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Date	Time	RSVP
November 10, 2021	11:00 a.m.–12:00 p.m. ET / 4:00–5:00 p.m. GMT

About the Talk

Let’s learn Laravel and build an app in 1 hour!

See how Laravel — a popular PHP framework with expressive, elegant syntax — can be the foundation of your app, freeing you to create without sweating the small things.

What You’ll Learn

How to use Laravel
Laravel’s key concepts
How Laravel can be the foundation for your application

This Talk is Designed For

Any developer looking to build modern, full-stack web applications

Resources

Laravel docs

Source link

Cleaner Laravel Controllers with Route Model Binding

Introduction

Laravel as a framework either for building websites or a container to build APIs (lumen) has evolved as a developer’s framework of choice. Laravel comes with a lot of growing features – take for example Laravel’s events. Events in Laravel used to be a simple pub-sub library, but now Laravel events can broadcast all the way to the client and allows us to create real-time apps.

But that’s beside the point, today’s celebrity is Laravel’s route model binding.

What is Route Model Binding

Route model binding in Laravel provides a mechanism to inject a model instance into your routes. Still not clear on the meaning, here is an example. Say we want to get a post from the database, we could do something like this:

...
// the route parameter is the id of the post
// for example http://example.com/posts/53
Route::get('posts/{id}', function ($id) {

  // we have to find the post using the $id
  $post = Post::find($id);

  // if there is no post, 404
  if (!$post) return abort(404);

  // return the view and the post
  return view('post.show', compact('post'));
});
...

We could further go on to simplify this method into

...
// the route parameter is the id of the post
// for example http://awesome.dev/posts/53
Route::get('posts/{id}', function ($id) {

  // find the post or 404 if not found
  $post = Post::findOrFail($id);

  // return the view and the post
  return view('post.show', compact('post'));
});
...

But route model binding helps us get rid of extra keystrokes by simplifying both instances above into

...
// by using $post, we can inject the Post object
Route::get('posts/{post}', function ($post) {

  // we now have access to the $post object! no code necessary

  // return the view and the post
  return view('post.show', compact('post'));
});
...

This is made possible by telling Laravel to inject a Post model into any route controller that has a {post} parameter attached to it.

Laravel currently supports two types of route model bindings. We have:

Implicit model binding
explicit model binding

Note: The example of route model binding listed above is explicit.

Implicit Model Binding

While we’ve seen explicit model binding, here’s an example of implicit model binding now:

Route::get('posts/{post}', function (AppPost $post) {
  // be awesome. enjoy having the $post object
});

Laravel is smart enough to know that since a Post model is being injected into the controller closure, it should get the id parameter from the route and get the details for the user.

Accessing a post will still be done using http://awesome.example.com/posts/24.

Changing the Model’s Route Key

If you would like the implicit model binding to use a database column other than id when retrieving models, you may override the getRouteKeyName method on your Eloquent model.

For instance, if we wanted to use the slug instead of the id, we could do the following:

class Post extends Model {
  public function getRouteKeyName() {
    return 'slug';
  }
}

Then we could access our route using http://awesome.example.com/posts/my-post-slug instead of http://awesome.example.com/posts/24.

Explicit Model Binding

Just like the name implies, you have to explicitly tell Laravel you want it to bind a url parameter to a particular model. There are two ways to do this, we could bind a parameter to a model using the provided Route facade or carry out this binding in app/Providers/RouteServiceProvider.php (I prefer this method).

Using the `Route` Facade

Using the Route facade to bind a parameter to a model, we can do something like this:

Route::bind('post', 'AppPost');

We could also give our binding more meaning, for example, what if we want a post only if is a draft? For that, we could change the second parameter of the Route::bind to a closure which takes the route parameter as its value.

Route::bind('post', function ($value) {
  return AppPost::find($value)->where('status', '=', 'published')->first();
});

Using the `RouteServiceProvider`

The only difference between using the Route facade and RouteServiceProvider class is that – registering your bindings is done in the boot method of the RouteServiceProvider class (location is app/Providers directory) and the bind method is called on the $router object injected into the method. Quick example

public function boot(Router $router)
{
  parent::boot($router);

  $router->bind('post', function ($value) {
    return AppPost::find($value)->where('status', '=', 'published')->first();
  });
}

Custom Exceptions for Route Model Binding

I build a lot of APIs, so custom exceptions for route model bindings are actually more useful for people like me. Laravel provides an easy way for us to do this. Still in the boot method of the RouteServiceProvider class, call the model method on the $router object.

The model method takes three arguments, the arguments are similar to that of the bind method, with a new addition the third argument which is a closure that throws the new exception.

$router->model($routeParameter, $modelToBind, function () {
  throw new NotFoundHTTPException;
});

Conclusion

You can read more about route model binding in the documentation.

