From 898b52edcb47bcb3e9d6106e74ca73e74ea01e70 Mon Sep 17 00:00:00 2001
From: sillylaird <sillyfanboy@gmail.com>
Date: Thu, 3 Sep 2026 00:33:59 +0000
Subject: import live www.sillylaird.ca webroot

---
 partials/proxy_helpers.php | 80 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 partials/proxy_helpers.php

(limited to 'partials/proxy_helpers.php')

diff --git a/partials/proxy_helpers.php b/partials/proxy_helpers.php
new file mode 100644
index 0000000..59ac3cb
--- /dev/null
+++ b/partials/proxy_helpers.php
@@ -0,0 +1,80 @@
+<?php
+// partials/proxy_helpers.php — small shared helpers for the *-proxy.php endpoints.
+//
+// - lastfm_api_key():       read LASTFM_API_KEY from env (with legacy fallback).
+// - proxy_host_is_safe():   reject hosts that resolve to private/reserved IPs (SSRF guard).
+// - proxy_rate_limit():     simple per-IP sliding-window limit, file-backed.
+
+if (!function_exists('lastfm_api_key')) {
+    function lastfm_api_key(): string {
+        $env = getenv('LASTFM_API_KEY');
+        if (is_string($env) && $env !== '') return $env;
+        throw new RuntimeException('LASTFM_API_KEY is not set in the php-fpm environment');
+    }
+}
+
+if (!function_exists('proxy_host_is_safe')) {
+    function proxy_host_is_safe(string $host): bool {
+        if ($host === '') return false;
+        // Reject anything that looks like a literal IPv6 with brackets stripped earlier.
+        $records = @dns_get_record($host, DNS_A | DNS_AAAA);
+        $ips = [];
+        if (is_array($records)) {
+            foreach ($records as $r) {
+                if (!empty($r['ip']))    $ips[] = $r['ip'];
+                if (!empty($r['ipv6']))  $ips[] = $r['ipv6'];
+            }
+        }
+        // Also check if the host is itself an IP literal.
+        if (filter_var($host, FILTER_VALIDATE_IP)) {
+            $ips[] = $host;
+        }
+        if (!$ips) return false; // unresolvable -> deny
+        foreach ($ips as $ip) {
+            $ok = filter_var(
+                $ip,
+                FILTER_VALIDATE_IP,
+                FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE
+            );
+            if ($ok === false) return false;
+        }
+        return true;
+    }
+}
+
+if (!function_exists('proxy_rate_limit')) {
+    /**
+     * Returns true if the request is allowed. Uses a tiny file per
+     * (endpoint, client IP) holding recent unix timestamps.
+     */
+    function proxy_rate_limit(string $endpoint, int $max = 30, int $windowSec = 60): bool {
+        $ip   = $_SERVER['REMOTE_ADDR'] ?? '0.0.0.0';
+        $key  = preg_replace('/[^A-Za-z0-9._-]/', '_', $endpoint . '_' . $ip);
+        $dir  = sys_get_temp_dir() . '/sillylaird_ratelimit';
+        if (!is_dir($dir)) @mkdir($dir, 0700, true);
+        $file = $dir . '/' . $key;
+
+        $now    = time();
+        $cutoff = $now - $windowSec;
+
+        $fp = @fopen($file, 'c+');
+        if (!$fp) return true; // fail-open: don't block legit traffic on disk error
+        try {
+            flock($fp, LOCK_EX);
+            $data = stream_get_contents($fp);
+            $stamps = $data === '' ? [] : array_map('intval', explode("\n", trim($data)));
+            $stamps = array_values(array_filter($stamps, fn($t) => $t >= $cutoff));
+            if (count($stamps) >= $max) {
+                return false;
+            }
+            $stamps[] = $now;
+            ftruncate($fp, 0);
+            rewind($fp);
+            fwrite($fp, implode("\n", $stamps));
+            return true;
+        } finally {
+            flock($fp, LOCK_UN);
+            fclose($fp);
+        }
+    }
+}
-- 
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