building Node.js video streaming in 5 minutes
Tags: javascript, node, tutorial, wordpress
Published: 2022-03-03 10:37:51

hi folks, in this blog we will build a Node.js video streaming application in like 10 minutes.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/y5q6x7div0uqhpxnblqz.gif)

### prerequisite
- install Node.js in your computer


## what is streaming

Streams are collections of data — just like arrays or strings. The difference is that streams might not be available all at once, and they don’t have to fit in memory. This makes streams really powerful when working with large amounts of data, or data that’s coming from an external source one chunk at a time.

##  setup [ 1 ] - Geting started 
1 - create folder and name it `vido-streaming`
2 - initialize npm in your project `npm init -y`
3 - install this packages

dependencies.
```
#### npm install express
```

#### development dependencies.
```
npm install -D nodemon
```

#### add this script to your `package.json` file.
```json
"start": "nodemon index.js"
```
## setup [2]  - setup Node.js server

1 - create `index.js` file in your project root.
2 - add this code below 

```js 
const express = require("express");

const app = express(); // setup express application
const PORT = process.env.PORT || 3000;

app.listen(PORT, () => {
  console.log("SERVER STARTED AT PORT: " + PORT);
});
```

this code starting web server using `express` framework and listening to port: `3000`.

## setup [3] - serving html page

now we want to serve an html page with video element to the Frontend.

1 - create `public` folder in your project root.
2 - create `index.html` file in created folder (`public`) and add this html code.

```html

<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Home | Video Streaming</title>
  </head>
  <body>
    <video 
    controls 
    src="/video" 
    id="video-stream" 
    poster="/poster.jpeg" 
    width="700"
    >
	</video>
  </body>
</html>
```

- `controls` :  Specifies that video controls should be displayed (such as a play/pause button etc).

- `src` : Specifies the URL of the video file.

- `poster`: Specifies an image to be shown while the video is downloading, or until the user hits the play button.

### serving html file
we need to send the html page to the users. add this code below in `index.js` file.
```js
app.get("/", (req, res) => {
try {
	res.sendFile(__dirname + "/public/index.html");
} catch (err) {
	res.status(500).send("internal server error occurred")
}
});
```
what that code does, is listening to get request in base URL of the application, when it get the response will be send file by using `sendFile` and first parameter is  html file path.

note:  `__dirname` is the root path of the current directory. 


## Serving Poster Image - setup [4]
poster is image will be shown until the video is downloading or user click the video.
note : you need to any image you want in public directory that you make.
see the code below

```js
app.get("/:file_name", (req, res) => {
	try {
		res.sendFile(__dirname + req.params.file_name);
	} catch (err) {
		res.status(500).send("internal server error occurred");
	}
});
```

## Streaming video - setup[5] and Final
### import required node.js modules
when streaming the video we need to import two Node.js build-in library in the top of file.
```js
const  fs = require("fs");
const  path = require("path");
```
`fs` : **file system module** allows you to work with the file system on your computer. To include the File System module.

`path`: **allows you to interact with file paths easily**. The path module has many useful properties and methods to access and manipulate paths in the file system.

### setup video API function
add this code before Serving Poster Image function, because nodejs will go throw the express middlewares and if the requested url is `/video`  it will be match the  Serving Poster Image middlewaree not the video middleware.
note : you need to add random video in public file.
```js
app.get("/video", (req, res) => {
// indicates the part of a document that the server should return
// on this measure in bytes for example: range = 0-6 bytes.
const  range = req.headers.range;
if (!range) res.status(400).send("Range must be provided");

const  videoPath = path.join(__dirname, "public", "video.mp4");
// extract video size by using statSyn()
const  videoSize = fs.statSync(videoPath).size;
// 10 powered by 6 equal 1000000bytes = 1mb
const  chunkSize = 10 ** 6; 

// calculating video where to start and where to end.
const  start = Number(range.replace(/\D/g, ""));
const  end = Math.min(start + chunkSize, videoSize - 1);
const  contentLength = end - start + 1;

// setup video headers
const  headers = {
"Content-Range":  `bytes ${start}-${end}/${videoSize}`,
"Accept-Ranges":  "bytes",
"Content-Length":  contentLength,
"Content-Type":  "video/mp4",
};

res.writeHead(206, headers);
// creating readStream (stdin).
const  videoStream = fs.createReadStream(videoPath, { start, end });

// create live stream pipe line
videoStream.pipe(res);
});
```

### and then run ` npm run start`. to see your work.

### what is pipe() in streaming
  Streams make for quite a handy abstraction, and there's a lot you can do with them - as an example,  `stream.pipe()`, the method used to take a readable stream and connect it to a writeable stream. the writable stream is user we request him the data buffers.

project source code: https://github.com/alguerocode/video-streaming
follow me in github: [alguerocode](https://github.com/alguerocode)

thank you for reading.