| 1 |
<?php |
| 2 |
|
| 3 |
/** |
| 4 |
* The tools a connection is offered, and the calls they make. |
| 5 |
*/ |
| 6 |
|
| 7 |
namespace Extendify\Mcp; |
| 8 |
|
| 9 |
defined('ABSPATH') || die('No direct access.'); |
| 10 |
|
| 11 |
/** |
| 12 |
* The model supplies arguments and never a path. Abilities a plugin registers |
| 13 |
* after we ship are reachable without a plugin release. |
| 14 |
*/ |
| 15 |
class Surface |
| 16 |
{ |
| 17 |
// phpcs:disable PSR12.Properties.ConstantVisibility.NotFound |
| 18 |
/** |
| 19 |
* Model APIs cap a tool name at 64 characters. |
| 20 |
*/ |
| 21 |
const MAX_NAME = 64; |
| 22 |
|
| 23 |
/** |
| 24 |
* A client validates the schema it is handed, and a plugin may write keys JSON Schema lacks. |
| 25 |
*/ |
| 26 |
const SCHEMA_KEYWORDS = [ |
| 27 |
'additionalProperties', |
| 28 |
'anyOf', |
| 29 |
'const', |
| 30 |
'default', |
| 31 |
'description', |
| 32 |
'enum', |
| 33 |
'exclusiveMaximum', |
| 34 |
'exclusiveMinimum', |
| 35 |
'format', |
| 36 |
'items', |
| 37 |
'maxItems', |
| 38 |
'maxLength', |
| 39 |
'maximum', |
| 40 |
'minItems', |
| 41 |
'minLength', |
| 42 |
'minimum', |
| 43 |
'multipleOf', |
| 44 |
'oneOf', |
| 45 |
'pattern', |
| 46 |
'properties', |
| 47 |
'required', |
| 48 |
'title', |
| 49 |
'type', |
| 50 |
'uniqueItems', |
| 51 |
]; |
| 52 |
|
| 53 |
const HINTS = [ |
| 54 |
'readonly' => 'readOnlyHint', |
| 55 |
'destructive' => 'destructiveHint', |
| 56 |
'idempotent' => 'idempotentHint', |
| 57 |
]; |
| 58 |
// phpcs:enable PSR12.Properties.ConstantVisibility.NotFound |
| 59 |
|
| 60 |
/** |
| 61 |
* @param array $grants - What the connection is allowed to do. |
| 62 |
* @return array |
| 63 |
*/ |
| 64 |
public static function tools(array $grants) |
| 65 |
{ |
| 66 |
$tools = []; |
| 67 |
foreach (self::offered($grants) as $tool) { |
| 68 |
$tools[] = $tool['definition']; |
| 69 |
} |
| 70 |
|
| 71 |
return $tools; |
| 72 |
} |
| 73 |
|
| 74 |
/** |
| 75 |
* @param array $params - The tools/call params. |
| 76 |
* @param array $grants - What the connection is allowed to do. |
| 77 |
* @param array $connection - The connection the call arrived on. |
| 78 |
* @return array|\WP_Error |
| 79 |
*/ |
| 80 |
public static function call(array $params, array $grants, array $connection = []) |
| 81 |
{ |
| 82 |
$name = (string) ($params['name'] ?? ''); |
| 83 |
$started = microtime(true); |
| 84 |
$outcome = ['outcome' => 'error', 'error' => '']; |
| 85 |
|
| 86 |
try { |
| 87 |
$offered = self::offered($grants); |
| 88 |
if (!isset($offered[$name])) { |
| 89 |
$outcome = ['outcome' => 'refused', 'error' => sprintf('Unknown tool: %s', $name)]; |
| 90 |
|
| 91 |
return new \WP_Error('extendify_mcp_unknown_tool', $outcome['error']); |
| 92 |
} |
| 93 |
|
| 94 |
$tool = $offered[$name]; |
| 95 |
$arguments = is_array($params['arguments'] ?? null) ? $params['arguments'] : []; |
| 96 |
|
| 97 |
$answered = Guard::during(function () use ($tool, $arguments) { |
| 98 |
return isset($tool['handler']) |
| 99 |
? self::handled($tool, $arguments) |
| 100 |
: self::answer(\rest_do_request(self::abilityRequest($tool, $arguments)), $tool); |
