/**
* Given a type and a value AST node known to match this type, build a
* runtime value.
*
* @param TypeInterface $type
* @param $ast
* @param null $variables
*
* @return array|mixed|null|string
*/
protected static function coerceValueAST(TypeInterface $type, $ast, $variables = NULL)
{
if ($type instanceof NonNullModifier) {
// Note: we're not checking that the result of coerceValueAST is non-null.
// We're assuming that this query has been validated and the value used
// here is of the correct type.
return self::coerceValueAST($type->getWrappedType(), $ast, $variables);
}
if (!$ast) {
return NULL;
}
if ($ast::KIND === Node::KIND_VARIABLE) {
$variableName = $ast->get('name')->get('value');
if (!isset($variables, $variables[$variableName])) {
return NULL;
}
// Note: we're not doing any checking that this variable is correct. We're
// assuming that this query has been validated and the variable usage here
// is of the correct type.
return $variables[$variableName];
}
if ($type instanceof ListModifier) {
$itemType = $type->getWrappedType();
if ($ast::KIND === Node::KIND_ARRAY_VALUE) {
$tmp = [];
foreach ($ast->get('values') as $itemAST) {
$tmp[] = self::coerceValueAST($itemType, $itemAST, $variables);
}
return $tmp;
} else {
return [self::coerceValueAST($itemType, $ast, $variables)];
}
}
if ($type instanceof InputObjectType) {
$fields = $type->getFields();
if ($ast::KIND !== Node::KIND_OBJECT_VALUE) {
return NULL;
}
$asts = array_reduce($ast->get('fields'), function ($carry, $field) {
$carry[$field->get('name')->get('value')] = $field;
return $carry;
}, []);
$object = [];
foreach ($fields as $name => $item) {
$field = $asts[$name];
$fieldValue = self::coerceValueAST($item->getType(), $field ? $field->get('value') : NULL, $variables);
$object[$name] = $fieldValue === NULL ? $item->getDefaultValue() : $fieldValue;
}
return $object;
}
if ($type instanceof ScalarType || $type instanceof EnumType) {
$coerced = $type->coerceLiteral($ast);
if (isset($coerced)) {
return $coerced;
}
}
return NULL;
}
/**
* 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 `coerce` method of GraphQL type definition.
*
* Otherwise, the field type expects a sub-selection set, and will complete the
* value by evaluating all sub-selections.
*
* @param ExecutionContext $context
* @param TypeInterface $type
* @param $asts
* @param $result
*
* @return array|mixed|null|string
*
* @throws \Exception
*/
protected static function completeField(ExecutionContext $context, TypeInterface $type, $asts, &$result)
{
// If field type is NonNullModifier, complete for inner type, and throw field error
// if result is null.
if ($type instanceof NonNullModifier) {
$completed = self::completeField($context, $type->getWrappedType(), $asts, $result);
if ($completed === NULL) {
throw new \Exception('Cannot return null for non-nullable type.');
}
return $completed;
}
// If result is null-like, return null.
if (!isset($result)) {
return NULL;
}
// If field type is List, complete each item in the list with the inner type
if ($type instanceof ListModifier) {
$itemType = $type->getWrappedType();
if (!(is_array($result) || $result instanceof \ArrayObject)) {
throw new \Exception('User Error: expected iterable, but did not find one.');
}
$tmp = [];
foreach ($result as $item) {
$tmp[] = self::completeField($context, $itemType, $asts, $item);
}
return $tmp;
}
// If field type is Scalar or Enum, coerce to a valid value, returning
// null if coercion is not possible.
if ($type instanceof ScalarType || $type instanceof EnumType) {
if (!method_exists($type, 'coerce')) {
throw new \Exception('Missing coerce method on type.');
}
return $type->coerce($result);
}
// Field type must be Object, Interface or Union and expect
// sub-selections.
$objectType = $type instanceof ObjectType ? $type : ($type instanceof InterfaceType || $type instanceof UnionType ? $type->resolveType($result) : NULL);
if (!$objectType) {
return NULL;
}
// Collect sub-fields to execute to complete this value.
$subFieldASTs = new \ArrayObject();
$visitedFragmentNames = new \ArrayObject();
$count = count($asts);
for ($i = 0; $i < $count; $i++) {
$selectionSet = $asts[$i]->get('selectionSet');
if ($selectionSet) {
$subFieldASTs = self::collectFields($context, $objectType, $selectionSet, $subFieldASTs, $visitedFragmentNames);
}
}
return self::executeFields($context, $objectType, $result, $subFieldASTs);
}