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Dependency Injection with CakePHP

Let’s talk about Dependency Injection!

SOLID principles

As you know SOLID is an acronym for the  five object-oriented design principles. In this topic, we will focus on Interface segregation principle and Dependency inversion principle.

Interface segregation principle states that a client must not be forced to implement an interface that they do not use, or clients shouldn’t be forced to depend on methods they do not use. In other words, having  many client-specific interfaces is better than one general-purpose interface.

From the other side, Dependency inversion principle states that objects must depend on abstractions, not on concretions. It states that the high-level module must not depend on the low-level module, but they should depend on abstractions.

To follow Dependency inversion principle, we need to construct low-level modules and pass them to constructors, and that might create a lot of manual work for developers. The dependency injection container is created specifically for solving the problem with manual construction of an object, before creating a specific object.

If we follow interface segregation principle when developing application modules, it would be easy to configure a container and switch module dependency. This is where the interface shows its incredible power.

 

Few words about CakePHP Events System

CakePHP Events System was created to allow injecting some logic using listeners. However, in some cases, it is used to get results from code that will be created by the module user. When an event is dispatched by the listener, it can return the result.

Callback injection through the event system has some drawbacks. First of all, parameters passed to the event need to pass as a hash array. So unfortunately, there is no way to check that all params are really passed or to be sure that all passed params have correct types.

Is there a way to solve this problem? Yes, and containers could help with that. Instead of passing events, we can get the required object from the container and call it method. But you could say: wait, we don't know what object could be used in client code within the developed plugin. That's fine, and this  is where interface segregation principle can help.

In our plugin, we define an interface for each such case, and instead of dispatching an event, we can easily get an object from the container by interface.

 

    $updater = $container->get(AfterLoginInterface::class);

    if ($updater !== null) {

        $user = $updater->afterLogin($user);

    }

 

In the Application::services method, users link the interface with the specific class.

 

    public function services(ContainerInterface $container): void

    {

        $container->add(AfterLoginInterface::class, MyAfterLogin::class);

    }

 

In some of default behavior needed we can map service class for container to default implementation using Plugin::services method.

 

    public function services(ContainerInterface $container): void

    {

        if (!$container->has(AfterLoginInterface::class)) {

            $container->add(AfterLoginInterface::class, NullAfterLogin::class);

        }

    }

 

Container propagation

Dependency injection is an experimental feature.

Initial implementation limited by Controllers constructors and methods, and Commands constructors.

If we want to access the container in other parts of the application, we may want to propagate it from app level. The most logical way would be to implement middleware and store the container inside the request attribute.

 

<?php

declare(strict_types=1);

 

namespace App\Middleware;

 

use Cake\Core\ContainerInterface;

use Psr\Http\Message\ResponseInterface;

use Psr\Http\Message\ServerRequestInterface;

use Psr\Http\Server\MiddlewareInterface;

use Psr\Http\Server\RequestHandlerInterface;

use RuntimeException;

 

/**

 * Container Injector Middleware

 */

class ContainerInjectorMiddleware implements MiddlewareInterface

{

    /**

     * @var \Cake\Core\ContainerInterface

     */

    protected $container;

 

    /**

     * Constructor

     *

     * @param \Cake\Core\ContainerInterface $container The container to build controllers with.

     */

    public function __construct(ContainerInterface $container)

    {

        $this->container = $container;

    }

 

    /**

     * Serve assets if the path matches one.

     *

     * @param \Psr\Http\Message\ServerRequestInterface $request The request.

     * @param \Psr\Http\Server\RequestHandlerInterface $handler The request handler.

     * @return \Psr\Http\Message\ResponseInterface A response.

     */

    public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface

    {

        return $handler->handle($request->withAttribute('container', $this->container));

    }

 

That’s it! I hope that this will help you when you are baking with dependency injections. If you run into any problems, there are many support channels that allow the CakePHP community to help  You can check them out under the community tab at CakePHP.org.

