Cakephp need session var in model - php

Question

I give. Been searching and trying different stuff for hours.
Using Cakephp 2.3.5.
I'll get straight to it.
I want to use a session variable in my Category model, but it doesn't like it when I try any of the following...
$this->Session->read('market_id')
CakeSession::read('market_id')
SessionHelper::read('market_id')
Here is the model snippet where I'm trying to use it...
public $hasAndBelongsToMany = array(
'Vendor' => array(
'className' => 'Vendor',
'joinTable' => 'categories_vendors',
'foreignKey' => 'category_id',
'associationForeignKey' => 'vendor_id',
'unique' => 'keepExisting',
'conditions' => array( 'market_id' => ???? )
)
);
I'm stuck like a wheelbarrow in the mud. I've read countless opinions of why I shouldn't use session data in the model, but this makes perfect sense to me since it will never be called without this value set, and it should never return anything other than the vendors with that market_id. But that value does change.
I'm completely guilty of doing everything I can to avoid messing with my models. The whole skinny controller idea... yea... nice thought, but I just haven't figured it out yet. And so it goes. The first time I try to modify a model... I can't figure out how.

Answer 1

I've read countless opinions of why I shouldn't use session data in the model
That's correct. It will cause tight coupling as well and make it harder to test. And it's not only valid for models but everything. Don't create tight coupled code.
It is better to pass data and objects around. For example:
// Model Method
public function getSomething($someSessionValue) { /*...*/ }
// Controller
$this->SomeModel->getSomething($this->Session->read('something'));
If you need your data in a lot methods you can set it:
public function setSomeModelProperty($value) {
$this->_someProperty = value; // _ because it should be protected, the _ is the convention for that in CakePHP
}
However, I personally would very like go for passing the data to each method. But it depends on the whole scenario.
And you can't do this any way because it will cause a syntax error. You can't use variables or properties in the property declaration.
'conditions' => array( 'market_id' => ???? )
So bind it later by a method like
public function bindVendors($marketId) {
$this->bindModel(/*...*/);
}
when needed.
Or even better, simply use the conditions only when needed and declare them in your find options:
[
'contain' => [
'Vendor' => [
'conditions' => /* conditions here */
]
]
]