Allow passing DocumentNode to get_response to bypass validation

to add support for persisted queries, we want to bypass repeated validation of
queries that have already been parsed and validated.

This allows that by letting the user pass in the `DocumentNode` directly which
bypasses much of the parsing and validation, making the query processing faster.

graphql_server/__init__.py

@@ -25,7 +25,7 @@
 
 from graphql.error import GraphQLError
 from graphql.execution import ExecutionResult, execute
-from graphql.language import OperationType, parse
+from graphql.language import OperationType, parse, DocumentNode
 from graphql.pyutils import AwaitableOrValue
 from graphql.type import GraphQLSchema, validate_schema
 from graphql.utilities import get_operation_ast
@@ -61,7 +61,7 @@
 
 @dataclass
 class GraphQLParams:
-    query: str
+    query: str | DocumentNode
     variables: Optional[Dict[str, Any]] = None
     operation_name: Optional[str] = None
 
@@ -158,16 +158,13 @@ def run_http_query(
     all_params: List[GraphQLParams] = [
         get_graphql_params(entry, extra_data) for entry in data
     ]
-    # print("GET ROOT VALUE 0", type(request_method), all_params)
-    # print(dict(schema=schema, all_params=all_params, catch_exc=catch_exc, allow_only=allow_only_query, run_sync=run_sync))
 
     results: List[Optional[AwaitableOrValue[ExecutionResult]]] = [
         get_response(
             schema, params, catch_exc, allow_only_query, run_sync, **execute_options
         )
         for params in all_params
     ]
-    # print("GET ROOT VALUE 1")
 
     return GraphQLResponse(results=results, params=all_params)
 
@@ -314,6 +311,55 @@ def assume_not_awaitable(_value: Any) -> bool:
     return False
 
 
+def parse_document(
+    schema: GraphQLSchema,
+    params: GraphQLParams,
+    allow_only_query: bool = False,
+    validation_rules: Optional[Collection[Type[ASTValidationRule]]] = None,
+    max_errors: Optional[int] = None,
+) -> Optional[Dict]:
+    if not params.query:
+        raise HttpQueryError(400, "Must provide query string.")
+
+    if not isinstance(params.query, str) and not isinstance(params.query, DocumentNode):
+        raise HttpQueryError(400, "Unexpected query type.")
+
+    if isinstance(params.query, DocumentNode):
+        return params.query
+    schema_validation_errors = validate_schema(schema)
+    if schema_validation_errors:
+        return ExecutionResult(data=None, errors=schema_validation_errors)
+
+    try:
+        document = parse(params.query)
+    except GraphQLError as e:
+        return ExecutionResult(data=None, errors=[e])
+    except Exception as e:
+        e = GraphQLError(str(e), original_error=e)
+        return ExecutionResult(data=None, errors=[e])
+
+    if allow_only_query:
+        operation_ast = get_operation_ast(document, params.operation_name)
+        if operation_ast:
+            operation = operation_ast.operation.value
+            if operation != OperationType.QUERY.value:
+                raise HttpQueryError(
+                    405,
+                    f"Can only perform a {operation} operation" " from a POST request.",
+                    headers={"Allow": "POST"},
+                )
+
+    validation_errors = validate(
+        schema,
+        document,
+        rules=validation_rules,
+        max_errors=max_errors,
+    )
+    if validation_errors:
+        return ExecutionResult(data=None, errors=validation_errors)
+    return document
+
+
 def get_response(
     schema: GraphQLSchema,
     params: GraphQLParams,
@@ -334,44 +380,18 @@ def get_response(
     belong to an exception class specified by catch_exc.
     """
     # noinspection PyBroadException
+    document = parse_document(
+        schema,
+        params,
+        allow_only_query,
+        validation_rules,
+        max_errors,
+    )
+    if isinstance(document, ExecutionResult):
+        return document
+    if not isinstance(document, DocumentNode):
+        raise Exception("GraphQL query could not be parsed properly.")
     try:
-        if not params.query:
-            raise HttpQueryError(400, "Must provide query string.")
-
-        # Sanity check query
-        if not isinstance(params.query, str):
-            raise HttpQueryError(400, "Unexpected query type.")
-
-        schema_validation_errors = validate_schema(schema)
-        if schema_validation_errors:
-            return ExecutionResult(data=None, errors=schema_validation_errors)
-
-        try:
-            document = parse(params.query)
-        except GraphQLError as e:
-            return ExecutionResult(data=None, errors=[e])
-        except Exception as e:
-            e = GraphQLError(str(e), original_error=e)
-            return ExecutionResult(data=None, errors=[e])
-
-        if allow_only_query:
-            operation_ast = get_operation_ast(document, params.operation_name)
-            if operation_ast:
-                operation = operation_ast.operation.value
-                if operation != OperationType.QUERY.value:
-                    raise HttpQueryError(
-                        405,
-                        f"Can only perform a {operation} operation"
-                        " from a POST request.",
-                        headers={"Allow": "POST"},
-                    )
-
-        validation_errors = validate(
-            schema, document, rules=validation_rules, max_errors=max_errors
-        )
-        if validation_errors:
-            return ExecutionResult(data=None, errors=validation_errors)
-
         execution_result = execute(
             schema,
             document,