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Quick start with Migrations plugin

In a previous post I gave an overview of the CakePHP Migrations plugin, what it does and why you should use it in your applications. This article will explain how to use it in a practical way. We are going to bake a simple blog application recipe application and see how migrations are integrated in the development process.

Since we recently moved all our open source projects on http://cakedc.github.com/, this sample application source code is also available there: Sample Migrations Application - Github (it is a CakePHP 1.3 application). Ready?

Bake a new application and add the migrations plugin

First of all, we need to bake a new CakePHP application. Easy enough to do using cake bake, then configure your database (an empty database is sufficient for now) and check that the home page is all green! If you have not set up your environment to use the CakePHP command line yet, take some time to do so... it worth it!

Adding the migrations plugin might also be a straightforward task. You can either download the archive containing the plugin code and unzip it in the "/plugins/migrations" folder of your application, or  add it as a git submodule with the following command:

git submodule add git://github.com/CakeDC/Migrations.git plugins/migrations

Then check that it is correctly installed by executing the following command from your application root:

cake migration help

If you see a list of available commands you can move on next step.

Create initial tables and bake the MVC

We now need something to migrate! Let's create some tables in the database. The application will have Users who can publish Recipes, each one having several Ingredients (of course Ingredients can be used in many Recipes). Here is a SQL dump of this simple database schema:

CREATE TABLE `ingredients` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(100) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;

CREATE TABLE `ingredients_recipes` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `ingredient_id` int(11) NOT NULL,
  `recipe_id` int(11) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;

CREATE TABLE `recipes` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `user_id` int(11) NOT NULL,
  `name` varchar(100) NOT NULL,
  `content` text NOT NULL,
  `created` datetime NOT NULL,
  `modified` datetime NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;

CREATE TABLE `users` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(100) NOT NULL,
  `password` varchar(255) NOT NULL,
  `created` datetime NOT NULL,
  `modified` datetime NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1;

As our goal here is not to focus on the application code itself, baked MVC from these tables might be sufficient... just run the command cake bake all for User, Recipe and Ingredient to bake'em all!

At this point we must have an application with an initial architecture ready to share. To start from here, one will just have to checkout the related commit... but don't you see a problem with this? How will he create the initial database? Maybe we could send him the SQL dump by email, or better commit it with the application! It is where the Migrations plugin comes in.

Generate the initial migration

"Be kind with your coworkers and include the database schema with your code... along with some sample data."

Let's use the migrations shell to generate an agnostic database schema containing our 4 tables, and an initial admin user account. To do so we just need to run the following command:

cake migration generate

After entering a name for the migration and selected the database dump option, we might have a new "/config/migrations" directory containing two files:

  • map.php representing the different migrations order,
  • name_of_the_migration.php a migration file containing all the necessary information to create your actual database. In the sample application it is named: "001_added_users_recipes_and_ingredients_tables.php". You might have noticed that we added a 001 prefix to the migration name to make it easier to see migrations order, it is a good practice.

We can now open the generated migration file (/config/migrations/001_added_users_recipes_and_ingredients_tables.php) and take a look at it. If you need more information and understand all available migration directives, you can read the plugin documentation.

For now we are just going to focus on the empty "after()" callback. This callback is triggered once the migration has been executed, and allow you to do whatever you want, given the direction of the migration: applied (up) or reverted (down). We are going to use this callback to create an initial admin User. Here is the code of the callback (as you are a CakePHP developer you might understand it quite easily):

function after($direction) {
	if ($direction === 'up') {
		if (!class_exists('Security')) {
			App::import('Core', 'Security');
		}

		$User = $this->generateModel('User');
		$user = array(
			'User' => array(
				'name' => 'admin',
				'password' => Security::hash('unsecurepassword', null, true)));
		$User->save($user);
	}
	return true;
}

Notice the use of the generateModel() method provided by the Migrations plugin. It is a shorthand allowing you to cleanly load a model in the callback to insert new data or update the existing. We could explain the reason of it more deeply but it is not the goal of this article, so just keep in mind that it is the best way to load a Model from callbacks!

Here we are! We can now share the application with anyone. After checked out the application, one will just have to run cake migration all to turn an empty database to a database containing all the needed tables, and an initial admin user to start using the application.

Categorize the recipes!

As the application evolves, we need to sort recipes by categories. This change involves two changes in the current database schema: a new categories table must be created, and a category_id field added to the recipes table.

Note: If you later want to use the migrations diff feature to generate a migration containing a diff between your previous database schema and the current one, you have to generate a Cake Schema of your database at this point. Simply run cake schema generate.

We can now update the recipes table and create a new categories table. Here is a simple SQL script:

CREATE TABLE `categories` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(100) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1;
ALTER TABLE `recipes` ADD `category_id` INT NOT NULL

Bake the MVC for categories and update recipes view pages to display the category so the application reflect these database changes. Before sharing these code changes, we need to generate a second migration describing the above SQL snippet in an agnostic way... and creating initial categories!

