webonyx / graphql-php

src/Utils/AST.php

<?php

declare(strict_types=1);

namespace GraphQL\Utils;

use ArrayAccess;
use Exception;
use GraphQL\Error\Error;
use GraphQL\Error\InvariantViolation;
use GraphQL\Language\AST\BooleanValueNode;
use GraphQL\Language\AST\DocumentNode;
use GraphQL\Language\AST\EnumValueNode;
use GraphQL\Language\AST\FloatValueNode;
use GraphQL\Language\AST\IntValueNode;
use GraphQL\Language\AST\ListTypeNode;
use GraphQL\Language\AST\ListValueNode;
use GraphQL\Language\AST\Location;
use GraphQL\Language\AST\NamedTypeNode;
use GraphQL\Language\AST\NameNode;
use GraphQL\Language\AST\Node;
use GraphQL\Language\AST\NodeKind;
use GraphQL\Language\AST\NodeList;
use GraphQL\Language\AST\NonNullTypeNode;
use GraphQL\Language\AST\NullValueNode;
use GraphQL\Language\AST\ObjectFieldNode;
use GraphQL\Language\AST\ObjectValueNode;
use GraphQL\Language\AST\OperationDefinitionNode;
use GraphQL\Language\AST\StringValueNode;
use GraphQL\Language\AST\ValueNode;
use GraphQL\Language\AST\VariableNode;
use GraphQL\Type\Definition\EnumType;
use GraphQL\Type\Definition\IDType;
use GraphQL\Type\Definition\InputObjectType;
use GraphQL\Type\Definition\InputType;
use GraphQL\Type\Definition\ListOfType;
use GraphQL\Type\Definition\NonNull;
use GraphQL\Type\Definition\ScalarType;
use GraphQL\Type\Definition\Type;
use GraphQL\Type\Schema;
use stdClass;
use Throwable;
use Traversable;
use function array_combine;
use function array_key_exists;
use function array_map;
use function count;
use function floatval;
use function intval;
use function is_array;
use function is_bool;
use function is_float;
use function is_int;
use function is_object;
use function is_string;
use function iterator_to_array;
use function property_exists;

/**
 * Various utilities dealing with AST
 */
class AST
{
    /**
     * Convert representation of AST as an associative array to instance of GraphQL\Language\AST\Node.
     *
     * For example:
     *
     * ```php
     * AST::fromArray([
     *     'kind' => 'ListValue',
     *     'values' => [
     *         ['kind' => 'StringValue', 'value' => 'my str'],
     *         ['kind' => 'StringValue', 'value' => 'my other str']
     *     ],
     *     'loc' => ['start' => 21, 'end' => 25]
     * ]);
     * ```
     *
     * Will produce instance of `ListValueNode` where `values` prop is a lazily-evaluated `NodeList`
     * returning instances of `StringValueNode` on access.
     *
     * This is a reverse operation for AST::toArray($node)
     *
     * @param mixed[] $node
     *
     * @api
     */
    public static function fromArray(array $node) : Node
    {
        if (! isset($node['kind']) || ! isset(NodeKind::$classMap[$node['kind']])) {
            throw new InvariantViolation('Unexpected node structure: ' . Utils::printSafeJson($node));
        }

        $kind     = $node['kind'] ?? null;
        $class    = NodeKind::$classMap[$kind];
        $instance = new $class([]);

        if (isset($node['loc'], $node['loc']['start'], $node['loc']['end'])) {
            $instance->loc = Location::create($node['loc']['start'], $node['loc']['end']);
        }

        foreach ($node as $key => $value) {
            if ($key === 'loc' || $key === 'kind') {
                continue;
            }
            if (is_array($value)) {
                if (isset($value[0]) || empty($value)) {
                    $value = new NodeList($value);
                } else {
                    $value = self::fromArray($value);
                }
            }
            $instance->{$key} = $value;
        }

        return $instance;
    }

    /**
     * Convert AST node to serializable array
     *
     * @return mixed[]
     *
     * @api
     */
    public static function toArray(Node $node)
    {
        return $node->toArray(true);
    }

    /**
     * Produces a GraphQL Value AST given a PHP value.
     *
     * Optionally, a GraphQL type may be provided, which will be used to
     * disambiguate between value primitives.
     *
     * | PHP Value     | GraphQL Value        |
     * | ------------- | -------------------- |
     * | Object        | Input Object         |
     * | Assoc Array   | Input Object         |
     * | Array         | List                 |
     * | Boolean       | Boolean              |
     * | String        | String / Enum Value  |
     * | Int           | Int                  |
     * | Float         | Int / Float          |
     * | Mixed         | Enum Value           |
     * | null          | NullValue            |
     *
     * @param Type|mixed|null $value
     *
     * @return ObjectValueNode|ListValueNode|BooleanValueNode|IntValueNode|FloatValueNode|EnumValueNode|StringValueNode|NullValueNode
     *
     * @api
     */
    public static function astFromValue($value, InputType $type)
    {
        if ($type instanceof NonNull) {
            $astValue = self::astFromValue($value, $type->getWrappedType());
            if ($astValue instanceof NullValueNode) {
                return null;
            }