Latest articles

Build a Single Page Application Using CakePHP and InertiaJS

Build a Single Page Application using CakePHP and InertiaJS

  The Inertia Plugin allows a CakePHP application to integrate Vue 3 components in the front end, without the need to write a specific API for data transfer. This is done  by adding a Middleware and view classes that facilitate the conversion of objects and data in JSON almost automatically, as well as the direct load in the components. The plugin is thought of as a base to extend and use your app’s specific controllers and views from. Just because  it works out of the box doesn't mean it is intended to be used exactly as is,  but this will  provide you a good kick start. See the repo here: https://github.com/CakeDC/cakephp-inertia

Requirements

  • CakePHP 4.5
  • PHP >= 8.1
  • NodeJS 18.9 (only for build Vue Components, not required on running site)

 

Step 1: Create a basic CakePHP install

  For this example I will use a basic installation using Docker and Composer.  First you must create project from cakephp/app  
$> composer create-project --prefer-dist cakephp/app:~4.5 inertia_app $> cd inertia_app $> cp config/app_local.example.php config/app_local.php
  Then write an docker-compose.yml file as:
version: '3' services:   psql13:     image: postgres:13     container_name: inertia-app-postgres13     volumes:       - ./tmp/data/inertia-postgres13__db:/var/lib/postgresql:delegated     environment:       - POSTGRES_USER=my_app       - POSTGRES_PASSWORD=secret       - POSTGRES_DB=my_app       - PGUSER=my_app       - PGDATABASE=my_app       - PGPASSWORD=secret     ports:       - '7432:5432'     cakephp:     image: webdevops/php-nginx:8.1     container_name: inertia-app-cakephp     working_dir: /application     volumes:       - ./:/application:cached       - ~/.ssh:/home/application/.ssh:ro     environment:       - WEB_DOCUMENT_ROOT=/application/webroot       - DATABASE_URL=postgres://my_app:secret@inertia-app-postgres13:5432/my_app     ports:       - "9099:80"
  Launch the container and go to http://localhost:9099/  
$> docker-compose up -d
 

Step 2: Add CakePHP Inertia plugin

  Install plugin via command line:
$> composer require cakedc/cakephp-inertia
  Once installed enable it in src/Application.php, adding at the bottom of bootstrap function:
$this->addPlugin('CakeDC/Inertia');
  or by command line:
$> bin/cake plugin load CakeDC/Inertia

 

Step 3: Create Vue App and install it

  To create Vue App type in command line:
$> bin/cake create_vue_app
  This command create in the resources directory the files that use our App, also create in root directory the files:
  • webpack.mix.js
  • package.json
  Then in root directory install with NPM:
$> npm install

 

Step 4: Create simple SPA (Single Page Application)

  Create a single page called dashboard that show values sets in a controller action We need to first add InertiaResponseTrait  
use CakeDC\Inertia\Traits\InertiaResponseTrait;   class PagesController extends AppController {    use InertiaResponseTrait;    ...  ...   }
  Create a new function that would look like this:
public function dashboard() {   //set default php layout of plugin that use vue   $this->viewBuilder()->setTheme('CakeDC/Inertia');     $page = [       'text' => 'hello world 1',       'other' => 'hello world 2',   ];   $this->set(compact('page')); }
  in config/routes.php uncomment lines to catch all routes:
$builder->connect('/{controller}', ['action' => 'index']); $builder->connect('/{controller}/{action}/*', []);
and comment line:
$builder->connect('/pages/*', 'Pages::display');
  Then create file resources/js/Components/Pages/Dashboard.vue that would look like this:
<script setup> import Layout from '../Layout' import { Head } from '@inertiajs/vue3' import {onMounted} from "vue";   defineProps({     csrfToken: String,     flash: Array,     page: Array, })     onMounted(() => {     console.log('Component Dashboard onMounted hook called') }) </script>   <template>     <Layout>         <Head title="Welcome" />         <h1>Welcome</h1>         <p>{{page.text}}</p>         <p>{{page.other}}</p>     </Layout> </template>
  On root directory execute:
$> npm run dev
  IMPORTANT: Whenever you modify the .vue templates, you must run this script. Go to http://localhost:9099/pages/dashboard to see that Dashboard Vue Component prints values assignments on Dashboard CakePHP function.
   