| 101 |
}); |
| 102 |
$outcome = self::outcome($answered); |
| 103 |
|
| 104 |
return $answered; |
| 105 |
} catch (Refused $refused) { |
| 106 |
$outcome = ['outcome' => 'refused', 'error' => $refused->getMessage()]; |
| 107 |
|
| 108 |
return self::problem($refused->getMessage()); |
| 109 |
} catch (\Throwable $failed) { |
| 110 |
// Uncaught, this is WordPress's critical-error page, which no client can parse. |
| 111 |
$outcome = ['outcome' => 'error', 'error' => $failed->getMessage()]; |
| 112 |
|
| 113 |
return self::problem(sprintf('%s failed: %s', $name, $failed->getMessage())); |
| 114 |
} finally { |
| 115 |
$outcome['duration'] = microtime(true) - $started; |
| 116 |
Log::write($connection, $name, $outcome); |
| 117 |
} |
| 118 |
} |
| 119 |
|
| 120 |
/** |
| 121 |
* @param mixed $answered - What the tool answered with. |
| 122 |
* @return array |
| 123 |
*/ |
| 124 |
private static function outcome($answered) |
| 125 |
{ |
| 126 |
if (!is_array($answered) || empty($answered['isError'])) { |
| 127 |
return ['outcome' => 'ok', 'error' => '']; |
| 128 |
} |
| 129 |
|
| 130 |
return ['outcome' => 'error', 'error' => (string) ($answered['content'][0]['text'] ?? '')]; |
| 131 |
} |
| 132 |
|
| 133 |
/** |
| 134 |
* @param array $grants - What the connection is allowed to do. |
| 135 |
* @return array |
| 136 |
*/ |
| 137 |
public static function offered(array $grants) |
| 138 |
{ |
| 139 |
$offered = []; |
| 140 |
foreach (array_merge(self::written($grants), self::abilities($grants)) as $tool) { |
| 141 |
$name = $tool['definition']['name']; |
| 142 |
if (!isset($offered[$name])) { |
| 143 |
$offered[$name] = $tool; |
| 144 |
} |
| 145 |
} |
| 146 |
|
| 147 |
return $offered; |
| 148 |
} |
| 149 |
|
| 150 |
/** |
| 151 |
* @param array $grants - What the connection is allowed to do. |
| 152 |
* @return array |
| 153 |
*/ |
| 154 |
private static function written(array $grants) |
| 155 |
{ |
| 156 |
$tools = []; |
| 157 |
foreach (Tools::all() as $name => $tool) { |
| 158 |
if (!in_array($tool['mode'], $grants, true)) { |
| 159 |
continue; |
| 160 |
} |
| 161 |
|
| 162 |
if (!Allowed::forTool($name, $tool['mode'])) { |
| 163 |
continue; |
| 164 |
} |
| 165 |
|
| 166 |
// Clients treat a tool without readOnlyHint as a write and ask before every call. |
| 167 |
$definition = [ |
| 168 |
'name' => $name, |
| 169 |
'description' => $tool['description'], |
| 170 |
'inputSchema' => $tool['inputSchema'], |
| 171 |
'annotations' => ['readOnlyHint' => $tool['mode'] === Grants::READ] + ($tool['annotations'] ?? []), |
| 172 |
]; |
| 173 |
|
| 174 |
$tools[] = [ |
| 175 |
'mode' => $tool['mode'], |
| 176 |
'handler' => $tool['handler'], |
| 177 |
'definition' => $definition, |
| 178 |
]; |
| 179 |
} |
| 180 |
|
| 181 |
return $tools; |
| 182 |
} |
| 183 |
|
| 184 |
/** |
| 185 |
* @param array $tool - The tool being called. |
| 186 |
* @param array $arguments - The arguments the client called with. |
| 187 |
* @return array |
| 188 |
*/ |
| 189 |
private static function handled(array $tool, array $arguments) |
| 190 |
{ |
| 191 |
$arguments = self::valid($tool['definition']['inputSchema'], $arguments); |
