A complete Express 4 example using multer to read base64 png data and reading the file back to the client as binary data

Express with base64 file upload and read back to client

var express = require('express');
var fs = require('fs');
var multer = require('multer'); // v1.0.5

var app = express();
app.use(express.static('./public'));

var upload = multer(); // for parsing multipart/form-data

app.post('/testFormData', upload.array(), function(req, res) {
    var base64Data = req.body.testdot;
    console.log('writing file...', base64Data);
    fs.writeFile(__dirname + "/upload/out.png", base64Data, 'base64', function(err) {
        if (err) console.log(err);
        fs.readFile(__dirname + "/upload/out.png", function(err, data) {
            if (err) throw err;
            console.log('reading file...', data.toString('base64'));
            res.send(data);
        });
    });
});

var server = app.listen(8080, function() {
    var host = server.address().address;
    var port = server.address().port;
    console.log('Server listening at http://%s:%s', host, port);
});

do you have the client side code? this is unclear for me. thanks

How about uploading to amazon s3

I had a similar problem even with this fix but then resolved by additionally stripping off the header part of the string like so

let base64String = 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgA';
// Remove header
let base64Image = base64String.split(';base64,').pop();

this helps, thank you