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<?php
declare(strict_types=1);
namespace GraphQL\Executor;
use ArrayAccess;
use ArrayObject;
use Exception;
use GraphQL\Error\Error;
use GraphQL\Error\InvariantViolation;
use GraphQL\Error\Warning;
use GraphQL\Executor\Promise\Promise;
use GraphQL\Executor\Promise\PromiseAdapter;
use GraphQL\Language\AST\DocumentNode;
use GraphQL\Language\AST\FieldNode;
use GraphQL\Language\AST\FragmentDefinitionNode;
use GraphQL\Language\AST\FragmentSpreadNode;
use GraphQL\Language\AST\InlineFragmentNode;
use GraphQL\Language\AST\NodeKind;
use GraphQL\Language\AST\OperationDefinitionNode;
use GraphQL\Language\AST\SelectionSetNode;
use GraphQL\Type\Definition\AbstractType;
use GraphQL\Type\Definition\Directive;
use GraphQL\Type\Definition\FieldDefinition;
use GraphQL\Type\Definition\InterfaceType;
use GraphQL\Type\Definition\LeafType;
use GraphQL\Type\Definition\ListOfType;
use GraphQL\Type\Definition\NonNull;
use GraphQL\Type\Definition\ObjectType;
use GraphQL\Type\Definition\ResolveInfo;
use GraphQL\Type\Definition\Type;
use GraphQL\Type\Introspection;
use GraphQL\Type\Schema;
use GraphQL\Utils\TypeInfo;
use GraphQL\Utils\Utils;
use RuntimeException;
use SplObjectStorage;
use stdClass;
use Throwable;
use Traversable;
use function array_keys;
use function array_merge;
use function array_reduce;
use function array_values;
use function get_class;
use function is_array;
use function is_object;
use function is_string;
use function sprintf;
class ReferenceExecutor implements ExecutorImplementation
{
/** @var object */
private static $UNDEFINED;
/** @var ExecutionContext */
private $exeContext;
/** @var SplObjectStorage */
private $subFieldCache;
private function __construct(ExecutionContext $context)
{
if (! self::$UNDEFINED) {
self::$UNDEFINED = Utils::undefined();
}
$this->exeContext = $context;
$this->subFieldCache = new SplObjectStorage();
}
public static function create(
PromiseAdapter $promiseAdapter,
Schema $schema,
DocumentNode $documentNode,
$rootValue,
$contextValue,
$variableValues,
?string $operationName,
callable $fieldResolver
) {
$exeContext = self::buildExecutionContext(
$schema,
$documentNode,
$rootValue,
$contextValue,
$variableValues,
$operationName,
$fieldResolver,
$promiseAdapter
);
if (is_array($exeContext)) {
return new class($promiseAdapter->createFulfilled(new ExecutionResult(null, $exeContext))) implements ExecutorImplementation
{
/** @var Promise */
private $result;
public function __construct(Promise $result)
{
$this->result = $result;
}
public function doExecute() : Promise
{
return $this->result;
}
};
}
return new self($exeContext);
}
/**
* Constructs an ExecutionContext object from the arguments passed to
* execute, which we will pass throughout the other execution methods.
*
* @param mixed $rootValue
* @param mixed $contextValue
* @param mixed[]|Traversable $rawVariableValues
* @param string|null $operationName
*
* @return ExecutionContext|Error[]
*/
private static function buildExecutionContext(
Schema $schema,
DocumentNode $documentNode,
$rootValue,
$contextValue,
$rawVariableValues,
$operationName = null,
?callable $fieldResolver = null,
?PromiseAdapter $promiseAdapter = null
) {
$errors = [];
$fragments = [];
/** @var OperationDefinitionNode $operation */
$operation = null;
$hasMultipleAssumedOperations = false;
foreach ($documentNode->definitions as $definition) {
switch ($definition->kind) {
case NodeKind::OPERATION_DEFINITION:
if (! $operationName && $operation) {
$hasMultipleAssumedOperations = true;
}
if (! $operationName ||
(isset($definition->name) && $definition->name->value === $operationName)) {
$operation = $definition;
}
break;
case NodeKind::FRAGMENT_DEFINITION:
$fragments[$definition->name->value] = $definition;
break;
}
}
if ($operation === null) {
if ($operationName) {
$errors[] = new Error(sprintf('Unknown operation named "%s".', $operationName));
} else {
$errors[] = new Error('Must provide an operation.');
}
} elseif ($hasMultipleAssumedOperations) {
$errors[] = new Error(
'Must provide operation name if query contains multiple operations.'
