apply patch "Rose's hubris"

index.mjs

@@ -1,30 +1,44 @@
 import * as fs from 'node:fs';
-import express from 'express';
+import http from 'node:http';
 
-const sites = fs.readFileSync('./webring.txt', 'utf-8')
-	// split lines
-	.split(/\r?\n/)
-	// trim whitespace from each line
-	.map(site => site.trim())
-	// exclude empty lines and lines that start with # because why not
-	.filter(site => site && !site.startsWith('#'));
-
-// modulo that does the right thing with negatives
-// https://stackoverflow.com/a/4467559
 const mod = (n, m) => ((n % m) + m) % m;
+const stripURL = s => s.replace(/(^https?:\/\/|\/$)/g, '')
 
-function handle (offset, request, response) {
+const sitesArray = fs.readFileSync('./webring.txt', 'utf-8')
-	const from = request.query.from;
+	.match(/(?<!#.*)https?:\/\/[^\s]+(?=\s*$)/gmi)
-	const index = sites.findIndex(site => site === from);
+
-	if (!from || index === -1) {
+const sitesLookup = sitesArray.map(stripURL).reduce((acc, current, index) => ({
-		response.status(400).send('the provided site is not in the webring');
+	...acc, [current]: {
-		return;
+		'/next': sitesArray[mod(index + 1, sitesArray.length)],
+		'/prev': sitesArray[mod(index - 1, sitesArray.length)],
 	}
-	response.redirect(301, sites[mod(index + offset, sites.length)]);
+}), {})
+
+const redirect = (response, url) => {
+	response.setHeader('Location', url)
+	response.statusCode = 301
+	response.end()
 }
 
-express()
+const handle = (direction, from, response) => {
-	.get('/prev', (request, response) => handle(-1, request, response))
+	const destination = sitesLookup[stripURL(from)]?.[direction]
-	.get('/next', (request, response) => handle(+1, request, response))
+
-	.get('/list', (_, response) => response.type('txt').send(sites.join('\n')))
+	if (destination)
-	.listen(process.env.PORT || 8080);
+		return redirect(response, destination)
+
+	response.statusCode = 400
+	response.end('the provided site is not in the webring')
+}
+
+http.createServer((request, response) => {
+	const url = new URL(request.url, `http://${request.headers.host}`);
+
+	if (url.pathname === '/prev' || url.pathname === '/next') {
+		return handle(url.pathname, url.searchParams.get('from'), response)
+	} else if (url.pathname === '/list') {
+		return response.setHeader('Content-Type', 'text/plain').end(sitesArray.join('\n'))
+	}
+
+	response.statusCode = 404
+	response.end('not found')
+}).listen(process.env.PORT || 8080)