feat: add configurable HLS CORS allowlists

src/Cors/Origin.php

@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Plugin\AzuraCastOnDemandHls\Cors;
+
+use InvalidArgumentException;
+
+/** Validates and canonicalizes web origins used by the HLS CORS allowlist. */
+final class Origin
+{
+    public static function normalize(string $origin): string
+    {
+        $origin = trim($origin);
+        if ('' === $origin || 'null' === strtolower($origin)) {
+            throw new InvalidArgumentException('A CORS origin must be an absolute HTTP or HTTPS origin.');
+        }
+
+        $parts = parse_url($origin);
+        if (false === $parts
+            || !isset($parts['scheme'], $parts['host'])
+            || isset($parts['user'], $parts['pass'], $parts['query'], $parts['fragment'])
+            || (isset($parts['path']) && '/' !== $parts['path'])
+        ) {
+            throw new InvalidArgumentException(sprintf('Invalid CORS origin: %s', $origin));
+        }
+
+        $scheme = strtolower($parts['scheme']);
+        $host = strtolower($parts['host']);
+        if (!in_array($scheme, ['http', 'https'], true)
+            || '' === $host
+            || !preg_match('/^[a-z0-9.-]+$/D', $host)
+        ) {
+            throw new InvalidArgumentException(sprintf('Invalid CORS origin: %s', $origin));
+        }
+
+        $port = $parts['port'] ?? null;
+        if (null !== $port && ($port < 1 || $port > 65535)) {
+            throw new InvalidArgumentException(sprintf('Invalid CORS origin: %s', $origin));
+        }
+
+        if (('https' === $scheme && 443 === $port) || ('http' === $scheme && 80 === $port)) {
+            $port = null;
+        }
+
+        return $scheme . '://' . $host . (null === $port ? '' : ':' . $port);
+    }
+}