Model events and observers in Laravel - Step-by-Step Execution

Concept Flow - Model events and observers

Model Action Triggered

↓

Check for Registered Observer

Yes↓

Call Observer Method

↓

Execute Custom Logic

↓

Continue Model Process

↓

End

When a model action happens, Laravel checks if an observer is registered. If yes, it calls the observer method to run custom code before continuing.

Execution Sample

Laravel

use IlluminateSupportStr;

class UserObserver {
  public function creating(User $user) {
    $user->api_token = Str::random(60);
  }
}

User::observe(UserObserver::class);

User::create(['name' => 'Anna']);

This code sets an API token automatically when a new User is created using an observer.

Execution Table

Step	Event Triggered	Observer Method Called	Action Taken	Model State
1	User::create() called	No	Start creating user	User instance with name='Anna', api_token=null
2	creating event	creating()	Set api_token to random string	User instance with name='Anna', api_token='random60chars'
3	created event	No	User saved to database	User saved with name='Anna', api_token='random60chars'
4	End	No	Creation complete	User record exists with api_token

💡 User creation finishes after observer sets api_token during creating event

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
user->name	null	Anna	Anna	Anna	Anna
user->api_token	null	null	random60chars	random60chars	random60chars

Key Moments - 2 Insights

Why does the api_token get set before the user is saved?

Because the observer's creating() method runs during the 'creating' event, which happens before the model is saved, as shown in execution_table step 2.

What happens if no observer is registered?

The model events still fire, but no custom code runs. The execution_table shows 'No' under Observer Method Called when no observer is registered.

Visual Quiz - 3 Questions

Look at the execution_table at step 2. What change happens to the user model?

A api_token is set to a random string

B User name is changed to null

C User is saved to database

D No changes happen

💡 Hint

Check the 'Action Taken' and 'Model State' columns at step 2 in execution_table

At which step does the user get saved to the database?

A Step 1

B Step 2

C Step 3

D Step 4

💡 Hint

Look for 'User saved to database' in the 'Action Taken' column in execution_table

If the observer's creating() method was removed, what would happen to api_token?

A It would still be set automatically

B It would remain null

C User creation would fail

D api_token would be set after saving

💡 Hint

Refer to variable_tracker and execution_table steps where observer sets api_token

Concept Snapshot

Model events fire during model actions like creating or updating.
Observers listen to these events and run custom code.
Register observers with Model::observe(ObserverClass::class).
Observer methods run before or after model actions.
Use observers to keep model logic clean and reusable.

Full Transcript

In Laravel, model events happen during actions like creating or updating a model. Observers are classes that listen to these events and run custom code. For example, when creating a User, the creating event fires before saving. If an observer is registered, its creating() method runs and can modify the model, like setting an api_token. After that, the model saves with the updated data. This process helps keep code organized by separating event logic from controllers or models. The execution table shows each step: starting creation, observer setting api_token, saving the user, and finishing. Variables like user->api_token change during the observer method. If no observer is registered, the model still saves but without custom changes. Observers are registered using User::observe(UserObserver::class). This pattern helps automate tasks during model lifecycle events.