Hopefully this small, but neat feature can save you a few lines of code in your projects and make your controllers that much cleaner.

Source link

How To Update Database Records in Laravel Eloquent

Part of the Series:
A Practical Introduction to Laravel Eloquent ORM

Eloquent is an object relational mapper (ORM) that is included by default within the Laravel framework. In this project-based series, you’ll learn how to make database queries and how to work with relationships in Laravel Eloquent. To follow along with the examples demonstrated throughout the series, you’ll improve a demo application with new models and relationships. Visit the series introduction page for detailed instructions on how to download and set up the project.

In a previous section of this series, you updated an existing Artisan command in order to support the new lists feature. Although there are commands to insert and delete links, the demo application currently doesn’t have a command to edit existing links. This can be useful to move links between lists, for instance, or update a link description.

In this guide, you’ll create a new Artisan command to update existing links in the database.

From your terminal, first make sure you’re in your project’s root directory, then run the following to bootstrap a new Artisan command:

docker-compose exec app php artisan make:command LinkUpdate

This will create a new LinkUpdate.php file located at app/Console/Commands. Open the file in your code editor of choice:

app/Console/Commands/LinkUpdate.php

This file contains boilerplate code for a new Artisan command. You’ll update it to handle editing a link provided its unique id. This is what your handle() method needs to do:

Obtain an id provided by the user and check for the existence of a link with a matching id in the database.
If a valid link cannot be found, show an error message and exit.
If a valid link is found, prompt the user to provide updated values for the link description and link list.
Ask the user to confirm changes.
When confirmed, update the item in the database.

Start by including a couple use definitions at the top of the file, to facilitate referencing to the Link and LinkList classes later on:

app/Console/Commands/LinkUpdate.php

<?php

namespace AppConsoleCommands;

use AppModelsLink;
use AppModelsLinkList;
use IlluminateConsoleCommand;

...

To obtain the link id, you should set up a mandatory argument in the new link:update command, so that users are required to provide that parameter at run time. Locate the command signature definition at the top of the file and replace it with the highlighted line:

app/Console/Commands/LinkUpdate.php

...

class LinkUpdate extends Command
{
    /**
     * The name and signature of the console command.
     *
     * @var string
     */
    protected $signature="link:update {link_id}";
...

If you save the file and try to run the command now without an additional argument, you’ll get an error:

docker-compose exec app php artisan link:update

OutputNot enough arguments (missing: "link_id").

In the handle() method, you need to obtain the link id provided by the user and locate it in the database. This can be done with the argument() method that is provided through the parent Command class. Then, you can use the find() Eloquent method to query the database for a link with that id. If the find() method returns null, it means no link with that id was found, so the program should exit in error.

app/Console/Commands/LinkUpdate.php

...
   /**
     * Execute the console command.
     *
     * @return int
     */
    public function handle()
    {
        $link_id = $this->argument('link_id');
        $link = Link::find($link_id);

        if ($link === null) {
            $this->error("Invalid or non-existent link ID.");
            return 1;
        }

        // obtain updated information from user
    }
...

When a valid link is found, you need to prompt the user for the updated link information.You can do so using the ask method, highlighted in the next example:

app/Console/Commands/LinkUpdate.php: function handle()

...
        if ($link === null) {
            $this->error("Invalid or non-existent link ID.");
            return 1;
        }

        $link->description = $this->ask('Link Description (ENTER to keep current)') ?? $link->description;
        $list_name = $this->ask('Link List (ENTER to keep current)') ?? $link->link_list->title;
...

This code will prompt the user for an updated description and list, while keeping the current values as default in case a user doesn’t provide new ones, pressing ENTER to skip the prompt.

Once you have all this information, you can proceed to the update. It’s a good idea to use the confirm() method to have the user confirm the changes before you run the database update. This is how such code would look:

app/Console/Commands/LinkUpdate.php: function handle()

...
        $link->description = $this->ask('Link Description (ENTER to keep current)') ?? $link->description;
        $list_name = $this->ask('Link List (ENTER to keep current)') ?? $link->link_list->title;

        $this->info("Description: $link->description");
        $this->info("Listed in: " . $list_name);

        if ($this->confirm('Is this information correct?')) {
            //code that updates the link
        }
...

Inside the if block, you have to start by checking if the requested list exists, otherwise create a new list with the provided name. Then, you’ll use the associate() method to update the relationship between this link and its “parent” list. The save() method, finally, will persist the changes to the database:

app/Console/Commands/LinkUpdate.php: function handle()

...
        if ($this->confirm('Is this information correct?')) {
            $list = LinkList::firstWhere('slug', $list_name);
            if (!$list) {
                $list = new LinkList();
                $list->title = $list_name;
                $list->slug = $list_name;
                $list->save();
            }
            $link->link_list()->associate($list)->save();
            $this->info("Updated.");
        }
...

