colorlink
c63762487c
- /oauth/register creates a public (PKCE) client; client_id uses 'mcpc_' prefix so it is NOT accepted as a raw bearer by TokenManager::resolve() — only the human-approved JWT works - registered redirect_uris stored + enforced exactly at /authorize - registration_endpoint advertised in AS metadata - fixes Claude.ai reconnect loop (DCR was missing; /oauth/register was 404) Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Q8t9GEyyLZbUQu26na1JQg
466 lines
20 KiB
PHP
466 lines
20 KiB
PHP
<?php
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namespace AskTamMCP\MCP;
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defined('ABSPATH') || exit;
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/**
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* OAuth 2.0 server with:
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* - Dynamic Client Registration (RFC 7591) for MCP clients (Claude.ai)
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* - PKCE (S256) verification on token exchange
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* - redirect_uri allowlist per key + per registered client
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* - Short-lived JWT access tokens (not raw API keys)
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* - authorization_code + client_credentials grants
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*
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* Security note on DCR: registered client_ids use the 'mcpc_' prefix so they are
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* NOT accepted as raw bearer tokens by TokenManager::resolve() (which only accepts
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* 'mcp_'-prefixed raw keys). A registered client therefore cannot act as a credential
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* on its own — the only usable token is the short-lived JWT, which is issued only
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* after the site owner approves on the consent screen.
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*/
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class OAuthServer {
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// Allowed redirect_uri origins — Claude.ai callback
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private const ALLOWED_REDIRECT_HOSTS = [
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'claude.ai',
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'localhost',
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'127.0.0.1',
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];
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private const CLIENTS_OPTION = 'asktam_mcp_oauth_clients';
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public function registerRoutes(): void {
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register_rest_route('asktam-mcp/v1', '/oauth/register', [
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'methods' => 'POST',
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'callback' => [$this, 'handleRegister'],
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'permission_callback' => '__return_true',
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]);
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register_rest_route('asktam-mcp/v1', '/oauth/authorize', [
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'methods' => ['GET', 'POST'],
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'callback' => [$this, 'handleAuthorize'],
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'permission_callback' => '__return_true',
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]);
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register_rest_route('asktam-mcp/v1', '/oauth/token', [
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'methods' => 'POST',
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'callback' => [$this, 'handleToken'],
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'permission_callback' => '__return_true',
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]);
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register_rest_route('asktam-mcp/v1', '/oauth/metadata', [
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'methods' => 'GET',
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'callback' => [$this, 'handleMetadata'],
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'permission_callback' => '__return_true',
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]);
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add_action('rest_api_init', function () {
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register_rest_route('', '/.well-known/oauth-authorization-server', [
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'methods' => 'GET',
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'callback' => [$this, 'handleMetadata'],
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'permission_callback' => '__return_true',
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]);
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}, 20);
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}
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// -------------------------------------------------------------------------
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// Dynamic Client Registration (RFC 7591)
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// -------------------------------------------------------------------------
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public function handleRegister(\WP_REST_Request $request): \WP_REST_Response {
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$body = $request->get_json_params();
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if (!is_array($body) || empty($body)) {
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$body = $request->get_params();
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}
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$redirectUris = $body['redirect_uris'] ?? [];
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if (is_string($redirectUris)) $redirectUris = [$redirectUris];
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if (empty($redirectUris) || !is_array($redirectUris)) {
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return $this->oauthError('invalid_redirect_uri', 'redirect_uris is required', 400);
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}
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$clean = [];
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foreach ($redirectUris as $uri) {
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$uri = esc_url_raw((string) $uri);
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if (!$uri || !$this->isRedirectUriAllowed($uri)) {
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return $this->oauthError('invalid_redirect_uri', 'redirect_uri host not allowed: ' . $uri, 400);
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}
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$clean[] = $uri;
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}
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$clientName = sanitize_text_field($body['client_name'] ?? 'MCP Client');
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if ($clientName === '') $clientName = 'MCP Client';
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// DCR clients are public (PKCE); we do not issue a client_secret.
