Ricardo Cruz Ricardo Cruz - 4 months ago 53
Javascript Question

Empty Node.js/Express response

I have a POST request that I want to process:

var app = require('express')();
var bodyParser = require('body-parser');
app.use(bodyParser());
. . .
app.post('/signup', function(req, res) {
console.log('name: ' + req.body.name);
console.log('email: ' + req.body.email);
. . .
});


All seems well and dandy.

My client:

<html><body>
<form>
Name:<br>
<input type="text" name="name"><br>
Email:<br>
<input type="text" name="email"><br>
<input id="submit" type="submit" value="Submit">
</form>

<script type="text/javascript" src="https://code.jquery.com/jquery-3.0.0.min.js"></script>
<script>
$('input#submit').click(function() {
$.ajax({
url: 'http://localhost:5000/signup',
type: 'post',
dataType: 'json',
data: $('form').serialize(),
success: function(data) {
console.log('response:', data);
}
});
return false;
});
</script></body></html>


The problem?
success
is never called in the client. Eventually, Chrome JS-debug window shows:
net::ERR_EMPTY_RESPONSE
.

I have tried doing
res.send(200)
,
res.send('')
and
res.end()
in the server, but without success.

My Node.js version is 4.2.6, and I think my Express version is 4.4.1.

Answer

jQuery Docs

dataType - The type of data that you're expecting back from the server;

data - Data to be sent to the server;

So, your frontend application expect a valid JSON back, but primaries (string, number, boolean) aren't a valid JSON, they have to be converted.

In order to perform this on fly:

res.json('success');

or

res.status(200).json('success');

If you want to stick with send method, you could write:

res.send(JSON.stringify('success'));

Also, sometimes this problem is related to ipconfig in windows and network connection