How to trigger ModelObserver for all Model Events

Well I'd go with making a trait. Forget 'app\ModelObserver.php' make a 'app\ObservantTrait.php'

<?php

namespace App;

use App\Observers\ModelObserver;

trait ObservantTrait
{
    public static function bootObservantTrait()
    {
        static::observe(new ModelObserver);
    }
}

then for any models that need it.

class Blah extends Model
{
    use ObservantTrait;

  // ...
}

@phildawson Thank you so much for that. What is a trait? will the trait be used before or after Validation?

a trait is just a piece of reusable code http://php.net/manual/en/language.oop5.traits.php

Another example with Models would be.

class Attachment
{
    public function attachable()
    {
        return $this->morphTo();
    }
}

trait Attachable
{
    public function attachments()
    {
        return $this->morphMany(Attachment::class, 'attachable');
    }
}

class Person {
    use Attachable;

}

class Event {
    use Attachable;
    
}

Both Person and Event Models will have the attachments method as if it was:

class Attachment
{
    public function attachable()
    {
        return $this->morphTo();
    }
}

class Person {
    public function attachments()
    {
        return $this->morphMany(Attachment::class, 'attachable');
    }

}

class Event {
    public function attachments()
    {
        return $this->morphMany(Attachment::class, 'attachable');
    }
}

think of it as copy+paste.

The Laravel specific thing to take note of that I mentioned is:

If an Eloquent model uses a trait that has a method matching the bootNameOfTrait naming convention, that trait method will be called when the Eloquent model is booted, giving you an opportunity to register a global scope, or do anything else you want.

@phildawson Thank you for your help.

I made the change but it is not working like expected.

Here is my Account Model code

in my ModelObserver class I tried to do dd($values) in side my saving event and I did not get any values. it is like the observer never fires off.

@malhayek the use trait needs to be inside the class you want to use it. The use outside the class is for importing into the current namespace.

namespace App\Models;

...
use App\ObservantTrait;

class Account extends Model
{
    use ObservantTrait;

If ObservantTrait.php is put in the same Models folder and namespace App\Models then you can omit the use outside the class.

In my example above I should have added the App namespace to make clearer where Blah was.

namespace App;

class Blah extends Model
{
    use ObservantTrait;

  // ...
}

@phildawson, when I put use ObservantTrait

I get this error Trait 'App\Models\ObservantTrait' not found

Is your file App\Models\ObservantTrait.php with a namespace App\Models; at the top of it?

If you are keeping it in App\ObservantTrait.php with namespace App; then you need to use 'use' outside to import the class into the current namespace and use inside the class. Example just above.

1. populate a column called "created_by" when a new record is added to the db
2. populate a column called "modified_by" when existing record in updated
3. populate a column called "purged_by" when existing record is soft deleted

@malhayek You do realise Eloquent does this automatically (except the column are named updated_at and deleted_at in the case of the latter two).

With regards to trimming user-submitted values, you could create a trait that overrides the model setAttribute() method to trim strings:

trait TrimScalarValues
{
    public function setAttribute($key, $value)
    {
        if (is_scalar($value)) {
            $value = trim($value);
        }

        return $this->setAttribute($key, $value);
    }
}

Usage:

class SomeModel extends Model
{
    use TrimScalarValues; // Don’t forget to import full namespace
}

@martinbean
The trait TrimScalarValues seems to be not saving the records. when I save a record I should be routed to the app.dev/accounts page. But when using the TrimScalarValues I get a blank page and no routing take place.

Also, When using ObservantTrait trait suggested by @phildawson the field updated_by are not populated like expected.

