metasync / wp-mcp-server / class-mcp-json-rpc-handler.php

class-mcp-json-rpc-handler.php in Search Atlas SEO – OTTO AI SEO Automation for WordPress 2.6.22, at wp-mcp-server/class-mcp-json-rpc-handler.php

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1	<?php
2	/**
3	* MCP JSON-RPC 2.0 Handler
4	*
5	* Handles parsing, validation, and routing of JSON-RPC 2.0 requests
6	* according to the Model Context Protocol specification.
7	*
8	* @package MetaSync
9	* @subpackage MCP_Server
10	*/
11
12	if (!defined('ABSPATH')) {
13	exit;
14	}
15
16	class MCP_JSON_RPC_Handler {
17
18	/**
19	* JSON-RPC version
20	*/
21	const JSONRPC_VERSION = '2.0';
22
23	/**
24	* Error codes (JSON-RPC 2.0 standard + custom)
25	*/
26	const ERROR_PARSE_ERROR = -32700;
27	const ERROR_INVALID_REQUEST = -32600;
28	const ERROR_METHOD_NOT_FOUND = -32601;
29	const ERROR_INVALID_PARAMS = -32602;
30	const ERROR_INTERNAL_ERROR = -32603;
31	const ERROR_SERVER_ERROR = -32000;
32	const ERROR_RATE_LIMITED = -32029;
33
34	/**
35	* Method handlers
36	*
37	* @var array
38	*/
39	private $handlers = [];
40
41	/**
42	* Constructor
43	*/
44	public function __construct() {
45	// Register default handlers
46	$this->register_handler('initialize', [$this, 'handle_initialize']);
47	$this->register_handler('ping', [$this, 'handle_ping']);
48	}
49
50	/**
51	* Register a method handler
52	*
53	* @param string $method Method name
54	* @param callable $callback Handler callback
55	*/
56	public function register_handler($method, $callback) {
57	if (!is_callable($callback)) {
58	throw new InvalidArgumentException("Handler for method '{$method}' must be callable");
59	}
60	$this->handlers[$method] = $callback;
61	}
62
63	/**
64	* Handle incoming JSON-RPC request
65	*
66	* @param string $request_body Raw request body
67	* @return array Response array
68	*/
69	public function handle_request($request_body) {
70	// Parse JSON
71	$request = json_decode($request_body, true);
72
73	if (json_last_error() !== JSON_ERROR_NONE) {
74	return $this->error_response(null, self::ERROR_PARSE_ERROR, 'Parse error');
75	}
76
77	// Validate request structure
78	if (!$this->validate_request($request)) {
79	return $this->error_response(
80	isset($request['id']) ? $request['id'] : null,
81	self::ERROR_INVALID_REQUEST,
82	'Invalid Request'
83	);
84	}
85
86	$method = $request['method'];
87	$params = isset($request['params']) ? $request['params'] : [];
88	$id = isset($request['id']) ? $request['id'] : null;
89
90	// Check if handler exists
91	if (!isset($this->handlers[$method])) {
92	return $this->error_response($id, self::ERROR_METHOD_NOT_FOUND, "Method not found: {$method}");
93	}
94
95	try {
96	// Call handler
97	$result = call_user_func($this->handlers[$method], $params);
98	return $this->success_response($id, $result);
99	} catch (InvalidArgumentException $e) {
100	return $this->error_response($id, self::ERROR_INVALID_PARAMS, $e->getMessage());
101	} catch (Exception $e) {
102	// Log error
103	error_log('MCP JSON-RPC Error: ' . $e->getMessage());
104	return $this->error_response($id, self::ERROR_INTERNAL_ERROR, $e->getMessage());
105	}
106	}
107
108	/**
109	* Validate JSON-RPC request structure
110	*
111	* @param mixed $request Request data
112	* @return bool
113	*/
114	private function validate_request($request) {
115	if (!is_array($request)) {
116	return false;
117	}
118
119	// Must have jsonrpc, method
120	if (!isset($request['jsonrpc']) \|\| $request['jsonrpc'] !== self::JSONRPC_VERSION) {
121	return false;
122	}
123
124	if (!isset($request['method']) \|\| !is_string($request['method'])) {
125	return false;
126	}
127
128	// Params are optional but must be array or object if present
129	if (isset($request['params']) && !is_array($request['params'])) {
130	return false;
131	}
132
133	return true;
134	}
135
136	/**
137	* Create success response
138	*
139	* @param mixed $id Request ID
140	* @param mixed $result Result data
141	* @return array
142	*/
143	public function success_response($id, $result) {
144	return [
145	'jsonrpc' => self::JSONRPC_VERSION,
146	'id' => $id,
147	'result' => $result
148	];
149	}
150
151	/**
152	* Create error response
153	*
154	* @param mixed $id Request ID
155	* @param int $code Error code
156	* @param string $message Error message
157	* @param mixed $data Optional error data
158	* @return array
159	*/
160	public function error_response($id, $code, $message, $data = null) {
161	$error = [
162	'code' => $code,
163	'message' => $message
164	];
165
166	if ($data !== null) {
167	$error['data'] = $data;
168	}
169
170	return [
171	'jsonrpc' => self::JSONRPC_VERSION,
172	'id' => $id,
173	'error' => $error
174	];
175	}
176
177	/**
178	* Handle initialize method
179	*
180	* @param array $params Request parameters
181	* @return array
182	*/
183	private function handle_initialize($params) {
184	return [
185	'protocolVersion' => '2024-11-05',
186	'capabilities' => [
187	'tools' => [
188	'list' => true,
189	'call' => true
190	]
191	],
192	'serverInfo' => [
193	'name' => 'metasync-wordpress-mcp',
194	'version' => METASYNC_VERSION
195	]
196	];
197	}
198
199	/**
200	* Handle ping method
201	*
202	* @param array $params Request parameters
203	* @return array
204	*/
205	private function handle_ping($params) {
206	return ['status' => 'ok'];
207	}
208	}
209