How to convert this PHP to express.js/node

Question

How to convert this PHP to express.js/node

I am trying to make an endpoint that takes post data and saves it to a png file. This PHP code does that:

if (isset($GLOBALS["HTTP_RAW_POST_DATA"]))
{
    // Get the data
    $imageData=$GLOBALS['HTTP_RAW_POST_DATA'];

    // Remove the headers (data:,) part.  
    // A real application should use them according to needs such as to check image type
    $filteredData=substr($imageData, strpos($imageData, ",")+1);

    // Need to decode before saving since the data we received is already base64 encoded
    $unencodedData=base64_decode($filteredData);

    // Save file.  This example uses a hard coded filename for testing, 
    // but a real application can specify filename in POST variable
    $fp = fopen( 'test.png', 'wb' );
    fwrite( $fp, $unencodedData);
    fclose( $fp );
}

I am new to express and I have this:

app.use (function(req, res, next) {
    var data='';
    req.setEncoding('utf8');
    req.on('data', function(chunk) { 
       data += chunk;
    });

    req.on('end', function() {
        req.body = data;
        next();
    });
});

app.post('/upload', function(req, res){

    var testData = req.body;

    return res.send(testData);

});

And i'm getting a blank object. even though actual data is being POSTed. Can someone show me a good way to write the above code in express?

Thanks

php
javascript
node.js
post
express

Answer 1

So taking it from the handler:

var fs = require('fs');

app.post('/upload', function(req, res){

    var image = req.body;
    var noHeader = image.substring(image.indexOf(',') + 1);
    var decoded = new Buffer(noHeader, 'base64');

    fs.writeFile('testfile.png', decoded, function(err){

        res.send('done!');

    });

});