py_gql.validation#

Validation of GraphQL (query) documents.

Note

This module is only concerned with validating query documents, not SDL documents which are validated when using py_gql.build_schema or py_gql.schema.Schema.validate().

py_gql.validation.validate_ast(schema, document, *, validators=None, variables=None)[source]#

Check that an ast is a valid GraphQL query document.

This runs the parse tree through a list of validation callables given a Schema instance.

Warning

This assumes the ast is a document generated by py_gql.lang.parse() (as opposed to manually constructed) and will most likely break unexpectedly if that’s not the case.

Parameters:
Return type:

ValidationResult
Returns:

Validation result wrapping any validation error that occurred.
py_gql.validation.default_validator(schema, document, variables=None, *, validators=(<class 'py_gql.validation.rules.ExecutableDefinitionsChecker'>, <class 'py_gql.validation.rules.UniqueOperationNameChecker'>, <class 'py_gql.validation.rules.LoneAnonymousOperationChecker'>, <class 'py_gql.validation.rules.SingleFieldSubscriptionsChecker'>, <class 'py_gql.validation.rules.KnownTypeNamesChecker'>, <class 'py_gql.validation.rules.FragmentsOnCompositeTypesChecker'>, <class 'py_gql.validation.rules.VariablesAreInputTypesChecker'>, <class 'py_gql.validation.rules.ScalarLeafsChecker'>, <class 'py_gql.validation.rules.FieldsOnCorrectTypeChecker'>, <class 'py_gql.validation.rules.UniqueFragmentNamesChecker'>, <class 'py_gql.validation.rules.KnownFragmentNamesChecker'>, <class 'py_gql.validation.rules.NoUnusedFragmentsChecker'>, <class 'py_gql.validation.rules.PossibleFragmentSpreadsChecker'>, <class 'py_gql.validation.rules.NoFragmentCyclesChecker'>, <class 'py_gql.validation.rules.UniqueVariableNamesChecker'>, <class 'py_gql.validation.rules.NoUndefinedVariablesChecker'>, <class 'py_gql.validation.rules.NoUnusedVariablesChecker'>, <class 'py_gql.validation.rules.KnownDirectivesChecker'>, <class 'py_gql.validation.rules.UniqueDirectivesPerLocationChecker'>, <class 'py_gql.validation.rules.KnownArgumentNamesChecker'>, <class 'py_gql.validation.rules.UniqueArgumentNamesChecker'>, <class 'py_gql.validation.rules.values_of_correct_type.ValuesOfCorrectTypeChecker'>, <class 'py_gql.validation.rules.ProvidedRequiredArgumentsChecker'>, <class 'py_gql.validation.rules.VariablesInAllowedPositionChecker'>, <class 'py_gql.validation.rules.overlapping_fields_can_be_merged.OverlappingFieldsCanBeMergedChecker'>, <class 'py_gql.validation.rules.UniqueInputFieldNamesChecker'>))[source]#

Validate a GraphQL document using a collection of ValidationVisitor.

This is the default validator implementation and uses a chain of 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 validate_ast() and custom visitor classes a lambda or partial should be created.

Return type:Iterable[ValidationError]
class py_gql.validation.ValidationResult(errors=None)[source]#

Wrap a collection of ValidationError.

Instances are iterable and falsy when they contain at least one validation error.

class py_gql.validation.ValidationVisitor(schema, type_info)[source]#

Visitor class used for validating GraphQL documents.

Subclass this to implement custom validators. Use add_error() to register errors and py_gql.lang.visitor.SkipNode to prevent validating child nodes when parent node is invalid.

Parameters:
  • schema (Schema) – Schema to validate against (for known types, directives, etc.).
  • type_info (TypeInfoVisitor) – Type information collector provided by validate().
schema#

Schema to validate against (for known types, directives, etc.).

Type:py_gql.schema.Schema
type_info#

Type information collector provided by validate().

Type:TypeInfoVisitor
errors#

Collected errors.

Type:List[ValidationError]
add_error(message, nodes=None)[source]#

Register an error

Parameters:
  • message (str) – Error description
  • nodes (Optional[List[py_gql.lang.ast.Node]]) – Nodes where the error originated from.
Return type:

None
enter(node)[source]#

Process an AST node.

Implement this for the main visiting behavior (i.e. before a node’s children have been visited).

Return None to delete the node from it’s parent context or raise SkipNode to prevent any further processing (children do not get visited and leave doesn’t get called for that node).

Return type:~N
validation.SPECIFIED_RULES#

This is the list of ValidationVisitor from py_gql.validation.rules encoding all the validation rules defined in this section of the Spec.