            return $astValue;
        }

        if ($value === null) {
            return new NullValueNode([]);
        }

        // Convert PHP array to GraphQL list. If the GraphQLType is a list, but
        // the value is not an array, convert the value using the list's item type.
        if ($type instanceof ListOfType) {
            $itemType = $type->getWrappedType();
            if (is_array($value) || ($value instanceof Traversable)) {
                $valuesNodes = [];
                foreach ($value as $item) {
                    $itemNode = self::astFromValue($item, $itemType);
                    if (! $itemNode) {
                        continue;
                    }

                    $valuesNodes[] = $itemNode;
                }

                return new ListValueNode(['values' => new NodeList($valuesNodes)]);
            }

            return self::astFromValue($value, $itemType);
        }

        // Populate the fields of the input object by creating ASTs from each value
        // in the PHP object according to the fields in the input type.
        if ($type instanceof InputObjectType) {
            $isArray     = is_array($value);
            $isArrayLike = $isArray || $value instanceof ArrayAccess;
            if ($value === null || (! $isArrayLike && ! is_object($value))) {
                return null;
            }
            $fields     = $type->getFields();
            $fieldNodes = [];
            foreach ($fields as $fieldName => $field) {
                if ($isArrayLike) {
                    $fieldValue = $value[$fieldName] ?? null;
                } else {
                    $fieldValue = $value->{$fieldName} ?? null;
                }

                // Have to check additionally if key exists, since we differentiate between
                // "no key" and "value is null":
                if ($fieldValue !== null) {
                    $fieldExists = true;
                } elseif ($isArray) {
                    $fieldExists = array_key_exists($fieldName, $value);
                } elseif ($isArrayLike) {
                    $fieldExists = $value->offsetExists($fieldName);

The method offsetExists() does not exist on GraphQL\Type\Definition\Type.

                } else {
                    $fieldExists = property_exists($value, $fieldName);
                }

                if (! $fieldExists) {
                    continue;
                }

                $fieldNode = self::astFromValue($fieldValue, $field->getType());

                if (! $fieldNode) {
                    continue;
                }

                $fieldNodes[] = new ObjectFieldNode([
                    'name'  => new NameNode(['value' => $fieldName]),
                    'value' => $fieldNode,
                ]);
            }

            return new ObjectValueNode(['fields' => new NodeList($fieldNodes)]);
        }

        if ($type instanceof ScalarType || $type instanceof EnumType) {
            // Since value is an internally represented value, it must be serialized
            // to an externally represented value before converting into an AST.
            try {
                $serialized = $type->serialize($value);
            } catch (Throwable $error) {
                if ($error instanceof Error && $type instanceof EnumType) {
                    return null;
                }
                throw $error;
            }

            // Others serialize based on their corresponding PHP scalar types.
            if (is_bool($serialized)) {
                return new BooleanValueNode(['value' => $serialized]);
            }
            if (is_int($serialized)) {
                return new IntValueNode(['value' => $serialized]);
            }
            if (is_float($serialized)) {
                // int cast with == used for performance reasons
                // phpcs:ignore
                if ((int) $serialized == $serialized) {
                    return new IntValueNode(['value' => $serialized]);
                }

                return new FloatValueNode(['value' => $serialized]);
            }
            if (is_string($serialized)) {
                // Enum types use Enum literals.
                if ($type instanceof EnumType) {
                    return new EnumValueNode(['value' => $serialized]);
                }

                // ID types can use Int literals.
                $asInt = (int) $serialized;
                if ($type instanceof IDType && (string) $asInt === $serialized) {
                    return new IntValueNode(['value' => $serialized]);
                }

                // Use json_encode, which uses the same string encoding as GraphQL,
                // then remove the quotes.
                return new StringValueNode(['value' => $serialized]);
            }

            throw new InvariantViolation('Cannot convert value to AST: ' . Utils::printSafe($serialized));
        }

