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by dataduck 5439 days ago
Slightly OT extreme noob question: what is the core idea behind controllers? I've read some introductory Rails stuff but I never really got a good grasp of what the point of the controller is, most explanations seemingly reducing to "the thing that goes between the thinky bit and the user interface". I know I'm missing a lot, can anyone point me in the direction of some good reading material? My background isn't webdev so there's probably some missing assumed knowledge.
2 comments
ovi256 5439 days ago
The point of controllers would be to glue together front-end protocol (HTTP in case of web apps) code and hide this from back-end (model) code. Models should be written so that they could be reused in a desktop or mobile app for example without issue. A model would know to check auth or authorization, but would not know that the username and password were coming in through HTTP forms. The controller is the thin layer that hides that.

IMO, the controller is not reusable between frontends. A web user controller would need to be rewritten for a mobile app. The view and templates too, of course. Current technology makes it so that this is mostly a non-issue, as webapps (think: Rails, Django) are written in different languages and use different libraries from mobile apps (think: iOS apps, Android). But we must recognize this is an artefact of current technology that could change, and is not an ideal case.

Anyone writing mobile apps in "web" scripting languages ? AFAIK, the iOS app store forbids non-Objective C apps. I could be wrong.

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Swannie 5439 days ago
My original answer was longer, but this is hopefully clearer. Small programs are often split: Input Parsing. Process. Output presentation.

We can think of MVC where the View is the output presentation. The Model does the processing. The Controller does the initial input parsing, determining which part of the process to pass control to.

The Controller as "dispatcher" or coordinator.

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dataduck 5437 days ago
Thanks, this helps! Can you recommend any further reading? Or is it simpler than I'm thinking?
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