In modern software architecture, developers are constantly exploring new paradigms to enhance the performance, scalability, and maintainability of their applications. One such architectural pattern gaining popularity is Command Query Responsibility Segregation (CQRS). CQRS separates the responsibility of handling read and write operations, offering numerous benefits in complex systems. In this article, we'll delve into CQRS and explore its implementation in PHP.

What is CQRS?

CQRS, coined by Greg Young, is an architectural pattern that segregates the responsibility for handling read and write operations in a system. In traditional CRUD-based architectures, the same model is often used for both reading and writing data. However, CQRS advocates for a clear distinction between commands (write operations that modify state) and queries (read operations that retrieve data).

Key Concepts of CQRS:
   

. Command: Commands represent actions that modify the state of the system. They encapsulate the intent to perform an operation, such as creating, updating, or deleting data.
   
. Query: Queries retrieve data from the system without modifying its state. They are read-only operations used to fetch information for presentation or analysis.
   
. Command Handler: Responsible for processing commands by executing the necessary business logic and updating the system's state accordingly.
   
. Query Handler: Handles queries by retrieving data from the appropriate data source and returning the results to the caller.
   
. Separate Models: CQRS often involves maintaining separate models for commands and queries. This allows each model to be optimized for its specific use case, leading to improved performance and scalability.

Implementing CQRS in PHP:

Implementing CQRS in PHP involves structuring your application to separate command and query responsibilities effectively. Here's a high-level overview of how to implement CQRS in PHP:

1. Define Commands and Queries:

Start by defining the commands and queries your application will support. Commands should encapsulate actions that modify state, while queries should retrieve data.

class CreateProductCommand {
 public $name;
 public $price;
}

class GetProductQuery {
 public $productId;
}

2. Create Command and Query Handlers:

Next, implement handlers for processing commands and queries. Command handlers execute the necessary business logic to fulfill the command, while query handlers retrieve data based on the query criteria.

class CreateProductCommandHandler {
 public function handle(CreateProductCommand $command) {
 }
}

class GetProductQueryHandler {
 public function handle(GetProductQuery $query) {
 }
}

3. Use Separate Models:

Maintain separate models for commands and queries to optimize each for its specific purpose. This separation allows you to design models tailored to the needs of write and read operations.

class Product {
 public $name;
 public $price;
}

class ProductView {
 public $name;
 public $price;
}

4. Wiring Everything Together:

Finally, wire up your command and query handlers to the appropriate endpoints or controllers in your application. Dispatch commands to their respective handlers and invoke query handlers to retrieve data.

$command = new CreateProductCommand();
$command->name = "Example Product";
$command->price = 99.99;

$handler = new CreateProductCommandHandler();
$handler->handle($command);

$query = new GetProductQuery();
$query->productId = 123;

$handler = new GetProductQueryHandler();
$product = $handler->handle($query);

Benefits of CQRS in PHP:

-Improved Scalability: Separating read and write operations allows you to scale each independently based on demand.

-Enhanced Performance: Optimizing models and handlers for specific tasks can lead to improved performance and responsiveness.

-Simplified Maintenance: Clear separation of concerns makes the codebase easier to understand, maintain, and extend over time.

-Flexibility: CQRS enables flexibility in choosing the most suitable data storage and retrieval mechanisms for different use cases.

Conclusion:

CQRS is a powerful architectural pattern that offers numerous advantages for building complex and scalable PHP applications. By segregating command and query responsibilities, developers can achieve better performance, scalability, and maintainability in their systems. While implementing CQRS in PHP requires careful planning and design, the benefits it provides make it a compelling choice for projects requiring high performance and flexibility.

In the realm of web development, the Model-View-Controller (MVC) architectural pattern stands as one of the most influential paradigms. It provides a structured approach to designing web applications, promoting modularity, scalability, and maintainability. In this guide, we'll delve into the MVC framework in PHP, exploring its key components, principles, and benefits.

