Split parsing, validation and execution (#43) (#53)

Instead of graphql()/graphql_sync() we now call execute() directly.

This also allows adding custom validation rules and limiting the number
of reported errors.

Author: Cito

graphql_server/__init__.py

@@ -9,13 +9,16 @@
 import json
 from collections import namedtuple
 from collections.abc import MutableMapping
-from typing import Any, Callable, Dict, List, Optional, Type, Union
+from typing import Any, Callable, Collection, Dict, List, Optional, Type, Union
 
-from graphql import ExecutionResult, GraphQLError, GraphQLSchema, OperationType
-from graphql import format_error as format_error_default
-from graphql import get_operation_ast, parse
-from graphql.graphql import graphql, graphql_sync
+from graphql.error import GraphQLError
+from graphql.error import format_error as format_error_default
+from graphql.execution import ExecutionResult, execute
+from graphql.language import OperationType, parse
 from graphql.pyutils import AwaitableOrValue
+from graphql.type import GraphQLSchema, validate_schema
+from graphql.utilities import get_operation_ast
+from graphql.validation import ASTValidationRule, validate
 
 from .error import HttpQueryError
 from .version import version, version_info
@@ -223,36 +226,48 @@ def load_json_variables(variables: Optional[Union[str, Dict]]) -> Optional[Dict]
     return variables  # type: ignore
 
 
+def assume_not_awaitable(_value: Any) -> bool:
+    """Replacement for isawaitable if everything is assumed to be synchronous."""
+    return False
+
+
 def get_response(
     schema: GraphQLSchema,
     params: GraphQLParams,
     catch_exc: Type[BaseException],
     allow_only_query: bool = False,
     run_sync: bool = True,
+    validation_rules: Optional[Collection[Type[ASTValidationRule]]] = None,
+    max_errors: Optional[int] = None,
     **kwargs,
 ) -> Optional[AwaitableOrValue[ExecutionResult]]:
     """Get an individual execution result as response, with option to catch errors.
 
-    This does the same as graphql_impl() except that you can either
-    throw an error on the ExecutionResult if allow_only_query is set to True
-    or catch errors that belong to an exception class that you need to pass
-    as a parameter.
+    This will validate the schema (if the schema is used for the first time),
+    parse the query, check if this is a query if allow_only_query is set to True,
+    validate the query (optionally with additional validation rules and limiting
+    the number of errors), execute the request (asynchronously if run_sync is not
+    set to True), and return the ExecutionResult. You can also catch all errors that
+    belong to an exception class specified by catch_exc.
     """
-
     # noinspection PyBroadException
     try:
         if not params.query:
             raise HttpQueryError(400, "Must provide query string.")
 
+        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:
-            # Parse document to check that only query operations are used
-            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])
             operation_ast = get_operation_ast(document, params.operation_name)
             if operation_ast:
                 operation = operation_ast.operation.value
@@ -264,22 +279,21 @@ def get_response(
                         headers={"Allow": "POST"},
                     )
 
-        if run_sync:
-            execution_result = graphql_sync(
-                schema=schema,
-                source=params.query,
-                variable_values=params.variables,
-                operation_name=params.operation_name,
-                **kwargs,
-            )
-        else:
-            execution_result = graphql(  # type: ignore
-                schema=schema,
-                source=params.query,
-                variable_values=params.variables,
-                operation_name=params.operation_name,
-                **kwargs,
-            )
+        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,
+            variable_values=params.variables,
+            operation_name=params.operation_name,
+            is_awaitable=assume_not_awaitable if run_sync else None,
+            **kwargs,
+        )
+
     except catch_exc:
         return None
 

tests/test_query.py

@@ -2,6 +2,7 @@
 
 from graphql.error import GraphQLError
 from graphql.execution import ExecutionResult
+from graphql.validation import ValidationRule
 from pytest import raises
 
 from graphql_server import (
@@ -123,6 +124,68 @@ def test_reports_validation_errors():
     assert response.status_code == 400
 
 
+def test_reports_custom_validation_errors():
+    class CustomValidationRule(ValidationRule):
+        def enter_field(self, node, *_args):
+            self.report_error(GraphQLError("Custom validation error.", node))
+
+    results, params = run_http_query(
+        schema,
+        "get",
+        {},
+        query_data=dict(query="{ test }"),
+        validation_rules=[CustomValidationRule],
+    )
+
+    assert as_dicts(results) == [
+        {
+            "data": None,
+            "errors": [
+                {
+                    "message": "Custom validation error.",
+                    "locations": [{"line": 1, "column": 3}],
+                    "path": None,
+                }
+            ],
+        }
+    ]
+
+    response = encode_execution_results(results)
+    assert response.status_code == 400
+
+
+def test_reports_max_num_of_validation_errors():
+    results, params = run_http_query(
+        schema,
+        "get",
+        {},
+        query_data=dict(query="{ test, unknownOne, unknownTwo }"),
+        max_errors=1,
+    )
+
+    assert as_dicts(results) == [
+        {
+            "data": None,
+            "errors": [
+                {
+                    "message": "Cannot query field 'unknownOne' on type 'QueryRoot'.",
+                    "locations": [{"line": 1, "column": 9}],
+                    "path": None,
+                },
+                {
+                    "message": "Too many validation errors, error limit reached."
+                    " Validation aborted.",
+                    "locations": None,
+                    "path": None,
+                },
+            ],
+        }
+    ]
+
+    response = encode_execution_results(results)
+    assert response.status_code == 400
+
+
 def test_non_dict_params_in_non_batch_query():
     with raises(HttpQueryError) as exc_info:
         # noinspection PyTypeChecker