def test_supports_loading_multiple_keys_in_one_call():
def call_fn(keys):
return Promise.resolve(keys)
identity_loader = DataLoader(call_fn)
promise_all = identity_loader.load_many([1, 2])
assert isinstance(promise_all, Promise)
values = promise_all.get()
assert values == [1, 2]
promise_all = identity_loader.load_many([])
assert isinstance(promise_all, Promise)
values = promise_all.get()
assert values == []
def test_supports_loading_multiple_keys_in_one_call():
def call_fn(keys):
return Promise.resolve(keys)
identity_loader = DataLoader(call_fn)
promise_all = identity_loader.load_many([1, 2])
assert isinstance(promise_all, Promise)
values = promise_all.get()
assert values == [1, 2]
promise_all = identity_loader.load_many([])
assert isinstance(promise_all, Promise)
values = promise_all.get()
assert values == []
class ExternalRESTField(graphene.Field):
def __init__(self, rest_object_class, source_field_name='id', filter_field_name='id', is_top_level=False, many=False, *args, **kwargs):
assert is_top_level or not (source_field_name == 'id' and filter_field_name == 'id')
self.source_field_name = source_field_name
self.filter_field_name = filter_field_name
self.rest_object_class = rest_object_class
self.is_top_level = is_top_level
self.request_maker = RequestMaker(
filter_by_parent_fields=(not is_top_level),
filter_field_name=filter_field_name
)
def batch_load_fn(source_values):
self.request_maker.filter_values = source_values
response = self.request_maker.make_request()
return Promise.resolve(response.json()['results'])
self.data_loader = DataLoader(batch_load_fn)
self.many = many
if self.many:
super().__init__(graphene.List(rest_object_class), *args, **kwargs)
else:
super().__init__(rest_object_class, *args, **kwargs)
def get_resolver(self, parent_resolver):
if self.resolver:
return self.resolver
else:
return self.generate_resolver(get_actual_object_class(self.rest_object_class))
def generate_resolver(self, rest_object_class, *class_args, **class_kwargs):
def endpoint_resolver_promise(parent_object, results):
relevant_results = list(filter(lambda h: equals_or_contains(h[self.filter_field_name], getattr(parent_object, self.source_field_name)), results))
if not self.many:
assert len(relevant_results) == 1
relevant_results = relevant_results[0]
obj = reduce_fields_to_objects(rest_object_class, relevant_results, is_list=self.many)
return obj
def endpoint_resolver(parent_object, args, context, info):
# This is called for every parent object where we want nested objects.
# Therefore we don't want to do unnecessary computation (ex:
# processing query params/headers from the original request)
# Instead, we do initial processing in request_maker.initialize_x
# and final processing in request_maker.generate_x
self.request_maker.headers = context.headers
self.request_maker.data = context.data
self.request_maker.base_url = rest_object_class.base_url
self.request_maker.query_string = context.query_string
self.request_maker.graphql_arguments = args
if self.is_top_level:
response = self.request_maker.make_request()
return reduce_fields_to_objects(rest_object_class, response.json()['results'])
else:
source_values = getattr(parent_object, self.source_field_name)
if not is_non_str_iterable(source_values):
source_values = [source_values]
result = self.data_loader.load_many(source_values)
return result.then(
functools.partial(endpoint_resolver_promise, parent_object)
)
return endpoint_resolver