Understanding MVC Architecture:

MVC separates an application into three interconnected components, each with its distinct responsibility:

Model: The model represents the application's data and business logic. It encapsulates the data structure, database interactions, and validation rules. In MVC, the model is responsible for managing data persistence and state.

View: The view is responsible for presenting data to the user in a visually appealing format. It encompasses the HTML markup, CSS styling, and client-side scripting necessary to render the user interface. Views are typically passive components that receive data from the controller and display it to the user.

Controller: The controller acts as an intermediary between the model and the view. It processes user requests, invokes the appropriate methods in the model to retrieve or manipulate data, and selects the appropriate view to render the response. Controllers handle user input, orchestrate business logic, and coordinate the flow of data between the model and the view.

Implementing MVC Framework in PHP:

PHP offers a robust foundation for building MVC-based web applications. Let's explore how to implement each component of the MVC pattern in PHP:

Model:

In PHP, models typically represent data entities and interact with the database. They encapsulate data access logic and provide methods for querying, inserting, updating, and deleting records. Here's a simplified example of a model class:

class User { 
 public function getUserById($userId) { 
 } 

 public function updateUser($userId, $userData) { 
 }

}

View:

Views in PHP are responsible for generating HTML markup to render the user interface. They receive data from the controller and use it to dynamically generate the content displayed to the user. Views can include HTML templates with embedded PHP code or utilize template engines for better separation of concerns. Here's a basic example of a view:

<!DOCTYPE html>

<html>

<head> <title>User Profile</title>

</head>

<body> <h1>Welcome, <?php echo $user['username']; ?>!</h1> <p>Email: <?php echo $user['email']; ?></p>

</body>

</html>

Controller:

Controllers in PHP handle user requests, process input data, and interact with models to retrieve or manipulate data. They select the appropriate view to render the response and pass data to the view for presentation. Controllers are responsible for defining application routes and managing the overall application flow. Here's an example of a controller method:

class UserController { 
 public function profile($userId) { 
 $userModel = new User(); 
$userData = $userModel->getUserById($userId); 

include 'views/profile.php'; 
 }
}

Benefits of MVC Framework in PHP:

Separation of Concerns: MVC promotes a clear separation of concerns, making it easier to manage code complexity and maintainability.

Modularity: Components in MVC are modular and reusable, allowing developers to build and extend applications more efficiently.

Testability: With distinct components, it becomes easier to write unit tests for models, views, and controllers independently.

Scalability: MVC facilitates the scalability of web applications by enabling developers to add new features or modify existing ones without impacting other parts of the system.

Conclusion:

The MVC framework in PHP provides a robust architectural pattern for building scalable and maintainable web applications. By separating concerns into models, views, and controllers, developers can organize code more effectively, enhance testability, and streamline the development process. Whether you're building a simple blog or a complex enterprise application, leveraging the MVC pattern in PHP can significantly improve the quality and maintainability of your codebase.

Welcome back! If you’re new to this series have a look at Part 1 here

Today’s focus is on templating, the aesthetic that will make or break your web application.

Having a clean design with well defined CSS that’s responsive and user friendly goes a long way.

Developers often stick to their lane but delving into templating will bode in your favor, you can indeed
create a functional and launch-worthy application all on your own!

Let’s jump into it!

Structured structure

Everything you tackle should be found with ease down the line. Therefore careful planning is fundamental to the success and sustainability of your project. You’ll also find that clearly defining your work lends itself to more productivity overall as you spend less that explaining your work during a handover / looking for a specific piece of code or resource. You’ll probably end up spending more time on actual work.
Finding your own unique pattern with file structure and CSS identifiers will also work in your favor as something unique to your process will most likely be easier to remember and form a tactile relationship with.

Our project’s current structure looks like this:



>If you need to backtrack, Part 1 is a great place to start!

In part 1, we created our index.php which displays info from our database.

Let’s take this a step further and create a header and a footer for our index.php

Create a file called header.php and save this to your includes folder.

