# -*- coding: utf-8 -*-
from typing import (
Any,
Callable,
Dict,
Iterable,
Iterator,
List,
Optional,
Sequence,
Type,
)
from ..exc import ValidationError
from ..lang import ast as _ast
from ..lang.visitor import ChainedVisitor
from ..schema import Schema
from . import rules as _rules
from .visitors import TypeInfoVisitor, ValidationVisitor
Validator = Callable[
[Schema, _ast.Document, Optional[Dict[str, Any]]], Iterable[ValidationError]
]
SPECIFIED_RULES = (
_rules.ExecutableDefinitionsChecker,
_rules.UniqueOperationNameChecker,
_rules.LoneAnonymousOperationChecker,
_rules.SingleFieldSubscriptionsChecker,
_rules.KnownTypeNamesChecker,
_rules.FragmentsOnCompositeTypesChecker,
_rules.VariablesAreInputTypesChecker,
_rules.ScalarLeafsChecker,
_rules.FieldsOnCorrectTypeChecker,
_rules.UniqueFragmentNamesChecker,
_rules.KnownFragmentNamesChecker,
_rules.NoUnusedFragmentsChecker,
_rules.PossibleFragmentSpreadsChecker,
_rules.NoFragmentCyclesChecker,
_rules.UniqueVariableNamesChecker,
_rules.NoUndefinedVariablesChecker,
_rules.NoUnusedVariablesChecker,
_rules.KnownDirectivesChecker,
_rules.UniqueDirectivesPerLocationChecker,
_rules.KnownArgumentNamesChecker,
_rules.UniqueArgumentNamesChecker,
_rules.ValuesOfCorrectTypeChecker,
_rules.ProvidedRequiredArgumentsChecker,
_rules.VariablesInAllowedPositionChecker,
_rules.OverlappingFieldsCanBeMergedChecker,
_rules.UniqueInputFieldNamesChecker,
)
[docs]class ValidationResult:
"""
Wrap a collection of :class:`~py_gql.exc.ValidationError`.
Instances are iterable and falsy when they contain at least one validation
error.
"""
def __init__(self, errors: Optional[List[ValidationError]] = None):
self.errors = errors if errors is not None else []
def __bool__(self):
return not self.errors
def __iter__(self) -> Iterator[ValidationError]:
return iter(self.errors)
[docs]def default_validator(
schema: Schema,
document: _ast.Document,
variables: Optional[Dict[str, Any]] = None,
*,
validators: Sequence[Type[ValidationVisitor]] = SPECIFIED_RULES
) -> Iterable[ValidationError]:
"""
Validate a GraphQL document using a collection of :class:`ValidationVisitor`.
This is the default validator implementation and uses a chain of
:class:`~py_gql.validation.ValidationVisitor` classes, collecting all errors
by passing the document through all visitors in order.
The ordering allows visitors to rely on previous visitors having filtered
out invalid nodes.
In order to use this with :func:`~py_gql.validation.validate_ast` and custom
visitor classes a lambda or partial should be created.
"""
type_info = TypeInfoVisitor(schema)
visitors = [cls(schema, type_info) for cls in validators]
# Type info NEEDS to be first to be accurately used inside other validators
# so when a validator enters node the type stack has already been updated.
validator = ChainedVisitor(type_info, *visitors)
validator.visit(document)
return [error for visitor in visitors for error in visitor.errors]
[docs]def validate_ast(
schema: Schema,
document: _ast.Document,
*,
validators: Optional[Sequence[Validator]] = None,
variables: Optional[Dict[str, Any]] = None
) -> ValidationResult:
"""
Check that an ast is a valid GraphQL query document.
This runs the parse tree through a list of validation callables given a
:class:`~py_gql.schema.Schema` instance.
Warning:
This assumes the ast is a document generated by :func:`py_gql.lang.parse`
(as opposed to manually constructed) and will most likely break
unexpectedly if that's not the case.
Args:
schema: Schema to validate against (for known types, directives, etc.).
document: The parse tree root.
validators: List of validator callables to use.
Defaults to the rules defined in the specification.
variables: Raw, JSON decoded variables parsed from the request.
Returns:
Validation result wrapping any validation error that occurred.
"""
if validators is None:
validators = [default_validator]
return ValidationResult(
[
error
for validator in validators
for error in validator(schema, document, variables)
]
)