` where each * FieldSpec is an associative array with these keys: * * - `type` (string, required): one of `string`, `int`, `bool`, `array`, * `object`, `string|null`, `int|null`, `bool|null`, `array|null`, * `object|null`, `mixed`. `object` matches a non-empty associative * array (PHP has no first-class object distinct from assoc-array on * the wire). `mixed` is an escape hatch; use sparingly. * - `required` (bool, default true): whether the key MUST exist on the * payload. Required + null-allowed means the key is present but the * value may be null. * - `item_type` (string, optional): when `type` is `array`, every * element must match this primitive type. Default: no item check. * - `key_type` (string, optional): when `type` is `object`, every key * must match this type (typically `string`). Default: `string`. * - `value_type` (string, optional): when `type` is `object`, every * value must match this primitive type. Default: no value check. * - `enum` (array, optional): when present, the value must be * strictly equal to one of the listed scalars. Stricter than `type` * alone. * - `description` (string, optional): human-readable note. Ignored at * runtime; used by docs / future codegen. * * Unknown fields on the payload are reported as `unexpected_field` * violations. The schema is the closed contract: any new field on the * producer must be added to the schema in the same commit. * * Single entry point. `validate(array $schema, array $payload): * array` returns a list of human-readable violation strings, * empty when the payload conforms. Callers assert `$violations === []` * in tests, with the list embedded in the failure message so the test * report names the exact field(s) that drifted. */ class ABJ_404_Solution_PayloadSchema { /** * Validate a payload against a schema. * * @param array> $schema FieldSpec map. * @param array $payload Wire payload to check. * @param string $path Dotted path prefix used in recursive calls * and for error messages. Empty at the top level. * @return array Violation messages, empty on success. */ public static function validate(array $schema, array $payload, string $path = ''): array { $violations = []; foreach ($schema as $field => $spec) { $fieldPath = $path === '' ? (string)$field : $path . '.' . $field; $required = !isset($spec['required']) || $spec['required'] === true; if (!array_key_exists($field, $payload)) { if ($required) { $violations[] = sprintf('missing required field: %s', $fieldPath); } continue; } $value = $payload[$field]; $type = isset($spec['type']) && is_string($spec['type']) ? $spec['type'] : 'mixed'; $typeViolation = self::checkType($fieldPath, $type, $value); if ($typeViolation !== null) { $violations[] = $typeViolation; continue; } if (isset($spec['enum']) && is_array($spec['enum'])) { if (!in_array($value, $spec['enum'], true)) { $violations[] = sprintf( '%s value %s is not in enum [%s]', $fieldPath, self::renderScalar($value), implode(', ', array_map([self::class, 'renderScalar'], $spec['enum'])) ); continue; } } if (self::baseType($type) === 'array' && is_array($value) && isset($spec['item_type'])) { $itemType = (string)$spec['item_type']; foreach ($value as $i => $item) { $v = self::checkType($fieldPath . '[' . $i . ']', $itemType, $item); if ($v !== null) { $violations[] = $v; } } } if (self::baseType($type) === 'object' && is_array($value)) { $keyType = isset($spec['key_type']) ? (string)$spec['key_type'] : 'string'; $valueType = isset($spec['value_type']) ? (string)$spec['value_type'] : null; foreach ($value as $k => $v) { $kV = self::checkType($fieldPath . '/key', $keyType, $k); if ($kV !== null) { $violations[] = $kV; } if ($valueType !== null) { $vV = self::checkType($fieldPath . '[' . self::renderScalar($k) . ']', $valueType, $v); if ($vV !== null) { $violations[] = $vV; } } } } } foreach ($payload as $key => $_value) { if (!array_key_exists($key, $schema)) { $fieldPath = $path === '' ? (string)$key : $path . '.' . $key; $violations[] = sprintf('unexpected_field: %s (not declared in schema)', $fieldPath); } } return $violations; } /** * Check a single value against a primitive type spec. Returns null * when the value matches, a violation string otherwise. * * @param string $path * @param string $type * @param mixed $value * @return string|null */ private static function checkType(string $path, string $type, $value): ?string { $allowNull = self::typeAllowsNull($type); if ($value === null) { return $allowNull ? null : sprintf('%s is null but type %s disallows null', $path, $type); } $base = self::baseType($type); switch ($base) { case 'string': return is_string($value) ? null : self::typeMismatch($path, 'string', $value); case 'int': return is_int($value) ? null : self::typeMismatch($path, 'int', $value); case 'bool': return is_bool($value) ? null : self::typeMismatch($path, 'bool', $value); case 'array': if (!is_array($value)) { return self::typeMismatch($path, 'array', $value); } if (self::isAssoc($value)) { return sprintf('%s expected array (list), got object (associative)', $path); } return null; case 'object': if (!is_array($value)) { return self::typeMismatch($path, 'object', $value); } if ($value !== [] && !self::isAssoc($value)) { return sprintf('%s expected object (associative), got list', $path); } return null; case 'mixed': return null; default: return sprintf('%s schema type %s is unknown to the validator', $path, $type); } } private static function typeAllowsNull(string $type): bool { return substr($type, -5) === '|null' || $type === 'mixed'; } private static function baseType(string $type): string { if (substr($type, -5) === '|null') { return substr($type, 0, -5); } return $type; } /** * @param mixed $value */ private static function typeMismatch(string $path, string $expected, $value): string { return sprintf('%s expected %s, got %s', $path, $expected, self::describeType($value)); } /** * @param mixed $value */ private static function describeType($value): string { if (is_array($value)) { return self::isAssoc($value) ? 'object' : 'array'; } return gettype($value); } /** * Render a scalar for error messages. Falls back to gettype() for * non-scalars so the message stays readable even when the value is * an array or object. * * @param mixed $value */ private static function renderScalar($value): string { if (is_string($value)) { return "'" . $value . "'"; } if (is_int($value) || is_float($value)) { return (string)$value; } if (is_bool($value)) { return $value ? 'true' : 'false'; } if ($value === null) { return 'null'; } return self::describeType($value); } /** * @param array $arr */ private static function isAssoc(array $arr): bool { if ($arr === []) { return false; } // array_is_list() is PHP 8.1+; plugin still supports 7.4. Use the // canonical pre-8.1 idiom: a list has int-keyed sequential keys 0..N-1. return array_keys($arr) !== range(0, count($arr) - 1); } }