Next, create a file called footer.php and save this to your includes folder.

Your file structure should now look like this.

A header above all the rest

The header file will be a file we reuse throughout your web application. This file will contain important information that’s vital to the functionality and aesthetic of your website.
The type of info you’ll expect to see in a header.php file:
Script includes
Such as JQuery and important libraries
CSS includes
CSS files loaded from internal or external sources
Meta information
Contains important information that’s readable by search engines.
The basic structure of the beginning of your app, including your menu, and your logo.
For now, how header is going to have a basic layout.

Let’s get our HTML on!

<html>
<head>
<title>My Awesome CMS – Page Title</title>
</head>
<body>

A footer that sets the bar

Create a file called footer.php and save it to your includes folder (yourcms/includes/footer.php).

Add this code to your new file.

</body>
</html>

Next, let’s focus on the gravy… The CSS

CSS, when written beautifully, can truly set you apart.

You can tell your web application to load various styles to specific elements by defining unique identifiers.
Styles that are only used once are denoted with a # (a CSS “ID”) whereas styles that are reused multiple times are denoted with a . (a CSS “class”)

The best way to delve into the realm of CSS is to learn by experience.

Let’s create!

First, we need to create and load our CSS file. Remember our nifty new pal header.php? This created a convenient way to load our CSS file!

Add the following code to your header.php just above the </head> tag.

<link href=”../assets/css/style.css” type=”text/css” rel=”stylesheet”/> 

The ../ in the link to our stylesheet means we have to leave the current directory (the directory that header.php is in) and look for the assets/css/ directories.

Go ahead and create the css folder under your assets folder.

Next we’re going to create some simple CSS to test things out.

It’s time to add some style!

We are going to create two divs.
A div is a divider / section in HTML.
Add this to your index.php (located in your CMS’ root folder) above the <?php tag.

<div id="myfirstid"></div>
<div class="myfirstclass"></div>
<div class="myfirstclass"></div>
<div class="myfirstclass"></div>
<div class="myfirstclass"></div>
<div class="myfirstclass"></div>

Then, create a CSS file

Add this:

#myfirstid{
Background:lightblue;
Font-family:Arial;
Font-size:44px; 
Font-weight: Bold; 
}
.myfirstclass{
Font-size:15px;
Color: darkblue;
}

Save your newly created CSS to assets/css/ as style.css.

Pulling it all together, let’s see what we can do!

Let’s apply what we just learned to our index.php. But first, we should add our header.php and footer.php files.

Including everyone

Add this to the top of your index.php file:

include(‘includes/header.php’);

Remove the <divs> we used for practice earlier, we have something better in store!

Add this to the bottom of your index.php:

include(‘includes/footer.php’);

Next, let’s modify our code so we can add some style to the data we retrieve from our database.

Modify the following line:

foreach($getmydata as $mydata){ echo "Title: "; echo $mydata['title']; echo "<br/>"; echo "Content: "; echo $mydata['content']; echo "<br/>"; echo "Author: "; echo $mydata['author']; echo "<br/>"; echo "<br/>";

as follows:

?>

<div id=”myfirstid”>
<?php
foreach($getmydata as $mydata){
echo "<div class=”myfirstclass”>Title: "; 
echo $mydata['title']; 
echo "<br/>"; 
echo "Content: "; 
echo $mydata['content']; 
echo "<br/>"; 
echo "Author: "; 
echo $mydata['author']; 
echo "</div><br/><br/>";
}?>
</div>
<?php 

Your full index.php should now look like this:

<?php
include('includes/header.php');
include('includes/conn.php');

if ($letsconnect -> connect_errno) { echo "Error " . $letsconnect -> connect_error;

}else{

$getmydata=$letsconnect -> query("SELECT * FROM content");

?>
<div id="myfirstid">
<?php
foreach($getmydata as $mydata){
echo "<div class=”myfirstclass”>Title: "; 
echo $mydata['title']; 
echo "<br/>"; 
echo "Content: "; 
echo $mydata['content']; 
echo "<br/>"; 
echo "Author: "; 
echo $mydata['author']; 
echo "</div><br/><br/>";
}
?>
</div>
<?php 
}

$letsconnect -> close();
include('includes/footer.php');
?>

Go ahead, test it out!

