Code Away

A peek at creating the Django Admin interface for any model has floored me completely. I did make a feeble attempt to create something similar for this in Java way back in 2005, but it is quite a daunting task.

The integration offered by Django and RoR really makes one feel that not using these frameworks is just the thing why software developers are in demand today. Hire fifteen to do a job in php which two could do using Django.

Some may say these facilities are just keystroke-savers. Agreed. The important question is why do you not want to save those keystrokes . A common application development (without the right kind of framework) spends a significant amount of time (I’d hazard a guess of more than 25%) doing plumbing work. Lets take a Java example for an “edit” screen, which shows the user already stored data, and allows him to make changes:

• Take data from repository, probably as a generic List
  • Oh yeah, connect to the DB first, and run a DB Statement in a try-catch block, right within your business logic
• Populate a data bean with all the data. All manually. If the DB cursor contains 25 columns, have a object with 25 attributes, 25 getters, 25 setters and populate all attributes one by one.
• Send the data bean to the view
• In the view, have hard-coded UI components for each attribute of the data bean to be displayed. For any related queries to be executed, hard code page links which will fetch those.
• On event of user clicking OK, program a set of validations to ensure user has not entered bad values. Most of these are not business validations, but checks to ensure no bad characters are present in the input.
• Populate user entered values obtained through form into a data bean
• Code a SQL Update script which will take each value from the data bean and update the backend
• commit (don’t forget that!)
• Rinse-and-repeat for all related queries

Any framework support (struts, spring, hibernate) is a keystroke saver in addition to being responsible for formalizing (a subset of) the programming for the application. Django and RoR simply take the integration between MVC to the next level. I had mailed a friend a few months ago about what Rails has:

1. Integration with AJAX: You see whether the type of request from the client (browser) is ajax or plain HTTP. You use those conditions to provide a specific response. In case it is an ajax request, you can play directly with elements rendered in the browser (e.g. Put text “Saved Successfully” in the information bar and blink it once). This integration, and resulting 5 lines of code is far faster than anything we would do by ourselves. (client side use ajax-specific library functions to send request, then check XML returned and perform activities in browser using javascript again). This integration is thanks to use of inbuilt prototype and scriptaculous libraries

2. Test Integration: I know that if a nice high-level test framework didn’t exist already, we would never get serious about writing real automated tests. It would always be like “lets develop this cool feature now that we have time… we’ll check out tests later”. Fortunately, tests are easy to write, and we can start small. (full page tests and all can be written later). We can also write Model level tests for ensuring relationships etc. N e a t.

3. MVC Integration: Neat MVC code, easy to write. Controllers and views nicely integrated. All variables declared in controller are directly available to views. Which should have always been the case, but in other barebones J2EE/php, you need to pass a data object explicitly, because MVC is not mandated.

4. Fixtures: Stuff to fill your “Test” database with data. Easy to write YAML (byebye XML). This will auto-run when you run tests, so your test database is ready with required data. If you don’t know yet, Rails will auto-create dev, test, prod databases for easy demarcation. Rails will also auto-clone the dev database schema to test database prior to loading fixtures.

The learning curve is a bit high, and I am spending a lot more time understanding the components in comparison to J2EE. Yet, given the benefits, I think it is well worth the effort.