Trello.com - technologies used

From http://adamgent.com/post/10225284147/trello-from-fogcreek-using-nodejs - 

• Nodejs for Webserver 
• Express for MVC
• JQuery
• Backbone
• SocketIO
• JQueryUI

 It's all written in Coffee Script as well. Mongo stores our permanent data, and we're using Redis as a transient data store.


From http://stackoverflow.com/questions/5053167/backbone-js-versus-express-versus-ext-js-and-jspp - 

backbone.js is a client-side MVC framework.

JSPP is a means you can write inline server-side code (like PHP or ASP) for nodejs

Express is a node.js specific server-side framework for web development.

Ext JS is a framework for making web applications and widgets.

There all very different. There isn't any point in a direct comparison without you telling us what you want to use them for.

To vaguely answer your question. IMHO I would say using backbone.js on the client and on nodejs is great for MVC centric design.

Express is a great layer of abstraction on nodejs because it beats writing the code yourself. Use it to serve content to your clients.

Ext JS is not free.

JSPP looks like ASP/PHP!

Finding out which apps are using which ports on your machine

http://blogs.msdn.com/b/bgroth/archive/2004/11/11/256190.aspx

Above link suggests using "netstat" along with "tasklist"

Another way is to use "netstat" along with Task Manager

Step 1: Open Task Manager  -- select "View" -- select "Select Columns" -- check PID
Find out PID of the process whose port info you are after.

Step 2: (From above link)
C:\>NetStat -o

PID will displayed in the last column. Use PID from Step 1

Example: To find the port that "sqlservr.exe" is using, we first find out the PID from Task Manager ,which is 1660
If we now type "netstat -o" in a command prompt window, we will be able to see which port is being used by that PID ie 1660

WCF Callbacks related - Steps to do on client-side when using wsDualHttpBinding

Client = WPF app (chat application)
WCF Service = uses wsDualHttpBinding (to make callbacks to the clients)
OS= Windows XP
(The whole project is an implementation of  - http://www.eggheadcafe.com/tutorials/aspnet/b5ada8df-58c5-492f-b368-457b3a4f137c/notify-client-applications-using-wcf-callbacks.aspx )

After initially developing the client (a WPF app) and the WCF Service on the same machine, we moved the WCF Service to a test server.

I received the error message - The caller was not authenticated by the service..

Upon googling, it turned out that this is the common error message that is received when developers typically move their WCF Service to another machine.

1. In client's app.config file :

<security mode="None">
                        <message clientCredentialType="None" negotiateServiceCredential="false" />
                    </security>


2. Specified "clientBaseAddress" attribute for "binding" element in client's app.config:

clientBaseAddress="http://system2:8001/TempUri/"

(I used machine-name or IP address instead of "localhost" in clientBaseAddress)

3. Add 8001 port to Firewall's Exception list

Did the following to make the WPF app, running as a non-admin , to receive the callback properly from the WCF service. This will take care of the following error -
HTTP could not register URL http://*:8001/TempUri/. Your process does not have access rights to this namespace


4. Download HttpNamespaceManager tool from http://blogs.msdn.com/b/paulwh/archive/2007/05/04/addressaccessdeniedexception-http-could-not-register-url-http-8080.aspx
HttpNamespaceManager.zip

5. Add SDDL using HttpNamespaceManager tool - Add Users group AND give rights to Users group

6. (OPTIONAL step) Specifying clientBaseAddress via code instead of from app.config - If we do this, we do not have to change app.config when we install the app on the user's machine

// modify ClientBaseAddress to have this machine's IP address in the Url
// The ClientBaseAddress is needed for the Service to contact the client

WSDualHttpBinding w = (WSDualHttpBinding)this.chatServiceClient.Endpoint.Binding;

w.ClientBaseAddress = new Uri("http://" + getIPAddress() + ":8001/TempUri");      

chatServiceClient.Endpoint.Binding = w;

........
........
........

private string getIPAddress()
{
string myClientMachineName = System.Net.Dns.GetHostName();
        IPHostEntry myClientMachineAddressList = System.Net.Dns.GetHostEntry(myClientMachineName);
        return myClientMachineAddressList.AddressList[0].ToString();
}

WCF CallBacks related - Assign ClientBaseAddress in code

Update ClientBaseAddress via code

WCF Callbacks

The below is a good example of using WCF Callbacks -
http://www.eggheadcafe.com/tutorials/aspnet/b5ada8df-58c5-492f-b368-457b3a4f137c/notify-client-applications-using-wcf-callbacks.aspx

But I have stripped down the code for the 'client' to the below, to understand the main steps more easily.
By 'stripping down', I mean, I removed error checking code and made the MainWindow class implement the callback function