 

Step 5: Bake CRUD system

  For this example, we use sql file on config/sql/example/postgresql.pgsql   That creates a database with the relations     Once the database has been created, bake models and controllers as normal using:
$> bin/cake bake model Pages --theme CakeDC/Inertia $> bin/cake bake controller Pages --theme CakeDC/Inertia $> bin/cake bake model Tags --theme CakeDC/Inertia $> bin/cake bake controller Tags --theme CakeDC/Inertia $> bin/cake bake model Categories --theme CakeDC/Inertia $> bin/cake bake controller Categories --theme CakeDC/Inertia
  and bake templates using vue_template instead of template as:
$> bin/cake bake vue_template Pages --theme CakeDC/Inertia $> bin/cake bake vue_template Tags --theme CakeDC/Inertia $> bin/cake bake vue_template Categories --theme CakeDC/Inertia
  Again run:
$> npm run dev
  You can the results from this example by going to http://localhost:9099/pages/index   In the following recording you can see how to add, edit and delete a record without reloading the page at any time.

 

Step 6: Using prefix and adding a navigation menu

  Add route to prefix Admin on config/routes.php
$builder->prefix('admin', function (RouteBuilder $builder) {    $builder->fallbacks(DashedRoute::class); });
  To generate controllers and template with a prefix use --prefix option of bake command as:
$> bin/cake bake controller Pages --prefix Admin --theme CakeDC/Inertia $> bin/cake bake controller Tags --prefix Admin --theme CakeDC/Inertia $> bin/cake bake controller Categories --prefix Admin --theme CakeDC/Inertia $> bin/cake bake vue_template Pages --prefix Admin --theme CakeDC/Inertia $> bin/cake bake vue_template Tags --prefix Admin --theme CakeDC/Inertia $> bin/cake bake vue_template Categories --prefix Admin --theme CakeDC/Inertia
  You can add a horizontal menu to navigate through controllers   Edit resources/Components/Layout.vue and put inside header tag links as:
<header>    <Link as="button" href="/pages/index" class="button shadow radius right small">Pages</Link>    <Link as="button" href="/tags/index" class="button shadow radius right small">Tags</Link>    <Link as="button" href="/categories/index" class="button shadow radius right small">Categories</Link> </header>
  Again run:
$> npm run dev
  You can see the results from this  example by going to http://localhost:9099/admin/pages/index   In the following recording you can see how to add, edit and delete a record without reloading the page at any time and navigate through pages, tags and categories.

  Hopefully this example will make your experience easier! Let us know: [email protected].

When and why should you upgrade to CakePHP 5?

CakePHP 5.0.0 was released on September 10th. The current version as of today is 5.0.3 (released Nov 28th and compatible with PHP 8.3 https://github.com/cakephp/cakephp/releases/tag/5.0.3). You might be asking yourself some questions related to the upgrade… here's what we've been recommending to our clients to do since version 5 was released. Leaving aside the obvious reasons for an upgrade, today we're going to categorize the decision from 2 different points of view: Your current CakePHP version, and your role in the project.

When should you upgrade? 

  We are going to use current CakePHP version as the main criteria: * If you are in CakePHP <= 2   * We strongly recommend an upgrade as soon as possible. If you are unable to upgrade, try to keep your PHP version and all the underlying dependencies as fresh as you can and isolate the application as much as possible. If your application is internal, consider using a VPN blocking all outside traffic. If your site is open to the public, consider using an isolated environment, hardened. Adding a web application firewall and a strict set of rules could also help to mitigate potential security issues. Even if CakePHP is very secure, the older versions of CakePHP, like  1 and 2  have a very old code base , and other vendors/ libraries could be a serious security risk for your project at this point.   * If you are in CakePHP 3.x   * The effort to upgrade at least to CakePHP 4.x should not be a blocker. We would recommend upgrading at least to the latest CakePHP 4.5.x. You can actually "ignore" the deprecations for now, you don't need to plan for upgrading your authentication/authorization layers just yet, focus on getting your project stable and up to CakePHP 4.5.x in the first round.   * If you are in CakePHP 4.x   * Upgrading to CakePHP 5.x is not an immediate priority for you.   * I would say, 2024 is a good time to start planning for an upgrade. Feature and bugfix releases for 4.x will continue until September 2025. Security fixes will continue for 4.x until September 2026. You have plenty of time to consider an upgrade, and take advantage of newer (and faster!) PHP versions.  

