Which Code Should Go Where in MVC Structure

Question

My problem is in somewhere between model and controller.Everything works perfect for me when I use MVC just for crud (create, read, update, delete).I have separate models for each database table .I access these models from controller , to crud them . For example , in contacts application,I have actions (create, read, update, delete) in controller(contact) to use model's (contact) methods (create, read, update, delete).

The problem starts when I try to do something more complicated. There are some complex processes which I do not know where should I put them.

1. For example , in registering user process. I can not just finish this process in user model because , I have to use other models too (sending mails , creating other records for user via other models) and do lots of complex validations via other models.
2. For example , in some complex searching processes , I have to access lots of models (articles, videos, images etc.)
3. Or, sometimes , I have to use apis to decide what I will do next or which database model I will use to record data

So where is the place to do this complicated processes. I do not want to do them in controllers , Because sometimes I should use these processes in other controllers too. And I do not want to put these process in models because , I use models as database access layers .May be I am wrong,I want to know . Thank you for your answer .

Answer 1

Just a short comment (no solution) AFAIK that is an eternal question - MVC is just a pattern, and as such, is in theory implementable cleanly. In practise, due to limitations set by available tools (such as programming language library contents and UI component interface design..) you have to make local decisions. The important thing is that you aim to separate these...and not have everything in one mess. I take my comment off the air and am left to see if someone has a "final solution".

Answer 2

For simple tasks I would write action helpers (e.g. sendNewsletter).

For sophistocated tasks I woud create services (eg. email, auth etc.).