Laravel: How to Check if a View Exists

Introduction

Laravel is a potent PHP framework that streamlines the development of web applications with elegant and expressive syntax. A key part of any Laravel application is its views, which are responsible for presenting information to the user. But as applications evolve, views might be moved, renamed, or deleted, which may lead to situations where you try to render a view that no longer exists. In this tutorial, we’ll explore how to check if a view exists in Laravel to prevent such errors from happening.

Checking View Existence in Laravel

Before diving into how to check for views, let’s briefly understand what views are in Laravel. Views in Laravel are stored in the /resources/views directory. They are typically written in the Blade templating engine, which provides a convenient way to work with HTML templates by using PHP.

Basic Check

To check if a view exists, Laravel provides a simple method using the View facade. Here’s a basic example:

$exists = View::exists('admin.dashboard');
if ($exists) {
    // The view exists
} else {
    // The view does not exist
}

This code checks whether the ‘admin.dashboard’ view is present in the resources/views/admin directory.

Checking View Existence in Controllers

In the context of a controller, you might want to choose to render a view based on its existence:

use Illuminate\Support\Facades\View;

public function showDashboard(){
    if (View::exists('admin.dashboard')) {
        return view('admin.dashboard');
    }

    return view('fallback');
}

If the ‘admin.dashboard’ view exists, it will be returned by the controller. Otherwise, a fallback view is returned instead.

View Existence in Blade Templates

You can also check for the existence of another view from within a Blade template:

@if(View::exists('partials.header'))
    @include('partials.header')
@endif

This checks if the ‘partials.header’ view file exists before including it in the current Blade template.

Advanced View Existence Check with Custom Logic

For more sophisticated scenarios, you can wrap the existence check within your own custom logic. Here’s an example using Laravel’s dependency injection:

use Illuminate\Contracts\Views\Factory as ViewFactory;

public function showDashboard(ViewFactory $view){
    $viewName = 'admin.dashboard';

    return $view->exists($viewName) ? view($viewName) : view('fallback');
}

This example uses type-hinted dependency injection to access the View factory and performs the check.

View Existence Check for Notifications

If you are using custom email notifications and want to check if a view exists before you select a template to send, here’s an approach:

use Illuminate\Support\Facades\View;

public function toMail($notifiable){
    $viewName = $this->type == 'welcome' ? 'emails.welcome' : 'emails.default';
    if (View::exists($viewName)) {
        return (new MailMessage)->view($viewName);
    }

    throw new Exception('View does not exist.');
}

This snippet checks for the presence of an email view before constructing the MailMessage object.

Combining View Checks with Authorization

Another dimension where checking for view existence can be useful is when combined with user authorization. Here’s an example where we return a view only if it exists and the user has the proper permissions:

use Illuminate\Support\Facades\View;
use Illuminate\Support\Facades\Gate;

public function show($viewName)
{
    abort_unless(
        View::exists($viewName) && Gate::allows('view', $viewName),
        404
    );

    return view($viewName);
}

If the view exists and the user is authorized to see it, we render the view, otherwise, a 404 response is triggered.

Error Handling for Non-Existent Views

In cases where you require strict error handling, here’s how you might throw exceptions for non-existent views:

use Illuminate\Support\Facades\View;
use InvalidArgumentException;

public function showReport()
{
    $viewName = 'reports.summary';

    if (!View::exists($viewName)) {
        throw new InvalidArgumentException('View not found');
    }

    return view($viewName);
}

This ensures the calling code is made aware immediately if expected views are missing by throwing an exception.

Logging Missing Views

For purposes such as debugging or monitoring, you might want to log the cases where views are missing:

use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\View;

public function showStats()
{
    $viewName = 'admin.stats';

    if (!View::exists($viewName)) {
        Log::warning('Attempted to load missing view: ' . $viewName);
        return view('fallback');
    }

    return view($viewName);
}

Missing views will be recorded in Laravel’s log, alerting you to potential issues.

Conclusion

To conclude, checking if a view exists in Laravel is a straightforward yet important task that can prevent runtime errors and improve the user experience. By using the methods described in this tutorial, you can ensure that your Laravel application handles missing views gracefully, whether in development or production.