 | Auction Net
Before I start talking about the technical details of the implementations,
let's first take a look at the functional design of the example application.
You
will build a simple e-commerce site that you will call Auction Net.
Functional design
Auction Net will be an auction Web application, as the name suggests. It
will allow people to sell (list) items and for other uses to buy (bid) on
those same items. There are a lot of potential complexities in an auction
Web application, but I will simplify things greatly so you can focus on how
to use Scala, Lift, and jQuery to easily create a Comet-style application.
After you see how easy it is to create a Comet application using Lift, it
can be tempting to start using Comet everywhere. It is similar to when Ajax
applications first started appearing. You often saw some sites overuse Ajax
and create a less functional application.
This site needs to let people sign up for the application and become
registered users, which is common functionality, and something that would
not benefit from Comet. A typical registration/login process is sufficient.
After the users have registered, they need to be able to sell an item, so
you
need a way to create new items and to list existing items. Again, this is
something that would not greatly benefit from Comet-style interactivity.
Finally, you want users to also bid on items. This is where Comet becomes a
nice feature. You want a user to see the current high bid for an item, and
have the bid update automatically when another user bids on it.
You should now have a basic idea of how you want the site to work. You can list out
several domain objects: user, item, and bid. For each object you can also list
the operations you want to be able to perform on them. These operations can
be used as the basis for several pages, some of which can be very
interactive using Comet. Now let's look at how you implement all of this by
using Lift.
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