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diff --git a/docs/api-guide/generic-views.md b/docs/api-guide/generic-views.md index 20f1be63..1a060a32 100644..100755 --- a/docs/api-guide/generic-views.md +++ b/docs/api-guide/generic-views.md @@ -18,7 +18,7 @@ If the generic views don't suit the needs of your API, you can drop down to usin Typically when using the generic views, you'll override the view, and set several class attributes. class UserList(generics.ListCreateAPIView): - model = User + queryset = User.objects.all() serializer_class = UserSerializer permission_classes = (IsAdminUser,) paginate_by = 100 @@ -26,17 +26,16 @@ Typically when using the generic views, you'll override the view, and set severa For more complex cases you might also want to override various methods on the view class. For example. class UserList(generics.ListCreateAPIView): - model = User + queryset = User.objects.all() serializer_class = UserSerializer permission_classes = (IsAdminUser,) - def get_paginate_by(self, queryset): + def get_paginate_by(self): """ Use smaller pagination for HTML representations. """ - page_size_param = self.request.QUERY_PARAMS.get('page_size') - if page_size_param: - return int(page_size_param) + if self.request.accepted_renderer.format == 'html': + return 20 return 100 For very simple cases you might want to pass through any class attributes using the `.as_view()` method. For example, your URLconf might include something the following entry. @@ -47,134 +46,127 @@ For very simple cases you might want to pass through any class attributes using # API Reference -The following classes are the concrete generic views. If you're using generic views this is normally the level you'll be working at unless you need heavily customized behavior. - -## CreateAPIView - -Used for **create-only** endpoints. - -Provides `post` method handlers. - -Extends: [GenericAPIView], [CreateModelMixin] +## GenericAPIView -## ListAPIView +This class extends REST framework's `APIView` class, adding commonly required behavior for standard list and detail views. -Used for **read-only** endpoints to represent a **collection of model instances**. +Each of the concrete generic views provided is built by combining `GenericAPIView`, with one or more mixin classes. -Provides a `get` method handler. +### Attributes -Extends: [MultipleObjectAPIView], [ListModelMixin] +**Basic settings**: -## RetrieveAPIView +The following attributes control the basic view behavior. -Used for **read-only** endpoints to represent a **single model instance**. +* `queryset` - The queryset that should be used for returning objects from this view. Typically, you must either set this attribute, or override the `get_queryset()` method. +* `serializer_class` - The serializer class that should be used for validating and deserializing input, and for serializing output. Typically, you must either set this attribute, or override the `get_serializer_class()` method. +* `lookup_field` - The field that should be used to lookup individual model instances. Defaults to `'pk'`. The URL conf should include a keyword argument corresponding to this value. More complex lookup styles can be supported by overriding the `get_object()` method. -Provides a `get` method handler. +**Shortcuts**: -Extends: [SingleObjectAPIView], [RetrieveModelMixin] +* `model` - This shortcut may be used instead of setting either (or both) of the `queryset`/`serializer_class` attributes, although using the explicit style is generally preferred. If used instead of `serializer_class`, then then `DEFAULT_MODEL_SERIALIZER_CLASS` setting will determine the base serializer class. -## DestroyAPIView +**Pagination**: -Used for **delete-only** endpoints for a **single model instance**. +The following attibutes are used to control pagination when used with list views. -Provides a `delete` method handler. +* `paginate_by` - The size of pages to use with paginated data. If set to `None` then pagination is turned off. If unset this uses the same value as the `PAGINATE_BY` setting, which defaults to `None`. +* `paginate_by_param` - The name of a query parameter, which can be used by the client to overide the default page size to use for pagination. If unset this uses the same value as the `PAGINATE_BY_PARAM` setting, which defaults to `None`. +* `pagination_serializer_class` - The pagination serializer class to use when determining the style of paginated responses. Defaults to the same value as the `DEFAULT_PAGINATION_SERIALIZER_CLASS` setting. +* `page_kwarg` - The name of a URL kwarg or URL query parameter which can be used by the client to control which page is requested. Defaults to `'page'`. -Extends: [SingleObjectAPIView], [DestroyModelMixin] +**Filtering**: -## UpdateAPIView +* `filter_backends` - A list of filter backend classes that should be used for filtering the queryset. Defaults to the same value as the `DEFAULT_FILTER_BACKENDS` setting. -Used for **update-only** endpoints for a **single model instance**. +### Methods -Provides `put` and `patch` method handlers. +**Base methods**: -Extends: [SingleObjectAPIView], [UpdateModelMixin] +#### `get_queryset(self)` -## ListCreateAPIView +Returns the queryset that should be used for list views, and that should be used as the base for lookups in detail views. Defaults to returning the queryset specified by the `queryset` attribute, or the default queryset for the model if the `model` shortcut is being used. -Used for **read-write** endpoints to represent a **collection of model instances**. +May be overridden to provide dynamic behavior such as returning a queryset that is specific to the user making the request. -Provides `get` and `post` method handlers. +For example: -Extends: [MultipleObjectAPIView], [ListModelMixin], [CreateModelMixin] + def get_queryset(self): + return self.user.accounts.all() -## RetrieveUpdateAPIView +#### `get_object(self)` -Used for **read or update** endpoints to represent a **single model instance**. - -Provides `get`, `put` and `patch` method handlers. +Returns an object instance that should be used for detail views. Defaults to using the `lookup_field` parameter to filter the base queryset. -Extends: [SingleObjectAPIView], [RetrieveModelMixin], [UpdateModelMixin] +May be overridden to provide more complex behavior such as object lookups based on more than one URL kwarg. -## RetrieveDestroyAPIView +For example: -Used for **read or delete** endpoints to represent a **single model instance**. + def get_object(self): + queryset = self.get_queryset() + filter = {} + for field in self.multiple_lookup_fields: + filter[field] = self.kwargs[field] + return get_object_or_404(queryset, **filter) -Provides `get` and `delete` method handlers. +#### `get_serializer_class(self)` -Extends: [SingleObjectAPIView], [RetrieveModelMixin], [DestroyModelMixin] +Returns the class that should be used for the serializer. Defaults to returning the `serializer_class` attribute, or dynamically generating a serializer class if the `model` shortcut is being used. -## RetrieveUpdateDestroyAPIView +May be override to provide dynamic behavior such as using different serializers for read and write operations, or providing different serializers to different types of uesr. -Used for **read-write-delete** endpoints to represent a **single model instance**. +For example: -Provides `get`, `put`, `patch` and `delete` method handlers. + def get_serializer_class(self): + if self.request.user.is_staff: + return FullAccountSerializer + return BasicAccountSerializer -Extends: [SingleObjectAPIView], [RetrieveModelMixin], [UpdateModelMixin], [DestroyModelMixin] +#### `get_paginate_by(self)` ---- +Returns the page size to use with pagination. By default this uses the `paginate_by` attribute, and may be overridden by the cient if the `paginate_by_param` attribute is set. -# Base views +You may want to override this method to provide more complex behavior such as modifying page sizes based on the media type of the response. -Each of the generic views provided is built by combining one of the base views below, with one or more mixin classes. +For example: -## GenericAPIView + def get_paginate_by(self): + self.request.accepted_renderer.format == 'html': + return 20 + return 100 -Extends REST framework's `APIView` class, adding support for serialization of model instances and model querysets. +**Save hooks**: -**Methods**: +The following methods are provided as placeholder interfaces. They contain empty implementations and are not called directly by `GenericAPIView`, but they are overridden and used by some of the mixin classes. -* `get_serializer_context(self)` - Returns a dictionary containing any extra context that should be supplied to the serializer. Defaults to including `'request'`, `'view'` and `'format'` keys. -* `get_serializer_class(self)` - Returns the class that should be used for the serializer. -* `get_serializer(self, instance=None, data=None, files=None, many=False, partial=False)` - Returns a serializer instance. * `pre_save(self, obj)` - A hook that is called before saving an object. * `post_save(self, obj, created=False)` - A hook that is called after saving an object. +The `pre_save` method in particular is a useful hook for setting attributes that are implicit in the request, but are not part of the request data. For instance, you might set an attribute on the object based on the request user, or based on a URL keyword argument. -**Attributes**: - -* `model` - The model that should be used for this view. Used as a fallback for determining the serializer if `serializer_class` is not set, and as a fallback for determining the queryset if `queryset` is not set. Otherwise not required. -* `serializer_class` - The serializer class that should be used for validating and deserializing input, and for serializing output. If unset, this defaults to creating a serializer class using `self.model`, with the `DEFAULT_MODEL_SERIALIZER_CLASS` setting as the base serializer class. - -## MultipleObjectAPIView - -Provides a base view for acting on a single object, by combining REST framework's `APIView`, and Django's [MultipleObjectMixin]. - -**See also:** ccbv.co.uk documentation for [MultipleObjectMixin][multiple-object-mixin-classy]. + def pre_save(self, obj): + """ + Set the object's owner, based on the incoming request. + """ + obj.owner = self.request.user -**Attributes**: +Remember that the `pre_save()` method is not called by `GenericAPIView` itself, but it is called by `create()` and `update()` methods on the `CreateModelMixin` and `UpdateModelMixin` classes. -* `queryset` - The queryset that should be used for returning objects from this view. If unset, defaults to the default queryset manager for `self.model`. -* `paginate_by` - The size of pages to use with paginated data. If set to `None` then pagination is turned off. If unset this uses the same value as the `PAGINATE_BY` setting, which defaults to `None`. -* `paginate_by_param` - The name of a query parameter, which can be used by the client to overide the default page size to use for pagination. If unset this uses the same value as the `PAGINATE_BY_PARAM` setting, which defaults to `None`. - -## SingleObjectAPIView - -Provides a base view for acting on a single object, by combining REST framework's `APIView`, and Django's [SingleObjectMixin]. - -**See also:** ccbv.co.uk documentation for [SingleObjectMixin][single-object-mixin-classy]. +**Other methods**: -**Attributes**: +You won't typically need to override the following methods, although you might need to call into them if you're writing custom views using `GenericAPIView`. -* `queryset` - The queryset that should be used when retrieving an object from this view. If unset, defaults to the default queryset manager for `self.model`. -* `pk_kwarg` - The URL kwarg that should be used to look up objects by primary key. Defaults to `'pk'`. [Can only be set to non-default on Django 1.4+] -* `slug_url_kwarg` - The URL kwarg that should be used to look up objects by a slug. Defaults to `'slug'`. [Can only be set to non-default on Django 1.4+] -* `slug_field` - The field on the model that should be used to look up objects by a slug. If used, this should typically be set to a field with `unique=True`. Defaults to `'slug'`. +* `get_serializer_context(self)` - Returns a dictionary containing any extra context that should be supplied to the serializer. Defaults to including `'request'`, `'view'` and `'format'` keys. +* `get_serializer(self, instance=None, data=None, files=None, many=False, partial=False)` - Returns a serializer instance. +* `get_pagination_serializer(self, page)` - Returns a serializer instance to use with paginated data. +* `paginate_queryset(self, queryset)` - Paginate a queryset if required, either returning a page object, or `None` if pagination is not configured for this view. +* `filter_queryset(self, queryset)` - Given a queryset, filter it with whichever filter backends are in use, returning a new queryset. --- # Mixins -The mixin classes provide the actions that are used to provide the basic view behaviour. Note that the mixin classes provide action methods rather than defining the handler methods such as `.get()` and `.post()` directly. This allows for more flexible composition of behaviour. +The mixin classes provide the actions that are used to provide the basic view behavior. Note that the mixin classes provide action methods rather than defining the handler methods such as `.get()` and `.post()` directly. This allows for more flexible composition of behavior. ## ListModelMixin @@ -182,9 +174,7 @@ Provides a `.list(request, *args, **kwargs)` method, that implements listing a q If the queryset is populated, this returns a `200 OK` response, with a serialized representation of the queryset as the body of the response. The response data may optionally be paginated. -If the queryset is empty this returns a `200 OK` reponse, unless the `.allow_empty` attribute on the view is set to `False`, in which case it will return a `404 Not Found`. - -Should be mixed in with [MultipleObjectAPIView]. +If the queryset is empty this returns a `200 OK` response, unless the `.allow_empty` attribute on the view is set to `False`, in which case it will return a `404 Not Found`. ## CreateModelMixin @@ -194,47 +184,157 @@ If an object is created this returns a `201 Created` response, with a serialized If the request data provided for creating the object was invalid, a `400 Bad Request` response will be returned, with the error details as the body of the response. -Should be mixed in with any [GenericAPIView]. - ## RetrieveModelMixin Provides a `.retrieve(request, *args, **kwargs)` method, that implements returning an existing model instance in a response. -If an object can be retrieve this returns a `200 OK` response, with a serialized representation of the object as the body of the response. Otherwise it will return a `404 Not Found`. - -Should be mixed in with [SingleObjectAPIView]. +If an object can be retrieved this returns a `200 OK` response, with a serialized representation of the object as the body of the response. Otherwise it will return a `404 Not Found`. ## UpdateModelMixin Provides a `.update(request, *args, **kwargs)` method, that implements updating and saving an existing model instance. +Also provides a `.partial_update(request, *args, **kwargs)` method, which is similar to the `update` method, except that all fields for the update will be optional. This allows support for HTTP `PATCH` requests. + If an object is updated this returns a `200 OK` response, with a serialized representation of the object as the body of the response. If an object is created, for example when making a `DELETE` request followed by a `PUT` request to the same URL, this returns a `201 Created` response, with a serialized representation of the object as the body of the response. If the request data provided for updating the object was invalid, a `400 Bad Request` response will be returned, with the error details as the body of the response. -A boolean `partial` keyword argument