Is it possible to change the behavior in view of existing apps after new app is installed with touching the existing apps?

Question

Let's take an example of two apps:

• Stock
• StockBalance

So IceCream was developed first, and all the views are Stock are created using the generic Class-Based Views - SListView, SCreateView,SDetailView, SUpdateView and SDeleteView. And the URL mapping are as follows:

• /stock/ - SListView
• /stock/new - SCreateView
• /stock/(id) - SDetailView
• /stock/(id)/edit - SUpdateView
• /stock/(id)/delete - SDeleteView

And later StockBalance is being developed. Without touching the code from the Stock app, how can I change the behavior of the each view? And what is the common method in Django to do that?

What I want to archieve is that:

• When user visits /stock/new , he would be able to create a new stock with the initial stock balance.
• When user visits /stock/(id) , he would be able to read the stock detail as well as the stock balance.

Answer 1

You can insert the URL mappings of StockBalance in front of those of Stock. This ensures those URLs will be found first by Django and thus you can fully reimplement (inherit / override / etc) what those views will do.

So:

• /stock/new = implemented by new app
• /stock/{id} = implemented by new app
• /stock/... = all others, as before