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$scopes = 'read,write,admin,woocommerce';
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$clientId = 'mcpc_' . bin2hex(random_bytes(24));
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global $wpdb;
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$table = $wpdb->prefix . 'asktam_mcp_keys';
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$wpdb->insert($table, [
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'name' => 'oauth: ' . $clientName,
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'api_key' => $clientId,
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'scopes' => $scopes,
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'created_at' => current_time('mysql'),
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'is_active' => 1,
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]);
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// Store the registered redirect_uris so /authorize can enforce an exact match.
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$reg = get_option(self::CLIENTS_OPTION, []);
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if (!is_array($reg)) $reg = [];
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$reg[$clientId] = [
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'client_name' => $clientName,
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'redirect_uris' => $clean,
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'created_at' => time(),
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];
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if (count($reg) > 50) $reg = array_slice($reg, -50, 50, true); // bound growth
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update_option(self::CLIENTS_OPTION, $reg, false);
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return new \WP_REST_Response([
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'client_id' => $clientId,
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'client_id_issued_at' => time(),
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'redirect_uris' => $clean,
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'grant_types' => ['authorization_code'],
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'response_types' => ['code'],
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'token_endpoint_auth_method' => 'none',
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'client_name' => $clientName,
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'scope' => str_replace(',', ' ', $scopes),
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], 201);
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}
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// -------------------------------------------------------------------------
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// Authorization endpoint
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// -------------------------------------------------------------------------
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public function handleAuthorize(\WP_REST_Request $request): void {
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$clientId = sanitize_text_field($request->get_param('client_id') ?? '');
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$redirectUri = esc_url_raw($request->get_param('redirect_uri') ?? '');
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$state = sanitize_text_field($request->get_param('state') ?? '');
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$codeChallenge = sanitize_text_field($request->get_param('code_challenge') ?? '');
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$challengeMethod = sanitize_text_field($request->get_param('code_challenge_method') ?? 'S256');
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$approved = sanitize_text_field($request->get_param('_mcp_approve') ?? '');
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// 1. Validate redirect_uri host
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if (!$this->isRedirectUriAllowed($redirectUri)) {
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wp_die('Invalid redirect_uri: host not in allowlist.', 'MCP Security Error', ['response' => 400]);
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}
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// 1b. If this client_id was issued via DCR, enforce its registered redirect_uris exactly.
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$reg = get_option(self::CLIENTS_OPTION, []);
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if (is_array($reg) && isset($reg[$clientId])) {
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$registered = $reg[$clientId]['redirect_uris'] ?? [];
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if (!empty($registered) && !in_array($redirectUri, $registered, true)) {
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$this->redirectError($redirectUri, 'invalid_request', $state, 'redirect_uri not registered for this client');
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return;
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}
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}
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// 2. Validate client_id
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global $wpdb;
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$table = $wpdb->prefix . 'asktam_mcp_keys';
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$row = $wpdb->get_row(
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$wpdb->prepare("SELECT * FROM {$table} WHERE api_key = %s AND is_active = 1", $clientId),
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ARRAY_A
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);
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if (!$row) {
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$this->redirectError($redirectUri, 'invalid_client', $state);
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return;
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}
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// 3. PKCE: require code_challenge for authorization_code flow
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if (empty($codeChallenge)) {
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$this->redirectError($redirectUri, 'invalid_request', $state, 'PKCE code_challenge is required');
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return;
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}
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// 4. POST: user approved
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if ($_SERVER['REQUEST_METHOD'] === 'POST' && $approved === '1') {
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$code = 'mcp_code_' . bin2hex(random_bytes(16));
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set_transient('asktam_mcp_code_' . $code, [
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'client_id' => $clientId,
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'redirect_uri' => $redirectUri,
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'scopes' => $row['scopes'],
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'key_id' => $row['id'],
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'code_challenge' => $codeChallenge,
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'challenge_method' => $challengeMethod,
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], 300); // 5 min
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wp_redirect(add_query_arg(['code' => $code, 'state' => $state], $redirectUri));
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exit;
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}
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// 5. GET: render approval page
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$this->renderApprovalPage($row, $clientId, $redirectUri, $state, $codeChallenge, $challengeMethod);
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}
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// -------------------------------------------------------------------------
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// Token endpoint
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// -------------------------------------------------------------------------
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public function handleToken(\WP_REST_Request $request): \WP_REST_Response {
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$grantType = $request->get_param('grant_type') ?? '';
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return match ($grantType) {
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'authorization_code' => $this->handleAuthCodeExchange($request),
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'client_credentials' => $this->handleClientCredentials($request),