This is the complete LinkUpdate.php file for your reference:

app/Console/Commands/LinkUpdate.php

<?php

namespace AppConsoleCommands;

use AppModelsLink;
use AppModelsLinkList;
use IlluminateConsoleCommand;

class LinkUpdate extends Command
{
    /**
     * The name and signature of the console command.
     *
     * @var string
     */
    protected $signature="link:update {link_id}";

    /**
     * The console command description.
     *
     * @var string
     */
    protected $description = 'Update a link in the database';

    /**
     * Create a new command instance.
     *
     * @return void
     */
    public function __construct()
    {
        parent::__construct();
    }

    /**
     * Execute the console command.
     *
     * @return int
     */
    public function handle()
    {
        $link_id = $this->argument('link_id');
        $link = Link::find($link_id);

        if ($link === null) {
            $this->error("Invalid or non-existent link ID.");
            return 1;
        }

        $link->description = $this->ask('Link Description (ENTER to keep current)') ?? $link->description;
        $list_name = $this->ask('Link List (ENTER to keep current)') ?? $link->link_list->title;

        $this->info("Description: $link->description");
        $this->info("Listed in: " . $list_name);

        if ($this->confirm('Is this information correct?')) {
            $list = LinkList::firstWhere('slug', $list_name);
            if (!$list) {
                $list = new LinkList();
                $list->title = $list_name;
                $list->slug = $list_name;
                $list->save();
            }
            $link->link_list()->associate($list)->save();
            $this->info("Updated.");
        }

        return 0;
    }
}

Note: For more detailed information on Artisan commands, check our guide on How To Create Artisan Commands to Manage Database Records in Laravel, which is part of our introductory Laravel series.

Save the file when you’re finished. Then, use the link:show command to obtain all links and its respective IDs:

docker-compose exec app php artisan link:show

Output+----+-------------------------------------------------+--------------+----------------------------------+
| id | url                                             | list         | description                      |
+----+-------------------------------------------------+--------------+----------------------------------+
| 1  | https://digitalocean.com/community              | default      | DO Community                     |
| 2  | https://digitalocean.com/community/tags/laravel | default      | Laravel Tutorias at DigitalOcean |
| 3  | https://digitalocean.com/community/tags/php     | default      | PHP Tutorials at DigitalOcean    |
| 4  | https://twitter.com/digitalocean                | social       | Twitter                          |
| 5  | https://dev.to/digitalocean                     | social       | DEV.to                           |
| 6  | https://laravel.com/docs/8.x/eloquent           | default      | Laravel Eloquent Docs            |
+----+-------------------------------------------------+--------------+----------------------------------+

Then, choose an item to edit. For instance, you may want to create a digitalocean list for the links that point to the DigitalOcean website (that would correspond to items with IDs 1, 2, and 3 in the previous example output).

To update the link with ID 1, run:

docker-compose exec app php artisan link:update 1

Output Link Description (ENTER to keep current):
 > DO Community

 Link List (ENTER to keep current):
 > digitalocean

Description: DO Community
Listed in: digitalocean

 Is this information correct? (yes/no) [no]:
 > y

Updated.

Then, run the link:show command again to see the updated information:

Output+----+-------------------------------------------------+--------------+----------------------------------+
| id | url                                             | list         | description                      |
+----+-------------------------------------------------+--------------+----------------------------------+
| 1  | https://digitalocean.com/community              | digitalocean | DO Community                     |
| 2  | https://digitalocean.com/community/tags/laravel | digitalocean | Laravel Tutorias at DigitalOcean |
| 3  | https://digitalocean.com/community/tags/php     | digitalocean | PHP Tutorials at DigitalOcean    |
| 4  | https://twitter.com/digitalocean                | social       | Twitter                          |
| 5  | https://dev.to/digitalocean                     | social       | DEV.to                           |
| 6  | https://laravel.com/docs/8.x/eloquent           | default      | Laravel Eloquent Docs            |
+----+-------------------------------------------------+--------------+----------------------------------+

In this guide, you learned how to update database records with Laravel Eloquent. You have upgraded the demo application to include a new command that allows users to edit existing links in the database.

In the next and final part of this series, you’ll create a new command to delete a list of links.

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Laravel

Build an App With Laravel in 1 Hour

How to Join

About the Talk

What You’ll Learn

This Talk is Designed For

Resources

Cleaner Laravel Controllers with Route Model Binding

Introduction

What is Route Model Binding

Implicit Model Binding

Changing the Model’s Route Key

Explicit Model Binding

Using the Route Facade

Using the RouteServiceProvider

Custom Exceptions for Route Model Binding

Conclusion

How To Update Database Records in Laravel Eloquent

Using the `Route` Facade

Using the `RouteServiceProvider`