refactor: JS served vanilla, no more NPM or Express

server.js

@@ -1,14 +1,33 @@
 'use strict';
 
-const path = require('path');
-const express = require('express');
+const http = require('node:http');
+const fs = require('node:fs');
+const path = require('node:path');
+const { URL } = require('node:url');
 const { gregorianToRepublican } = require('./src/republicanCalendar');
 
-const app = express();
-const port = process.env.PORT || 3000;
+const PORT = process.env.PORT || 3000;
+const PUBLIC_DIR = path.join(__dirname, 'public');
+const LOCALES_DIR = path.join(__dirname, 'locales');
 
-app.use(express.static(path.join(__dirname, 'public')));
-app.use('/locales', express.static(path.join(__dirname, 'locales')));
+const MIME_TYPES = {
+  '.html': 'text/html; charset=utf-8',
+  '.css': 'text/css; charset=utf-8',
+  '.js': 'text/javascript; charset=utf-8',
+  '.json': 'application/json; charset=utf-8',
+  '.svg': 'image/svg+xml',
+  '.png': 'image/png',
+  '.ico': 'image/x-icon',
+};
+
+function sendJson(res, statusCode, payload) {
+  const body = JSON.stringify(payload);
+  res.writeHead(statusCode, {
+    'Content-Type': 'application/json; charset=utf-8',
+    'Content-Length': Buffer.byteLength(body),
+  });
+  res.end(body);
+}
 
 function nowUtc() {
   const now = new Date();
@@ -22,17 +41,17 @@ function nowUtc() {
 function convertAndRespond(res, gregorianDate) {
   try {
     const republicanDate = gregorianToRepublican(gregorianDate);
-    res.json({ ok: true, republicanDate });
+    sendJson(res, 200, { ok: true, republicanDate });
   } catch (error) {
     if (error.message === 'BEFORE_EPOCH') {
-      res.status(400).json({
+      sendJson(res, 400, {
         ok: false,
         error: 'BEFORE_EPOCH',
         message: 'The Republican calendar begins on 22 September 1792.',
       });
       return;
     }
-    res.status(400).json({
+    sendJson(res, 400, {
       ok: false,
       error: 'INVALID_DATE',
       message: 'The given date does not exist in the Gregorian calendar.',
@@ -40,27 +59,71 @@ function convertAndRespond(res, gregorianDate) {
   }
 }
 
-app.get('/api/today', (req, res) => {
-  convertAndRespond(res, nowUtc());
-});
+/** Serves a file from rootDir, rejecting any path that escapes it. */
+function serveStatic(res, rootDir, requestPath) {
+  const decodedPath = decodeURIComponent(requestPath.split('?')[0]);
+  const safeSuffix = path.normalize(decodedPath).replace(/^([.][.][/\\])+/, '');
+  const filePath = path.resolve(rootDir, `.${path.sep}${safeSuffix}`);
 
-app.get('/api/convert', (req, res) => {
-  const year = Number.parseInt(req.query.year, 10);
-  const month = Number.parseInt(req.query.month, 10);
-  const day = Number.parseInt(req.query.day, 10);
-
-  if (!Number.isInteger(year) || !Number.isInteger(month) || !Number.isInteger(day)) {
-    res.status(400).json({
-      ok: false,
-      error: 'INVALID_DATE',
-      message: 'year, month and day query parameters are required integers.',
-    });
+  if (filePath !== rootDir && !filePath.startsWith(rootDir + path.sep)) {
+    res.writeHead(403, { 'Content-Type': 'text/plain; charset=utf-8' });
+    res.end('Forbidden');
     return;
   }
 
-  convertAndRespond(res, { year, month, day });
+  fs.readFile(filePath, (readErr, content) => {
+    if (readErr) {
+      res.writeHead(404, { 'Content-Type': 'text/plain; charset=utf-8' });
+      res.end('Not found');
+      return;
+    }
+    const ext = path.extname(filePath).toLowerCase();
+    res.writeHead(200, { 'Content-Type': MIME_TYPES[ext] || 'application/octet-stream' });
+    res.end(content);
+  });
+}
+
+const server = http.createServer((req, res) => {
+  if (req.method !== 'GET') {
+    res.writeHead(405, { 'Content-Type': 'text/plain; charset=utf-8' });
+    res.end('Method not allowed');
+    return;
+  }
+
+  const requestUrl = new URL(req.url, `http://${req.headers.host || 'localhost'}`);
+  const pathname = requestUrl.pathname;
+
+  if (pathname === '/api/today') {
+    convertAndRespond(res, nowUtc());
+    return;
+  }
+
+  if (pathname === '/api/convert') {
+    const year = Number.parseInt(requestUrl.searchParams.get('year'), 10);
+    const month = Number.parseInt(requestUrl.searchParams.get('month'), 10);
+    const day = Number.parseInt(requestUrl.searchParams.get('day'), 10);
+
+    if (!Number.isInteger(year) || !Number.isInteger(month) || !Number.isInteger(day)) {
+      sendJson(res, 400, {
+        ok: false,
+        error: 'INVALID_DATE',
+        message: 'year, month and day query parameters are required integers.',
+      });
+      return;
+    }
+
+    convertAndRespond(res, { year, month, day });
+    return;
+  }
+
+  if (pathname.startsWith('/locales/')) {
+    serveStatic(res, LOCALES_DIR, pathname.slice('/locales'.length));
+    return;
+  }
+
+  serveStatic(res, PUBLIC_DIR, pathname === '/' ? '/index.html' : pathname);
 });
 
-app.listen(port, () => {
-  console.log(`Calendrier republicain server listening on port ${port}`);
+server.listen(PORT, () => {
+  console.log(`Calendrier republicain server listening on port ${PORT}`);
 });