may be supplied to the `.update()` method. If `partial` is set to `True`, all fields for the update will be optional. This allows support for HTTP `PATCH` requests. - -Should be mixed in with [SingleObjectAPIView]. - ## DestroyModelMixin Provides a `.destroy(request, *args, **kwargs)` method, that implements deletion of an existing model instance. If an object is deleted this returns a `204 No Content` response, otherwise it will return a `404 Not Found`. -Should be mixed in with [SingleObjectAPIView]. +--- + +# Concrete View Classes + +The following classes are the concrete generic views. If you're using generic views this is normally the level you'll be working at unless you need heavily customized behavior. + +## CreateAPIView + +Used for **create-only** endpoints. + +Provides a `post` method handler. + +Extends: [GenericAPIView], [CreateModelMixin] + +## ListAPIView + +Used for **read-only** endpoints to represent a **collection of model instances**. + +Provides a `get` method handler. + +Extends: [GenericAPIView], [ListModelMixin] + +## RetrieveAPIView + +Used for **read-only** endpoints to represent a **single model instance**. + +Provides a `get` method handler. + +Extends: [GenericAPIView], [RetrieveModelMixin] + +## DestroyAPIView + +Used for **delete-only** endpoints for a **single model instance**. + +Provides a `delete` method handler. + +Extends: [GenericAPIView], [DestroyModelMixin] + +## UpdateAPIView + +Used for **update-only** endpoints for a **single model instance**. + +Provides `put` and `patch` method handlers. + +Extends: [GenericAPIView], [UpdateModelMixin] + +## ListCreateAPIView + +Used for **read-write** endpoints to represent a **collection of model instances**. + +Provides `get` and `post` method handlers. + +Extends: [GenericAPIView], [ListModelMixin], [CreateModelMixin] + +## RetrieveUpdateAPIView + +Used for **read or update** endpoints to represent a **single model instance**. + +Provides `get`, `put` and `patch` method handlers. + +Extends: [GenericAPIView], [RetrieveModelMixin], [UpdateModelMixin] + +## RetrieveDestroyAPIView + +Used for **read or delete** endpoints to represent a **single model instance**. + +Provides `get` and `delete` method handlers. + +Extends: [GenericAPIView], [RetrieveModelMixin], [DestroyModelMixin] + +## RetrieveUpdateDestroyAPIView + +Used for **read-write-delete** endpoints to represent a **single model instance**. + +Provides `get`, `put`, `patch` and `delete` method handlers. + +Extends: [GenericAPIView], [RetrieveModelMixin], [UpdateModelMixin], [DestroyModelMixin] + +--- + +# Customizing the generic views + +Often you'll want to use the existing generic views, but use some slightly customized behavior. If you find yourself reusing some bit of customized behavior in multiple places, you might want to refactor the behavior into a common class that you can then just apply to any view or viewset as needed. + +## Creating custom mixins + +For example, if you need to lookup objects based on multiple fields in the URL conf, you could create a mixin class like the following: + + class MultipleFieldLookupMixin(object): + """ + Apply this mixin to any view or viewset to get multiple field filtering + based on a `lookup_fields` attribute, instead of the default single field filtering. + """ + def get_object(self): + queryset = self.get_queryset() # Get the base queryset + queryset = self.filter_queryset(queryset) # Apply any filter backends + filter = {} + for field in self.lookup_fields: + filter[field] = self.kwargs[field] + return get_object_or_404(queryset, **filter) # Lookup the object + +You can then simply apply this mixin to a view or viewset anytime you need to apply the custom behavior. + + class RetrieveUserView(MultipleFieldLookupMixin, generics.RetrieveAPIView): + queryset = User.objects.all() + serializer_class = UserSerializer + lookup_fields = ('account', 'username') + +Using custom mixins is a good option if you have custom behavior that needs to be used + +## Creating custom base classes + +If you are using a mixin across multiple views, you can take this a step further and create your own set of base views that can then be used throughout your project. For example: + + class BaseRetrieveView(MultipleFieldLookupMixin, + generics.RetrieveAPIView): + pass + + class BaseRetrieveUpdateDestroyView(MultipleFieldLookupMixin, + generics.RetrieveUpdateDestroyAPIView): + pass + +Using custom base classes is a good option if you have custom behavior that consistently needs to be repeated across a large number of views throughout your project. [cite]: https://docs.djangoproject.com/en/dev/ref/class-based-views/#base-vs-generic-views -[MultipleObjectMixin]: https://docs.djangoproject.com/en/dev/ref/class-based-views/mixins-multiple-object/ -[SingleObjectMixin]: https://docs.djangoproject.com/en/dev/ref/class-based-views/mixins-single-object/ -[multiple-object-mixin-classy]: http://ccbv.co.uk/projects/Django/1.4/django.views.generic.list/MultipleObjectMixin/ -[single-object-mixin-classy]: http://ccbv.co.uk/projects/Django/1.4/django.views.generic.detail/SingleObjectMixin/ [GenericAPIView]: #genericapiview -[SingleObjectAPIView]: #singleobjectapiview -[MultipleObjectAPIView]: #multipleobjectapiview [ListModelMixin]: #listmodelmixin [CreateModelMixin]: #createmodelmixin [RetrieveModelMixin]: #retrievemodelmixin |