Nothing different than what we did previously: run cake migration generate, give a name to the migration, and choose between generating a diff from the schema.php file (if one was generated), generating a dump of the database (we will remove unnecessary instructions later) or generating an empty migration file. Once generated, it is always important to check the generated directives for the migration and fix them if needed. The migration must look like this:

var $migration = array(
	'up' => array(
		'create_table' => array(
			'categories' => array(
				'id' => array('type' => 'integer', 'null' => false, 'default' => NULL, 'key' => 'primary'),
				'name' => array('type' => 'string', 'null' => false, 'default' => NULL, 'length' => 100),
				'indexes' => array(
					'PRIMARY' => array('column' => 'id', 'unique' => 1),
				),
				'tableParameters' => array('charset' => 'latin1', 'collate' => 'latin1_swedish_ci', 'engine' => 'MyISAM'),
			),
		),
		'create_field' => array(
			'recipes' => array(
				'category_id' => array('type' => 'integer', 'null' => false, 'default' => NULL)
			),
		),
	),
	'down' => array(
		'drop_table' => array(
			'categories'
		),
		'drop_field' => array(
			'recipes' => array(
				'category_id'
			),
		),
	),
);

If you understood what we did in the first migration callback to add an initial user you might be able to implement this one. We would like to add initial categories: Starters, Main Dish and Desserts.

For lazy people, the code is here:

function after($direction) {
	if ($direction === 'up') {
		$Category = $this->generateModel('Category');
		$categories = array(
			array('name' => 'Starters'),
			array('name' => 'Main Dish'),
			array('name' => 'Desserts'));
		$Category->saveAll($categories);
	}
	return true;
}

Here we are again! The changes are ready to commit, and the commit will contains both code and database changes. One could update the database after checking out this commit by running: cake migration all.

The end

I hope this very simple use case and the code we built will help you to start using Migrations. As you could see it is very simple to use and will make your life much more easier: you would not have to worry anymore about the state of your database schema.

The source code of this tutorial is available on Github. If you found any bug or have any suggestion about the Migrations plugin, please create a ticket on Github. Comment this article if you have any question, and do not hesitate to share it if you found it useful!

Latest articles

CakeFest 2021 Recap

Here we are again coming off of the CakeFest sugar high! I don’t even know where to begin.    Unfortunately, or fortunately - I haven’t decided, we had to do another virtual event. The safety of speakers, staff and attendees is very important to us, so a physical event was not the best option in our opinion with traveling.    However, after this event, I started thinking about the people who were able to attend from the comfort of their own homes or offices. These people may not have been able to travel or attend otherwise, and that gives me our silver lining. Not to mention that we had more ticket sales this year than any of our previous events (at least that I can remember).    The theme, for me anyway, ha ha, was traveling the world, ironically. We started in the Canary Islands, traveled to Germany, to Canada, to England and Austria. We had new faces from the US, the Czech Republic and even Japan - and more! This is, as I’ve mentioned, one of the best things about the CakePHP community, we have community members all over the world. This was our chance to come together.    So let’s get to the event. Here’s what you may have missed: 

Workshops:

Workshop 1 Jorge González (Twitter: @steinkelz) Topics covered included: 0:00 - Docker development environment for CakePHP 15:56 - Middlewares  30:05 - Security 1:31:36 - Performance optimization 2:04:49 - Events   Workshop 2 Michael Hoffmann (Twitter: @cleptric) Topics covered included: 0:00:00 -Setup login action in CakePHP 0:29:10 - Vite with hot reloading Vue.js tailwind css   Workshop 3 Mark Story (Twitter: @mark_story) Topics covered included: 0:04:25 - Leveraging new style fixtures 0:48:26 - Using the DI container 1:30:13 - Browser automation testing with Panther. 2:17:13 - Helpers you may need.
 

Talks:

* Juan Pablo Ramirez (Twitter: @jpramidev) gave the keynote talk on behalf of Passbolt. * Sho Ito (Twitter: @itosho) taught us all about Components * Yuki Kanazawa (Twitter: @yakitori009) and this talk about Automatically Distributing Reference Queries to    Read Replica in CakePHP4 * Mark Scherer (Twitter: @dereuromark) schooled attendees on IDE in CakePHP development * Jiri Havlicek (Twitter: @Jerryhavl) played a big role in fighting COVID-19 by helping create a  contact tracing app (developed with CakePHP) in Czech Republic * Chris Miller (Twitter: @ccmiller2019) explained standards and why we use them * Kevin Phifer (Twitter: @lordsimal)  joined in to explain how to re-use code - utility classes and PHP namespaces * Paul Henriks created a plugin with attendees LIVE * Ed Barnard (Twitter: @ewbarnard) brought the dragons! He talked about finding the Joy in Software Development * Chris Hartjes (Twitter: @grmpyprogrammer) delivered a Grumpy Programmer's Guide to being a senior developer  * Joe Ferguson (Twitter: @joepferguson) shared his knowledge on Modern Infrastructure as code with Ansible * Timo Stark (Twitter: @linux_lenny) shared details about NGINX Unit - and how to modernize your CakePHP deployments

Trivia and giveaways 

Cake ceremony dedicated to Mark Story

We took this time to thank and acknowledge Mark Story for all of his hard work and dedication that he puts into CakePHP. He then headed the cake cutting ceremony (virtually of course) as speakers and attendees enjoyed their own treats!   See the full archive here: https://cakefest.org/archive/virtual-2021  

So what’s to come? 

