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 2.5.23, 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
33	/**
34	* Method handlers
35	*
36	* @var array
37	*/
38	private $handlers = [];
39
40	/**
41	* Constructor
42	*/
43	public function __construct() {
44	// Register default handlers
45	$this->register_handler('initialize', [$this, 'handle_initialize']);
46	$this->register_handler('ping', [$this, 'handle_ping']);
47	}
48
49	/**
50	* Register a method handler
51	*
52	* @param string $method Method name
53	* @param callable $callback Handler callback
54	*/
55	public function register_handler($method, $callback) {
56	if (!is_callable($callback)) {
57	throw new InvalidArgumentException("Handler for method '{$method}' must be callable");
58	}
59	$this->handlers[$method] = $callback;
60	}
61
62	/**
63	* Handle incoming JSON-RPC request
64	*
65	* @param string $request_body Raw request body
66	* @return array Response array
67	*/
68	public function handle_request($request_body) {
69	// Parse JSON
70	$request = json_decode($request_body, true);
71
72	if (json_last_error() !== JSON_ERROR_NONE) {
73	return $this->error_response(null, self::ERROR_PARSE_ERROR, 'Parse error');
74	}
75
76	// Validate request structure
77	if (!$this->validate_request($request)) {
78	return $this->error_response(
79	isset($request['id']) ? $request['id'] : null,
80	self::ERROR_INVALID_REQUEST,
81	'Invalid Request'
82	);
83	}
84
85	$method = $request['method'];
86	$params = isset($request['params']) ? $request['params'] : [];
87	$id = isset($request['id']) ? $request['id'] : null;
88
89	// Check if handler exists
90	if (!isset($this->handlers[$method])) {
91	return $this->error_response($id, self::ERROR_METHOD_NOT_FOUND, "Method not found: {$method}");
92	}
93
94	try {
95	// Call handler
96	$result = call_user_func($this->handlers[$method], $params);
97	return $this->success_response($id, $result);
98	} catch (InvalidArgumentException $e) {
99	return $this->error_response($id, self::ERROR_INVALID_PARAMS, $e->getMessage());
100	} catch (Exception $e) {
101	// Log error
102	error_log('MCP JSON-RPC Error: ' . $e->getMessage());
103	return $this->error_response($id, self::ERROR_INTERNAL_ERROR, 'Internal error');
104	}
105	}
106
107	/**
108	* Validate JSON-RPC request structure
109	*
110	* @param mixed $request Request data
111	* @return bool
112	*/
113	private function validate_request($request) {
114	if (!is_array($request)) {
115	return false;
116	}
117
118	// Must have jsonrpc, method
119	if (!isset($request['jsonrpc']) \|\| $request['jsonrpc'] !== self::JSONRPC_VERSION) {
120	return false;
121	}
122
123	if (!isset($request['method']) \|\| !is_string($request['method'])) {
124	return false;
125	}
126
127	// Params are optional but must be array or object if present
128	if (isset($request['params']) && !is_array($request['params'])) {
129	return false;
130	}
131
132	return true;
133	}
134
135	/**
136	* Create success response
137	*
138	* @param mixed $id Request ID
139	* @param mixed $result Result data
140	* @return array
141	*/
142	public function success_response($id, $result) {
143	return [
144	'jsonrpc' => self::JSONRPC_VERSION,
145	'id' => $id,
146	'result' => $result
147	];
148	}
149
150	/**
151	* Create error response
152	*
153	* @param mixed $id Request ID
154	* @param int $code Error code
155	* @param string $message Error message
156	* @param mixed $data Optional error data
157	* @return array
158	*/
159	public function error_response($id, $code, $message, $data = null) {
160	$error = [
161	'code' => $code,
162	'message' => $message
163	];
164
165	if ($data !== null) {
166	$error['data'] = $data;
167	}
168
169	return [
170	'jsonrpc' => self::JSONRPC_VERSION,
171	'id' => $id,
172	'error' => $error
173	];
174	}
175
176	/**
177	* Handle initialize method
178	*
179	* @param array $params Request parameters
180	* @return array
181	*/
182	private function handle_initialize($params) {
183	return [
184	'protocolVersion' => '2024-11-05',
185	'capabilities' => [
186	'tools' => [
187	'list' => true,
188	'call' => true
189	]
190	],
191	'serverInfo' => [
192	'name' => 'metasync-wordpress-mcp',
193	'version' => METASYNC_VERSION
194	]
195	];
196	}
197
198	/**
199	* Handle ping method
200	*
201	* @param array $params Request parameters
202	* @return array
203	*/
204	private function handle_ping($params) {
205	return ['status' => 'ok'];
206	}
207	}
208