);
}
$variableValues = null;
if ($operation !== null) {
[$coercionErrors, $coercedVariableValues] = Values::getVariableValues(
$schema,
$operation->variableDefinitions ?: [],
$rawVariableValues ?: []
);
if (empty($coercionErrors)) {
$variableValues = $coercedVariableValues;
} else {
$errors = array_merge($errors, $coercionErrors);
}
}
if (! empty($errors)) {
return $errors;
}
Utils::invariant($operation, 'Has operation if no errors.');
Utils::invariant($variableValues !== null, 'Has variables if no errors.');
return new ExecutionContext(
$schema,
$fragments,
$rootValue,
$contextValue,
$operation,
$variableValues,
$errors,
$fieldResolver,
$promiseAdapter
);
}
public function doExecute() : Promise
{
// Return a Promise that will eventually resolve to the data described by
// The "Response" section of the GraphQL specification.
//
// If errors are encountered while executing a GraphQL field, only that
// field and its descendants will be omitted, and sibling fields will still
// be executed. An execution which encounters errors will still result in a
// resolved Promise.
$data = $this->executeOperation($this->exeContext->operation, $this->exeContext->rootValue);
$result = $this->buildResponse($data);
// Note: we deviate here from the reference implementation a bit by always returning promise
// But for the "sync" case it is always fulfilled
return $this->isPromise($result)
? $result
: $this->exeContext->promises->createFulfilled($result);
}
/**
* @param mixed|Promise|null $data
*
* @return ExecutionResult|Promise
*/
private function buildResponse($data)
{
if ($this->isPromise($data)) {
return $data->then(function ($resolved) {
return $this->buildResponse($resolved);
});
}
if ($data !== null) {
$data = (array) $data;
}
return new ExecutionResult($data, $this->exeContext->errors);
}
/**
* Implements the "Evaluating operations" section of the spec.
*
* @param mixed[] $rootValue
*
* @return Promise|stdClass|mixed[]
*/
private function executeOperation(OperationDefinitionNode $operation, $rootValue)
{
$type = $this->getOperationRootType($this->exeContext->schema, $operation);
$fields = $this->collectFields($type, $operation->selectionSet, new ArrayObject(), new ArrayObject());
$path = [];
// Errors from sub-fields of a NonNull type may propagate to the top level,
// at which point we still log the error and null the parent field, which
// in this case is the entire response.
//
// Similar to completeValueCatchingError.
try {
$result = $operation->operation === 'mutation' ?
$this->executeFieldsSerially($type, $rootValue, $path, $fields) :
$this->executeFields($type, $rootValue, $path, $fields);
if ($this->isPromise($result)) {
return $result->then(
null,
function ($error) {
$this->exeContext->addError($error);
return $this->exeContext->promises->createFulfilled(null);
}
);
}
return $result;
} catch (Error $error) {
$this->exeContext->addError($error);
return null;
}
}
/**
* Extracts the root type of the operation from the schema.
*
* @return ObjectType
*
* @throws Error
*/
private function getOperationRootType(Schema $schema, OperationDefinitionNode $operation)
{
switch ($operation->operation) {
case 'query':
$queryType = $schema->getQueryType();
if (! $queryType) {
throw new Error(
'Schema does not define the required query root type.',
[$operation]
);
}
return $queryType;
case 'mutation':
$mutationType = $schema->getMutationType();
if (! $mutationType) {
throw new Error(
'Schema is not configured for mutations.',
[$operation]
);
}
return $mutationType;
case 'subscription':
$subscriptionType = $schema->getSubscriptionType();
if (! $subscriptionType) {
throw new Error(
'Schema is not configured for subscriptions.',
[$operation]
);
}
return $subscriptionType;
default:
throw new Error(
'Can only execute queries, mutations and subscriptions.',
[$operation]
);
}
}
/**
* Given a selectionSet, adds all of the fields in that selection to
* the passed in map of fields, and returns it at the end.
*
* CollectFields requires the "runtime type" of an object. For a field which
* returns an Interface or Union type, the "runtime type" will be the actual
* Object type returned by that field.