        throw new Error('Unknown type: ' . Utils::printSafe($type) . '.');
    }

    /**
     * Produces a PHP value given a GraphQL Value AST.
     *
     * A GraphQL type must be provided, which will be used to interpret different
     * GraphQL Value literals.
     *
     * Returns `null` when the value could not be validly coerced according to
     * the provided type.
     *
     * | GraphQL Value        | PHP Value     |
     * | -------------------- | ------------- |
     * | Input Object         | Assoc Array   |
     * | List                 | Array         |
     * | Boolean              | Boolean       |
     * | String               | String        |
     * | Int / Float          | Int / Float   |
     * | Enum Value           | Mixed         |
     * | Null Value           | null          |
     *
     * @param VariableNode|NullValueNode|IntValueNode|FloatValueNode|StringValueNode|BooleanValueNode|EnumValueNode|ListValueNode|ObjectValueNode|null $valueNode
     * @param mixed[]|null                                                                                                                             $variables
     *
     * @return mixed[]|stdClass|null
     *
     * @throws Exception
     *
     * @api
     */
    public static function valueFromAST(?ValueNode $valueNode, Type $type, ?array $variables = null)
    {
        $undefined = Utils::undefined();

        if ($valueNode === null) {
            // When there is no AST, then there is also no value.
            // Importantly, this is different from returning the GraphQL null value.
            return $undefined;
        }

        if ($type instanceof NonNull) {
            if ($valueNode instanceof NullValueNode) {
                // Invalid: intentionally return no value.
                return $undefined;
            }

            return self::valueFromAST($valueNode, $type->getWrappedType(), $variables);
        }

        if ($valueNode instanceof NullValueNode) {
            // This is explicitly returning the value null.
            return null;
        }

        if ($valueNode instanceof VariableNode) {
            $variableName = $valueNode->name->value;

            if (! $variables || ! array_key_exists($variableName, $variables)) {
                // No valid return value.
                return $undefined;
            }

            $variableValue = $variables[$variableName] ?? null;
            if ($variableValue === null && $type instanceof NonNull) {
                return $undefined; // Invalid: intentionally return no value.
            }

            // Note: This does no further checking that this variable is correct.
            // This assumes that this query has been validated and the variable
            // usage here is of the correct type.
            return $variables[$variableName];
        }

        if ($type instanceof ListOfType) {
            $itemType = $type->getWrappedType();

            if ($valueNode instanceof ListValueNode) {
                $coercedValues = [];
                $itemNodes     = $valueNode->values;
                foreach ($itemNodes as $itemNode) {
                    if (self::isMissingVariable($itemNode, $variables)) {
                        // If an array contains a missing variable, it is either coerced to
                        // null or if the item type is non-null, it considered invalid.
                        if ($itemType instanceof NonNull) {
                            // Invalid: intentionally return no value.
                            return $undefined;
                        }
                        $coercedValues[] = null;
                    } else {
                        $itemValue = self::valueFromAST($itemNode, $itemType, $variables);
                        if ($undefined === $itemValue) {
                            // Invalid: intentionally return no value.
                            return $undefined;
                        }
                        $coercedValues[] = $itemValue;
                    }
                }

                return $coercedValues;
            }
            $coercedValue = self::valueFromAST($valueNode, $itemType, $variables);
            if ($undefined === $coercedValue) {
                // Invalid: intentionally return no value.
                return $undefined;
            }

            return [$coercedValue];
        }

        if ($type instanceof InputObjectType) {
            if (! $valueNode instanceof ObjectValueNode) {
                // Invalid: intentionally return no value.
                return $undefined;
            }

            $coercedObj = [];
            $fields     = $type->getFields();
            $fieldNodes = Utils::keyMap(
                $valueNode->fields,
                static function ($field) {
                    return $field->name->value;
                }
            );
            foreach ($fields as $field) {
                $fieldName = $field->name;
                /** @var VariableNode|NullValueNode|IntValueNode|FloatValueNode|StringValueNode|BooleanValueNode|EnumValueNode|ListValueNode|ObjectValueNode $fieldNode */
                $fieldNode = $fieldNodes[$fieldName] ?? null;

                if ($fieldNode === null || self::isMissingVariable($fieldNode->value, $variables)) {

The property value does not seem to exist on GraphQL\Language\AST\ObjectValueNode.

The property value does not exist on GraphQL\Language\AST\ListValueNode. Did you mean values?

The property value does not seem to exist on GraphQL\Language\AST\NullValueNode.

The property value does not seem to exist on GraphQL\Language\AST\VariableNode.

                    if ($field->defaultValueExists()) {
                        $coercedObj[$fieldName] = $field->defaultValue;
                    } elseif ($field->getType() instanceof NonNull) {
                        // Invalid: intentionally return no value.
                        return $undefined;
                    }
                    continue;
                }