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default => $this->oauthError('unsupported_grant_type', 'Supported: authorization_code, client_credentials', 400),
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};
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}
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private function handleAuthCodeExchange(\WP_REST_Request $request): \WP_REST_Response {
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$code = $request->get_param('code') ?? '';
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$codeVerifier = $request->get_param('code_verifier') ?? '';
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$redirectUri = $request->get_param('redirect_uri') ?? '';
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if (empty($code)) {
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return $this->oauthError('invalid_request', 'Missing code', 400);
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}
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$codeData = get_transient('asktam_mcp_code_' . $code);
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if (!$codeData) {
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return $this->oauthError('invalid_grant', 'Authorization code expired or invalid', 400);
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}
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// Always delete — one-time use
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delete_transient('asktam_mcp_code_' . $code);
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// PKCE verification
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if (!empty($codeData['code_challenge'])) {
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if (empty($codeVerifier)) {
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return $this->oauthError('invalid_grant', 'PKCE code_verifier is required', 400);
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}
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$method = $codeData['challenge_method'] ?? 'S256';
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$challenge = $codeData['code_challenge'];
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$valid = match ($method) {
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'S256' => hash_equals($challenge, rtrim(strtr(base64_encode(hash('sha256', $codeVerifier, true)), '+/', '-_'), '=')),
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'plain' => hash_equals($challenge, $codeVerifier),
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default => false,
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};
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if (!$valid) {
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return $this->oauthError('invalid_grant', 'PKCE verification failed', 400);
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}
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}
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// redirect_uri must match what was used in /authorize
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if (!empty($codeData['redirect_uri']) && $redirectUri !== $codeData['redirect_uri']) {
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return $this->oauthError('invalid_grant', 'redirect_uri mismatch', 400);
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}
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// Fetch key row and issue JWT
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global $wpdb;
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$row = $wpdb->get_row(
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$wpdb->prepare("SELECT * FROM {$wpdb->prefix}asktam_mcp_keys WHERE id = %d AND is_active = 1", $codeData['key_id']),
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ARRAY_A
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);
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if (!$row) {
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return $this->oauthError('invalid_grant', 'Key no longer active', 400);
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}
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$accessToken = \AskTamMCP\Core\TokenManager::issue($row);
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return new \WP_REST_Response([
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'access_token' => $accessToken,
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'token_type' => 'bearer',
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'expires_in' => 3600,
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'scope' => $row['scopes'],
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], 200);
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}
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private function handleClientCredentials(\WP_REST_Request $request): \WP_REST_Response {
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[$clientId, $clientSecret] = $this->extractCredentials($request);
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if (empty($clientId) || empty($clientSecret)) {
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return $this->oauthError('invalid_client', 'Missing client_id or client_secret', 401);
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}
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global $wpdb;
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$row = $wpdb->get_row(
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$wpdb->prepare("SELECT * FROM {$wpdb->prefix}asktam_mcp_keys WHERE api_key = %s AND is_active = 1", $clientId),
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ARRAY_A
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);
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if (!$row || !hash_equals($clientId, $clientSecret)) {
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return $this->oauthError('invalid_client', 'Invalid credentials', 401);
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}
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$accessToken = \AskTamMCP\Core\TokenManager::issue($row);
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return new \WP_REST_Response([
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'access_token' => $accessToken,
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'token_type' => 'bearer',
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'expires_in' => 3600,
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'scope' => $row['scopes'],
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], 200);
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}
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// -------------------------------------------------------------------------
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// Metadata
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// -------------------------------------------------------------------------
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public function handleMetadata(): \WP_REST_Response {
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$base = rest_url('asktam-mcp/v1');
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return new \WP_REST_Response([
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'issuer' => get_site_url(),
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'authorization_endpoint' => $base . '/oauth/authorize',
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'token_endpoint' => $base . '/oauth/token',
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'registration_endpoint' => $base . '/oauth/register',
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'token_endpoint_auth_methods_supported' => ['client_secret_post', 'client_secret_basic', 'none'],
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'grant_types_supported' => ['authorization_code', 'client_credentials'],
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'response_types_supported' => ['code'],
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'code_challenge_methods_supported' => ['S256', 'plain'],
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'scopes_supported' => ['read', 'write', 'admin', 'woocommerce'],
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]);
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}
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// -------------------------------------------------------------------------
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// Security helpers
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// -------------------------------------------------------------------------
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/**
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* Validate redirect_uri against an allowlist of trusted hosts.
