Question

I am writing an application for Android 2.3.5 (that will also be compatible with iOS). I wish to transfer data from the app’s HTML/Javascript to a Python program on a server (which uses the Twisted engine to retrieve the data).

I’ve tried many things and looked at various forums, answers, tutorials, and web pages–including most of them here–and can’t find an answer. Here’s the relevant Javascript I have in my index.html file:

<script src="socket-lib/socket.io.js"></script>
<script type="text/javascript" charset="utf-8">
function sendData() {
    try {
        var socket = io.connect('http://mywebsite.com:12345');
        socket.on('connect', function(data) {
            socket.send('Hello.');
            socket.on('message', function (msg) {
                socket.send('This is where I send data?');
            });
        });
    }
    catch(err) {
        alert('ERROR: socket.io encountered a problem:\n\n' + err);
    }
} // end of sendData

If you can’t tell, I’m still pretty confused how this works; I can’t even test anything. The error that keeps coming up is ReferenceError: io is not defined. Some sites used something like var io = require('socket.io');. But then it results in the same error: ReferenceError: require is not defined.

I put the socket-lib folder in assets/www, where any other Javascript source should go. This is also where the index.html file is. Many sites use <script src="/socket.io/socket.io.js"></script>, but this makes no sense to me. Many sites also imply the use of node.js, but I never see it anywhere.

How can I make this work?

Reply edits:

I tried it in Chrome, and it’s giving me an Uncaught ReferenceError: require is not defined for the socket.io.js file. So I decide to source in require.js right before it. Then it gives the error Uncaught Error: Module name "socket.io-client" has not been loaded yet for context. Since I’m not using this, I care not. When I try the connection, though, it gives the same io is not defined error. When I define it as var io = require('socket.io'), the error is Error: Module name "socket.io" has not been loaded yet for context: _ http://requirejs.org/docs/errors.html#notloaded. I looked at the website, and it doesn’t help me at all. When I try to put “require” as a function argument, another error occurs: TypeError: undefined is not a function.

Answer 1

I found the answer for anyone who gets immensely confused by the horrible lack of documentation of socket.io.

You cannot source /socket-lib/socket.io.js,

you must source http://yourwebsite.com:12345/socket.io/socket.io.js.

The server automatically does the rest for you.