Does custom validation logic belong in Doctrine models (CodeIgniter context)? - php

Question

I'm a big fan of Doctrine, but in the past have primarily used it for an easier and more OO way of accessing my database. Lately though I've found myself wanted to do MORE with the models though, to make my code more semantic or logical, and easy to use.
For an example, let's use a Stack Overflow Question and corresponding Answers. A Question can contain one or more Answers. In the past, I might do something like this (everything below is sudo code btw):
/*
* METHOD ONE: Note that this is IMO not that semantic or OO
*/
Class QuestionController{
//.......
public function addAnswer($whichQuestionId, $answerTitle, $answerCopy, $answerAuthorId)
{
//Look, I'm validating stuff here in my controller action
if(!strlen($answerTitle) || !strlen($answerCopy) || !strlen($answerAuthorId))
throw new \Exception('Invalid answer stuff!!');
//Notice here I'm actually doing some DB quering with
$author = $entityManager->find('\StackOverflow\User', $answerAuthorId);
if($author->getIsBanned())
throw new \Exception('This is user can not post answer, they are banned!');
//OK, things are valid, now we're going to load then question and create a new answer
$question = $entityManager->find('\StackOverflow\Question', $whichQuestionId)
$answer = new \StackOverflow\Answer;
$answer->setAuthor($author);
$answer->setTitle($answerTitle);
$answer->setContent($answerCopy);
$question->addAnswer($answer);
//Let's pretend we persisted everything correctly...
//Done!
}
//.......
}
Class \StackOverflow\Answer{
//Normal auto generated stuff here
}
Class \StackOverflow\Qusetion{
//Normal auto generated stuff here
}
OK, so note that I'm doing all of my validation in an controller action, which works fine, but if I want to add a answer to a question in a different controller all together then that's not very dry. I could put this validation logic in a "helper" of some sort, but that doesn't seem to be particularly OO either.
I'd RATHER do something like this (not totally well though out, but hopefully you get the idea)
/*
* METHOD TWO: Hopefully a bit more OO...
*/
Class QuestionController{
public function addAnswer($whichQuestionId, $answerTitle, $answerCopy, $answerAuthorId)
{
$result = new \stdObject();
try{
$question = $entityManager->find('\StackOverflow\Question', $whichQuestionId);
$answer = new \StackOverflow\Answer;
$answer->setAuthor($author);
$answer->setTitle($answerTitle);
$answer->setContent($answerCopy);
//THIS IS NEW!
$answer->validate();
//note that perhaps to take this a step futher, in the \StackOverflow\Question class
//I might actually call the validate function, so it's a bit more transaparent
$question->addAnswer($answer);
//Let's pretend we persisted everything correctly...
//Done!
$result->success = true;
$result->message = 'New answer added!';
}
catch(Exception $e)
{
$result->success = false;
$result->message = $e->getMessage();
}
return json_encode($result);
}
}
Class \StackOverflow\Answer{
//ALL NORMAL AUTO GENERATED GETTERS/SETTERS/ETC HERE
//CUSTOM FUNCTION - perhaps called by one of the LifeCycle callback things that Doctrine has?
public function validate()
{
//Look, I'm validating stuff here in my controller action
if(!strlen($this->getTitle()) || !strlen($this->getContent()) || !strlen($this->getAuthor()))
throw new \Exception('Invalid answer stuff!!');
//Notice here I'm actually doing some DB quering INSIDE of another model
$author = $entityManager->find('\StackOverflow\User', $answerAuthorId);
if($author->getIsBanned())
throw new \Exception('This is user can not post answer, they are banned!');
}
}
Class \StackOverflow\Question{
//Normal auto generated stuff here
}
So this is perhaps a bit better I suppose, is this the correct way to do things with Doctrine? Is it OK to call other models within an existing model, or to otherwise use the Doctrine Entity Manager in this way? Is there a cleaner way of doing this?
This specific example is pretty simple, but in real life I have a relationship similar to this but the "Answer" has much more complex and ugly validation, requiring lookups to other tables, getting information about the "Question" for it's validation, etc. It also might update the "User" in our example, for instance adding a new Answer to a Question might update the User's "QuestionsAnswered" value. I'd rather this happen transparently, without having to know it's really happening. I'd like to simply add an answer to a question, and all of the validation and cascading changes happen automatically behind the scenes.

Answer 1

There is no right or wrong answer to this. Its ultimately your choice as to how heavy your models in comparison with controllers.
My suggestion is to pick one way to do it, and stay consistent.
I would make a note that the validation should be related to the object that you are working with. Checking if a user is banned within the answer validation is probably not the best place to do that. Instead you should be checking that data related to the answer is valid.