| 192 |
if (\is_wp_error($arguments)) { |
| 193 |
return self::problem($arguments->get_error_message()); |
| 194 |
} |
| 195 |
|
| 196 |
$answered = call_user_func([Handlers::class, $tool['handler']], $arguments); |
| 197 |
|
| 198 |
return \is_wp_error($answered) ? self::problem($answered->get_error_message()) : self::json($answered); |
| 199 |
} |
| 200 |
|
| 201 |
/** |
| 202 |
* A model that reads why its arguments were turned down can correct itself. |
| 203 |
* |
| 204 |
* @param array $schema - The tool's input schema. |
| 205 |
* @param array $arguments - The arguments the client called with. |
| 206 |
* @return array|\WP_Error |
| 207 |
*/ |
| 208 |
private static function valid(array $schema, array $arguments) |
| 209 |
{ |
| 210 |
// A client needs {} for a tool taking nothing, and the validator fatals indexing a stdClass. |
| 211 |
$schema['properties'] = (array) ($schema['properties'] ?? []); |
| 212 |
foreach ($schema['properties'] as $key => $property) { |
| 213 |
if (!isset($arguments[$key]) && array_key_exists('default', (array) $property)) { |
| 214 |
$arguments[$key] = $property['default']; |
| 215 |
} |
| 216 |
} |
| 217 |
|
| 218 |
$checked = \rest_validate_value_from_schema($arguments, $schema, 'arguments'); |
| 219 |
if (\is_wp_error($checked)) { |
| 220 |
return $checked; |
| 221 |
} |
| 222 |
|
| 223 |
return (array) \rest_sanitize_value_from_schema($arguments, $schema, 'arguments'); |
| 224 |
} |
| 225 |
|
| 226 |
/** |
| 227 |
* @param string $message - What went wrong, for the model to read. |
| 228 |
* @return array |
| 229 |
*/ |
| 230 |
private static function problem($message) |
| 231 |
{ |
| 232 |
return ['content' => [['type' => 'text', 'text' => $message]], 'isError' => true]; |
| 233 |
} |
| 234 |
|
| 235 |
/** |
| 236 |
* @param array $grants - What the connection is allowed to do. |
| 237 |
* @return array |
| 238 |
*/ |
| 239 |
private static function abilities(array $grants) |
| 240 |
{ |
| 241 |
if (!function_exists('wp_get_abilities')) { |
| 242 |
return []; |
| 243 |
} |
| 244 |
|
| 245 |
$tools = []; |
| 246 |
foreach (\wp_get_abilities() as $ability) { |
| 247 |
if (!$ability->get_meta_item('show_in_rest')) { |
| 248 |
continue; |
| 249 |
} |
| 250 |
|
| 251 |
$annotations = (array) $ability->get_meta_item('annotations'); |
| 252 |
$mode = Allowed::forAbility($ability->get_name(), $annotations); |
| 253 |
if ($mode === null || !in_array($mode, $grants, true)) { |
| 254 |
continue; |
| 255 |
} |
| 256 |
|
| 257 |
$tools[] = self::ability($ability, $annotations, $mode); |
| 258 |
} |
| 259 |
|
| 260 |
return $tools; |
| 261 |
} |
| 262 |
|
| 263 |
/** |
| 264 |
* The run controller insists on the method an ability's annotations imply. |
| 265 |
* |
| 266 |
* @param \WP_Ability $ability - The registered ability. |
| 267 |
* @param array $annotations - Its meta annotations. |
| 268 |
* @param string $mode - The grant it needs. |
| 269 |
* @return array |
| 270 |
*/ |
| 271 |
private static function ability($ability, array $annotations, $mode) |
| 272 |
{ |
| 273 |
$method = 'POST'; |
| 274 |
