fs.writeSync output string as an int array - json

Question

I use express router to catch a ajax post data, which is a stringified JSON obj:
router.all('/ajax/setup/save/asset', function (req, res) {
console.log('POST: /ajax/setup/save/asset');
var fileName = path.join(jsonFileNamePrefix, jsonFileName_asset);
req.on('data', function(chunk) {
console.log('POST: DATA: ' + chunk);
fd = fs.openSync(fileName, 'w');
console.log('Opened file: ' + fileName);
fs.writeSync(fd, chunk);
console.log('Wrote ' + chunk + ' into file ' + fileName);
fs.closeSync(fd);
console.log('Closed file: ' + fileName);
res.end();
console.log('res.end()');
});
});
Then the console logs:
POST: /ajax/setup/save/asset
POST: DATA: {"asset":"test"}
Opened file: /srv/data/asset.json
Wrote {"asset":"test"} into file /srv/data/asset.json
Closed file: /srv/data/asset.json
res.end()
However, the file is actually written as:
[123,34,97,115,115,101,116,34,58,34,116,101,115,116,34,125]
Tried telling fs.writeSync to use 'utf8', 'hex' encoding, still got same result.
Also tried JSON.parse and then JSON.stringify the incoming data chunk, didn't help either..

Answer 1

The req object in your code is actually an instance of the http.IncomingMessage stream.
When it provides information via the data event, this information is provided as a buffer.
Additionally, not all the data for the request is guaranteed to be available in the first call to the handler.
There are several ways to capture this data into a useable string. You could create a new string and simply concat the chunks together
router.all('/ajax/setup/save/asset', function (req, res) {
var buf = ''
req.on('data', function(chunk){
buf += chunk.toString();
});
req.on('end', function(){
console.log(buf);
});
});