Advance Nodejs

Author: prabaprakash

Advance Nodejs/19. transformstream.js

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+const { Transform } = require('stream');
+
+class ReplaceText extends Transform {
+
+  constructor(char) {
+    super();
+    this.replaceChar = char;
+  }
+
+  _transform(chunk, encoding, callback) {
+      const transformChunk = chunk.toString()
+        .replace(/[a-z]|[A-Z]|[0-9]/g, this.replaceChar);
+      this.push(transformChunk)
+      callback();
+  }
+
+  _flush(callback) {
+     this.push('more stuff is being passed...');
+     callback();
+  }
+
+}
+
+var xStream = new ReplaceText('XX');
+
+process.stdin
+  .pipe(xStream)
+  .pipe(process.stdout);

Advance Nodejs/20. httpserver, video server.js

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+const { createServer } = require('http');
+const { stat, createReadStream } = require('fs');
+const { promisify } = require('util');
+const fileName = '../../powder-day.mp4';
+const fileInfo = promisify(stat);
+
+createServer(async (req, res) => {
+  const { size } = await fileInfo(fileName);
+  res.writeHead(200, {
+    'Content-Length': size,
+    'Content-Type': 'video/mp4'
+  });
+  createReadStream(fileName).pipe(res);
+}).listen(3000, () => console.log('server running - 3000'));

Advance Nodejs/21. httpServer, Video Server, Range.js

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+const { createServer } = require('http');
+const { stat, createReadStream } = require('fs');
+const { promisify } = require('util');
+const fileName = '../../powder-day.mp4';
+const fileInfo = promisify(stat);
+
+createServer(async (req, res) => {
+  const { size } = await fileInfo(fileName);
+  const range = req.headers.range;
+  if (range) {
+    let [start, end] = range.replace(/bytes=/, '').split('-');
+    start = parseInt(start, 10);
+    end = end ? parseInt(end, 10) : size - 1;
+    res.writeHead(206, {
+       'Content-Range': `bytes ${start}-${end}/${size}`,
+       'Accept-Ranges': 'bytes',
+       'Content-Length': (end-start) + 1,
+       'Content-Type': 'video/mp4'
+    })
+    createReadStream(fileName, { start, end }).pipe(res);
+  } else {
+    res.writeHead(200, {
+      'Content-Length': size,
+      'Content-Type': 'video/mp4'
+    });
+    createReadStream(fileName).pipe(res);
+  }
+}).listen(3000, () => console.log('server running - 3000'));

Advance Nodejs/22. httpServer, Video Server, Upload, Play.js

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+const { createServer } = require('http');
+const {
+  stat,
+  createReadStream,
+  createWriteStream 
+} = require('fs');
+const { promisify } = require('util');
+const fileName = '../../powder-day.mp4';
+const fileInfo = promisify(stat);
+
+const respondWithVideo = async (req, res) => {
+  const { size } = await fileInfo(fileName);
+  const range = req.headers.range;
+  if (range) {
+    let [start, end] = range.replace(/bytes=/, '').split('-');
+    start = parseInt(start, 10);
+    end = end ? parseInt(end, 10) : size - 1;
+    res.writeHead(206, {
+       'Content-Range': `bytes ${start}-${end}/${size}`,
+       'Accept-Ranges': 'bytes',
+       'Content-Length': (end-start) + 1,
+       'Content-Type': 'video/mp4'
+    })
+    createReadStream(fileName, { start, end }).pipe(res);
+  } else {
+    res.writeHead(200, {
+      'Content-Length': size,
+      'Content-Type': 'video/mp4'
+    });
+    createReadStream(fileName).pipe(res);
+  }
+}
+
+createServer((req, res) => {
+  if (req.method === 'POST') {
+    req.pipe(res);
+    req.pipe(process.stdout);
+    req.pipe(createWriteStream('./upload.file'));
+  } else if (req.url === '/video') {
+    respondWithVideo(req, res);
+  } else {
+    res.writeHead(200, { 'Content-Type': 'text/html' });
+    res.end(`
+      <form enctype="multipart/form-data" method="POST" action="/">
+        <input type="file" name="upload-file" />
+        <button>Upload File</button>
+      </form>
+    `);
+  }
+
+}).listen(3000, () => console.log('server running - 3000'));