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* Revise documentation - Add missing reference to `flask-graphql` in integrations - align documentation for resolver arguments (use root for 1st argument instead of self) - explore use of `parent` instead of `root` for first argument - clarify resolvers and object type documentation - add documentation for Meta class options for ObjectType - expand quickstart documentation for first time users - streamline order of documentation for first time users (broad -> specific) - document resolver quirks * explict imports from graphene * rename doc refs for resolvers * suggestions typos and graphene import
141 lines
3.5 KiB
ReStructuredText
141 lines
3.5 KiB
ReStructuredText
.. _Scalars:
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Scalars
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=======
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All Scalar types accept the following arguments. All are optional:
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``name``: *string*
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Override the name of the Field.
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``description``: *string*
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A description of the type to show in the GraphiQL browser.
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``required``: *boolean*
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If ``True``, the server will enforce a value for this field. See `NonNull <../list-and-nonnull.html#nonnull>`_. Default is ``False``.
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``deprecation_reason``: *string*
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Provide a deprecation reason for the Field.
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``default_value``: *any*
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Provide a default value for the Field.
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Base scalars
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------------
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Graphene defines the following base Scalar Types:
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``graphene.String``
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Represents textual data, represented as UTF-8
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character sequences. The String type is most often used by GraphQL to
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represent free-form human-readable text.
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``graphene.Int``
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Represents non-fractional signed whole numeric
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values. Int is a signed 32‐bit integer per the
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`GraphQL spec <https://facebook.github.io/graphql/June2018/#sec-Int>`_
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``graphene.Float``
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Represents signed double-precision fractional
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values as specified by
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`IEEE 754 <http://en.wikipedia.org/wiki/IEEE_floating_point>`_.
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``graphene.Boolean``
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Represents `true` or `false`.
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``graphene.ID``
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Represents a unique identifier, often used to
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refetch an object or as key for a cache. The ID type appears in a JSON
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response as a String; however, it is not intended to be human-readable.
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When expected as an input type, any string (such as `"4"`) or integer
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(such as `4`) input value will be accepted as an ID.
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Graphene also provides custom scalars for Dates, Times, and JSON:
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``graphene.types.datetime.Date``
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Represents a Date value as specified by `iso8601 <https://en.wikipedia.org/wiki/ISO_8601>`_.
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``graphene.types.datetime.DateTime``
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Represents a DateTime value as specified by `iso8601 <https://en.wikipedia.org/wiki/ISO_8601>`_.
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``graphene.types.datetime.Time``
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Represents a Time value as specified by `iso8601 <https://en.wikipedia.org/wiki/ISO_8601>`_.
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``graphene.types.json.JSONString``
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Represents a JSON string.
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Custom scalars
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--------------
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You can create custom scalars for your schema.
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The following is an example for creating a DateTime scalar:
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.. code:: python
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import datetime
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from graphene.types import Scalar
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from graphql.language import ast
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class DateTime(Scalar):
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'''DateTime Scalar Description'''
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@staticmethod
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def serialize(dt):
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return dt.isoformat()
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@staticmethod
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def parse_literal(node):
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if isinstance(node, ast.StringValue):
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return datetime.datetime.strptime(
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node.value, "%Y-%m-%dT%H:%M:%S.%f")
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@staticmethod
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def parse_value(value):
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return datetime.datetime.strptime(value, "%Y-%m-%dT%H:%M:%S.%f")
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Mounting Scalars
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----------------
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Scalars mounted in a ``ObjectType``, ``Interface`` or ``Mutation`` act as
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``Field``\ s.
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.. code:: python
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class Person(graphene.ObjectType):
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name = graphene.String()
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# Is equivalent to:
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class Person(graphene.ObjectType):
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name = graphene.Field(graphene.String)
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**Note:** when using the ``Field`` constructor directly, pass the type and
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not an instance.
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Types mounted in a ``Field`` act as ``Argument``\ s.
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.. code:: python
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graphene.Field(graphene.String, to=graphene.String())
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# Is equivalent to:
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graphene.Field(graphene.String, to=graphene.Argument(graphene.String))
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