*
* @param ArrayObject $fields
* @param ArrayObject $visitedFragmentNames
*
* @return ArrayObject
*/
private function collectFields(
ObjectType $runtimeType,
SelectionSetNode $selectionSet,
$fields,
$visitedFragmentNames
) {
$exeContext = $this->exeContext;
foreach ($selectionSet->selections as $selection) {
switch ($selection->kind) {
case NodeKind::FIELD:
if (! $this->shouldIncludeNode($selection)) {
break;
}
$name = self::getFieldEntryKey($selection);
if (! isset($fields[$name])) {
$fields[$name] = new ArrayObject();
}
$fields[$name][] = $selection;
break;
case NodeKind::INLINE_FRAGMENT:
if (! $this->shouldIncludeNode($selection) ||
! $this->doesFragmentConditionMatch($selection, $runtimeType)
) {
break;
}
$this->collectFields(
$runtimeType,
$selection->selectionSet,
$fields,
$visitedFragmentNames
);
break;
case NodeKind::FRAGMENT_SPREAD:
$fragName = $selection->name->value;
if (! empty($visitedFragmentNames[$fragName]) || ! $this->shouldIncludeNode($selection)) {
break;
}
$visitedFragmentNames[$fragName] = true;
/** @var FragmentDefinitionNode|null $fragment */
$fragment = $exeContext->fragments[$fragName] ?? null;
if (! $fragment || ! $this->doesFragmentConditionMatch($fragment, $runtimeType)) {
break;
}
$this->collectFields(
$runtimeType,
$fragment->selectionSet,
$fields,
$visitedFragmentNames
);
break;
}
}
return $fields;
}
/**
* Determines if a field should be included based on the @include and @skip
* directives, where @skip has higher precedence than @include.
*
* @param FragmentSpreadNode|FieldNode|InlineFragmentNode $node
*
* @return bool
*/
private function shouldIncludeNode($node)
{
$variableValues = $this->exeContext->variableValues;
$skipDirective = Directive::skipDirective();
$skip = Values::getDirectiveValues(
$skipDirective,
$node,
$variableValues
);
if (isset($skip['if']) && $skip['if'] === true) {
return false;
}
$includeDirective = Directive::includeDirective();
$include = Values::getDirectiveValues(
$includeDirective,
$node,
$variableValues
);
return ! isset($include['if']) || $include['if'] !== false;
}
/**
* Implements the logic to compute the key of a given fields entry
*
* @return string
*/
private static function getFieldEntryKey(FieldNode $node)
{
return $node->alias ? $node->alias->value : $node->name->value;
}
/**
* Determines if a fragment is applicable to the given type.
*
* @param FragmentDefinitionNode|InlineFragmentNode $fragment
*
* @return bool
*/
private function doesFragmentConditionMatch(
$fragment,
ObjectType $type
) {
$typeConditionNode = $fragment->typeCondition;
if ($typeConditionNode === null) {
return true;
}
$conditionalType = TypeInfo::typeFromAST($this->exeContext->schema, $typeConditionNode);
if ($conditionalType === $type) {
return true;
}
if ($conditionalType instanceof AbstractType) {
return $this->exeContext->schema->isPossibleType($conditionalType, $type);
}
return false;
}
/**
* Implements the "Evaluating selection sets" section of the spec
* for "write" mode.
*
* @param mixed[] $sourceValue
* @param mixed[] $path
* @param ArrayObject $fields
*
* @return Promise|stdClass|mixed[]
*/
private function executeFieldsSerially(ObjectType $parentType, $sourceValue, $path, $fields)
{
$result = $this->promiseReduce(
array_keys($fields->getArrayCopy()),
function ($results, $responseName) use ($path, $parentType, $sourceValue, $fields) {
$fieldNodes = $fields[$responseName];
$fieldPath = $path;
$fieldPath[] = $responseName;
$result = $this->resolveField($parentType, $sourceValue, $fieldNodes, $fieldPath);
if ($result === self::$UNDEFINED) {
return $results;
}
$promise = $this->getPromise($result);
if ($promise) {
return $promise->then(static function ($resolvedResult) use ($responseName, $results) {
$results[$responseName] = $resolvedResult;
return $results;
});
}
$results[$responseName] = $result;
return $results;
},
[]
);
if ($this->isPromise($result)) {
return $result->then(static function ($resolvedResults) {
return self::fixResultsIfEmptyArray($resolvedResults);
});
}
return self::fixResultsIfEmptyArray($result);
}
/**
* Resolves the field on the given source object. In particular, this
* figures out the value that the field returns by calling its resolve function,
* then calls completeValue to complete promises, serialize scalars, or execute
* the sub-selection-set for objects.
*
* @param object|null $source
* @param FieldNode[] $fieldNodes
* @param mixed[] $path
*
* @return mixed[]|Exception|mixed|null
*/
private function resolveField(ObjectType $parentType, $source, $fieldNodes, $path)
{
$exeContext = $this->exeContext;
$fieldNode = $fieldNodes[0];
$fieldName = $fieldNode->name->value;
$fieldDef = $this->getFieldDef($exeContext->schema, $parentType, $fieldName);
if (! $fieldDef) {
return self::$UNDEFINED;
}
$returnType = $fieldDef->getType();
// The resolve function's optional third argument is a collection of
// information about the current execution state.