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* Only claude.ai and localhost are allowed by default.
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* Filterable for custom setups.
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*/
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private function isRedirectUriAllowed(string $uri): bool {
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if (empty($uri)) return false;
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$host = parse_url($uri, PHP_URL_HOST);
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if (!$host) return false;
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$allowed = apply_filters('asktam_mcp_allowed_redirect_hosts', self::ALLOWED_REDIRECT_HOSTS);
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foreach ($allowed as $allowedHost) {
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// Exact match or subdomain match
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if ($host === $allowedHost || str_ends_with($host, '.' . $allowedHost)) {
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return true;
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}
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}
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return false;
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}
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private function redirectError(string $redirectUri, string $error, string $state, string $description = ''): void {
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if ($redirectUri && $this->isRedirectUriAllowed($redirectUri)) {
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$params = ['error' => $error, 'state' => $state];
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if ($description) $params['error_description'] = $description;
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wp_redirect(add_query_arg($params, $redirectUri));
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exit;
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}
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status_header(400);
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header('Content-Type: text/plain');
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echo "OAuth error: {$error}";
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exit;
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}
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private function extractCredentials(\WP_REST_Request $request): array {
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$clientId = $request->get_param('client_id');
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$clientSecret = $request->get_param('client_secret');
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if (!empty($clientId) && !empty($clientSecret)) {
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return [$clientId, $clientSecret];
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}
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$auth = $request->get_header('Authorization');
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if ($auth && str_starts_with($auth, 'Basic ')) {
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$decoded = base64_decode(substr($auth, 6));
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if ($decoded && str_contains($decoded, ':')) {
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[$clientId, $clientSecret] = explode(':', $decoded, 2);
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return [trim($clientId), trim($clientSecret)];
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}
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}
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return [$clientId ?? '', ''];
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}
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private function oauthError(string $error, string $description, int $status): \WP_REST_Response {
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return new \WP_REST_Response(['error' => $error, 'error_description' => $description], $status);
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}
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// -------------------------------------------------------------------------
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// Approval page UI
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// -------------------------------------------------------------------------
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private function renderApprovalPage(array $row, string $clientId, string $redirectUri, string $state, string $codeChallenge, string $challengeMethod): void {
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$siteName = get_bloginfo('name');
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$keyName = esc_html($row['name']);
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$scopes = array_map('trim', explode(',', $row['scopes']));
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$actionUrl = rest_url('asktam-mcp/v1/oauth/authorize');
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while (ob_get_level()) ob_end_clean();
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status_header(200);
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header('Content-Type: text/html; charset=UTF-8');
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header('X-Robots-Tag: noindex');
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?>
