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Diffstat (limited to 'docs/api-guide/fields.md')
| -rw-r--r-- | docs/api-guide/fields.md | 179 |
1 files changed, 27 insertions, 152 deletions
diff --git a/docs/api-guide/fields.md b/docs/api-guide/fields.md index 50a09701..5bc8f7f7 100644 --- a/docs/api-guide/fields.md +++ b/docs/api-guide/fields.md @@ -2,11 +2,11 @@ # Serializer fields -> Flat is better than nested. +> Each field in a Form class is responsible not only for validating data, but also for "cleaning" it -- normalizing it to a consistent format. > -> — [The Zen of Python][cite] +> — [Django documentation][cite] -Serializer fields handle converting between primative values and internal datatypes. They also deal with validating input values, as well as retrieving and setting the values from their parent objects. +Serializer fields handle converting between primitive values and internal datatypes. They also deal with validating input values, as well as retrieving and setting the values from their parent objects. --- @@ -28,7 +28,7 @@ Defaults to the name of the field. ### `read_only` -Set this to `True` to ensure that the field is used when serializing a representation, but is not used when updating an instance dureing deserialization. +Set this to `True` to ensure that the field is used when serializing a representation, but is not used when updating an instance during deserialization. Defaults to `False` @@ -41,7 +41,7 @@ Defaults to `True`. ### `default` -If set, this gives the default value that will be used for the field if none is supplied. If not set the default behaviour is to not populate the attribute at all. +If set, this gives the default value that will be used for the field if none is supplied. If not set the default behavior is to not populate the attribute at all. ### `validators` @@ -96,9 +96,9 @@ Would produce output similar to: 'expired': True } -By default, the `Field` class will perform a basic translation of the source value into primative datatypes, falling back to unicode representations of complex datatypes when necessary. +By default, the `Field` class will perform a basic translation of the source value into primitive datatypes, falling back to unicode representations of complex datatypes when necessary. -You can customize this behaviour by overriding the `.to_native(self, value)` method. +You can customize this behavior by overriding the `.to_native(self, value)` method. ## WritableField @@ -110,6 +110,24 @@ A generic field that can be tied to any arbitrary model field. The `ModelField` **Signature:** `ModelField(model_field=<Django ModelField class>)` +## SerializerMethodField + +This is a read-only field. It gets its value by calling a method on the serializer class it is attached to. It can be used to add any sort of data to the serialized representation of your object. The field's constructor accepts a single argument, which is the name of the method on the serializer to be called. The method should accept a single argument (in addition to `self`), which is the object being serialized. It should return whatever you want to be included in the serialized representation of the object. For example: + + from rest_framework import serializers + from django.contrib.auth.models import User + from django.utils.timezone import now + + class UserSerializer(serializers.ModelSerializer): + + days_since_joined = serializers.SerializerMethodField('get_days_since_joined') + + class Meta: + model = User + + def get_days_since_joined(self, obj): + return (now() - obj.date_joined).days + --- # Typed Fields @@ -211,151 +229,8 @@ Signature and validation is the same as with `FileField`. --- -**Note:** `FileFields` and `ImageFields` are only suitable for use with MultiPartParser, since eg json doesn't support file uploads. +**Note:** `FileFields` and `ImageFields` are only suitable for use with MultiPartParser, since e.g. json doesn't support file uploads. Django's regular [FILE_UPLOAD_HANDLERS] are used for handling uploaded files. ---- - -# Relational Fields - -Relational fields are used to represent model relationships. They can be applied to `ForeignKey`, `ManyToManyField` and `OneToOneField` relationships, as well as to reverse relationships, and custom relationships such as `GenericForeignKey`. - -## RelatedField - -This field can be applied to any of the following: - -* A `ForeignKey` field. -* A `OneToOneField` field. -* A reverse OneToOne relationship -* Any other "to-one" relationship. - -By default `RelatedField` will represent the target of the field using it's `__unicode__` method. - -You can customise this behaviour by subclassing `ManyRelatedField`, and overriding the `.to_native(self, value)` method. - -## ManyRelatedField - -This field can be applied to any of the following: - -* A `ManyToManyField` field. -* A reverse ManyToMany relationship. -* A reverse ForeignKey relationship -* Any other "to-many" relationship. - -By default `ManyRelatedField` will represent the targets of the field using their `__unicode__` method. - -For example, given the following models: - - class TaggedItem(models.Model): - """ - Tags arbitrary model instances using a generic relation. - - See: https://docs.djangoproject.com/en/dev/ref/contrib/contenttypes/ - """ - tag = models.SlugField() - content_type = models.ForeignKey(ContentType) - object_id = models.PositiveIntegerField() - content_object = GenericForeignKey('content_type', 'object_id') - - def __unicode__(self): - return self.tag - - - class Bookmark(models.Model): - """ - A bookmark consists of a URL, and 0 or more descriptive tags. - """ - url = models.URLField() - tags = GenericRelation(TaggedItem) - -And a model serializer defined like this: - - class BookmarkSerializer(serializers.ModelSerializer): - tags = serializers.ManyRelatedField(source='tags') - - class Meta: - model = Bookmark - exclude = ('id',) - -Then an example output format for a Bookmark instance would be: - - { - 'tags': [u'django', u'python'], - 'url': u'https://www.djangoproject.com/' - } - -## PrimaryKeyRelatedField / ManyPrimaryKeyRelatedField - -`PrimaryKeyRelatedField` and `ManyPrimaryKeyRelatedField` will represent the target of the relationship using it's primary key. - -By default these fields are read-write, although you can change this behaviour using the `read_only` flag. - -**Arguments**: - -* `queryset` - By default `ModelSerializer` classes will use the default queryset for the relationship. `Serializer` classes must either set a queryset explicitly, or set `read_only=True`. -* `null` - If set to `True`, the field will accept values of `None` or the emptystring for nullable relationships. - -## SlugRelatedField / ManySlugRelatedField - -`SlugRelatedField` and `ManySlugRelatedField` will represent the target of the relationship using a unique slug. - -By default these fields read-write, although you can change this behaviour using the `read_only` flag. - -**Arguments**: - -* `slug_field` - The field on the target that should be used to represent it. This should be a field that uniquely identifies any given instance. For example, `username`. -* `queryset` - By default `ModelSerializer` classes will use the default queryset for the relationship. `Serializer` classes must either set a queryset explicitly, or set `read_only=True`. -* `null` - If set to `True`, the field will accept values of `None` or the emptystring for nullable relationships. - -## HyperlinkedRelatedField / ManyHyperlinkedRelatedField - -`HyperlinkedRelatedField` and `ManyHyperlinkedRelatedField` will represent the target of the relationship using a hyperlink. - -By default, `HyperlinkedRelatedField` is read-write, although you can change this behaviour using the `read_only` flag. - -**Arguments**: - -* `view_name` - The view name that should be used as the target of the relationship. **required**. -* `format` - If using format suffixes, hyperlinked fields will use the same format suffix for the target unless overridden by using the `format` argument. -* `queryset` - By default `ModelSerializer` classes will use the default queryset for the relationship. `Serializer` classes must either set a queryset explicitly, or set `read_only=True`. -* `slug_field` - The field on the target that should be used for the lookup. Default is `'slug'`. -* `pk_url_kwarg` - The named url parameter for the pk field lookup. Default is `pk`. -* `slug_url_kwarg` - The named url parameter for the slug field lookup. Default is to use the same value as given for `slug_field`. -* `null` - If set to `True`, the field will accept values of `None` or the emptystring for nullable relationships. - -## HyperLinkedIdentityField - -This field can be applied as an identity relationship, such as the `'url'` field on a HyperlinkedModelSerializer. - -This field is always read-only. - -**Arguments**: - -* `view_name` - The view name that should be used as the target of the relationship. **required**. -* `format` - If using format suffixes, hyperlinked fields will use the same format suffix for the target unless overridden by using the `format` argument. -* `slug_field` - The field on the target that should be used for the lookup. Default is `'slug'`. -* `pk_url_kwarg` - The named url parameter for the pk field lookup. Default is `pk`. -* `slug_url_kwarg` - The named url parameter for the slug field lookup. Default is to use the same value as given for `slug_field`. - -# Other Fields - -## SerializerMethodField - -This is a read-only field. It gets its value by calling a method on the serializer class it is attached to. It can be used to add any sort of data to the serialized representation of your object. The field's constructor accepts a single argument, which is the name of the method on the serializer to be called. The method should accept a single argument (in addition to `self`), which is the object being serialized. It should return whatever you want to be included in the serialized representation of the object. For example: - - from rest_framework import serializers - from django.contrib.auth.models import User - from django.utils.timezone import now - - class UserSerializer(serializers.ModelSerializer): - - days_since_joined = serializers.SerializerMethodField('get_days_since_joined') - - class Meta: - model = User - - def get_days_since_joined(self, obj): - return (now() - obj.date_joined).days - -[cite]: http://www.python.org/dev/peps/pep-0020/ +[cite]: https://docs.djangoproject.com/en/dev/ref/forms/api/#django.forms.Form.cleaned_data [FILE_UPLOAD_HANDLERS]: https://docs.djangoproject.com/en/dev/ref/settings/#std:setting-FILE_UPLOAD_HANDLERS |