diff options
Diffstat (limited to 'docs/api-guide')
| -rw-r--r-- | docs/api-guide/fields.md | 55 | ||||
| -rw-r--r-- | docs/api-guide/pagination.md | 2 | ||||
| -rw-r--r-- | docs/api-guide/permissions.md | 2 | ||||
| -rw-r--r-- | docs/api-guide/relations.md | 2 | ||||
| -rw-r--r-- | docs/api-guide/routers.md | 2 | ||||
| -rw-r--r-- | docs/api-guide/serializers.md | 58 | ||||
| -rw-r--r-- | docs/api-guide/validators.md | 2 | ||||
| -rw-r--r-- | docs/api-guide/viewsets.md | 3 |
8 files changed, 106 insertions, 20 deletions
diff --git a/docs/api-guide/fields.md b/docs/api-guide/fields.md index 391a52e5..e4ef1d4a 100644 --- a/docs/api-guide/fields.md +++ b/docs/api-guide/fields.md @@ -310,6 +310,9 @@ Used by `ModelSerializer` to automatically generate fields if the corresponding **Signature:** `ChoiceField(choices)` - `choices` - A list of valid values, or a list of `(key, display_name)` tuples. +- `allow_blank` - If set to `True` then the empty string should be considered a valid value. If set to `False` then the empty string is considered invalid and will raise a validation error. Defaults to `False`. + +Both the `allow_blank` and `allow_null` are valid options on `ChoiceField`, although it is highly recommended that you only use one and not both. `allow_blank` should be preferred for textual choices, and `allow_null` should be preferred for numeric or other non-textual choices. ## MultipleChoiceField @@ -318,6 +321,9 @@ A field that can accept a set of zero, one or many values, chosen from a limited **Signature:** `MultipleChoiceField(choices)` - `choices` - A list of valid values, or a list of `(key, display_name)` tuples. +- `allow_blank` - If set to `True` then the empty string should be considered a valid value. If set to `False` then the empty string is considered invalid and will raise a validation error. Defaults to `False`. + +As with `ChoiceField`, both the `allow_blank` and `allow_null` options are valid, although it is highly recommended that you only use one and not both. `allow_blank` should be preferred for textual choices, and `allow_null` should be preferred for numeric or other non-textual choices. --- @@ -453,7 +459,7 @@ If you want to create a custom field, you'll need to subclass `Field` and then o The `.to_representation()` method is called to convert the initial datatype into a primitive, serializable datatype. -The `to_internal_value()` method is called to restore a primitive datatype into its internal python representation. +The `to_internal_value()` method is called to restore a primitive datatype into its internal python representation. This method should raise a `serializer.ValidationError` if the data is invalid. Note that the `WritableField` class that was present in version 2.x no longer exists. You should subclass `Field` and override `to_internal_value()` if the field supports data input. @@ -498,6 +504,53 @@ As an example, let's create a field that can be used represent the class name of """ return obj.__class__.__name__ +#### Raising validation errors + +Our `ColorField` class above currently does not perform any data validation. +To indicate invalid data, we should raise a `serializers.ValidationError`, like so: + + def to_internal_value(self, data): + if not isinstance(data, six.text_type): + msg = 'Incorrect type. Expected a string, but got %s' + raise ValidationError(msg % type(data).__name__) + + if not re.match(r'^rgb\([0-9]+,[0-9]+,[0-9]+\)$', data): + raise ValidationError('Incorrect format. Expected `rgb(#,#,#)`.') + + data = data.strip('rgb(').rstrip(')') + red, green, blue = [int(col) for col in data.split(',')] + + if any([col > 255 or col < 0 for col in (red, green, blue)]): + raise ValidationError('Value out of range. Must be between 0 and 255.') + + return Color(red, green, blue) + +The `.fail()` method is a shortcut for raising `ValidationError` that takes a message string from the `error_messages` dictionary. For example: + + default_error_messages = { + 'incorrect_type': 'Incorrect type. Expected a string, but got {input_type}', + 'incorrect_format': 'Incorrect format. Expected `rgb(#,#,#)`.', + 'out_of_range': 'Value out of range. Must be between 0 and 255.' + } + + def to_internal_value(self, data): + if not isinstance(data, six.text_type): + msg = 'Incorrect type. Expected a string, but got %s' + self.fail('incorrect_type', input_type=type(data).