How to decode a binary buffer to an image in node.js?

Question

I'm receiving an image in a binary stream as shown below, however when I try to create a buffer with the following data the buffer appears to be empty. Is the problem that buffer doesn't understand this format?

V�q)�EB\u001599!F":"��\u000b��3��5%�L�\u0018��pO^::�~��m�<\u001e��L��k�%G�$b\u0003\u0011��=q�V=��A\u0018��O��U��m�B��\u00038��0a�_��#\u001b��\f��(�3�\u0003��nGjr��Mt\�\u0014g��~�#�Q�� g�K��s��@C��\u001cS�`\u000bps�Gnzq�Rg�\fu��C\u0015�\u001d3�E.BI\u0007��

var buffer = new Buffer(req.body, 'binary')
    console.log("BUFFER:" + buffer)
fs.writeFile('test.jpg', buffer, function(err,written){
   if(err) console.log(err);
    else {
     console.log("Successfully written");
    }
});

berthni · Accepted Answer · 2015-09-30 23:49:53Z

1

I think you should set the encoding when you call fs.writeFile like this :

fs.writeFile('test.jpg', buffer, 'binary', function(err) {

answered Sep 30, 2015 at 23:49

berthni

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4 Comments

Sarodh Uggalla Over a year ago

problem occurs before that I believe. When I log buffer it is empty and buffer.length returns 0 as well.

berthni Over a year ago

Then may be req.body is empty ?

Sarodh Uggalla Over a year ago

what I put in the quote I directly copied from logging out req.body.

Jason Livesay Over a year ago

Did you check the buffer byteLength?

Sarodh Uggalla · Accepted Answer · 2015-10-01 20:24:22Z

1

Problem was body-parser doesn't parse content-type: octet-stream and I was overriding the header to parse it as an url-encoded-form which the buffer didn't understand even though I was able to log the req.body. The middleware below allows for the parsing of content-type: octet-stream for body-parser.

app.use(function(req, res, next) {
   var contentType = req.headers['content-type'] || ''
   var mime = contentType.split(';')[0];
    // Only use this middleware for content-type: application/octet-stream
    if(mime != 'application/octet-stream') {
        return next();
    }
   var data = '';
   req.setEncoding('binary');
    req.on('data', function(chunk) { 
       data += chunk;
   });
   req.on('end', function() {
      req.rawBody = data;
      next();
  });
});

edited Oct 1, 2015 at 20:24

answered Oct 1, 2015 at 18:23

Sarodh Uggalla

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