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CakePHP Query Builder

CakePHP’s  database Query Builder provides a simple to use fluent interface for creating and operating database queries. It can be used to accomplish most database operations in your application, and works on all supported database systems.


Query builders allow us to create database queries that work with any supported database, without having to worry about differences between SQL implementations in the different database systems.


The CakePHP query builder uses PDO parameter binding to protect your application against SQL injection attacks. There is no need to clean strings being passed as bindings.


For creating a Query object in CakePHP, the easiest way is using find() from a Table object. In CakePHP, queries are lazily evaluated,  which means that they are not evaluated until any of the following actions happens: the query is iterated through a foreach, it’s called first(), all(), toList(), toArray(). 


You can check all the SQL queries that CakePHP is generating, you just need to enable the Database Logging. See here:  https://book.cakephp.org/4/en/orm/database-basics.html#query-logging


Let’s do a few samples using the Query Builder - this is the ER diagram of the database that we will be using for the queries. We have Orders, ProductsUsers and Items that will store the products sold in each order and the quantity sold.

Let’s create some queries using the Query Builder SQL Functions: https://book.cakephp.org/4/en/orm/query-builder.html#using-sql-functions. SQL Functions as part of the Query Builder are abstractions of  some commonly used SQL functions,  and they allow the ORM to choose the specific implementation your application needs based on the Database that is being used. For example, CONCAT is implemented in a different way in MySQL and Postgres, using concat() function will work if you use MySQL or Postgres

 

Imagine we want to build a report of the products sold, including the following:

  1. Display the product in the following format “Products.name - Products.description”.

  2. Total of products sold.

  3. Total of products in stock..

  4. Total amount on sold products.

First, we need to build the Query object using find(), this needs to be done from the Table. $query = Table->find();.

We want to get a report of the products sold and the current stock. Initially, we would need to build a subquery using ItemsTable where the information related to the products sold is present.  Don’t forget to use identifier() when referencing any column. This will tell us  the items sold per product. 

$itemsQuery = $this->Items->find() ->where(['Items.product_id' => $query->identifier('Products.id')]);

Now, let’s build each query needed for the information required:

  1. Let’s start displaying the  product in the following format: “Products.name - Products.description”. Using concat() we could get it:

    $query->select([

                'display_name' => $query->func()->concat([

                    $query->identifier('Products.name'), ' - ',  $query->identifier('Products.description')]),

            ]);

  2. Total of products sold. Using sum() we could get it, we just need to sum Items.quantity per each product,  this  is why we use $itemsQuery and then we sum the quantity per each product.

    $query->select([
      'quantity_sold' => $itemsQuery->select(['sum' => $itemsQuery->func()->sum($query->identifier('Items.quantity'))]),
    ]);

     

  3. To get the income, we need to multiply the Quantity of items  *  Price  and sum all of them. 

      $query->select([
              'income' => $itemsQuery->select(['sum' => $itemsQuery->func()->sum($query->newExpr('Items.quantity * Items.unit_price'))
                ])]);

     

  4. Stock. to get the stock we need to take advantage of the quantity_sold we just got in #2, and subtract it from the real quantity Products.quantity. For getting this, we would need to create a subquery in the FROM clause using the previous queries, and then subtract in the target query something like quantity - quantity_sold.

    $products = $query->cleanCopy()->select([
                'id' => 'ProductDetails.id',
                'price' => 'ProductDetails.price',
                'quantity' => 'ProductDetails.quantity',
                'display_name' => 'ProductDetails.displaye_name',
                'quantity_sold' => 'ProductDetails.quantity_sold',
                'income' => 'ProductDetails.income',
                'stock' => $query->newExpr('ProductDetails.quantity - ProductDetails.quantity_sold'),
            ])->from([
              'ProductDetails' => $query->cleanCopy()->select([
                    'id' => 'Products.id',
                    'price' => 'Products.price',
                    'quantity' => 'Products.quantity',
                    'display_name' => $query->func()->concat([$query->identifier('Products.name'), ' -  ', $query->identifier('Products.description')]),
                  'quantity_sold' => $itemsQuery->select(['sum' => $itemsQuery->func()->sum($query->identifier('Items.quantity'))]),
                  'income' => $itemsQuery->cleanCopy()->select(['sum' => $itemsQuery->func()->sum($query->newExpr('Items.quantity * Items.unit_price'))]),           ])
        ]);

     

Notice that we are using cleanCopy(), this is useful when the same Query object is affected previously by a select(), from() or where clauses, if you run this same example without using cleanCopy() you will get unexpected results. 

The SQL query generated is this:

SELECT ProductDetails.id AS id,
       ProductDetails.price AS price,
       ProductDetails.quantity AS quantity,
       ProductDetails.display_name AS display_name,
       ProductDetails.quantity_sold AS quantity_sold,
       ProductDetails.income AS income,
       (ProductDetails.quantity - ProductDetails.quantity_sold) AS stock
FROM
  (SELECT Products.id AS id,
          Products.price AS price,
          Products.quantity AS quantity,
          (CONCAT(Products.name, :param0, Products.description)) AS display_name,

     (SELECT (SUM(Items.quantity)) AS SUM
      FROM items Items
      WHERE Items.product_id = (Products.id)) AS quantity_sold,

     (SELECT (SUM(Items.quantity * Items.unit_price)) AS SUM
      FROM items Items
      WHERE Items.product_id = (Products.id)) AS income
   FROM products Products) ProductDetails


CakePHP QueryBuilder gives a ton of possibilities to create queries with clean and robust code. So go play with it and enjoy!

 

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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