geo-country.ts89 lines · main

1	import { headers } from 'next/headers';
2	import ip3country from 'ip3country';
3
4	/**
5	* Self-hosted IP → country lookup for the public /contact page.
6	*
7	* Uses ip3country — a tiny (<300KB), zero-dependency, embedded IP2Location
8	* LITE table. Everything happens in-process: no external API call, no
9	* account, no per-request network hop, so it can run inside a server
10	* component on every render without leaking the visitor's IP to a third
11	* party.
12	*
13	* The detected country drives the LOCKED "country" field on the contact
14	* form — it is shown read-only and submitted alongside the message so an
15	* operator can see where a request came from. It is a hint, never a hard
16	* gate: when the IP can't be resolved (localhost, IPv6, private ranges,
17	* unknown blocks) the field falls back to "unknown" and stays locked.
18	*/
19
20	export interface DetectedCountry {
21	/** ISO 3166-1 alpha-2 country code, e.g. "US". */
22	code: string;
23	/** Human-readable English country name, e.g. "United States". */
24	name: string;
25	}
26
27	// init() builds the lookup tables and is relatively CPU-heavy, so do it
28	// once per process and reuse it across requests.
29	let initialized = false;
30	function ensureInit(): void {
31	if (!initialized) {
32	ip3country.init();
33	initialized = true;
34	}
35	}
36
37	/** First, left-most IP in a comma-separated `x-forwarded-for` chain. */
38	function firstForwardedIp(value: string | null): string | null {
39	if (!value) return null;
40	const first = value.split(',')[0]?.trim();
41	return first && first.length > 0 ? first : null;
42	}
43
44	// ip3country resolves IPv4 dot-decimal addresses; anything else (IPv6,
45	// garbage) is skipped so we never surface a wrong country.
46	function isIpv4(ip: string): boolean {
47	return /^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/.test(ip);
48	}
49
50	/** Map an ISO 3166-1 alpha-2 code to an English display name. */
51	function codeToName(code: string): string {
52	try {
53	const display = new Intl.DisplayNames(['en'], { type: 'region' });
54	return display.of(code) ?? code;
55	} catch {
56	return code;
57	}
58	}
59
60	/**
61	* Resolve the current request's visitor country from request headers.
62	* Reads the FIRST ip in `x-forwarded-for` (Traefik forwards the real
63	* client there), falling back to `x-real-ip`. Returns null when the
64	* country can't be determined (localhost, IPv6, unknown block) — the
65	* caller then renders a locked "unknown" field.
66	*
67	* Server-only: relies on `next/headers`.
68	*/
69	export async function detectCountry(): Promise<DetectedCountry | null> {
70	let ip: string | null = null;
71	try {
72	const h = await headers();
73	ip = firstForwardedIp(h.get('x-forwarded-for')) ?? firstForwardedIp(h.get('x-real-ip'));
74	} catch {
75	return null;
76	}
77	if (!ip || !isIpv4(ip)) return null;
78
79	ensureInit();
80	let code: string | null = null;
81	try {
82	code = ip3country.lookupStr(ip);
83	} catch {
84	return null;
85	}
86	if (!code) return null;
87
88	return { code, name: codeToName(code) };
89	}