Any ideas of the problem? Thank you

Here is my full code

I have a new folder "app\Traits" inside of it I have 2 files

1. TrimScalarValues.php which contains the following code

<?php

namespace App\Traits;

trait TrimScalarValues
{
    public function setAttribute($key, $value)
    {
        if (is_scalar($value)) {
            $value = $this->emptyStringToNull(trim($value));
        }

        return $this->setAttribute($key, $value);
    }


    /**
     * return null value if the string is empty otherwise it returns what every the value is
     *
    */
    private function emptyStringToNull($string)
    {
        //trim every value
        $string = trim($string);

        if ($string === ''){
           return null;
        }

        return $string;
    }
}

2. RecordSignature.php which contains the following code

<?php

namespace App\Traits;

use app\Observers\ModelSignature;

trait RecordSignature
{
    
    public static function bootObservantTrait()
    {
        static::observe(new ModelSignature);
    }
}

Then I have Observer "app\Observers\ModelSignature.php" which contains the following code

<?php 

namespace App\Observers;

class ModelSignature {

    protected $userID;

    public function __construct($userID){
        $this->userID =  Auth::id();
    }


    public function updating($model)
    {
        $model->modfied_by = $this->userID;
    }


    public function creating($model)
    {
        $model->created_by = $this->userID;
    }


    public function removing($model)
    {
        $model->purged_by = $this->userID;
    }

}

Finally I have a "app\Models\Account.php" files which contains the following code

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use App\Models\industry;
use App\Traits\RecordSignature;
use App\Traits\TrimScalarValues;


class Account extends Model
{
    use RecordSignature, TrimScalarValues;
    /**
     * The database table used by the model.
     *
     * @var string
    */
    protected $table = 'accounts';

    protected $primaryKey = 'account_id';

    const CREATED_AT = 'created_on';

    const UPDATED_AT = 'modified_on';

    const REMOVED_AT = 'purged_on';


    /**
     * The attributes that are mass assignable.
     *
     * @var array
    */
    protected $fillable = ['client_id','account_name', 'company_code', 'legal_name', 'created_by','modified_by','instrucations'];

    /**
     * The attributes excluded from the model's JSON form.
     *
     * @var array
    */
    //protected $hidden = ['account_id', 'remember_token'];


    protected $guarded = ['account_id'];

    /**
     * Get the industry record associated with the account.
    */
    public function industry()
    {
        return $this->hasOne(industry, industry::primaryKey);
    }

    public function pk(){

        return $this->primaryKey;
    }
    
}

@malhayek That seems to be more a problem with your routing/controller. The trait just trims values as they’re set on the model. It doesn’t handle any redirecting or anything like that (and a model shouldn’t).

@martinbean but it works if I do not use the trait.

These are my routes

Route::bind('account', function($id){
    return Account::where('account_id', $id)->first();
});

Route::get('accounts', array(
    'as' => 'accounts_index_path',
    'uses' => 'AccountController@index')
);

Route::get('account/create', array(
    'as' => 'account_create_path',
    'uses' => 'AccountController@create')
);

Route::post('account/store', array(
    'as' => 'account_store_path',
    'uses' => 'AccountController@store')
);

Route::get('account/{account}', array(
    'as' => 'account_show_path',
    'uses' => 'AccountController@show')
)->where('account', '[0-9]+');

Route::get('account/{account}/edit', array(
    'as' => 'account_edit_path',
    'uses' => 'AccountController@edit')
)->where('account', '[0-9]+');

Route::put('account/{account}/update', array(
    'as' => 'account_update_path',
    'uses' => 'AccountController@update')
)->where('account', '[0-9]+');

@malhayek Then check your error log. The trait was written off the cuff and not tested.

@martinbean, thank you so much the code finally worked after change the return value from $this->setAttribute .... to parent::setAttribute

<?php

namespace App\Traits;

trait TrimScalarValues
{
    public function setAttribute($key, $value)
    {
        if (is_scalar($value)) {
            $value = $this->emptyStringToNull( trim($value) );

        }

        return parent::setAttribute($key, $value);
    }


    /**
     * return null value if the string is empty otherwise it returns what every the value is
     *
    */
    public function emptyStringToNull($string)
    {
        //trim every value
        $string = trim($string);

        if ($string === ""){
           return null;
        }

        return $string;
    }
}

The only problem is the the created_by, modified_by, removing_by is not updating.