54 lines
1.4 KiB
PHP
54 lines
1.4 KiB
PHP
<?php
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require_once __DIR__ . '/_helpers.php';
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/**
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* Short URL Integrity Verification API
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* GET: Return the hash and HMAC signature for client-side verification.
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*
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* Security: Allows client-side detection of server-side tampering.
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* The HMAC secret is stored in data/secret.key (auto-generated on first run).
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*/
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header('Content-Type: application/json');
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send_security_headers();
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if ($_SERVER['REQUEST_METHOD'] !== 'GET') {
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http_response_code(405);
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echo json_encode(['error' => 'Method not allowed']);
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exit;
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}
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$code = $_GET['code'] ?? '';
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if (empty($code) || !preg_match('/^[a-z0-9]{4,10}$/', $code)) {
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http_response_code(400);
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echo json_encode(['error' => 'Invalid code']);
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exit;
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}
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$dbFile = __DIR__ . '/../data/urls.json';
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if (!file_exists($dbFile)) {
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http_response_code(404);
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echo json_encode(['error' => 'Invoice not found']);
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exit;
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}
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$urls = json_decode(file_get_contents($dbFile), true) ?: [];
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if (!isset($urls[$code])) {
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http_response_code(404);
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echo json_encode(['error' => 'Invoice not found']);
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exit;
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}
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$data = $urls[$code];
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$hash = is_array($data) ? $data['h'] : $data;
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$signature = is_array($data) ? $data['s'] : null;
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// Re-derive expected signature so client can verify
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$expected = $signature ? hash_hmac('sha256', $hash, get_hmac_secret()) : null;
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echo json_encode([
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'code' => $code,
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'hash' => $hash,
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'signature' => $expected
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]);
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