There’s a lot to unpack and I will break things down a little more during our next tutorial!

Challenge

Study the final index.php and try to form a few theories about why closing a php tag is necessary before adding raw html.

Next Up: #CodeWithMe Part 4: Building A Good Base

Composer is the way that that PHP developers manage libraries and their dependencies. Previously, developers mainly stuck to existing frameworks. If you were a Symfony developer, you used Symfony and libraries built around it. You didn’t dare cross the line to Zend Framework. These days however, developers focus less on frameworks, and more on the libraries they need to build the project they are working on. This decoupling of projects from frameworks is largely possible because of Composer and the ecosystem that has built up around it.

Like PHP, Composer is easy to get started in, but complex enough to take time and practice to master. The Composer manual does a great job of getting you up and running quickly, but some of the commands are involved enough so that many developers miss some of their power because they simply don’t understand.

I’ve picked out five commands that every user of Composer should master. In each section I give you a little insight into the command, how it is used, when it is used and why this one is important.

1: Require

Sample:

$ composer require monolog/monolog

Require is the most common command that most developers will use when using Composer. In addition to the vendor/package, you can also specify a version number to load along with modifiers. For instance, if you want version 1.18.0 of monolog specifically and never want the update command to update this, you would use this command.

$ composer require monolog/monolog:1.18.0

This command will not grab the current version of monolog (currently 1.18.2) but will instead install the specific version 1.18.0.

If you always want the most recent version of monolog greater than 1.8.0 you can use the > modifier as shown in this command.

$ composer require monolog/monolog:>1.18.0

If you want the latest in patch in your current version but don’t want any minor updates that may introduce new features, you can specify that using the tilde.

$ composer require monolog/monolog:~1.18.0

The command above will install the latest version of monolog v1.18. Updates will never update beyond the latest 1.18 version.

If you want to stay current on your major version but never want to go above it you can indicate that with the caret.

$ composer require monolog/monolog:^1.18.0

The command above will install the latest version of monolog 1. Updates continue to update beyond 1.18, but will never update to version 2.

There are other options and flags for require, you can find the complete documentation of the command here.

2: Install a package globally

The most common use of Composer is to install and manage a library within a given project. There are however, times when you want to install a given library globally so that all of your projects can use it without you having to specifically require it in each project. Composer is up to the challenge with a modifier to the require command we discussed above, global. The most common use of this is when you are using Composer to manage packages like PHPUnit.

$ composer global require "phpunit/phpunit:^5.3.*"

The command above would install PHPUnit globally. It would also allow it to be updated throughout the 5.0.0 version because we specified ~5.3.* as the version number. You should be careful in installing packages globally. As long as you do not need different versions for different projects you are ok. However, should you start a project and want to use PHPUnit 6.0.0 (when it releases) but PHPUnit 6 breaks backwards compatibility with the PHPUnit 5.* version, you would have trouble. Either you would have to stay with PHPUnit 5 for your new project, or you would have to test all your projects to make sure that your Unit Tests work after upgrading to PHPUnit 6.

Globally installed projects are something to be thought through carefully. When in doubt, install the project locally.

3: Update a single library with Composer

One of the great powers of Composer is that developers can now easily keep their dependencies up-to-date. Not only that, as we discussed in tip #1, each developer can define exactly what “up-to-date” means for them. With this simple command, Composer will check all of your dependencies in a project and download/install the latest applicable versions.

$ composer update

What about those times when you know that a new version of a specific package has released and you want it, but nothing else updated. Composer has you covered here too.

