crosenblum crosenblum - 1 year ago 120
jQuery Question

How to do sockets in jQuery?

This is a very complex and niche question, so there may not be a realistic answer for what I need to do.

I have an assignment to work with a wireless receiver, that needs more than jQuery's get/post functionality.

Because of cross-domain issues, this jQuery get's executed inside an Adobe Air App, created in Aptana IDE.

It has to be an adobe air, because the web server, will not be close to where the wireless receiver eventually get's connected to.

So I need an app, that can communicate with the 2Know Renaissance Wireless Receiver.

I have created an app that does some of the communication fine. Here are the steps I can do so far.


  1. Connect to the receiver

  2. See how many handheld devices are connected to the receiver

  3. Then there is supposed to be some back/forth communication, and that's not easy with in ajax at least in my knowledge.



Here is the code I have been working with, this is about the 24th version, and this is as far I have gotten.

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>2Know Wireless Communicator</title>
</head>
<body>
<h1>Current Status/Prograess</h1>

<!--- step 1. is server connected --->
<div id="server_status" style="font-size:12px;"></div>

<!--- step 2. list number of devices connected --->
<div id="device_count" style="font-size:12px;"></div>
<div id="device_info" style="font-size:12px;"></div>

<!--- step 3.a Service Handler handler status / csh = Service Handler handler --->
<div id="csh_status" style="font-size:12px;"></div>

<!--- step 3.b disconnect status handler handler of many handlers --->
<div id="dis_status" style="font-size:12px;"></div>

<!--- step 4. test sending a question to a device --->
<div id="post_results" style="font-size:12px;"></div>

<!-- load the local jquery -->
<script type="text/javascript" src="lib/jquery/jquery-1.4.2.js"></script>
<script type="text/javascript" src="lib/jquery/json_parse.js"></script>
<script type="text/javascript" src="lib/jquery/jparse.min.js"></script>
<script type="text/javascript" src="lib/air/AIRAliases.js"></script>
<script type="text/javascript" src="lib/air/AIRIntrospector.js" />
<!-- Include service monitor framework -->
<script type="application/x-shockwave-flash" src="lib/air/servicemonitor.swf"></script>


<script type="text/javascript">
function watch_connection() {
// do ajax get
$.ajax({
type: "GET",
datatype: "xml",
url: "http://my_ip_address:port/Services/ConnectServiceHandler",
success: function(response){
$('#post_results').html(response);
},
error:function (xhr, ajaxOptions, thrownError){
$('#post_results').html("readyState: "+xhr.readyState+"\nstatus: "+xhr.status);
}
});
setTimeout(function(){watch_connection;}, 100);
}

function disconnect_service_handler() {

// step 1. create xml document of data to send
var xml_string = '<data><disconnect_handler service="64"/></data>';

// step 2. post this to the registration service
$.ajax({
type: "POST",
datatype: "xml",
url:"http://my_ip_address:port/Services/DisconnectServiceHandler",
data: xml_string,
beforeSend: function(xhr){
xhr.withCredentials = true;
},
timeout: (2 * 1000),
success: function(response){

// parse the response
$(response).find("status").each(function() {
// get the status code
var disconnect_status = $(this).attr('code');

if (disconnect_status == 200) {
// change status bar message
$('#dis_status').html('Disconnecting: [200 Disconnected]');

// call connection using new guid
var my_guid = guid();
connect_service_handler(my_guid);
}

if (disconnect_status == 304) {
// change status bar message
$('#dis_status').html('Disconnecting: [304 No handler found]');
}


if (disconnect_status == 400) {
// change status bar message
$('#dis_status').html('Disconnecting: [400 Bad Request]');
}

if (disconnect_status == 401) {
// change status bar message
$('#dis_status').html('Disconnecting: [401 Not Found]');
}

if (disconnect_status == 500) {
// change status bar message
$('#dis_status').html('Disconnecting: [500 Internal Server Failure]');
}

if (disconnect_status == 501) {
// change status bar message
$('#dis_status').html('Disconnecting: [503 Service Unavailable]');
}


});


},
error:function (xhr, ajaxOptions, thrownError){
$('#dis_status').html('Disconnecting: [Disconnect Failure]');
}

});
}
function S4() {
return (((1+Math.random())*0x10000)|0).toString(16).substring(1);
}
function guid() {
return (S4()+S4()+"-"+S4()+"-"+S4()+"-"+S4()+"-"+S4()+S4()+S4());
}
function connect_service_handler(my_guid) {

