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graphene-django/graphene_django/fields.py

232 lines
7.3 KiB

from functools import partial
import six
from django.db.models.query import QuerySet
from graphql_relay.connection.arrayconnection import (
connection_from_list_slice,
get_offset_with_default,
)
from promise import Promise
from graphene import NonNull
from graphene.relay import ConnectionField, PageInfo
from graphene.types import Field, List
from .settings import graphene_settings
from .utils import maybe_queryset
class DjangoListField(Field):
def __init__(self, _type, *args, **kwargs):
from .types import DjangoObjectType
if isinstance(_type, NonNull):
_type = _type.of_type
# Django would never return a Set of None vvvvvvv
super(DjangoListField, self).__init__(List(NonNull(_type)), *args, **kwargs)
assert issubclass(
self._underlying_type, DjangoObjectType
), "DjangoListField only accepts DjangoObjectType types"
@property
def _underlying_type(self):
_type = self._type
while hasattr(_type, "of_type"):
_type = _type.of_type
return _type
@property
def model(self):
return self._underlying_type._meta.model
def get_default_queryset(self):
return self.model._default_manager.get_queryset()
@staticmethod
def list_resolver(
django_object_type, resolver, default_queryset, root, info, **args
):
queryset = maybe_queryset(resolver(root, info, **args))
if queryset is None:
queryset = default_queryset
if isinstance(queryset, QuerySet):
# Pass queryset to the DjangoObjectType get_queryset method
queryset = maybe_queryset(django_object_type.get_queryset(queryset, info))
return queryset
def get_resolver(self, parent_resolver):
_type = self.type
if isinstance(_type, NonNull):
_type = _type.of_type
django_object_type = _type.of_type.of_type
return partial(
self.list_resolver,
django_object_type,
parent_resolver,
self.get_default_queryset(),
)
class DjangoConnectionField(ConnectionField):
def __init__(self, *args, **kwargs):
self.on = kwargs.pop("on", False)
self.max_limit = kwargs.pop(
"max_limit", graphene_settings.RELAY_CONNECTION_MAX_LIMIT
)
self.enforce_first_or_last = kwargs.pop(
"enforce_first_or_last",
graphene_settings.RELAY_CONNECTION_ENFORCE_FIRST_OR_LAST,
)
super(DjangoConnectionField, self).__init__(*args, **kwargs)
@property
def type(self):
from .types import DjangoObjectType
_type = super(ConnectionField, self).type
non_null = False
if isinstance(_type, NonNull):
_type = _type.of_type
non_null = True
assert issubclass(
_type, DjangoObjectType
), "DjangoConnectionField only accepts DjangoObjectType types"
assert _type._meta.connection, "The type {} doesn't have a connection".format(
_type.__name__
)
connection_type = _type._meta.connection
if non_null:
return NonNull(connection_type)
return connection_type
@property
def connection_type(self):
type = self.type
if isinstance(type, NonNull):
return type.of_type
return type
@property
def node_type(self):
return self.connection_type._meta.node
@property
def model(self):
return self.node_type._meta.model
def get_manager(self):
if self.on:
return getattr(self.model, self.on)
else:
return self.model._default_manager
@classmethod
def resolve_queryset(cls, connection, queryset, info, args):
# queryset is the resolved iterable from ObjectType
return connection._meta.node.get_queryset(queryset, info)
@classmethod
def resolve_connection(cls, connection, args, iterable, max_limit=None):
iterable = maybe_queryset(iterable)
if isinstance(iterable, QuerySet):
list_length = iterable.count()
list_slice_length = (
min(max_limit, list_length) if max_limit is not None else list_length
)
else:
list_length = len(iterable)
list_slice_length = (
min(max_limit, list_length) if max_limit is not None else list_length
)
# If after is higher than list_length, connection_from_list_slice
# would try to do a negative slicing which makes django throw an
# AssertionError
after = min(get_offset_with_default(args.get("after"), -1) + 1, list_length)
if max_limit is not None and "first" not in args:
args["first"] = max_limit
connection = connection_from_list_slice(
iterable[after:],
args,
slice_start=after,
list_length=list_length,
list_slice_length=list_slice_length,
connection_type=connection,
edge_type=connection.Edge,
pageinfo_type=PageInfo,
)
connection.iterable = iterable
connection.length = list_length
return connection
@classmethod
def connection_resolver(
cls,
resolver,
connection,
default_manager,
queryset_resolver,
max_limit,
enforce_first_or_last,
root,
info,
**args
):
first = args.get("first")
last = args.get("last")
if enforce_first_or_last:
assert first or last, (
"You must provide a `first` or `last` value to properly paginate the `{}` connection."
).format(info.field_name)
if max_limit:
if first:
assert first <= max_limit, (
"Requesting {} records on the `{}` connection exceeds the `first` limit of {} records."
).format(first, info.field_name, max_limit)
args["first"] = min(first, max_limit)
if last:
assert last <= max_limit, (
"Requesting {} records on the `{}` connection exceeds the `last` limit of {} records."
).format(last, info.field_name, max_limit)
args["last"] = min(last, max_limit)
# eventually leads to DjangoObjectType's get_queryset (accepts queryset)
# or a resolve_foo (does not accept queryset)
iterable = resolver(root, info, **args)
if iterable is None:
iterable = default_manager
# thus the iterable gets refiltered by resolve_queryset
# but iterable might be promise
iterable = queryset_resolver(connection, iterable, info, args)
on_resolve = partial(
cls.resolve_connection, connection, args, max_limit=max_limit
)
if Promise.is_thenable(iterable):
return Promise.resolve(iterable).then(on_resolve)
return on_resolve(iterable)
def get_resolver(self, parent_resolver):
return partial(
self.connection_resolver,
parent_resolver,
self.connection_type,
self.get_manager(),
self.get_queryset_resolver(),
self.max_limit,
self.enforce_first_or_last,
)
def get_queryset_resolver(self):
return self.resolve_queryset