Why should you upgrade? 

  We are going to use your role in the project to provide some good reasons: * If you are a developer   * More strict types, meaning better IDE support and more errors catched at development time.   * New features in CakePHP 5.x will make your code more readable, like Typed finder parameters https://book.cakephp.org/5/en/appendices/5-0-migration-guide.html#typed-finder-parameters      * Quality of life features, reducing development time like https://book.cakephp.org/5/en/appendices/5-0-migration-guide.html#plugin-installer   * Compatibility with PHP 8.3 for extra performance & support   * If you are a manager   * Ensure your development team is forced to drop old auth code and embrace the new authentication/authorization layer https://book.cakephp.org/5/en/appendices/5-0-migration-guide.html#auth   * The new authentication layer will allow you to easily integrate features like single sign on, two factor authentication or hardware keys (like Yubikeys), as there are plugins available handling all these features.   * Get an extended support window. CakePHP is one of the longest maintained frameworks out there, upgrading to CakePHP 5 will keep your core maintained past 2026.   * Upgrade to PHP 8.3 and force legacy vendors to be up to date with the new version, this will also push your team to get familiar with the new PHP core features.   * If you are an investor, not directly related with the project day-to-day operations   * Secure your inversion for a longer period.   * Reduce your exposure to security issues.   * Send a strong message to your partners, keeping your product updated with the latest technology trends.   * Send a strong message to your team, investing in the upgrade of your application will let them know the project is aiming for a long term future.   In conclusion, upgrading to CakePHP 5 is a good move for 2024 whether you're a developer, manager, or investor. The version 5 is stable and ready to go. Staying current becomes not just a best practice but a strategic advantage.   If you are in doubt, feel free to contact us. We'll review your case (for free) and provide an actionable recommendation based on your current situation in the next business day.  

A quick CakePHP Local environment with DDEV

In the realm of web development, a seamless local environment is the bedrock for efficient and stress-free coding. Enter DDEV, a powerful tool that simplifies the setup process and empowers developers to dive into their projects with ease. In this blog post, we'll embark on a journey to demystify the process of setting up a local development environment using DDEV. Whether you're a seasoned developer or just starting in the world of web development, optimizing your local environment can significantly enhance your workflow.

Pre Conditions :

Install Docker https://docs.docker.com/get-docker/ and install DDEV https://ddev.readthedocs.io/en/stable/

Step 1: Create a new CakePHP project skeleton 

composer create-project cakephp/app myproject A new folder "myproject" will be created with a CakePHP project skeleton inside. Go to this new directory and proceed with the following instructions.

Step 2: Initial ddev setup

Run ddev config
This will do the initial ddev setup, press enter for all questions.  Run ddev auth ssh
This will add ssh key authentication to the ddev-ssh-auth container

Step 3: Adjust the settings

Inside "myproject" a new .ddev folder will be created, open config.yaml  and adjust there: php version, database and the database url environment.  For PHP:
php_version: "8.1"

For the database: database: type: mysql version: "8.0" For the environment variable: web_environment: - DATABASE_URL=mysql://db:db@db/db

Step 4: Start ddev

ddev start  This will spin up the project.

Step 5: Open your application

ddev launch This will open your project in a browser.   Once you have the application up and running, some useful commands you could run are:
  • ddev composer to execure composer
  • ddev mysql to get into the database
  • ddev ssh takes you into the web container.
In this link https://ddev.readthedocs.io/en/latest/users/usage/cli/ you can see more useful commands.   Hope you enjoy playing with DDEV!

 

   

 

 

We Bake with CakePHP