First!  Videos are starting to be released. With the help of community member Aroop Roelofs, we will be releasing these videos faster than expected. Ticket holders have been receiving access, and they will be released publicly in the coming days.  In regards to future events, it’s up in the air. We will have some internal discussions about safety measures and restrictions, then we will weigh the option between another virtual or physical event. We will, of course, reach out to the community for their input.  I will close by just saying THANK YOU. Thank you for making my job worth it. When an event runs smoothly and gets so much great feedback, that is a direct reflection from the community support. We hope you all will continue to join us in years to come!    Thanks for baking!  

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.

One CakePHP Project Per Day

The whole team here at CakeDC are big supporters and contributors of the CakePHP community. For this month, I decided to do “one CakePHP project per day” to share with the community.  Here are some of my projects so far:

Project 01 - Notes App

A one page note application using CakePHP 4 and Bootstrap 5. This project is  a good starting point to learn the framework. Link: https://github.com/rochamarcelo/one-project-a-day-challenge-01-notes  

Project 02 - Contact List

An application to manage contacts - you are able to list, add, edit and delete contacts, upload contact avatar images or use avatar images from gravatar.com . It was built using CakePHP 4, plugin friendsofcake/search, plugin josegonzalez/cakephp-upload, Gravatar, and Bootstrap 5.  Link: https://github.com/rochamarcelo/one-project-a-day-challenge-02-contact-list  

Project 03 - Recipe Box

An application to manage recipes, using CakePHP 4,  CouchDB and Bootstrap 5. This one is a good starting point to learn to use CouchDB with CakePHP, including how to list, add and edit recipes (documents). Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-03-recipe-box  

Project 04 - Service Plan with Exchange rate

An application to list services and apply exchange rate using the api https://exchangeratesapi.io/documentation/ and CakePHP 4. In this one you see the custom namespace WebService to handle logic related to api as client. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-04-service-plans-ex-rate  

Project 05 - Polls

A fun poll app, using the awesome Bulma CSS Framework and CakePHP 4. A good example of model association and the CounterCache Behavior. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-05-polls-emmy  

Project 06 - Movie Theater Schedule

An application to see which movies are in the theaters and which hours by screen each day of the week. A good example of complex queries, model associations and seed data. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-06-movie-theater-schedule  

Project 07 - Podcast Finder

An application to help easily find podcasts and download episodes. In the source code you’ll find how to use the itunes api,  a structure to handle Model actions (that I think is a good option to make your models cleaner), and a way to parse podcasts feed (XML); example usage of dependency injection. The application was built with CakePHP 4 and Bulma CSS Framework. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-07-podcast-finder  

Project 08 - Url Shortener

An application to create short urls - a good example of how to create custom routes and use custom primary key types for a model. The application was built with CakePHP 4. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-08-url-shortener  

Project 09 - Quiz

Users can list quizzes, create quizzes and answer at any time. A good example of how to use MongoDB with CakePHP 4 with a base structure for Collection classes.  Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-09-quiz  

Project 10 - File Transfer

An application to easily send files to anyone, create an account, upload the file and inform the person email to send to. Built with CakePHP 4, plugin CakeDC/Users,  plugin Josegonzalez/Upload,  plugin friendsofcake/bootstrap-ui, SMTP and Bootstrap. A good example to see the usage of these plugins. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-10-file-transfer  

Project 11 - Tasks

A one page application for  users to manage their tasks. The user can create and remove decks, create and complete tasks, and list tasks grouped by decks. Built with CakePHP 4, plugin CakeDC/Users and Bootstrap 5 Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-11-tasks  

Project 12 - Blog

A blog website with blog posts and tags management, WYSIWYG editor, blog search, tags filtering. Built with CakePHP 4, CakeDC/Users plugin, friendsofcake/bootstrap-ui, Muffin/Slug, friendsofcake/search and Bootstrap 4 . A good example of usage of custom routes, route prefix, finders and multiple plugins. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-12-blog  

Project 13 - Olympic Medal Count

Perfect time for this project, right?! An application to display olympic medal count by country and sports. The source code uses CouterCache behavior and aggregated query. Built with CakePHP 4 and Bootstrap 5. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-13-olympic-medal-count
 

Project 14 - Smart Home Dashboard

An awesome dashboard to manage smart devices using MQTT Messaging, CakePHP 4, CakeDC/Users plugin, php-mqtt/client (testing with Mosquitto Broker) and Bootstrap 5. The application is able to publish messages to change device status and subscribe for status changes. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-14-smart-home-dashboard-mqtt    I hope that this initiative will somehow inspire others to put their Cake skills to work, and share their projects with the community. If you’d like to see my future projects and posts, you can follow me on Twitter, and I will share them all there! https://twitter.com/mrcodex

We Bake with CakePHP