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107 lines
2.6 KiB
ReStructuredText
107 lines
2.6 KiB
ReStructuredText
ObjectTypes
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===========
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An ObjectType is the single, definitive source of information about your
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data. It contains the essential fields and behaviors of the data you’re
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querying.
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The basics:
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- Each ObjectType is a Python class that inherits from
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``graphene.ObjectType``.
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- Each attribute of the ObjectType represents a ``Field``.
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Quick example
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-------------
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This example model defines a Person, with a first and a last name:
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.. code:: python
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import graphene
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class Person(graphene.ObjectType):
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first_name = graphene.String()
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last_name = graphene.String()
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full_name = graphene.String()
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def resolve_full_name(self):
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return '{} {}'.format(self.first_name, self.last_name)
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**first\_name** and **last\_name** are fields of the ObjectType. Each
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field is specified as a class attribute, and each attribute maps to a
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Field.
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The above ``Person`` ObjectType has the following schema representation:
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.. code::
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type Person {
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firstName: String
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lastName: String
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fullName: String
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}
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Resolvers
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---------
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A resolver is a method that resolves certain fields within a
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``ObjectType``. If not specififed otherwise, the resolver of a
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field is the ``resolve_{field_name}`` method on the ``ObjectType``.
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By default resolvers take the arguments ``args``, ``context`` and ``info``.
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NOTE: The resolvers on a ``ObjectType`` are always treated as ``staticmethod``\ s,
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so the first argument to the resolver method ``self`` (or ``root``) need
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not be an actual instance of the ``ObjectType``.
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Quick example
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~~~~~~~~~~~~~
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This example model defines a ``Query`` type, which has a reverse field
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that reverses the given ``word`` argument using the ``resolve_reverse``
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method in the class.
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.. code:: python
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import graphene
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class Query(graphene.ObjectType):
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reverse = graphene.String(word=graphene.String())
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def resolve_reverse(self, word):
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return word[::-1]
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Resolvers outside the class
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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A field can use a custom resolver from outside the class:
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.. code:: python
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import graphene
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def reverse(root, word):
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return word[::-1]
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class Query(graphene.ObjectType):
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reverse = graphene.String(word=graphene.String(), resolver=reverse)
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Instances as data containers
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----------------------------
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Graphene ``ObjectType``\ s can act as containers too. So with the
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previous example you could do:
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.. code:: python
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peter = Person(first_name='Peter', last_name='Griffin')
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peter.first_name # prints "Peter"
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peter.last_name # prints "Griffin"
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.. _Interface: /docs/interfaces/
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