                $fieldValue = self::valueFromAST(
                    $fieldNode !== null ? $fieldNode->value : null,
                    $field->getType(),
                    $variables
                );

                if ($undefined === $fieldValue) {
                    // Invalid: intentionally return no value.
                    return $undefined;
                }
                $coercedObj[$fieldName] = $fieldValue;
            }

            return $coercedObj;
        }

        if ($type instanceof EnumType) {
            if (! $valueNode instanceof EnumValueNode) {
                return $undefined;
            }
            $enumValue = $type->getValue($valueNode->value);
            if (! $enumValue) {
                return $undefined;
            }

            return $enumValue->value;
        }

        if ($type instanceof ScalarType) {
            // Scalars fulfill parsing a literal value via parseLiteral().
            // Invalid values represent a failure to parse correctly, in which case
            // no value is returned.
            try {
                return $type->parseLiteral($valueNode, $variables);
            } catch (Throwable $error) {
                return $undefined;
            }
        }

        throw new Error('Unknown type: ' . Utils::printSafe($type) . '.');
    }

    /**
     * Returns true if the provided valueNode is a variable which is not defined
     * in the set of variables.
     *
     * @param VariableNode|NullValueNode|IntValueNode|FloatValueNode|StringValueNode|BooleanValueNode|EnumValueNode|ListValueNode|ObjectValueNode $valueNode
     * @param mixed[]                                                                                                                             $variables
     *
     * @return bool
     */
    private static function isMissingVariable(ValueNode $valueNode, $variables)
    {
        return $valueNode instanceof VariableNode &&
            (count($variables) === 0 || ! array_key_exists($valueNode->name->value, $variables));
    }

    /**
     * Produces a PHP value given a GraphQL Value AST.
     *
     * Unlike `valueFromAST()`, no type is provided. The resulting PHP value
     * will reflect the provided GraphQL value AST.
     *
     * | GraphQL Value        | PHP Value     |
     * | -------------------- | ------------- |
     * | Input Object         | Assoc Array   |
     * | List                 | Array         |
     * | Boolean              | Boolean       |
     * | String               | String        |
     * | Int / Float          | Int / Float   |
     * | Enum                 | Mixed         |
     * | Null                 | null          |
     *
     * @param Node         $valueNode
     * @param mixed[]|null $variables
     *
     * @return mixed
     *
     * @throws Exception
     *
     * @api
     */
    public static function valueFromASTUntyped($valueNode, ?array $variables = null)
    {
        switch (true) {
            case $valueNode instanceof NullValueNode:
                return null;
            case $valueNode instanceof IntValueNode:
                return intval($valueNode->value, 10);
            case $valueNode instanceof FloatValueNode:
                return floatval($valueNode->value);
            case $valueNode instanceof StringValueNode:
            case $valueNode instanceof EnumValueNode:
            case $valueNode instanceof BooleanValueNode:
                return $valueNode->value;
            case $valueNode instanceof ListValueNode:
                return array_map(
                    static function ($node) use ($variables) {
                        return self::valueFromASTUntyped($node, $variables);
                    },
                    iterator_to_array($valueNode->values)
                );
            case $valueNode instanceof ObjectValueNode:
                return array_combine(
                    array_map(
                        static function ($field) {
                            return $field->name->value;
                        },
                        iterator_to_array($valueNode->fields)
                    ),
                    array_map(
                        static function ($field) use ($variables) {
                            return self::valueFromASTUntyped($field->value, $variables);
                        },
                        iterator_to_array($valueNode->fields)
                    )
                );
            case $valueNode instanceof VariableNode:
                $variableName = $valueNode->name->value;

                return $variables && isset($variables[$variableName])
                    ? $variables[$variableName]
                    : null;
        }

        throw new Error('Unexpected value kind: ' . $valueNode->kind . '.');
    }

    /**
     * Returns type definition for given AST Type node
     *
     * @param NamedTypeNode|ListTypeNode|NonNullTypeNode $inputTypeNode
     *
     * @return Type|null
     *
     * @throws Exception
     *
     * @api
     */
    public static function typeFromAST(Schema $schema, $inputTypeNode)
    {
        if ($inputTypeNode instanceof ListTypeNode) {
            $innerType = self::typeFromAST($schema, $inputTypeNode->type);

            return $innerType ? new ListOfType($innerType) : null;
        }
        if ($inputTypeNode instanceof NonNullTypeNode) {
            $innerType = self::typeFromAST($schema, $inputTypeNode->type);

            return $innerType ? new NonNull($innerType) : null;
        }
        if ($inputTypeNode instanceof NamedTypeNode) {
            return $schema->getType($inputTypeNode->name->value);
        }

        throw new Error('Unexpected type kind: ' . $inputTypeNode->kind . '.');
    }

    /**
     * Returns operation type ("query", "mutation" or "subscription") given a document and operation name
     *
     * @param string $operationName
     *
     * @return bool
     *
     * @api
     */
    public static function getOperation(DocumentNode $document, $operationName = null)
    {
        if ($document->definitions) {
            foreach ($document->definitions as $def) {
                if (! ($def instanceof OperationDefinitionNode)) {
                    continue;
                }

                if (! $operationName || (isset($def->name->value) && $def->name->value === $operationName)) {
                    return $def->operation;
                }
            }
        }

        return false;
    }
}