// step 1. create xml document of data to send
var xml_string = '<data><connect_handler service="64"><application id="'+my_guid+'" name="MikesBigEar" /></connect_handler></data>';

// step 2. post this to the registration service
$.ajax({
type: "POST",
datatype: "xml",
url:"http://my_ip_address:port/Services/ConnectServiceHandler",
data: xml_string,
beforeSend: function(xhr){
xhr.withCredentials = true;
},
timeout: (2 * 1000),
success: function(response){

// parse the response
$(response).find("status").each(function() {

// get the status code
var connection_status = $(this).attr('code');

if (connection_status == 200) {
// change status bar message
$('#csh_status').html('Service Handler: [200 Connected]');
// keep connection open keep socket alive
// sends http request to us via post
// sends the incoming request id and device address back to make sure it goes to the correct device
// ask for user id or user authentication
// for user authentication can either use built-in user authentication or ask a question
// http 1.1 keep alive header
$('#post_results').html('Attempting to check for next piece of data...');
watch_connection();
}

if (connection_status == 303) {
// change status bar message
$('#csh_status').html('Service Handler: [303 The handler is assigned to another application]');
var my_guid = guid();
connect_service_handler(my_guid);
}

if (connection_status == 400) {
// change status bar message
$('#csh_status').html('Service Handler: [400 Bad Request]');
disconnect_service_handler();
}

if (connection_status == 401) {
// change status bar message
$('#csh_status').html('Service Handler: [401 Not Found]');
disconnect_service_handler();
}

if (connection_status == 500) {
// change status bar message
$('#csh_status').html('Service Handler: [500 Internal Server Failure]');
disconnect_service_handler();
}

if (connection_status == 501) {
// change status bar message
$('#csh_status').html('Service Handler: [501 Service Unavailable]');
disconnect_service_handler();
}


});

// pass the xml to the textarea
// $('#process').val('ConnectServiceHandler');
// $('#show_errors_here').val(response);

},
error:function (xhr, ajaxOptions, thrownError){
$('#csh_status').html('Service Handler: [Connection Failure]');
// alert("readyState: "+xhr.readyState+"\nstatus: "+xhr.status);
// alert("responseText: "+xhr.responseText);
// alert(xhr.status);
// alert(thrownError);
}

});

// set timed re-check and store it
// setTimeout(function(){connect_service_handler(my_guid);}, 8000);


}

function get_device_count(my_guid) {
// get the total number of devices

// default receiver status
var receiver_status = '';


$('#device_count').html('Device Count: [Checking...]');
$('#device_info').html('');

// get the wireless receiver status via ajax xml
$.ajax({
type: "GET",
url:"http://my_ip_address:port/Services/GetDevices",
beforeSend: function(xhr){
xhr.withCredentials = true;
},
timeout: (2 * 1000),
success: function(response){

$(response).find("status").each(function() {
// get the status code
var receiver_status = $(this).attr('code');

if (receiver_status == 200) {
// change status bar message
$('#device_count').html('Device Count: [200 Connected]');
}

if (receiver_status == 400) {
// change status bar message
$('#device_count').html('Device Count: [400 Bad Request]');
}

if (receiver_status == 401) {
// change status bar message
$('#device_count').html('Device Count: [401 Not Found]');
}

if (receiver_status == 500) {
// change status bar message
$('#device_count').html('Device Count: [500 Internal Server Failure]');
}

if (receiver_status == 501) {
// change status bar message
$('#device_count').html('Device Count: [501 Service Unavailable]');
}


});

var device_count = 0;

// add to div
$('#device_info').append('<ul style="font-size:10px;">');

$(response).find("device").each(function() {

// get each property
var device_status = $(this).attr('status');
var short_address = $(this).attr('short_address');
var mac_address = $(this).attr('mac_address');
var pan_id = $(this).attr('pan_id');
var type = $(this).attr('type');

device_count = device_count + 1;

// get session data
$(this).find("session").each(function() {

// get session data
var created_date = $(this).attr('date');
var created_time = $(this).attr('time');

});

$('#device_info').append('<li style="list-style:none;">Device #'+device_count+'<ul>');

// add list item
$('#device_info').append('<li> Mac Address: ['+mac_address+']</li>');
$('#device_info').append('<li> Short Address: ['+short_address+']</li>');
$('#device_info').append('<li> Pan ID: ['+pan_id+']</li>');

$('#device_info').append('</ul></li><br/>');

// send request to this device
// post_live_activity(mac_address,my_guid);



});