$ composer update monolog/monolog

This command will ignore everything else, and only update the monolog package and it’s dependencies.

It’s great that you can update everything, but there are times when you know that updating one or more of your packages is going to break things in a way that you aren’t ready to deal with. Composer allows you the freedom to cherry-pick the packages that you want to update, and leave the rest for a later time.

4: Don’t install dev dependencies

In a lot of projects I am working on, I want to make sure that the libraries I download and install are working before I start working with them. To this end, many packages will include things like Unit Tests and documentation. This way I can run the unit Tests on my own to validate the package first. This is all fine and good, except when I don’t want them. There are times when I know the package well enough, or have used it enough, to not have to bother with any of that.

Many packages create a distribution package that does not contain tests or docs. (The League of Extraordinary Packages does this by default on all their packages.) If you specify the --prefer-dist flag, Composer will look for a distribution file and use it instead of pulling directly from github. Of course if you want want to make sure you get the full source and all the artifacts, you can use the --prefer-src flag.

5: Optimize your autoload

Regardless of whether you --prefer-dist or --prefer-source, when your package is incorporated into your project with require, it just adds it to the end of your autoloader. This isn’t always the best solution. Therefore Composer gives us the option to optimize the autoloader with the --optimize switch. Optimizing your autoloader converts your entire autoloader into classmaps. Instead of the autoloader having to use file_exists() to locate a file, Composer creates an array of file locations for each class. This can speed up your application by as much as 30%.

$ composer dump-autoload --optimize

The command above can be issued at any time to optimize your autoloader. It’s a good idea to execute this before moving your application into production.

$ composer require monolog/monolog:~1.18.0 -o

You can also use the optimize flag with the require command. Doing this every time you require a new package will keep your autoloader up-to-date. That having said, it’s still a good idea to get in the habit of using the first command as a safety net when you roll to production, just to make sure.

BONUS: Commit your composer.lock

After you have installed your first package with composer, you now have two files in the root of your project, composer.json and composer.lock. Of the two, composer.lock is the most important one. It contains detailed information about every package and version installed. When you issue a composer install in a directory with a composer.lock file, composer will install the exact same packages and versions. Therefore, by pulling a git repo on a production server will replicate the exact same packages in production that were installed in development. Of course the corollary of this is that you never want to commit your vendor/ directory. Since you can recreate it exactly, there is no need to store all of that code in your repo.

It is recommended that also commit your composer.json. When you check out your repo into production and do an install, composer will use the composer.lock instead of the composer.json when present. This means that your production environment is setup exactly like your development environment.

It took me quite some time to settle on my first blog post in this series and I found myself thinking about the most requested functionality in my career – The good ‘ol Custom CMS – typically geared towards clients that want a straight forward, secure solution that can be expanded upon in a modular format and that’s their IP.

This will be our starting point. A blank slate to build something epic with clean code and even cleaner design. And in the spirit of building from scratch, I will refrain from using classes or a framework. The main reasoning behind this is to truly get everyone acquainted with and excited about PHP development.

Join me as I transform rudimentary code into something extraordinary that can be morphed into just about any Content, PHP, and MySQL driven project. So without further ado, let’s jump into it!

The bare necessities

If you’re just getting started with development, there’s a nifty bite sized server called UniformServer that will be your best friend throughout your coding career. PHPMyAdmin (an awesome visual db management tool) comes built in so if you’re looking for a work right out of the box solution, this is it.

Alternatively, you can opt for XAMPP or use an alternative server of your choice.

Now here’s where the exciting stuff begins, mapping things out.

I don’t see this done/encouraged often enough. Feel free to grab a piece of paper to logically map out your steps or produce a rough draft of where you’d like this project to go.

In this tutorial, I would like to achieve the following:

DB, DB, Set up your DB.

This requires a bit of planning but let’s start of with the basic structure we need to see this through.

We are going to need a user table and a content table and are a few ways to tackle this.