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<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8">
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<meta name="viewport" content="width=device-width, initial-scale=1">
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<title>Authorize — <?php echo esc_html($siteName); ?></title>
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<style>
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* { box-sizing: border-box; margin: 0; padding: 0; }
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body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; background: #f0f2f5; display: flex; align-items: center; justify-content: center; min-height: 100vh; padding: 20px; }
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.card { background: #fff; border-radius: 16px; box-shadow: 0 4px 32px rgba(0,0,0,.12); max-width: 420px; width: 100%; padding: 40px 36px; }
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.logo { display: flex; align-items: center; gap: 12px; margin-bottom: 32px; }
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.logo strong { font-size: 17px; color: #1a1a1a; }
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h2 { font-size: 22px; color: #1a1a1a; margin-bottom: 10px; }
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p { color: #666; font-size: 14px; line-height: 1.65; margin-bottom: 22px; }
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.key-box { background: #f8f9ff; border: 1.5px solid #d0d9ff; border-radius: 10px; padding: 16px 18px; margin-bottom: 28px; }
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.key-box .lbl { font-size: 11px; font-weight: 600; text-transform: uppercase; letter-spacing: .6px; color: #888; margin-bottom: 5px; }
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.key-box .val { font-size: 15px; font-weight: 700; color: #1a1a1a; margin-bottom: 10px; }
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.scopes { display: flex; flex-wrap: wrap; gap: 6px; }
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.scope { background: #ede9fe; color: #5b21b6; border-radius: 5px; padding: 3px 10px; font-size: 12px; font-weight: 600; }
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.security-note { background: #fff8ed; border: 1px solid #f5d87a; border-radius: 8px; padding: 10px 14px; margin-bottom: 20px; font-size: 12px; color: #7a5c00; }
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.btns { display: flex; gap: 10px; }
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.btn { flex: 1; padding: 13px; border-radius: 9px; border: none; font-size: 15px; font-weight: 700; cursor: pointer; }
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.approve { background: #2271b1; color: #fff; }
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.deny { background: #f5f5f5; color: #444; border: 1.5px solid #ddd; }
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.note { margin-top: 20px; font-size: 12px; color: #aaa; text-align: center; line-height: 1.5; }
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</style>
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</head>
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<body>
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<div class="card">
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<div class="logo">
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<svg width="36" height="36" viewBox="0 0 36 36" fill="none"><circle cx="18" cy="18" r="18" fill="#2271b1"/><path d="M11 26L18 11L25 26" stroke="white" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round"/><path d="M13.5 21H22.5" stroke="white" stroke-width="2.5" stroke-linecap="round"/></svg>
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<strong>AskTam MCP — <?php echo esc_html($siteName); ?></strong>
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</div>
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<h2>Authorize Access</h2>
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<p>An AI client is requesting access to your WordPress site using this API key:</p>
|
|
|
|
<div class="key-box">
|
|
<div class="lbl">API Key</div>
|
|
<div class="val"><?php echo $keyName; ?></div>
|
|
<div class="scopes">
|
|
<?php foreach ($scopes as $s): ?>
|
|
<span class="scope"><?php echo esc_html($s); ?></span>
|
|
<?php endforeach; ?>
|
|
</div>
|
|
</div>
|
|
|
|
<div class="security-note">
|
|
🔒 Access token expires in <strong>1 hour</strong>. Your API key is never shared with the client.
|
|
</div>
|
|
|
|
<form method="post" action="<?php echo esc_url($actionUrl); ?>">
|
|
<input type="hidden" name="client_id" value="<?php echo esc_attr($clientId); ?>">
|
|
<input type="hidden" name="redirect_uri" value="<?php echo esc_attr($redirectUri); ?>">
|
|
<input type="hidden" name="state" value="<?php echo esc_attr($state); ?>">
|
|
<input type="hidden" name="code_challenge" value="<?php echo esc_attr($codeChallenge); ?>">
|
|
<input type="hidden" name="code_challenge_method" value="<?php echo esc_attr($challengeMethod); ?>">
|
|
<input type="hidden" name="_mcp_approve" value="1">
|
|
<div class="btns">
|
|
<button type="submit" class="btn approve">Approve</button>
|
|
<button type="button" class="btn deny" onclick="window.location='<?php echo esc_js(add_query_arg(['error' => 'access_denied', 'state' => $state], $redirectUri)); ?>'">Deny</button>
|
|
</div>
|
|
</form>
|
|
|
|
<div class="note">Only approve if you initiated this from Claude.ai or a trusted MCP client.</div>
|
|
</div>
|
|
</body>
|
|
</html>
|
|
<?php
|
|
exit;
|
|
}
|
|
}
|