// end list
$('#device_info').append('</ul>');

if (device_count === 0) {
$('#device_count').html('Device Count: [0 Devices Found]');
} else if (device_count > 0) {
$('#device_count').html('Device Count: [' + device_count + ' Devices Found]');
}


},
error:function (xhr, ajaxOptions, thrownError){
$('#device_count').html('Device Count: [Connection Failure]');
// alert(xhr.status);
// alert(thrownError);
}
});

// set timed re-check and store it
setTimeout(function(){get_device_count(my_guid);}, 13000);
}
function get_server_status(my_guid) {

// default receiver status
var receiver_status = '';

// get the Renaissance Wireless Server via ajax xml
$.ajax({
type: "GET",
url:"http://my_ip_address:port/Services/GetAccessPoints",
timeout: (2 * 1000),
beforeSend: function(xhr){
xhr.withCredentials = true;
},
success: function(response){

$(response).find("status").each(function() {
// get the status code
var receiver_status = $(this).attr('code');

if (receiver_status == 200) {

// change status bar message
$('#server_status').html('Renaissance Wireless Server: [200 Connected]');

// step 2. get device count
get_device_count(my_guid);

// step 3.part 1 get the guid to be used as the application id
// var my_guid = guid();

// step 3. part 2 connect to a service handler whatever that means
connect_service_handler(my_guid);

}

if (receiver_status == 400) {

// change status bar message
$('#server_status').html('Renaissance Wireless Server: [400 Bad Request]');

// set timed re-check and store it
setTimeout(function(){get_server_status(my_guid);}, 12300);

}

if (receiver_status == 401) {

// change status bar message
$('#server_status').html('Renaissance Wireless Server: [401 Not Found]');

// set timed re-check and store it
setTimeout(function(){get_server_status(my_guid);}, 12300);
}

if (receiver_status == 500) {

// change status bar message
$('#server_status').html('Renaissance Wireless Server: [500 Internal Server Failure]');

// set timed re-check and store it
setTimeout(function(){get_server_status(my_guid);}, 12300);

}

if (receiver_status == 501) {

// change status bar message
$('#server_status').html('Renaissance Wireless Server: [503 Service Unavailable]');

// set timed re-check and store it
setTimeout(function(){get_server_status(my_guid);}, 12300);

}
// pass the xml to the textarea
// $('#process').val('GetAccessPoints');
// $('#show_errors_here').val(response);

});

},
error:function (xhr, ajaxOptions, thrownError){
$('#server_status').html('Renaissance Wireless Server: [Connection Failure]');
// alert(xhr.status);
// alert(thrownError);
}
});

// set timed re-check and store it
// setTimeout(function(){get_server_status(my_guid);}, 12300);
}

$(document).ready(function() {

// step 3.part 1 get the guid to be used as the application id
var my_guid = guid();

// step 1 validate
get_server_status(my_guid);

// step 2. get device count
get_device_count();

// step 3.part 1 get the guid to be used as the application id
// var my_guid = guid();

// step 3. part 2 connect to a service handler whatever that means
// connect_service_handler(my_guid);


});
</script>
</body>
</html>


My question simply is there a different jquery plugin I should be using, or am I approaching this wrong?

Thank You...

Answer Source

I don't fully understand the issue, so it is a bit tricky to make recomendations, but at least can help with some different transport ideas.

Asking jQuery to do socket communication is as far as I know outside of the scope of jQuery. jQuery is really just using XMLHttpRequest, which is not going to work for persistent sockets.

Idea 1

What about using the ActionScript Socket class http://livedocs.adobe.com/flash/9.0/ActionScriptLangRefV3/flash/net/Socket.html

You could embed the flash movie in your html page and call it from javascript http://www.hariscusto.com/programming/communication-between-javascript-and-actionscript-as3-and-vice-versa/

Idea 2

You could also consider node.js on the web server and the great socket.io module for taking advantage of websockets inside air and then do bi-directional communication between the air client and the server. socket.io has a great browser client in addition to the server side support. See http://socket.io/

Here is an interesting post on Fedex's Techie Blog about using jQuery together with socket.io and node.js - http://spiritconsulting.com.ar/fedex/2010/11/events-with-jquery-nodejs-and-socket-io/

Idea 3 (New)

There is an air javascript socket class available to html air developers. I just stumbled accross it here:

Home / HTML Developer’s Guide for Adobe AIR / Networking and communication

http://help.adobe.com/en_US/air/html/dev/WSb2ba3b1aad8a27b0-181c51321220efd9d1c-8000.html

There are several different socket apis depending on your needs

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