solution

src/createServer.js

@@ -1,8 +1,172 @@
 'use strict';
 
+const http = require('http');
+const fs = require('fs/promises');
+const path = require('path');
+
+class CustomServer extends http.Server {
+  #endpoints = {};
+
+  get(endpoint, cb) {
+    if (!this.#endpoints.hasOwnProperty(endpoint)) {
+      this.#endpoints[endpoint] = {};
+    }
+
+    this.#endpoints[endpoint].get = cb;
+  }
+
+  post(endpoint, cb) {
+    if (!this.#endpoints.hasOwnProperty(endpoint)) {
+      this.#endpoints[endpoint] = {};
+    }
+
+    this.#endpoints[endpoint].post = cb;
+  }
+
+  useCb(req, res) {
+    const normalizeMethod = req.method.toLowerCase();
+    const normalizeUrl = new URL(req.url, `http://${req.headers.host}`);
+    const urlPath = normalizeUrl.pathname || '/';
+
+    if (!this.#endpoints.hasOwnProperty(urlPath)) {
+      throw new Error(404);
+    } else if (!this.#endpoints[urlPath].hasOwnProperty(normalizeMethod)) {
+      throw new Error(405);
+    }
+
+    const cb = this.#endpoints[urlPath][normalizeMethod];
+
+    return cb(req, res);
+  }
+
+  initServer() {
+    this.on('request', async (req, res) => {
+      try {
+        this.useCb(req, res);
+      } catch (err) {
+        const status = Number(err.message) || 520;
+
+        res.statusCode = status;
+
+        switch (status) {
+          case 404:
+            res.end('The requested resource could not be found on this server');
+            break;
+          case 405:
+            res.end(
+              'The requested HTTP method is not supported for this endpoint',
+            );
+            break;
+
+          default:
+            res.statusCode = 520;
+            res.end('The server returned an unknown error.');
+        }
+      }
+    });
+  }
+}
+
 function createServer() {
-  /* Write your code here */
-  // Return instance of http.Server class
+  const server = new CustomServer();
+
+  server.initServer();
+
+  server.get('/', (_r, res) => {
+    const form = `<form method='POST' action="http://localhost:5701/add-expense">
+        <input name="date" required type="date" />
+        <input name="title" required type="text" />
+        <input name="amount" required type="text" />
+        <input type="submit" />
+      </form>`;
+
+    res.writeHead(200, { 'Content-Type': 'text/html' });
+    res.end(form);
+  });
+
+  server.post('/add-expense', async (req, res) => {
+    const pathToDb = path.resolve(__dirname, '..', 'db', 'expense.json');
+    const chunks = [];
+
+    for await (const chunk of req) {
+      chunks.push(chunk);
+    }
+
+    const data = Buffer.concat(chunks).toString();
+    let dataObject;
+
+    switch (req.headers['content-type']) {
+      case 'application/json':
+        dataObject = JSON.parse(data);
+        break;
+      case 'application/x-www-form-urlencoded':
+        const entriesForObj = new URLSearchParams(data);
+
+        dataObject = Object.fromEntries(entriesForObj);
+        break;
+      default:
+        res.writeHead(400, { 'Content-Type': 'text/plain' });
+        res.end('Сontent type not supported');
+
+        return;
+    }
+
+    const { date, title, amount } = dataObject;
+
+    if (!date || !title || !amount) {
+      res.writeHead(400, { 'Content-Type': 'text/plain' });
+      res.end('Invalid data');
+
+      return;
+    }
+
+    try {
+      await fs.access(path.join(pathToDb, '..'), fs.constants.F_OK);
+    } catch (_e) {
+      try {
+        await fs.mkdir(path.join(pathToDb, '..'), { recursive: true });
+      } catch (_err) {
+        res.writeHead(500, { 'Content-Type': 'text/plain' });
+        res.end('Something went wrong');
+
+        return;
+      }
+    }
+
+    let expensesList;
+    let readedData = await fs.readFile(pathToDb).catch((_e) => {
+      readedData = `[]`;
+    });
+
+    try {
+      expensesList = JSON.parse(readedData);
+
+      if (!Array.isArray(expensesList)) {
+        expensesList = JSON.stringify([dataObject], null, 2);
+      } else {
+        const copyList = [...expensesList, dataObject];
+
+        expensesList = JSON.stringify(copyList, null, 2);
+      }
+    } catch (err) {
+      expensesList = JSON.stringify([dataObject], null, 2);
+    }
+
+    try {
+      await fs.writeFile(pathToDb, expensesList);
+    } catch (_er) {
+      res.writeHead(500, { 'Content-Type': 'text/plain' });
+      res.end('Something went wrong');
+
+      return;
+    }
+
+    res.statusCode = 200;
+    res.setHeader('Content-Type', 'text/html');
+    res.end(`<pre>${expensesList}</pre>`);
+  });
+
+  return server;
 }
 
 module.exports = {