if (!empty($annotations['readonly'])) { |
| 275 |
$method = 'GET'; |
| 276 |
} elseif (!empty($annotations['destructive']) && !empty($annotations['idempotent'])) { |
| 277 |
$method = 'DELETE'; |
| 278 |
} |
| 279 |
|
| 280 |
// An ability may branch its whole input with oneOf rather than name properties. |
| 281 |
$schema = self::normalize($ability->get_input_schema()); |
| 282 |
$schema['type'] = 'object'; |
| 283 |
|
| 284 |
$definition = [ |
| 285 |
'name' => self::name($ability->get_name()), |
| 286 |
'description' => $ability->get_description(), |
| 287 |
'inputSchema' => $schema, |
| 288 |
]; |
| 289 |
$output = self::normalize($ability->get_output_schema()); |
| 290 |
if (($output['type'] ?? '') === 'object') { |
| 291 |
$definition['outputSchema'] = $output; |
| 292 |
} |
| 293 |
|
| 294 |
$hints = self::hints($annotations); |
| 295 |
if ($hints) { |
| 296 |
$definition['annotations'] = $hints; |
| 297 |
} |
| 298 |
|
| 299 |
return [ |
| 300 |
'mode' => $mode, |
| 301 |
'method' => $method, |
| 302 |
'ability' => $ability->get_name(), |
| 303 |
'definition' => $definition, |
| 304 |
]; |
| 305 |
} |
| 306 |
|
| 307 |
/** |
| 308 |
* WordPress leaves an annotation null, and an absent hint takes MCP's default. |
| 309 |
* |
| 310 |
* @param array $annotations - The ability's meta annotations. |
| 311 |
* @return array |
| 312 |
*/ |
| 313 |
private static function hints(array $annotations) |
| 314 |
{ |
| 315 |
$hints = []; |
| 316 |
foreach (self::HINTS as $annotation => $hint) { |
| 317 |
if (isset($annotations[$annotation])) { |
| 318 |
$hints[$hint] = (bool) $annotations[$annotation]; |
| 319 |
} |
| 320 |
} |
| 321 |
|
| 322 |
return $hints; |
| 323 |
} |
| 324 |
|
| 325 |
/** |
| 326 |
* The run controller reads input from the query except on a POST. |
| 327 |
* |
| 328 |
* @param array $tool - The tool being called. |
| 329 |
* @param array $arguments - The arguments the client called with. |
| 330 |
* @return \WP_REST_Request |
| 331 |
*/ |
| 332 |
private static function abilityRequest(array $tool, array $arguments) |
| 333 |
{ |
| 334 |
$request = new \WP_REST_Request($tool['method'], '/wp-abilities/v1/abilities/' . $tool['ability'] . '/run'); |
| 335 |
if ($tool['method'] !== 'POST') { |
| 336 |
$request->set_query_params(['input' => $arguments]); |
| 337 |
|
| 338 |
return $request; |
| 339 |
} |
| 340 |
|
| 341 |
$request->set_header('Content-Type', 'application/json'); |
| 342 |
$request->set_body(\wp_json_encode(['input' => (object) $arguments])); |
| 343 |
|
| 344 |
return $request; |
| 345 |
} |
| 346 |
|
| 347 |
/** |
| 348 |
* @param \WP_REST_Response $response - What the REST server answered. |
| 349 |
* @param array $tool - The tool that was called. |
| 350 |
* @return array |
| 351 |
*/ |
| 352 |
private static function answer($response, array $tool) |
| 353 |
{ |
| 354 |
$data = $response->get_data(); |
| 355 |
$answer = self::json($data); |
| 356 |
if ($response->is_error()) { |
| 357 |
$answer['isError'] = true; |
| 358 |
|
| 359 |
return $answer; |
| 360 |
} |
| 361 |
|
| 362 |
// A tool that named an output schema owes the client a result shaped like it. |
