How can I read and download a file from a ReadableStream on an API call (Node.js)?

I am using ssh2-sftp-client to get files from a remote server, I'm running into an issue reading and downloading these files once I get() them.

At first, I was able to use the get() method to download the file when the API was hit - I could also return the whole file contents in a console.log statement then it started returning Buffer content. I updated with this:

npm install ssh2-sftp-client@3.1.0

And now I get a ReadbleStream.

function getFile(req,res) {
    sftp.connect(config).then(() => {
        return sftp.get(process.env.SFTP_PATH  + '/../...xml',true);
    }).then((stream)=>{
        const outFile = fs.createWriteStream('...xml')
        stream.on('data', (c) => {
            console.log(`Received ${c.length} bytes of data.`);
           outFile.write(c);  
           res.send('ok')         
          });
         stream.on('close', function() {    
        });
    }).catch((err) => {
        console.log(err, 'catch error');
    });

};

I have the above code that returns a stream but I'm not sure how to get the file - the write() method doesn't seem to work here.

Any advice or suggestions on how I can use this library to read and download files would be greatly appreciated

First, don't use version 3.x. That version has been deprecated. The most recent version is v4.1.0 and has had significant cleanup work to fix a number of small bugs.

If all you want to do is download the files, then use the fastGet() method. It takes 2 args, source path and destination path. It is a lot faster than plain get as it does the download in parallel.

If you don't want to do that, then the get() method has a number of options. If you only pass in one arg (source) it will return a buffer. If you pass in 2 args, the second arg must be either a string (path to local file) or a writeable stream. If a writeable stream, the data will be piped into that stream.