1 files changed, 60 insertions, 0 deletions
diff --git a/src/lib/ip.ts b/src/lib/ip.ts
new file mode 100644
index 0000000..5cd7757
--- /dev/null
+++ b/src/lib/ip.ts
@@ -0,0 +1,60 @@
+export const IP_ADDRESS_HEADERS = [
+  'true-client-ip', // CDN
+  'cf-connecting-ip', // Cloudflare
+  'fastly-client-ip', // Fastly
+  'x-nf-client-connection-ip', // Netlify
+  'do-connecting-ip', // Digital Ocean
+  'x-real-ip', // Reverse proxy
+  'x-appengine-user-ip', // Google App Engine
+  'x-forwarded-for',
+  'forwarded',
+  'x-client-ip',
+  'x-cluster-client-ip',
+  'x-forwarded',
+];
+
+export function getIpAddress(headers: Headers) {
+  const customHeader = process.env.CLIENT_IP_HEADER;
+
+  if (customHeader && headers.get(customHeader)) {
+    return headers.get(customHeader);
+  }
+
+  const header = IP_ADDRESS_HEADERS.find(name => {
+    return headers.get(name);
+  });
+
+  const ip = headers.get(header);
+
+  if (header === 'x-forwarded-for') {
+    return ip?.split(',')?.[0]?.trim();
+  }
+
+  if (header === 'forwarded') {
+    const match = ip.match(/for=(\[?[0-9a-fA-F:.]+\]?)/);
+
+    if (match) {
+      return match[1];
+    }
+  }
+
+  return ip;
+}
+
+export function stripPort(ip: string) {
+  if (ip.startsWith('[')) {
+    const endBracket = ip.indexOf(']');
+    if (endBracket !== -1) {
+      return ip.slice(0, endBracket + 1);
+    }
+  }
+
+  const idx = ip.lastIndexOf(':');
+  if (idx !== -1) {
+    if (ip.includes('.') || /^[a-zA-Z0-9.-]+$/.test(ip.slice(0, idx))) {
+      return ip.slice(0, idx);
+    }
+  }
+
+  return ip;
+}