#23 Understanding Streams in Practice | Fundamentals of NODE JS | A Complete NODE JS Course

[@iqronegoro1538]

very very very very very very very very clear explanation!

[@akhilkamath1266]

amazing explanation!

[@littlewonder8641]

Superb explanations and content materials.

[@sravanakumarpulivendula8573]

Hello Sir, minor correction. above example res.end() should be call rs.on('end') event otherwise completed data will not send to the client.

[@sajidalikhan5872]

@@Uiosrtk like this const server = http.createServer((req, res) => { let rs = fs.createReadStream("output.txt"); rs.on("data", (chunk) => { console.log("reading data"); res.write(chunk); }); res.on("end", () => { console.log("end response"); res.end(); }); rs.on("error", (error) => { res.end(error.message); }); });

[@sajidalikhan5872]

instead of res.end do rs.end

[@karimmuhammad7051]

in this case, so what is difference between this way and `readFile`? both of them wait read completly file then send back!

[@spatialnasir]

This is a wonderful explanation. However, it's a bit difficult to appreciate the streaming if you're not seeing the beginning and end of each stream chunk. So, here's a little improvement I tried: 1. I created a txt file that contains the exact text used by the author but each line is numbered. Here's the link to download it: drive.google.com/file/d/1VgzCFDkqgfrTCkcuj2MJVSQtd2mQzN1X/view?usp=sharing 2. I modified my code as follows: let part = 0; server.on('request', (req, res)=>{ let rs = fs.createReadStream('./Files/large-file.txt'); rs.on('data', (chunk)=>{ res.write(chunk); res.write(`............THIS CHUNK IS PART ${part}...............`); part += 1; }); rs.on('error', (error=>res.end(error.message))) // res.end('All done!'); }) Here, I added a variable called 'part' to keep track of how many chunks have been streamed. After writing each chunk, I write the current "part" to display the line where the chunk stopped. Then I increment the part "variable" For me, each chunk was about 680 lines long. I hope you also find it helpful.

[@mayanksinghal6794]

Hello, I am using your code. And with even streaming, my page is kept on loading the content for few mins. Can you help me to think why?

[@sajidalikhan5872]

@@mayanksinghal6794 const fs = require("fs"); const http = require("http"); const server = http.createServer((req, res) => { let rs = fs.createReadStream("outputu.txt"); rs.on("data", (chunk) => { console.log("reading data"); res.write(chunk); }); rs.on("end", () => { console.log("end response"); res.end(); }); rs.on("error", (error) => { res.end(error.message); }); }); server.listen("4000", "localhost", () => { console.log("Received request"); });

[@MayankSingh-ux9iz]

@@mayanksinghal6794 Same query? Does anybody knows why it happens?

[@dmitryfateev378]

This txt file with 1kk lines is around 80mb. My Chrome runs out of memory and crashes by trying to render the ton of text. Maybe that's the issue with "your page's loading for sooo long" in some way.

[@吳冠賢-t1v]

There is a little advise that you can print the new line by adding at head and tail of res.write(`............THIS CHUNK IS PART ${part}...............`);

[@muzamilhussain6459]

from where i can get the large-file.txt because it is not present in the github repo

[@mohitpandya_2228]

This data is practically too long to handle. I would suggest all the fellow coders to keep the data upto 50000 or 100000 to have a better result. Thank you. Happy learning :)

[@TheAbiGeorge]

Thank you 😍

[@rahulrock5282]

Very very nice bro i want to do file download like 1 gb data i have to query from db how to do it..

[@hassannouri9796]

❤❤❤

[@mayanksinghal6794]

Hey sir, My content of the input.txt file is not displaying on the local host screen. I have tried to change the file, and also my location of the file is correct. res.end is displayed but res.write is not displayed on the local host screen. HERE'S MY CODE: server.on("request", (req,res)=>{ let rs= fs.createReadStream("./files/start.txt", "utf-8") rs.on('data',(chunk)=>{ res.write(chunk) }) res.end("work is done"); })

[@didyouknow449]

that's because you are displaying ("work is done") and not the data , to fix it you need to call the end event in your case , rs.on("end", ()=>{res.end()])

[@shadabkhan681]

will you please tell me why I'm getting this error: events.js:292 throw er; // Unhandled 'error' event ^ Error [ERR_STREAM_WRITE_AFTER_END]: write after end at writeAfterEnd (_http_outgoing.js:668:15) at write_ (_http_outgoing.js:680:5) at ServerResponse.write (_http_outgoing.js:661:15) at ReadStream. (C:\Users\Shahdab\Documents\Shadab odejs\app.js:54:6) at ReadStream.emit (events.js:315:20) at addChunk (_stream_readable.js:309:12) at readableAddChunk (_stream_readable.js:284:9) at ReadStream.Readable.push (_stream_readable.js:223:10) at internal/fs/streams.js:226:14 at FSReqCallback.wrapper [as oncomplete] (fs.js:539:5) Emitted 'error' event on ServerResponse instance at: at writeAfterEndNT (_http_outgoing.js:727:7) at processTicksAndRejections (internal/process/task_queues.js:81:21) { code: 'ERR_STREAM_WRITE_AFTER_END' My code is same as yours code: server.on("request", (req, res) => { let rs = fs.createReadStream('file.txt') rs.on('data',(chunk)=>{ res.write(chunk) res.end() }) rs.on('error',(err)=>{ res.end(err.message) }) })

[@sajidalikhan5872]

Do like this const server = http.createServer((req, res) => { let rs = fs.createReadStream("output.txt"); rs.on("data", (chunk) => { console.log("reading data"); res.write(chunk); }); res.on("end", () => { console.log("end response"); res.end(); }); rs.on("error", (error) => { res.end(error.message); }); });

[@sajidalikhan5872]

instead of res.end do rs.end