View file vendor/laravel/framework/src/Illuminate/Foundation/Console/ObserverMakeCommand.php

<?php

namespace Illuminate\Foundation\Console;

use Illuminate\Console\GeneratorCommand;
use InvalidArgumentException;
use Symfony\Component\Console\Input\InputOption;

class ObserverMakeCommand extends GeneratorCommand
{
    /**
     * The console command name.
     *
     * @var string
     */
    protected $name = 'make:observer';

    /**
     * The console command description.
     *
     * @var string
     */
    protected $description = 'Create a new observer class';

    /**
     * The type of class being generated.
     *
     * @var string
     */
    protected $type = 'Observer';

    /**
     * Build the class with the given name.
     *
     * @param  string  $name
     * @return string
     */
    protected function buildClass($name)
    {
        $stub = parent::buildClass($name);

        $model = $this->option('model');

        return $model ? $this->replaceModel($stub, $model) : $stub;
    }

    /**
     * Replace the model for the given stub.
     *
     * @param  string  $stub
     * @param  string  $model
     * @return string
     */
    protected function replaceModel($stub, $model)
    {
        $modelClass = $this->parseModel($model);

        $replace = [
            'DummyFullModelClass' => $modelClass,
            '{{ namespacedModel }}' => $modelClass,
            '{{namespacedModel}}' => $modelClass,
            'DummyModelClass' => class_basename($modelClass),
            '{{ model }}' => class_basename($modelClass),
            '{{model}}' => class_basename($modelClass),
            'DummyModelVariable' => lcfirst(class_basename($modelClass)),
            '{{ modelVariable }}' => lcfirst(class_basename($modelClass)),
            '{{modelVariable}}' => lcfirst(class_basename($modelClass)),
        ];

        return str_replace(
            array_keys($replace), array_values($replace), $stub
        );
    }

    /**
     * Get the fully-qualified model class name.
     *
     * @param  string  $model
     * @return string
     *
     * @throws \InvalidArgumentException
     */
    protected function parseModel($model)
    {
        if (preg_match('([^A-Za-z0-9_/\\\\])', $model)) {
            throw new InvalidArgumentException('Model name contains invalid characters.');
        }

        return $this->qualifyModel($model);
    }

    /**
     * Get the stub file for the generator.
     *
     * @return string
     */
    protected function getStub()
    {
        return $this->option('model')
            ? $this->resolveStubPath('/stubs/observer.stub')
            : $this->resolveStubPath('/stubs/observer.plain.stub');
    }

    /**
     * Resolve the fully-qualified path to the stub.
     *
     * @param  string  $stub
     * @return string
     */
    protected function resolveStubPath($stub)
    {
        return file_exists($customPath = $this->laravel->basePath(trim($stub, '/')))
            ? $customPath
            : __DIR__.$stub;
    }

    /**
     * Get the default namespace for the class.
     *
     * @param  string  $rootNamespace
     * @return string
     */
    protected function getDefaultNamespace($rootNamespace)
    {
        return $rootNamespace.'\Observers';
    }

    /**
     * Get the console command arguments.
     *
     * @return array
     */
    protected function getOptions()
    {
        return [
            ['model', 'm', InputOption::VALUE_OPTIONAL, 'The model that the observer applies to.'],
        ];
    }
}