__name__) + + if not re.match(r'^rgb\([0-9]+,[0-9]+,[0-9]+\)$', data): + self.fail('incorrect_format') + + data = data.strip('rgb(').rstrip(')') + red, green, blue = [int(col) for col in data.split(',')] + + if any([col > 255 or col < 0 for col in (red, green, blue)]): + self.fail('out_of_range') + + return Color(red, green, blue) + +This style keeps you error messages more cleanly separated from your code, and should be preferred. + # Third party packages The following third party packages are also available. diff --git a/docs/api-guide/pagination.md b/docs/api-guide/pagination.md index 9b7086c5..83429292 100644 --- a/docs/api-guide/pagination.md +++ b/docs/api-guide/pagination.md @@ -128,7 +128,7 @@ For example, to nest a pair of links labelled 'prev' and 'next', and set the nam class CustomPaginationSerializer(pagination.BasePaginationSerializer): links = LinksSerializer(source='*') # Takes the page object as the source - total_results = serializers.Field(source='paginator.count') + total_results = serializers.ReadOnlyField(source='paginator.count') results_field = 'objects' diff --git a/docs/api-guide/permissions.md b/docs/api-guide/permissions.md index f068f0f7..ddcefadb 100644 --- a/docs/api-guide/permissions.md +++ b/docs/api-guide/permissions.md @@ -104,7 +104,7 @@ This permission is suitable if you want your API to only be accessible to regist The `IsAdminUser` permission class will deny permission to any user, unless `user.is_staff` is `True` in which case permission will be allowed. -This permission is suitable is you want your API to only be accessible to a subset of trusted administrators. +This permission is suitable if you want your API to only be accessible to a subset of trusted administrators. ## IsAuthenticatedOrReadOnly diff --git a/docs/api-guide/relations.md b/docs/api-guide/relations.md index a79b6ea5..e56db229 100644 --- a/docs/api-guide/relations.md +++ b/docs/api-guide/relations.md @@ -397,7 +397,7 @@ We could define a custom field that could be used to serialize tagged instances, return 'Note: ' + value.text raise Exception('Unexpected type of tagged object') -If you need the target of the relationship to have a nested representation, you can use the required serializers inside the `.to_native()` method: +If you need the target of the relationship to have a nested representation, you can use the required serializers inside the `.to_representation()` method: def to_representation(self, value): """ diff --git a/docs/api-guide/routers.md b/docs/api-guide/routers.md index 080230fa..929a1710 100644 --- a/docs/api-guide/routers.md +++ b/docs/api-guide/routers.md @@ -41,7 +41,7 @@ The example above would generate the following URL patterns: **Note**: The `base_name` argument is used to specify the initial part of the view name pattern. In the example above, that's the `user` or `account` part. -Typically you won't *need* to specify the `base-name` argument, but if you have a viewset where you've defined a custom `get_queryset` method, then the viewset may not have a `.queryset` attribute set. If you try to register that viewset you'll see an error like this: +Typically you won't *need* to specify the `base_name` argument, but if you have a viewset where you've defined a custom `get_queryset` method, then the viewset may not have a `.queryset` attribute set. If you try to register that viewset you'll see an error like this: 'base_name' argument not specified, and could not automatically determine the name from the viewset, as it does not have a '.queryset' attribute. diff --git a/docs/api-guide/serializers.md b/docs/api-guide/serializers.md index 0ee80d53..5fe6b4c2 100644 --- a/docs/api-guide/serializers.md +++ b/docs/api-guide/serializers.md @@ -96,7 +96,7 @@ If we want to be able to return complete object instances based on the validated If your object instances correspond to Django models you'll also want to ensure that these methods save the object to the database. For example, if `Comment` was a Django model, the methods might look like this: def create(self, validated_data): - return Comment.objcts.create(**validated_data) + return Comment.objects.create(**validated_data) def update(self, instance, validated_data): instance.email = validated_data.get('email', instance.email) @@ -104,7 +104,7 @@ If your object instances correspond to Django models you'll also