How to adapt Laravel controller code to follow DRY principle when there is overlap between assumptions?

Question

My aim is to adapt the following controller methods to follow the DRY principle by moving the validation to form requests. However, I have a problem which is that there are overlaps between validation for different methods. For example, let's say that the input form has only one field and that's name, and that it's related to a Task model. Let's consider 3 controller methods now:

• store method: validate that name isn't empty
• update method: validate that name isn't empty and that a Task with the given $id exists
• destroy method: validate that a Task with the given $id exists

So for the store method I am checking the first assumption, for the destroy method I am checking the second assumption, and for the update method I am checking both.

So, ideally, I would like to be able to do something like...

public function store(StoreTask $request)...
public function update(Store Task TaskExists $request, $id)...
public function destroy(TaskExists $id)...

...but I am very unclear on how to write the syntax for this, and whether there is some other approach which I'm missing to accomplish the same thing.

Answer 1

Validation:

With Route model binding Laravel will automatically inject the model instance so you don't have to query the database yourself and if you have the same validation for storing and updating a task you can use the same form request for both actions.

So in the end you would have something like this:

public function store(TaskRequest $request)...
public function update(TaskRequest $request, Task $task)...
public function destroy(Task $task)...

If you have different Validation rules for storing and updating, you can create two form requests:

public function store(StoreTaskRequest $request)...
public function update(UpdateTaskRequest $request, Task $task)...

And then either repeat your validation rules in both requests or use either a trait / separate class or method that contains the rules and merge them when needed.

This answer has some good suggestions.

Authorization:

To check if the user is allowed to edit/update the task I would use Laravel's Authorization.

In your case you could create a policy.

In your TaskPolicy:

public function update(User $user, Task $task)
{
    return $user->id === $task->user_id;
}

In your TaskController:

Constructor:

public function __construct()
{
    $this->authorizeResource(Task::class, 'task');
}

Or single action:

public function update(UpdateTaskRequest $request, Task $task)
{
    $this->authorize('update', $task);
}