Strategy for developing a multi function asp.net web application

I'm about to start a new project and want some advice on how to implement.

I need a web application which contains a booking module for reserving timeslots, and a time management module which will enable employees to clock in / clock out.

If I am writing an update to the time managment module, I don't want to disrupt the booking engine availability by releasing a new solution containing both modules.

to make things more difficult, there is some shared functionality like common users, roles and security.

Here's a suggestion I've gotten, which sounds a bit cruddy, but may be functional. Write a 'container' web application which consists of basically a frame, and authentication / security features. This then has links which, will load the开发者_运维百科 2 independantly built and released web applications into the frame.

I can see that say, if I wanted to update the time management module, I would only need to build and release this separately, and the rest of the solution would be 'untouched'

Any better alternatives?

Unless I am missing something, if you run ASPX.net (v2, 3, whatever) you can replace the ASPX files (including any CLASS Files) on the fly and the WEB SERVER will automagically "do the right thing."

So if you wrap your "modules" in classes, you can replace those files on a whim without harming the functionality of other classes (not modified.)

As I re-read this am I getting convinced that I am misunderstanding your goal...

Sounds like you what you want is to have some thing along the lines of the Composite Application Block but for a web application (the CAB is for a smart client application).

One of the main things you would want to do is reduce and abstract the coupling between the modules as much as possible.

Keeping the session in the database would go a long way help your ability to dynamically load modules into the application.

This would allow you to have the time management in one server and the booking engine in another. When you update the functionality of one you simply update one server while the other keeps on serving the user.

Add two class library to your web application. one for "booking module" and one for "time management" module. After compiling you will have one DLL for each module and put them in bin folder of web app (Visual Studio will do) then you can replace them separately when you need.

Maybe you know this already : Sessions are the heart of problems in web if misunderstood. Http is a connection-less protocol which means both sides of connection don't care about the flow of the communication. Simply a request has a single response. Without tracking a client how web applications can work ? assume we login to Yahoo mail. Single request (filled login page) is sent to server and a single response (inbox page) returns, then what if we want to see "Draft" folder ? To inspire state to HTTP a simple solution added which we know as "cookies". cookies are simple texts send with each request to a specified server. So on login page Yahoo server sends the response with some other text (cookie) which forces client (browser) to remember it and sent with every new request. This way Yahoo server (web application) can keep track of sequence of requests. This is why we should not simply close the browser window when we are done with yahoo and should logout. With logout yahoo server will forget about that cookie and any subsequent requests with that cookie are not accepted. So because Yahoo can't find out we closed the browser "connectionless" is a good name. How asp.net handle this ? simply asp.net uses a "session cookie" for any new request (requests without cookie) and let's you put your variables in "Session" object on server side. As long as we are at the same application we can use same session variables. What asp.net is doing behind is creating a table for "session Id" cookies and you "session variables". This is transparent to asp.net programmer. We just simply put a value in a session variable like this : session("Age") = 19; and read it when we need. ASP.NET take care of the rest with session cookies this way: you create a session variable (here "Age") so asp.net should track of this request; whatever is the response, asp.net adds a "session cookie" to it. "Session cookie" is a unique text which should be send by that client on consequent request till it expires (usually 20 minutes in asp.net). Use Firefox with "web developer" add-on to see and manipulate cookies.

Related concepts: session cookies vs permanent cookies, cookie properties (domain, expiration date, ...) how server deals with cookies (keeping in memory, storing in database, ...)