Downloaded file gets saved two times?

Question

I want to download a file that windows tells me is 76mb big (right click properties says 74mb). But when I download it with the code below, the file will be 139mb (properties says 142mb) big. It seems like the file gets saved two times resulting in a corrupted file.

const fs = require('fs');
const { http, https } = require('follow-redirects');

function download(url, callback) {
    var request = https.get(url, function (response) {
        var body = "";

        response.on("data", function (chunk) {
            body += chunk;
        });

        response.on("end", function () {
            callback(body);
        });

        request.on("error", function (e) {
            console.log("Error: " + e.message);
        });

    });
};

 let url = "https://github.com/TheOtherRolesAU/TheOtherRoles/releases/latest/download/TheOtherRoles.zip"
download(url, (body) => {
    console.log(body.length)
    fs.writeFile("test.zip", body, err => {
        if (err) console.error(err)
        console.log("Done");
    })
})

Any idea how this can happen? Any no, download() doesn't get called twice.

Edit: I forgot to mention but I am downloading from github and there is a redirect at the url and I am using this package as https : https://www.npmjs.com/package/follow-redirects

Answer 1

The library works fine, it's not being saved twice: you're not processing incoming data correctly: it's not a String , it's a Buffer , so you need to push each chunk, and then merge them and pass them to writer:

var body = [];

response.on("data", function (chunk) {
    body.push(chunk);
});

response.on("end", function () {
    callback(Buffer.concat(body));
});

or you can simply pipe the response to writeStream and replace all that code with one-liner:

const zip = fs.createWriteStream("test.zip");

//...

response.pipe(zip);