$info = new ResolveInfo(
$fieldName,
$fieldNodes,
$returnType,
$parentType,
$path,
$exeContext->schema,
$exeContext->fragments,
$exeContext->rootValue,
$exeContext->operation,
$exeContext->variableValues
);
if ($fieldDef->resolveFn !== null) {
$resolveFn = $fieldDef->resolveFn;
} elseif ($parentType->resolveFieldFn !== null) {
$resolveFn = $parentType->resolveFieldFn;
} else {
$resolveFn = $this->exeContext->fieldResolver;
}
// The resolve function's optional third argument is a context value that
// is provided to every resolve function within an execution. It is commonly
// used to represent an authenticated user, or request-specific caches.
$context = $exeContext->contextValue;
// Get the resolve function, regardless of if its result is normal
// or abrupt (error).
$result = $this->resolveOrError(
$fieldDef,
$fieldNode,
$resolveFn,
$source,
$context,
$info
);
$result = $this->completeValueCatchingError(
$returnType,
$fieldNodes,
$info,
$path,
$result
);
return $result;
}
/**
* This method looks up the field on the given type definition.
* It has special casing for the two introspection fields, __schema
* and __typename. __typename is special because it can always be
* queried as a field, even in situations where no other fields
* are allowed, like on a Union. __schema could get automatically
* added to the query type, but that would require mutating type
* definitions, which would cause issues.
*
* @param string $fieldName
*
* @return FieldDefinition
*/
private function getFieldDef(Schema $schema, ObjectType $parentType, $fieldName)
{
static $schemaMetaFieldDef, $typeMetaFieldDef, $typeNameMetaFieldDef;
$schemaMetaFieldDef = $schemaMetaFieldDef ?: Introspection::schemaMetaFieldDef();
$typeMetaFieldDef = $typeMetaFieldDef ?: Introspection::typeMetaFieldDef();
$typeNameMetaFieldDef = $typeNameMetaFieldDef ?: Introspection::typeNameMetaFieldDef();
if ($fieldName === $schemaMetaFieldDef->name && $schema->getQueryType() === $parentType) {
return $schemaMetaFieldDef;
}
if ($fieldName === $typeMetaFieldDef->name && $schema->getQueryType() === $parentType) {
return $typeMetaFieldDef;
}
if ($fieldName === $typeNameMetaFieldDef->name) {
return $typeNameMetaFieldDef;
}
$tmp = $parentType->getFields();
return $tmp[$fieldName] ?? null;
}
/**
* Isolates the "ReturnOrAbrupt" behavior to not de-opt the `resolveField`
* function. Returns the result of resolveFn or the abrupt-return Error object.
*
* @param FieldDefinition $fieldDef
* @param FieldNode $fieldNode
* @param callable $resolveFn
* @param mixed $source
* @param mixed $context
* @param ResolveInfo $info
*
* @return Throwable|Promise|mixed
*/
private function resolveOrError($fieldDef, $fieldNode, $resolveFn, $source, $context, $info)
{
try {
// Build hash of arguments from the field.arguments AST, using the
// variables scope to fulfill any variable references.
$args = Values::getArgumentValues(
$fieldDef,
$fieldNode,
$this->exeContext->variableValues
);
return $resolveFn($source, $args, $context, $info);
} catch (Exception $error) {
return $error;
} catch (Throwable $error) {
return $error;
}
}
/**
* This is a small wrapper around completeValue which detects and logs errors
* in the execution context.
*
* @param FieldNode[] $fieldNodes
* @param string[] $path
* @param mixed $result
*
* @return mixed[]|Promise|null
*/
private function completeValueCatchingError(
Type $returnType,
$fieldNodes,
ResolveInfo $info,
$path,
$result
) {
$exeContext = $this->exeContext;
// If the field type is non-nullable, then it is resolved without any
// protection from errors.
if ($returnType instanceof NonNull) {
return $this->completeValueWithLocatedError(
$returnType,
$fieldNodes,
$info,
$path,
$result
);
}
// Otherwise, error protection is applied, logging the error and resolving
// a null value for this field if one is encountered.
try {
$completed = $this->completeValueWithLocatedError(
$returnType,
$fieldNodes,
$info,
$path,
$result
);
$promise = $this->getPromise($completed);
if ($promise) {
return $promise->then(
null,
function ($error) use ($exeContext) {
$exeContext->addError($error);
return $this->exeContext->promises->createFulfilled(null);
}
);
}
return $completed;
} catch (Error $err) {
// If `completeValueWithLocatedError` returned abruptly (threw an error), log the error
// and return null.