| 363 |
if (isset($tool['definition']['outputSchema']) && (is_array($data) || is_object($data))) { |
| 364 |
$answer['structuredContent'] = (object) $data; |
| 365 |
} |
| 366 |
|
| 367 |
return $answer; |
| 368 |
} |
| 369 |
|
| 370 |
/** |
| 371 |
* @param mixed $data - What the tool answered with. |
| 372 |
* @return array |
| 373 |
*/ |
| 374 |
private static function json($data) |
| 375 |
{ |
| 376 |
$text = \wp_json_encode($data, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT); |
| 377 |
|
| 378 |
return ['content' => [['type' => 'text', 'text' => $text]]]; |
| 379 |
} |
| 380 |
|
| 381 |
/** |
| 382 |
* @param mixed $schema - A schema as a plugin registered it. |
| 383 |
* @return array |
| 384 |
*/ |
| 385 |
private static function normalize($schema) |
| 386 |
{ |
| 387 |
if (!is_array($schema)) { |
| 388 |
return []; |
| 389 |
} |
| 390 |
|
| 391 |
$kept = array_intersect_key($schema, array_flip(self::SCHEMA_KEYWORDS)); |
| 392 |
if (isset($kept['required']) && !is_array($kept['required'])) { |
| 393 |
unset($kept['required']); |
| 394 |
} |
| 395 |
|
| 396 |
if (isset($kept['properties']) && is_array($kept['properties'])) { |
| 397 |
$kept = array_merge($kept, self::describe($kept)); |
| 398 |
} |
| 399 |
|
| 400 |
if (isset($kept['items'])) { |
| 401 |
$kept['items'] = self::normalize($kept['items']); |
| 402 |
} |
| 403 |
|
| 404 |
foreach (['oneOf', 'anyOf'] as $branch) { |
| 405 |
if (isset($kept[$branch]) && is_array($kept[$branch])) { |
| 406 |
$kept[$branch] = array_map([self::class, 'normalize'], $kept[$branch]); |
| 407 |
} |
| 408 |
} |
| 409 |
|
| 410 |
return $kept; |
| 411 |
} |
| 412 |
|
| 413 |
/** |
| 414 |
* A plugin may spell required on the property, as a REST arg does; a client wants it on the object. |
| 415 |
* |
| 416 |
* @param array $schema - A schema whose properties need normalizing. |
| 417 |
* @return array |
| 418 |
*/ |
| 419 |
private static function describe(array $schema) |
| 420 |
{ |
| 421 |
$properties = []; |
| 422 |
$required = isset($schema['required']) ? $schema['required'] : []; |
| 423 |
foreach ($schema['properties'] as $name => $property) { |
| 424 |
if (!is_array($property)) { |
| 425 |
continue; |
| 426 |
} |
| 427 |
|
| 428 |
if (!empty($property['required'])) { |
| 429 |
$required[] = (string) $name; |
| 430 |
} |
| 431 |
|
| 432 |
$properties[$name] = self::normalize($property); |
| 433 |
} |
| 434 |
|
| 435 |
$described = ['properties' => (object) $properties]; |
| 436 |
if ($required) { |
| 437 |
$described['required'] = array_values(array_unique($required)); |
| 438 |
} |
| 439 |
|
| 440 |
return $described; |
| 441 |
} |
| 442 |
|
| 443 |
/** |
| 444 |
* @param string $subject - The ability name. |
| 445 |
* @return string |
| 446 |
*/ |
| 447 |
private static function name($subject) |
| 448 |
{ |
| 449 |
$name = strtolower(trim(preg_replace('/[^A-Za-z0-9]+/', '_', $subject), '_')); |
| 450 |
if (strlen($name) <= self::MAX_NAME) { |
| 451 |
return $name; |
| 452 |
} |
| 453 |
|
| 454 |
return substr($name, 0, self::MAX_NAME - 9) . '_' . substr(md5($name), 0, 8); |
| 455 |
} |
| 456 |
} |
| 457 |
|
