Create a text file in node.js from a string and stream it in response

Question

1. I am using express.js

2. I have a string "Hello world!"

3. I want a user to click on

   <a href=/download>Download</a>
   

4. The user should get Hello.txt download with the text in it, NOT open a tab with the text.

5. I have looked around for ways to achieve this, I am guessing it has something to do with creating readstreams from buffer and piping to response, but I most of the examples dealt with reading actual files from disk, I don't want to read from disk, i just want to respond with a file created from a string.

Thanks!

Pestilent

Do you want to create a download link and make the user to download the file? – Floriaflorian

Yeah download link, but creating a download link is not the main issue, how do i convert string "Hello World!" to a text file in response in expressjs. – Pestilent

try to use socket.io and send the txt file as a socket message instead of relying to req-res module – Floriaflorian

The question is how do you create THAT txt file. – Pestilent

Answer 1

I think I understand what you're trying to do. You want to send a .txt file to the client without actually creating a file on disc.

This is actually pretty basic, and extremely easy. All you have to do is set your MIME type in the header, however most browsers don't download .txt files by default. They just open and display the contents.

var text={"hello.txt":"Hello World!","bye.txt":"Goodbye Cruel World!"};
app.get('/files/:name',function(req,res){
   res.set({"Content-Disposition":"attachment; filename=\"req.params.name\""});
   res.send(text[req.params.name]);
});

As a future note, you can send any data that's stored as a variable. If you have a buffer loaded with an image, for example, you can send that the same way by just changing the Content-Type, otherwise the browser has no idea what data you're sending, and express I believe sets the default type to text/html. Here is a good reference to Internet Media Types and MIME types.

Baneful

"Content-Disposition":"attachment; filename=\"Hello.txt\"" will help, but only in some browsers. – Consistent

Hey thanks for this, up you got it right and i think your answer is almost there, except that i wanted to name the file too. – Pestilent

If this answer solved your problem could you please mark this as the solution? – Baneful

I think Content-type should be specified too. Some browsers like safari will add .html extension to file name. In my case I set: res.set({'Content-Disposition': 'attachment; filename=2015.csv','Content-type': 'text/csv'}); – Pyatt

This worked. Tiny note for future, I found it was necessary to include the double quotes around the filename, e.g. res.set({'Content-Disposition': 'attachment; filename=\"2015.csv\"','Content-type': 'text/csv'}); – Unwitting

@majorBummer It looks like (based on some docs; I haven't tested it) it now works in the current version of every major browser. I believe IE and Firefox had quirky behaviors when I wrote that comment. – Consistent

Answer 2

Try this:

router.get('/download', (req, res) => {
  var text = 'Hello world!'
  res.attachment('filename.txt')
  res.type('txt')
  res.send(text)
})

Karlynkarma

Answer 3

this is working for me !

var text="hello world";

res.setHeader('Content-type', "application/octet-stream");

res.setHeader('Content-disposition', 'attachment; filename=file.txt');

res.send(text);

Airily

This one worked well! – Perpetuity

Answer 4

Thanks for the help guys, this is what i ended up with: @aaron, is there a way for disposition to work in all browsers?

res.setHeader('Content-disposition', 'attachment; filename=theDocument.txt');
res.setHeader('Content-type', 'text/plain');
res.charset = 'UTF-8';
res.write("Hello, world");
res.end();

Pestilent

You specified that you were using express. If you're going to use express, I recommend actually using it. What you are doing is pure node.js – Baneful