$exeContext->addError($err);
return null;
}
}
/**
* This is a small wrapper around completeValue which annotates errors with
* location information.
*
* @param FieldNode[] $fieldNodes
* @param string[] $path
* @param mixed $result
*
* @return mixed[]|mixed|Promise|null
*
* @throws Error
*/
public function completeValueWithLocatedError(
Type $returnType,
$fieldNodes,
ResolveInfo $info,
$path,
$result
) {
try {
$completed = $this->completeValue(
$returnType,
$fieldNodes,
$info,
$path,
$result
);
$promise = $this->getPromise($completed);
if ($promise) {
return $promise->then(
null,
function ($error) use ($fieldNodes, $path) {
return $this->exeContext->promises->createRejected(Error::createLocatedError(
$error,
$fieldNodes,
$path
));
}
);
}
return $completed;
} catch (Exception $error) {
throw Error::createLocatedError($error, $fieldNodes, $path);
} catch (Throwable $error) {
throw Error::createLocatedError($error, $fieldNodes, $path);
}
}
/**
* Implements the instructions for completeValue as defined in the
* "Field entries" section of the spec.
*
* If the field type is Non-Null, then this recursively completes the value
* for the inner type. It throws a field error if that completion returns null,
* as per the "Nullability" section of the spec.
*
* If the field type is a List, then this recursively completes the value
* for the inner type on each item in the list.
*
* If the field type is a Scalar or Enum, ensures the completed value is a legal
* value of the type by calling the `serialize` method of GraphQL type
* definition.
*
* If the field is an abstract type, determine the runtime type of the value
* and then complete based on that type
*
* Otherwise, the field type expects a sub-selection set, and will complete the
* value by evaluating all sub-selections.
*
* @param FieldNode[] $fieldNodes
* @param string[] $path
* @param mixed $result
*
* @return mixed[]|mixed|Promise|null
*
* @throws Error
* @throws Throwable
*/
private function completeValue(
Type $returnType,
$fieldNodes,
ResolveInfo $info,
$path,
&$result
) {
$promise = $this->getPromise($result);
// If result is a Promise, apply-lift over completeValue.
if ($promise) {
return $promise->then(function (&$resolved) use ($returnType, $fieldNodes, $info, $path) {
return $this->completeValue($returnType, $fieldNodes, $info, $path, $resolved);
});
}
if ($result instanceof Exception || $result instanceof Throwable) {
throw $result;
}
// If field type is NonNull, complete for inner type, and throw field error
// if result is null.
if ($returnType instanceof NonNull) {
$completed = $this->completeValue(
$returnType->getWrappedType(),
$fieldNodes,
$info,
$path,
$result
);
if ($completed === null) {
throw new InvariantViolation(
'Cannot return null for non-nullable field ' . $info->parentType . '.' . $info->fieldName . '.'
);
}
return $completed;
}
// If result is null-like, return null.
if ($result === null) {
return null;
}
// If field type is List, complete each item in the list with the inner type
if ($returnType instanceof ListOfType) {
return $this->completeListValue($returnType, $fieldNodes, $info, $path, $result);
}
// Account for invalid schema definition when typeLoader returns different
// instance than `resolveType` or $field->getType() or $arg->getType()
if ($returnType !== $this->exeContext->schema->getType($returnType->name)) {
$hint = '';
if ($this->exeContext->schema->getConfig()->typeLoader) {
$hint = sprintf(
'Make sure that type loader returns the same instance as defined in %s.%s',
$info->parentType,
$info->fieldName
);
}
throw new InvariantViolation(
sprintf(
'Schema must contain unique named types but contains multiple types named "%s". %s ' .
'(see http://webonyx.github.io/graphql-php/type-system/#type-registry).',
$returnType,
$hint
)
);
}
// If field type is Scalar or Enum, serialize to a valid value, returning
// null if serialization is not possible.
if ($returnType instanceof LeafType) {
return $this->completeLeafValue($returnType, $result);
}
if ($returnType instanceof AbstractType) {
return $this->completeAbstractValue($returnType, $fieldNodes, $info, $path, $result);
}
// Field type must be Object, Interface or Union and expect sub-selections.
if ($returnType instanceof ObjectType) {
return $this->completeObjectValue($returnType, $fieldNodes, $info, $path, $result);
}
throw new RuntimeException(sprintf('Cannot complete value of unexpected type "%s".', $returnType));
}
/**
* @param mixed $value
*
* @return bool
*/
private function isPromise($value)
{
return $value instanceof Promise || $this->exeContext->promises->isThenable($value);
}
/**
* Only returns the value if it acts like a Promise, i.e. has a "then" function,
* otherwise returns null.
