def __init__(self, schema, document_ast, variable_values):
self.schema = schema
self.operation_defs = {}
self.fragment_defs = {}
self.visited_fragments = set()
for defn in document_ast.definitions:
if isinstance(defn, ast.OperationDefinition):
root_type = get_operation_root_type(schema, defn)
definition_variables = defn.variable_definitions or []
if definition_variables:
def_var_names = {
v.variable.name.value
for v in definition_variables
}
var_names_diff = def_var_names.difference(
{k
for k in variable_values if k in def_var_names})
# check if we are missing some of the definition variables
if var_names_diff:
msg = (f'Please check your query variables. The '
f'following variables are missing: '
f'[{", ".join(var_names_diff)}]')
raise ValueError(msg)
self.operation_defs[getattr(defn.name, 'value', root_type)] = {
'definition':
defn,
'parent_type':
root_type,
'variables':
get_variable_values(schema, definition_variables,
variable_values),
}
elif isinstance(defn, ast.FragmentDefinition):
self.fragment_defs[defn.name.value] = defn
def resolve_prefetch(
exe_context, # type: ExecutionContext
operation, # type: OperationDefinition
root_type=None, # type: Any
type_=None,
path=None,
selection_set=None, # type: Optional[SelectionSet]
action_id=None):
if path is None:
path = []
if type_ is None:
type_ = get_operation_root_type(exe_context.schema, operation)
if isinstance(type_, GraphQLList):
type_ = type_.of_type
if root_type is None:
root_type = type_.graphene_type
if selection_set is None:
selection_set = operation.selection_set
fields = collect_fields(exe_context, type_, selection_set,
DefaultOrderedDict(list), set())
try:
prefetch_fn = getattr(type_.graphene_type, "prefetch_fn")
except AttributeError:
prefetch_fn = None
for response_name, field_asts in fields.items():
# todo: 这里可能有bug
field_ast = field_asts[0]
field_name = field_ast.name.value
try:
field_def = get_field_def(exe_context.schema, type_, field_name)
except:
field_def = None
path_name = SKIP
if prefetch_fn:
try:
# 在 prefetch_fn 中进行类似于select_related prefetch_related等操作
# 告诉orm应该加载关系
# 返回的东西会被拼凑到path里面，如果返回SKIP，那么不会拼路径，如果不返回，那么字段名将拼凑到路径中
new_action_id = action_id
def set_action_id(x):
nonlocal new_action_id
new_action_id = x
def add_prefetch_info(x):
exe_context.context_value["prefetch"][action_id].append(x)
path_name = prefetch_fn(action_id=action_id,
prefetch_name=field_name,
prefetch_field_def=field_def,
path=path,
add_prefetch_info=add_prefetch_info,
set_action_id=set_action_id)
except:
traceback.print_exc()
if field_def and field_ast.selection_set:
if path_name == SKIP:
new_path = path
else:
new_path = path + [path_name]
resolve_prefetch(exe_context, operation, root_type, field_def.type,
new_path, field_ast.selection_set, new_action_id)