want to ensure instance.created = validated_data.get('created', instance.created) instance.save() return instance - + Now when deserializing data, we can call `.save()` to return an object instance, based on the validated data. comment = serializer.save() @@ -113,7 +113,7 @@ Calling `.save()` will either create a new instance, or update an existing insta # .save() will create a new instance. serializer = CommentSerializer(data=data) - + # .save() will update the existing `comment` instance. serializer = CommentSerializer(comment, data=data) @@ -140,7 +140,7 @@ For example: class ContactForm(serializers.Serializer): email = serializers.EmailField() message = serializers.CharField() - + def save(self): email = self.validated_data['email'] message = self.validated_data['message'] @@ -230,7 +230,7 @@ Serializer classes can also include reusable validators that are applied to the name = serializers.CharField() room_number = serializers.IntegerField(choices=[101, 102, 103, 201]) date = serializers.DateField() - + class Meta: # Each room only has one event per day. validators = UniqueTogetherValidator( @@ -326,9 +326,9 @@ Here's an example for an `update()` method on our previous `UserSerializer` clas # would need to be handled. profile = instance.profile - user.username = validated_data.get('username', instance.username) - user.email = validated_data.get('email', instance.email) - user.save() + instance.username = validated_data.get('username', instance.username) + instance.email = validated_data.get('email', instance.email) + instance.save() profile.is_premium_member = profile_data.get( 'is_premium_member', @@ -340,7 +340,7 @@ Here's an example for an `update()` method on our previous `UserSerializer` clas ) profile.save() - return user + return instance Because the behavior of nested creates and updates can be ambiguous, and may require complex dependancies between related models, REST framework 3 requires you to always write these methods explicitly. The default `ModelSerializer` `.create()` and `.update()` methods do not include support for writable nested representations. @@ -448,7 +448,7 @@ To do so, open the Django shell, using `python manage.py shell`, then import the id = IntegerField(label='ID', read_only=True) name = CharField(allow_blank=True, max_length=100, required=False) owner = PrimaryKeyRelatedField(queryset=User.objects.all()) - + ## Specifying which fields should be included If you only want a subset of the default fields to be used in a model serializer, you can do so using `fields` or `exclude` options, just as you would with a `ModelForm`. @@ -505,6 +505,21 @@ This option should be a list or tuple of field names, and is declared as follows Model fields which have `editable=False` set, and `AutoField` fields will be set to read-only by default, and do not need to be added to the `read_only_fields` option. +--- + +**Note**: There is a special-case where a read-only field is part of a `unique_together` constraint at the model level. In this case the field is required by the serializer class in order to validate the constraint, but should also not be editable by the user. + +The right way to deal with this is to specify the field explicitly on the serializer, providing both the `read_only=True` and `default=…` keyword arguments. + +One example of this is a read-only relation to the currently authenticated `User` which is `unique_together` with another identifier. In this case you would declare the user field like so: + + user = serializers.PrimaryKeyRelatedField(read_only=True, default=serializers.CurrentUserDefault()) + +Please review the [Validators Documentation](/api-guide/validators/) for details on the [UniqueTogetherValidator](/api-guide/validators/#uniquetogethervalidator) and [CurrentUserDefault](/api-guide/validators/#currentuserdefault) classes. + +--- + + ## Specifying additional keyword arguments for fields. There is also a shortcut allowing you to specify arbitrary additional keyword arguments on fields, using the `extra_kwargs` option. Similarly to `read_only_fields` this means you do not need to explicitly declare the field on the serializer. @@ -516,7 +531,7 @@ This option is a dictionary, mapping field names to a dictionary of keyword argu model = User fields = ('email', 'username', 'password') extra_kwargs = {'password': {'write_only': True}} - + def