*
* @param mixed $value
*
* @return Promise|null
*/
private function getPromise($value)
{
if ($value === null || $value instanceof Promise) {
return $value;
}
if ($this->exeContext->promises->isThenable($value)) {
$promise = $this->exeContext->promises->convertThenable($value);
if (! $promise instanceof Promise) {
throw new InvariantViolation(sprintf(
'%s::convertThenable is expected to return instance of GraphQL\Executor\Promise\Promise, got: %s',
get_class($this->exeContext->promises),
Utils::printSafe($promise)
));
}
return $promise;
}
return null;
}
/**
* Similar to array_reduce(), however the reducing callback may return
* a Promise, in which case reduction will continue after each promise resolves.
*
* If the callback does not return a Promise, then this function will also not
* return a Promise.
*
* @param mixed[] $values
* @param Promise|mixed|null $initialValue
*
* @return mixed[]
*/
private function promiseReduce(array $values, callable $callback, $initialValue)
{
return array_reduce(
$values,
function ($previous, $value) use ($callback) {
$promise = $this->getPromise($previous);
if ($promise) {
return $promise->then(static function ($resolved) use ($callback, $value) {
return $callback($resolved, $value);
});
}
return $callback($previous, $value);
},
$initialValue
);
}
/**
* Complete a list value by completing each item in the list with the
* inner type
*
* @param FieldNode[] $fieldNodes
* @param mixed[] $path
* @param mixed $result
*
* @return mixed[]|Promise
*
* @throws Exception
*/
private function completeListValue(ListOfType $returnType, $fieldNodes, ResolveInfo $info, $path, &$result)
{
$itemType = $returnType->getWrappedType();
Utils::invariant(
is_array($result) || $result instanceof Traversable,
'User Error: expected iterable, but did not find one for field ' . $info->parentType . '.' . $info->fieldName . '.'
);
$containsPromise = false;
$i = 0;
$completedItems = [];
foreach ($result as $item) {
$fieldPath = $path;
$fieldPath[] = $i++;
$completedItem = $this->completeValueCatchingError($itemType, $fieldNodes, $info, $fieldPath, $item);
if (! $containsPromise && $this->getPromise($completedItem)) {
$containsPromise = true;
}
$completedItems[] = $completedItem;
}
return $containsPromise ? $this->exeContext->promises->all($completedItems) : $completedItems;
}
/**
* Complete a Scalar or Enum by serializing to a valid value, throwing if serialization is not possible.
*
* @param mixed $result
*
* @return mixed
*
* @throws Exception
*/
private function completeLeafValue(LeafType $returnType, &$result)
{
try {
return $returnType->serialize($result);
} catch (Exception $error) {
throw new InvariantViolation(
'Expected a value of type "' . Utils::printSafe($returnType) . '" but received: ' . Utils::printSafe($result),
0,
$error
);
} catch (Throwable $error) {
throw new InvariantViolation(
'Expected a value of type "' . Utils::printSafe($returnType) . '" but received: ' . Utils::printSafe($result),
0,
$error
);
}
}
/**
* Complete a value of an abstract type by determining the runtime object type
* of that value, then complete the value for that type.
*
* @param FieldNode[] $fieldNodes
* @param mixed[] $path
* @param mixed[] $result
*
* @return mixed
*
* @throws Error
*/
private function completeAbstractValue(AbstractType $returnType, $fieldNodes, ResolveInfo $info, $path, &$result)
{
$exeContext = $this->exeContext;
$runtimeType = $returnType->resolveType($result, $exeContext->contextValue, $info);
if ($runtimeType === null) {
$runtimeType = self::defaultTypeResolver($result, $exeContext->contextValue, $info, $returnType);
}
$promise = $this->getPromise($runtimeType);
if ($promise) {
return $promise->then(function ($resolvedRuntimeType) use (
$returnType,
$fieldNodes,
$info,
$path,
&$result
) {
return $this->completeObjectValue(
$this->ensureValidRuntimeType(
$resolvedRuntimeType,
$returnType,
$info,
$result
),
$fieldNodes,
$info,
$path,
$result
);
});
}
return $this->completeObjectValue(
$this->ensureValidRuntimeType(
$runtimeType,
$returnType,
$info,
$result
),
$fieldNodes,
$info,
$path,
$result
);
}
/**
* If a resolveType function is not given, then a default resolve behavior is
* used which attempts two strategies:
*
* First, See if the provided value has a `__typename` field defined, if so, use
* that value as name of the resolved type.
