Source code for py_gql.validation.validate

# -*- coding: utf-8 -*-

from itertools import chain
from typing import Iterator, List, Optional, Sequence, Type

from ..exc import ValidationError
from ..lang import ast as _ast
from ..lang.visitor import ParallelVisitor
from ..schema import Schema
from ..utilities import TypeInfoVisitor
from . import rules as _rules
from .visitors import ValidationVisitor


[docs]class ValidationResult: """ Encode validation result by wrapping a collection of :class:`~py_gql.exc.ValidationError`. Instances are iterable and falsy when they contain at least one error. """ def __init__(self, errors: Optional[List[ValidationError]]): 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 validate_ast( schema: Schema, ast_root: _ast.Document, validators: Optional[Sequence[Type[ValidationVisitor]]] = None, ) -> ValidationResult: """ Check that an ast is a valid GraphQL query document by running the parse tree through a list of :class:`~py_gql.validation.ValidationVisitor` given a :class:`~py_gql.schema.Schema` instance. Warning: This assumes the ast is a valid document generated by :func:`py_gql.lang.parse` and will most likely break unexpectedly if that's not the case. Args: schema: Schema to validate against (for known types, directives, etc.). ast_root: The parse tree root. validators: List of validator classes (subclasses of :class:`py_gql.validation.ValidationVisitor`) to use. Defaults to :obj:`~py_gql.validation.SPECIFIED_RULES`. Returns: Validation result wrapping any validatione error that occured. """ type_info = TypeInfoVisitor(schema) if validators is None: validators = SPECIFIED_RULES def instantiate_validator(cls_, schema, type_info): if not issubclass(cls_, ValidationVisitor): raise TypeError( 'Expected ValidationVisitor subclass but got "%r"' % cls_ ) return cls_(schema, type_info) validator_instances = [ instantiate_validator(validator_, schema, type_info) for validator_ 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 = ParallelVisitor(type_info, *validator_instances) validator.visit(ast_root) return ValidationResult( list(chain(*[v.errors for v in validator_instances])) )