If you’re using the PHPMyAdmin tool you can create your database, add user permissions (Click on Permissions after creating your database), and create a table with ease.



If you’re like me and prefer to look at good ‘ol SQL then writing an SQL statement is the preferred approach.

CREATE TABLE <code>mydbname</code>.<code>content</code> ( <code>ID</code> INT(11) NOT NULL AUTO_INCREMENT , <code>title</code> VARCHAR(100) NOT NULL , <code>content</code> LONGTEXT NOT NULL , <code>author</code> VARCHAR(50) NOT NULL , PRIMARY KEY (<code>ID</code>)) ENGINE = MyISAM COMMENT = 'content table';

Understanding the SQL statement

In a nutshell we are creating a table with important fields. Namely:

####

ID | Title | Content | Author

#######

The ID field is our unique identifier.Now we can move on to the file structure.

Everything has a place in the file structure game

You can use a structure that speaks to your coding style / memory.

I tend to use the following:



Choose a name for your CMS, which should be placed at the webroot of your localhost/server.

Replicate the folder structure as per the above example.

Next, we’re going to create a basic connection file.

You can create a conn.php file in your root/includes folder.

The connection file will provide crucial information to connect to the database.

Type the following into your conn.php file, remember to include your own database credentials.

<?php

$letsconnect = new mysqli("localhost","dbuser","dbpass","dbname");

?>

Let’s go to the homepage (index.php)

Create a file called index.php at the root of your CMS folder.

I will be adding comments in my code to help you understand what each line does.

Comments are a useful tool for developers to add important notes private to their code.

We need to pull information from the database so it’s imperative that we include our connection file.

<?php

include('includes/conn.php');

if ($letsconnect -> connect_errno) { echo "Error " . $letsconnect -> connect_error;

}else{

$getmydata=$letsconnect -> query("SELECT * FROM content");

foreach($getmydata as $mydata){	echo "Title: ";	echo $mydata['title'];	echo "<br/>";	echo "Content: ";	echo $mydata['content'];	echo "<br/>";	echo "Author: ";	echo $mydata['author'];	echo "<br/>";	echo "<br/>";

}

}

$letsconnect -> close();

?>

Let’s get a (very) basic backend up and running

Create a file called index.php in your backend folder.

We need to create a basic form to capture our data.

Let’s code some HTML!

<html>

<head><title>Backend - Capture Content</title></head>

<body>

<form action="<?php $_SERVER[‘PHP_SELF’];?>" method="post">

<input type="text" name="title" placeholder="Content Title here" required/>

<textarea name="content">Content Here</textarea>

<input type="text" name="author" placeholder="Author" required/>

<input type="submit" value="Save My Data" name="savedata"/>

</form>

</body>

</html>

Next, we need to process the form data.

Type the following just above the

<form> 

tag.

<?php

if(isset($_POST['savedata'])){

include('../includes/conn.php');

if ($letsconnect->connect_error) {

die("Your Connection failed: " . $letsconnect->connect_error);

}else{

$sql = "INSERT INTO content(title,content,author)VALUES ('".$_POST["title"]."', '".$_POST["content"]."', '".$_POST["author"]."')";

if (mysqli_query($letsconnect, $sql)) {

echo "Your data was saved successfully!";

} else { echo "Error: " . $sql . "" . mysqli_error($letsconnect);

} $letsconnect->close();

}

}

?>

Note, this is a basic MySQL query to insert data. However, before using this in production it's important to add proper escaping and security to prevent SQL injections. This will be covered in the next article.

Congrats you made it to the end of tutorial 1!

Test out your creation, modify your content, and play around.

Go to your sitename/index.php to see your frontend after capturing data via sitename/backend/index.php

Next Up:

codewithme Now With Security, Functionality, and Aesthetics in mind.

Conclusion

Coding doesn’t have to be daunting and it’s my aim to divide a complex system into bitesized tutorials so you can truly use the knowledge you’ve acquired in your own projects.