*
* Otherwise, test each possible type for the abstract type by calling
* isTypeOf for the object being coerced, returning the first type that matches.
*
* @param mixed|null $value
* @param mixed|null $context
*
* @return ObjectType|Promise|null
*/
private function defaultTypeResolver($value, $context, ResolveInfo $info, AbstractType $abstractType)
{
// First, look for `__typename`.
if ($value !== null &&
(is_array($value) || $value instanceof ArrayAccess) &&
isset($value['__typename']) &&
is_string($value['__typename'])
) {
return $value['__typename'];
}
if ($abstractType instanceof InterfaceType && $info->schema->getConfig()->typeLoader) {
Warning::warnOnce(
sprintf(
'GraphQL Interface Type `%s` returned `null` from its `resolveType` function ' .
'for value: %s. Switching to slow resolution method using `isTypeOf` ' .
'of all possible implementations. It requires full schema scan and degrades query performance significantly. ' .
' Make sure your `resolveType` always returns valid implementation or throws.',
$abstractType->name,
Utils::printSafe($value)
),
Warning::WARNING_FULL_SCHEMA_SCAN
);
}
// Otherwise, test each possible type.
$possibleTypes = $info->schema->getPossibleTypes($abstractType);
$promisedIsTypeOfResults = [];
foreach ($possibleTypes as $index => $type) {
$isTypeOfResult = $type->isTypeOf($value, $context, $info);
if ($isTypeOfResult === null) {
continue;
}
$promise = $this->getPromise($isTypeOfResult);
if ($promise) {
$promisedIsTypeOfResults[$index] = $promise;
} elseif ($isTypeOfResult) {
return $type;
}
}
if (! empty($promisedIsTypeOfResults)) {
return $this->exeContext->promises->all($promisedIsTypeOfResults)
->then(static function ($isTypeOfResults) use ($possibleTypes) {
foreach ($isTypeOfResults as $index => $result) {
if ($result) {
return $possibleTypes[$index];
}
}
return null;
});
}
return null;
}
/**
* Complete an Object value by executing all sub-selections.
*
* @param FieldNode[] $fieldNodes
* @param mixed[] $path
* @param mixed $result
*
* @return mixed[]|Promise|stdClass
*
* @throws Error
*/
private function completeObjectValue(ObjectType $returnType, $fieldNodes, ResolveInfo $info, $path, &$result)
{
// If there is an isTypeOf predicate function, call it with the
// current result. If isTypeOf returns false, then raise an error rather
// than continuing execution.
$isTypeOf = $returnType->isTypeOf($result, $this->exeContext->contextValue, $info);
if ($isTypeOf !== null) {
$promise = $this->getPromise($isTypeOf);
if ($promise) {
return $promise->then(function ($isTypeOfResult) use (
$returnType,
$fieldNodes,
$path,
&$result
) {
if (! $isTypeOfResult) {
throw $this->invalidReturnTypeError($returnType, $result, $fieldNodes);
}
return $this->collectAndExecuteSubfields(
$returnType,
$fieldNodes,
$path,
$result
);
});
}
if (! $isTypeOf) {
throw $this->invalidReturnTypeError($returnType, $result, $fieldNodes);
}
}
return $this->collectAndExecuteSubfields(
$returnType,
$fieldNodes,
$path,
$result
);
}
/**
* @param mixed[] $result
* @param FieldNode[] $fieldNodes
*
* @return Error
*/
private function invalidReturnTypeError(
ObjectType $returnType,
$result,
$fieldNodes
) {
return new Error(
'Expected value of type "' . $returnType->name . '" but got: ' . Utils::printSafe($result) . '.',
$fieldNodes
);
}
/**
* @param FieldNode[] $fieldNodes
* @param mixed[] $path
* @param mixed[] $result
*
* @return mixed[]|Promise|stdClass
*
* @throws Error
*/
private function collectAndExecuteSubfields(
ObjectType $returnType,
$fieldNodes,
$path,
&$result
) {
$subFieldNodes = $this->collectSubFields($returnType, $fieldNodes);
return $this->executeFields($returnType, $result, $path, $subFieldNodes);
}
private function collectSubFields(ObjectType $returnType, $fieldNodes) : ArrayObject
{
if (! isset($this->subFieldCache[$returnType])) {
$this->subFieldCache[$returnType] = new SplObjectStorage();
}
if (! isset($this->subFieldCache[$returnType][$fieldNodes])) {
// Collect sub-fields to execute to complete this value.
