add solution

src/createServer.js

@@ -1,8 +1,110 @@
 'use strict';
 
+const http = require('http');
+const fs = require('fs');
+const zlib = require('zlib');
+const formidable = require('formidable');
+
 function createServer() {
-  /* Write your code here */
-  // Return instance of http.Server class
+  return http.createServer((req, res) => {
+    if (req.url === '/' && req.method === 'GET') {
+      res.writeHead(200, { 'Content-Type': 'text/html' });
+
+      res.end(`
+        <form action="/compress" method="POST" enctype="multipart/form-data">
+          <input type="file" name="file" required />
+          <select name="compressionType" required>
+            <option value="gzip">gzip</option>
+            <option value="deflate">deflate</option>
+            <option value="br">br</option>
+          </select>
+          <button type="submit">Compress</button>
+        </form>
+        `);
+    } else if (req.url === '/compress' && req.method === 'POST') {
+      const form = new formidable.IncomingForm();
+
+      form.parse(req, (error, fields, files) => {
+        if (error) {
+          res.statusCode = 400;
+
+          return res.end('Error parsing form');
+        }
+
+        const compressionType = String(fields.compressionType || '')
+          .trim()
+          .toLowerCase();
+
+        const supported = ['gzip', 'deflate', 'br'];
+
+        if (!supported.includes(compressionType)) {
+          res.statusCode = 400;
+
+          return res.end('Unsupported compression type');
+        }
+
+        const fileData = files.file?.[0];
+
+        if (!fileData) {
+          res.statusCode = 400;
+
+          return res.end('Error parsing file');
+        }
+
+        const uploadedFile = files.file?.[0];
+        const uploadedFilePath = uploadedFile?.filepath;
+
+        const originalNameSafe = uploadedFile.originalFilename || 'file';
+
+        if (!uploadedFilePath) {
+          res.statusCode = 400;
+
+          return res.end('File path not found');
+        }
+
+        let compressStream;
+
+        switch (compressionType) {
+          case 'gzip':
+            compressStream = zlib.createGzip();
+            break;
+          case 'deflate':
+            compressStream = zlib.createDeflate();
+            break;
+          case 'br':
+            compressStream = zlib.createBrotliCompress();
+            break;
+        }
+
+        const readStream = fs.createReadStream(uploadedFilePath);
+
+        readStream.on('error', () => {
+          res.statusCode = 500;
+          res.end('Error reading file');
+        });
+
+        compressStream.on('error', () => {
+          res.statusCode = 500;
+          res.end('Error compressing file');
+        });
+
+        res.writeHead(200, {
+          'Content-Type': 'application/octet-stream',
+          'Content-Disposition': `attachment; filename=${originalNameSafe}.${compressionType}`,
+        });
+
+        readStream.pipe(compressStream).pipe(res);
+      });
+    } else if (req.url === '/compress') {
+      res.statusCode = 400;
+
+      return res.end('Only POST allowed on /compress');
+    } else {
+      res.statusCode = 404;
+
+      return res.end('Not Found');
+    }
+  });
 }
 
 module.exports = {