargs): - model = self.resource.model - query_kwargs = self.get_query_kwargs(request, *args, **kwargs) - - try: - self.model_instance = self.get_instance(**query_kwargs) - except model.DoesNotExist: - raise ImmediateResponse(status=status.HTTP_404_NOT_FOUND) - - return Response(self.model_instance) - - -class CreateModelMixin(ModelMixin): - """ - Behavior to create a `model` instance on POST requests - """ - def post(self, request, *args, **kwargs): - model = self.resource.model - - # Copy the dict to keep self.CONTENT intact - content = dict(self.CONTENT) - m2m_data = {} - - for field in model._meta.many_to_many: - if field.name in content: - m2m_data[field.name] = ( - field.m2m_reverse_field_name(), content[field.name] - ) - del content[field.name] - - instance = model(**self.get_instance_data(model, content, *args, **kwargs)) - instance.save() - - for fieldname in m2m_data: - manager = getattr(instance, fieldname) - - if hasattr(manager, 'add'): - manager.add(*m2m_data[fieldname][1]) - else: - data = {} - data[manager.source_field_name] = instance - - for related_item in m2m_data[fieldname][1]: - data[m2m_data[fieldname][0]] = related_item - manager.through(**data).save() - - response = Response(instance, status=status.HTTP_201_CREATED) - - # Set headers - if hasattr(self.resource, 'url'): - response['Location'] = self.resource(self).url(instance) - return response - - -class UpdateModelMixin(ModelMixin): - """ - Behavior to update a `model` instance on PUT requests - """ - def put(self, request, *args, **kwargs): - model = self.resource.model - query_kwargs = self.get_query_kwargs(request, *args, **kwargs) - - # 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: - self.model_instance = self.get_instance(**query_kwargs) - - for (key, val) in self.CONTENT.items(): - setattr(self.model_instance, key, val) - except model.DoesNotExist: - self.model_instance = model(**self.get_instance_data(model, self.CONTENT, *args, **kwargs)) - self.model_instance.save() - return Response(self.model_instance) - - -class DeleteModelMixin(ModelMixin): - """ - Behavior to delete a `model` instance on DELETE requests - """ - def delete(self, request, *args, **kwargs): - model = self.resource.model - query_kwargs = self.get_query_kwargs(request, *args, **kwargs) - - try: - instance = self.get_instance(**query_kwargs) - except model.DoesNotExist: - raise ImmediateResponse(status=status.HTTP_404_NOT_FOUND) - - instance.delete() - return Response() - - -class ListModelMixin(ModelMixin): - """ - Behavior to list a set of `model` instances on GET requests - """ - - def get(self, request, *args, **kwargs): - queryset = self.get_queryset() - ordering = self.get_ordering() - query_kwargs = self.get_query_kwargs(request, *args, **kwargs) - - queryset = queryset.filter(**query_kwargs) - if ordering: - queryset = queryset.order_by(*ordering) - - return Response(queryset) - - -########## Pagination Mixins ########## - -class PaginatorMixin(object): - """ - Adds pagination support to GET requests - Obviously should only be used on lists :) - - A default limit can be set by setting `limit` on the object. This will also - be used as the maximum if the client sets the `limit` GET param - """ - limit = 20 - - def get_limit(self): - """ - Helper method to determine what the `limit` should be - """ - try: - limit = int(self.request.GET.get('limit', self.limit)) - return min(limit, self.limit) - except ValueError: - return self.limit - - def url_with_page_number(self, page_number): - """ - Constructs a url used for getting the next/previous urls - """ - url = URLObject(self.request.get_full_path()) - url = url.set_query_param('page', str(page_number)) - - limit = self.get_limit() - if limit != self.limit: - url = url.set_query_param('limit', str(limit)) - - return url - - def next(self, page): - """ - Returns a url to the next page of results (if any) - """ - if not page.has_next(): - return None - - return self.url_with_page_number(page.next_page_number()) - - def previous(self, page): - """ Returns a url to the previous page of results (if any) """ - if not page.has_previous(): - return None - - return self.url_with_page_number(page.previous_page_number()) - - def serialize_page_info(self, page): - """ - This is some useful information that is added to the response - """ - return { - 'next': self.next(page), - 'page': page.number, - 'pages': page.paginator.num_pages, - 'per_page': self.get_limit(), - 'previous': self.previous(page), - 'total': page.paginator.count, - } - - def filter_response(self, obj): - """ - Given the response content, paginate and then serialize. - - The response is modified to include to useful data relating to the number - of objects, number of pages, next/previous urls etc. etc. - - The serialised objects are put into `results` on this new, modified - response - """ - - # We don't want to paginate responses for anything other than GET requests - if self.request.method.upper() != 'GET': - return self._resource.filter_response(obj) - - paginator = Paginator(obj, self.get_limit()) - - try: - page_num = int(self.request.GET.get('page', '1')) - except ValueError: - raise ImmediateResponse( - {'detail': 'That page contains no results'}, - status=status.HTTP_404_NOT_FOUND) - - if page_num not in paginator.page_range: - raise ImmediateResponse( - {'detail': 'That page contains no results'}, - status=status.HTTP_404_NOT_FOUND) - - page = paginator.page(page_num) - - serialized_object_list = self._resource.filter_response(page.object_list) - serialized_page_info = self.serialize_page_info(page) - - serialized_page_info['results'] = serialized_object_list - - return serialized_page_info |