$subFieldNodes = new ArrayObject();
$visitedFragmentNames = new ArrayObject();
foreach ($fieldNodes as $fieldNode) {
if (! isset($fieldNode->selectionSet)) {
continue;
}
$subFieldNodes = $this->collectFields(
$returnType,
$fieldNode->selectionSet,
$subFieldNodes,
$visitedFragmentNames
);
}
$this->subFieldCache[$returnType][$fieldNodes] = $subFieldNodes;
}
return $this->subFieldCache[$returnType][$fieldNodes];
}
/**
* Implements the "Evaluating selection sets" section of the spec
* for "read" mode.
*
* @param mixed|null $source
* @param mixed[] $path
* @param ArrayObject $fields
*
* @return Promise|stdClass|mixed[]
*/
private function executeFields(ObjectType $parentType, $source, $path, $fields)
{
$containsPromise = false;
$finalResults = [];
foreach ($fields as $responseName => $fieldNodes) {
$fieldPath = $path;
$fieldPath[] = $responseName;
$result = $this->resolveField($parentType, $source, $fieldNodes, $fieldPath);
if ($result === self::$UNDEFINED) {
continue;
}
if (! $containsPromise && $this->getPromise($result)) {
$containsPromise = true;
}
$finalResults[$responseName] = $result;
}
// If there are no promises, we can just return the object
if (! $containsPromise) {
return self::fixResultsIfEmptyArray($finalResults);
}
// Otherwise, results is a map from field name to the result
// of resolving that field, which is possibly a promise. Return
// a promise that will return this same map, but with any
// promises replaced with the values they resolved to.
return $this->promiseForAssocArray($finalResults);
}
/**
* @see https://github.com/webonyx/graphql-php/issues/59
*
* @param mixed[] $results
*
* @return stdClass|mixed[]
*/
private static function fixResultsIfEmptyArray($results)
{
if ($results === []) {
return new stdClass();
}
return $results;
}
/**
* This function transforms a PHP `array<string, Promise|scalar|array>` into
* a `Promise<array<key,scalar|array>>`
*
* In other words it returns a promise which resolves to normal PHP associative array which doesn't contain
* any promises.
*
* @param (string|Promise)[] $assoc
*
* @return mixed
*/
private function promiseForAssocArray(array $assoc)
{
$keys = array_keys($assoc);
$valuesAndPromises = array_values($assoc);
$promise = $this->exeContext->promises->all($valuesAndPromises);
return $promise->then(static function ($values) use ($keys) {
$resolvedResults = [];
foreach ($values as $i => $value) {
$resolvedResults[$keys[$i]] = $value;
}
return self::fixResultsIfEmptyArray($resolvedResults);
});
}
/**
* @param string|ObjectType|null $runtimeTypeOrName
* @param FieldNode[] $fieldNodes
* @param mixed $result
*
* @return ObjectType
*/
private function ensureValidRuntimeType(
$runtimeTypeOrName,
AbstractType $returnType,
ResolveInfo $info,
&$result
) {
$runtimeType = is_string($runtimeTypeOrName) ?
$this->exeContext->schema->getType($runtimeTypeOrName) :
$runtimeTypeOrName;
if (! $runtimeType instanceof ObjectType) {
throw new InvariantViolation(
sprintf(
'Abstract type %s must resolve to an Object type at ' .
'runtime for field %s.%s with value "%s", received "%s". ' .
'Either the %s type should provide a "resolveType" ' .
'function or each possible type should provide an "isTypeOf" function.',
$returnType,
$info->parentType,
$info->fieldName,
Utils::printSafe($result),
Utils::printSafe($runtimeType),
$returnType
)
);
}
if (! $this->exeContext->schema->isPossibleType($returnType, $runtimeType)) {
throw new InvariantViolation(
sprintf('Runtime Object type "%s" is not a possible type for "%s".', $runtimeType, $returnType)
);
}
if ($runtimeType !== $this->exeContext->schema->getType($runtimeType->name)) {
throw new InvariantViolation(
sprintf(
'Schema must contain unique named types but contains multiple types named "%s". ' .
'Make sure that `resolveType` function of abstract type "%s" returns the same ' .
'type instance as referenced anywhere else within the schema ' .
'(see http://webonyx.github.io/graphql-php/type-system/#type-registry).',
$runtimeType,
$returnType
)
);
}
return $runtimeType;
}
}