1 files changed, 116 insertions, 0 deletions
diff --git a/lib/network/get-client-ip.ts b/lib/network/get-client-ip.ts
new file mode 100644
index 00000000..566700e9
--- /dev/null
+++ b/lib/network/get-client-ip.ts
@@ -0,0 +1,116 @@
+import { NextRequest } from 'next/server';
+
+export interface GetClientIpOptions {
+  /**
+   * Which index to take from a comma-separated forwarded-for list.
+   * 0 = leftmost (original client; default).
+   * -1 = rightmost (closest hop).
+   */
+  forwardedIndex?: number;
+
+  /**
+   * Custom header priority override. Default uses common reverse-proxy headers.
+   */
+  headerPriority?: readonly string[];
+
+  /**
+   * Value to return when nothing found.
+   * Default: 'unknown'
+   */
+  fallback?: string;
+}
+
+const DEFAULT_HEADER_PRIORITY = [
+  'x-forwarded-for',
+  'x-real-ip',
+  'cf-connecting-ip',
+  'vercel-forwarded-for',
+] as const;
+
+export function getClientIp(
+  req: NextRequest,
+  opts: GetClientIpOptions = {}
+): string {
+  const {
+    forwardedIndex = 0,
+    headerPriority = DEFAULT_HEADER_PRIORITY,
+    fallback = 'unknown',
+  } = opts;
+
+  for (const h of headerPriority) {
+    const raw = req.headers.get(h);
+    if (!raw) continue;
+
+    // headers like x-forwarded-for can be CSV
+    const parts = raw.split(',').map(p => p.trim()).filter(Boolean);
+    if (parts.length === 0) continue;
+
+    const idx =
+      forwardedIndex >= 0
+        ? forwardedIndex
+        : parts.length + forwardedIndex; // support -1 end indexing
+
+    const sel = parts[idx] ?? parts[0]; // safe fallback to 0
+    const norm = normalizeIp(sel);
+    if (norm) return norm;
+  }
+
+  return fallback;
+}
+
+/**
+ * Normalize IPv4/IPv6/port-suffixed forms to a canonical-ish string.
+ */
+export function normalizeIp(raw: string | null | undefined): string {
+  if (!raw) return '';
+
+  let ip = raw.trim();
+
+  // Strip brackets: [2001:db8::1]
+  if (ip.startsWith('[') && ip.endsWith(']')) {
+    ip = ip.slice(1, -1);
+  }
+
+  // IPv4:port (because some proxies send ip:port)
+  // Heuristic: if '.' present (IPv4-ish) and ':' present, drop port after last colon.
+  if (ip.includes('.') && ip.includes(':')) {
+    ip = ip.slice(0, ip.lastIndexOf(':'));
+  }
+
+  // IPv4-mapped IPv6 ::ffff:203.0.113.5
+  if (ip.startsWith('::ffff:')) {
+    ip = ip.substring(7);
+  }
+
+  return ip;
+}
+
+
+export interface RequestInfo {
+    ip: string;
+    userAgent: string;
+    referer?: string;
+    requestId: string;
+    method: string;
+    url: string;
+  }
+  
+  export function getRequestInfo(req: NextRequest, ipOpts?: GetClientIpOptions): RequestInfo {
+    const ip = getClientIp(req, ipOpts);
+    const userAgent = req.headers.get('user-agent')?.trim() || 'unknown';
+  
+    const refererRaw = req.headers.get('referer')?.trim();
+    const referer = refererRaw && refererRaw.length > 0 ? refererRaw : undefined;
+  
+    const { href, pathname } = req.nextUrl;
+  
+    return {
+      ip,
+      userAgent,
+      referer,
+      requestId: (globalThis.crypto?.randomUUID?.() ?? crypto.randomUUID()),
+      method: req.method,
+      url: href || pathname,
+    };
+  }
+  
+\ No newline at end of file