create(self, validated_data): user = User( email=validated_data['email'], @@ -567,13 +582,13 @@ There needs to be a way of determining which views should be used for hyperlinki By default hyperlinks are expected to correspond to a view name that matches the style `'{model_name}-detail'`, and looks up the instance by a `pk` keyword argument. -You can override a URL field view name and lookup field by using either, or both of, the `view_name` and `lookup_field` options in the `extra_field_kwargs` setting, like so: +You can override a URL field view name and lookup field by using either, or both of, the `view_name` and `lookup_field` options in the `extra_kwargs` setting, like so: class AccountSerializer(serializers.HyperlinkedModelSerializer): class Meta: model = Account fields = ('account_url', 'account_name', 'users', 'created') - extra_field_kwargs = { + extra_kwargs = { 'url': {'view_name': 'accounts', 'lookup_field': 'account_name'} 'users': {'lookup_field': 'username'} } @@ -656,7 +671,7 @@ To support multiple updates you'll need to do so explicitly. When writing your m * How do you determine which instance should be updated for each item in the list of data? * How should insertions be handled? Are they invalid, or do they create new objects? * How should removals be handled? Do they imply object deletion, or removing a relationship? Should they be silently ignored, or are they invalid? -* How should ordering be handled? Does changing the position of two items imply any state change or is it ignored? +* How should ordering be handled? Does changing the position of two items imply any state change or is it ignored? Here's an example of how you might choose to implement multiple updates: @@ -689,6 +704,21 @@ Here's an example of how you might choose to implement multiple updates: It is possible that a third party package may be included alongside the 3.1 release that provides some automatic support for multiple update operations, similar to the `allow_add_remove` behavior that was present in REST framework 2. +#### Customizing ListSerializer initialization + +When a serializer with `many=True` is instantiated, we need to determine which arguments and keyword arguments should be passed to the `.__init__()` method for both the child `Serializer` class, and for the parent `ListSerializer` class. + +The default implementation is to pass all arguments to both classes, except for `validators`, and any custom keyword arguments, both of which are assumed to be intended for the child serializer class. + +Occasionally you might need to explicitly specify how the child and parent classes should be instantiated when `many=True` is passed. You can do so by using the `many_init` class method. + + @classmethod + def many_init(cls, *args, **kwargs): + # Instantiate the child serializer. + kwargs['child'] = cls() + # Instantiate the parent list serializer. + return CustomListSerializer(*args, **kwargs) + --- # BaseSerializer diff --git a/docs/api-guide/validators.md b/docs/api-guide/validators.md index f087e191..8f5a8929 100644 --- a/docs/api-guide/validators.md +++ b/docs/api-guide/validators.md @@ -1,4 +1,4 @@ -<a class="github" href="validators.py"></a> +source: validators.py --- diff --git a/docs/api-guide/viewsets.md b/docs/api-guide/viewsets.md index 28186c64..3e37cef8 100644 --- a/docs/api-guide/viewsets.md +++ b/docs/api-guide/viewsets.md @@ -201,6 +201,8 @@ Note that you can use any of the standard attributes or method overrides provide def get_queryset(self): return self.request.user.accounts.all() +Note however that upon removal of the `queryset` property from your `ViewSet`, any associated [router][routers] will be unable to derive the base_name of your Model automatically, and so you you will have to specify the `base_name` kwarg as part of your [router registration][routers]. + Also note that although this class provides the complete set of create/list/retrieve/update/destroy actions by default, you can restrict the available operations by using the standard permission classes. ## ReadOnlyModelViewSet @@ -243,3 +245,4 @@ To create a base viewset class that provides `create`, `list` and `retrieve` ope By creating your own base `ViewSet` classes, you can provide common behavior that can be reused in multiple viewsets across your API. [cite]: http://guides.rubyonrails.org/routing.html +[routers]: routers.md |