Handling Missing Route Models and fallback in Laravel

When working with Laravel's routing system, handling missing route models can be a common scenario. By default, if a route model binding fails to find a matching model instance, Laravel returns a 404 error. However, in certain cases, you may want to redirect the user to a specific route instead as a fallback. This blog post explores how you can address this issue using Laravel's missing and Route::bind method.

Laravel's routing system allows you to define routes and bind them to model instances. This feature, known as route model binding, simplifies the process of retrieving models based on route parameters. When a route with a bound model is accessed, Laravel automatically fetches the corresponding model instance and injects it into the controller method.

By default, if the route model binding fails to find a matching model, Laravel throws a ModelNotFoundException and returns a 404 error. While this behavior is appropriate in many cases, there are scenarios where redirecting the user to a specific route is more desirable.

Problem Statement

Supposing you want to redirect missing blog posts on your blog to the most related blog post if the post is soft deleted and to the blog.index route, if the post doesn't exist on the database.

Solution: Introducing the `missing` and `Route::bind` method

The missing method provides a convenient way to handle missing route models in Laravel. It allows you to define a fallback action that executes when a bound model is not found. Instead of returning a 404 error, you can use the missing method to redirect the user to a different route.

Implementation Steps for `missing` method

To implement the missing method in your Laravel application for deleted model define your route and inside the missing method's callback function, you can define your redirect logic:

//In web.php
use Illuminate\Support\Facades\Redirect;

Route::get('/{blogPost}/{slug?}', 'show')->name('show')->missing(function (Request $request) {
    // Handle missing route model here
    return Redirect::route('blog.index');
});

In this example, the Redirect::route method is used to generate a redirect response to the 'blog.index' named route. By adding the missing method to the route definition, you were able to redirect the user to the 'blog.index' route when the specified blog post model was not found. Feel free to adjust the route name and any additional parameters or options according to your application's requirements.

Implementation Steps for `Route::bind` method

To implement Route::bind method for soft deleted methods, use the following steps in the RouteServiceProvider.php:

//RouteServiceProvider.php

Route::bind('blogPost', function ($key, $binder) {
            $model = BlogPost::where('id', $key);
            $find = $model->first();

            if ($find) {
                return $find;
            }

            //DO this only for certain controller methods
            if (in_array(explode('.', $binder->action['as'])[2], ['show'])) {
                // find with trashed
                $model = $model->withTrashed()->first();
                if ($model) {
                    //look for related books
                    $mostRelated = BlogPost::related($model->tags, $key)->first();
                    if ($mostRelated) {
                        return $mostRelated;
                    }
                }
            }

            //No abort(404) here, so that the ->missing in web.php can redirect
        });

Route Binding: The code starts with the declaration of a route binding for a parameter named 'blogPost'. This parameter will be used to retrieve a specific blog post based on its ID.
Model Retrieval: Inside the route binding function, the code initializes a variable $model with a query to retrieve a BlogPost instance where the ID matches the provided key.
Initial Check: The next step involves checking if a matching blog post is found. If the $find variable contains a non-null value, indicating that a blog post is found, it is returned immediately.

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Controller Method Check: The code then checks if the current controller method is one of the designated methods, such as the 'show' method. This check is done by extracting the method name from the action property of the $binder object. We want this to only happen for the 'show' method.
Retrieving Soft Deleted Models: If the controller method is in the designated list, the code proceeds to retrieve the BlogPost model using the withTrashed() method. This method retrieves the model instance even if it has been soft deleted. By calling first(), the code retrieves the first matching soft deleted model.
Searching for Related Blog Posts: If a soft deleted model is found, the code attempts to find the most related blog post using the related() method of the BlogPost model. This method takes the tags of the soft deleted model and the original key as parameters and returns the most relevant related blog post.
Returning the Result: If a related blog post is found, it is returned as the final result of the route binding.
Handling Missing Blog Posts: Importantly, the code does not invoke abort(404) if no blog post is found. Instead, it allows the ->missing method in the web.php file to handle the missing blog post scenario and perform a redirect accordingly.

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Conclusion

By utilizing Laravel's missing method, you can elegantly handle missing route models in your application. Instead of returning a generic 404 error, you have the flexibility to redirect the user to a specific route, providing a better user experience. Experiment with the missing method in your own Laravel projects and explore its potential to enhance your routing workflows. Understanding route binding in Laravel is crucial for building robust and efficient web applications.