PHP 7 Programming Blueprints Learn how to exploit the impressive power of PHP 7 with this collection of practical project blueprints – begin building better applications for the web today!
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First published: October 2016 Production reference: 2061016
Published by Packt Publishing Ltd. Livery Place 35 Livery Street Birmingham B3 2PB, UK. ISBN 978-1-78588-971-4 www.packtpub.com
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Credits Authors
Copy Editor
Jose Palala Martin Helmich
Safis Editing
Reviewer
Project Coordinator
Shuvankar Sarkar
Ulhas Kambali
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Chaitanya Nair
Rekha Nair
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About the Authors Jose Palala has been working professionally with PHP for at least 8 years. He has experience working with PHP frameworks such as Eden PHP, CodeIgniter, Laravel and Zend. He has worked for Philippine-based IT companies for at least 8 years, working on projects ranging from internal corporate systems and CMS websites. In his spare time, he regularly contributes back to the tech community in the Philippines. I would like to thank everyone at Packt Publishing, it’s been great working with them since Day 1. Super thanks to all to my colleagues, friends and family who have helped me to become a better developer and have helped me become what I am today.
Martin Helmich holds a Master's degree in Computer Science from the University of Applied Sciences in Osnabrück. He works as a software architect and specializes in building distributed applications using web technologies and Microservice Architectures. Besides programming in Go, PHP, Python and Node.JS, he also builds infrastructures using configuration management tools like SaltStack and container technologies like Docker.
He is an open source enthusiast and likes to make fun of people who are not using Linux. In his free time, you'll probably find him coding on one of his open source pet projects, listening to music or reading science-fiction literature.
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About the Reviewer Shuvankar Sarkar is an IT analyst and experienced in C#, .NET, PHP and web development. He is a technology enthusiast and maintains his blog at You can follow him on Twitter at @sonu041. He is interested in computer security as well. I would like to thank my family for making my life easier and full of happiness.
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Table of Contents Preface Chapter 1: Create a User Profile System and use the Null Coalesce Operator The null coalesce operator Separation of Concerns Creating views Create a profile input form Admin system Summary
Chapter 2: Build a Database Class and Simple Shopping Cart Building the database abstraction class Raw query method Create method
Read method Select all method Delete method Update method first_of method last_of method iterate_over method searchString method Using the convert_to_json method to implement a simple API Shopping Cart Building the shopping items list Item template rendering function
Adding checkboxes to the Shopping List page Cookies in PHP Building the Checkout page Thank you page Installing TCPDF Admin for managing purchases Summary
Authentication system Creating a social login for members Member dashboard Marketers dashboard Administration system for managing marketers
Custom template for our newsletter Link tracking AJAX socket chat for support Introduction to socket.io
Summary
Chapter 4: Build a Simple Blog with Search Capability using Elasticsearch Creating the CRUD and admin system Seeding the post table What is Elasticsearch? Installing Elasticsearch and the PHP client Building a PHP Elasticsearch tool
Adding documents to our Elasticsearch Querying Elasticsearch Installing Logstash Setting up the Logstash configuration Installing PHP Redis Encoding and decoding JSON messages
Storing Apache logs in Elasticsearch
Getting filtered data to display with Highcharts
Dashboard app for viewing Elasticsearch logs Simple search engine with result caching Cache basics Cache invalidation of Redis data
Using browser localStorage as cache Working with streams Storing and searching XML documents using PHP Using Elasticsearch to search a social network database Displaying randomized search engine results
Summary
Chapter 5: Creating a RESTful Web Service RESTful basics REST architectures Common HTTP methods and response codes First steps with the Slim framework [ ii ]
Installing Slim A small sample application Accepting URL parameters
Accepting HTTP requests with a message body The PSR-7 standard Middleware Implementing the REST service Designing the service Bootstrapping the project Building the persistence layer with MongoDB Adding and retrieving users Listing and searching users Deleting profiles Validating input Streams and large files Profile image upload Using GridFS storage Summary
Chapter 6: Building a Chat Application The WebSocket protocol First steps with Ratchet
Architectural considerations Getting started Testing WebSocket applications Playing with the event loop Implementing the chat application Bootstrapping the project server-side Bootstrapping the HTML user interface Building a simple chat application Receiving messages Sending messages Testing the application Keeping the connection from timing out Deployment options Bridging Ratchet and PSR-7 applications Accessing your application via the web server Adding authentication Creating the login form Checking the authorization [ iii ]
Chapter 7: Building an Asynchronous Microservice Architecture The target architecture ZeroMQ patterns Request/reply pattern Publish/subscribe pattern Push/pull pattern Bootstrapping the project Building the inventory service Getting started with ZeroMQ REQ/REP sockets Using JsonRPC for communication Making the inventory service multithreaded Building the checkout service Using react/zmq Working with promises Building the mailing service Building the shipping service PUSH/PULL for beginners Fan-out/fan-in Bridging ZeroMQ and HTTP
Summary
Chapter 8: Building a Parser and Interpreter for a Custom Language How interpreters and compilers work Languages and grammars Your first PEG parser Evaluating expressions Building an Abstract Syntax Tree Building a better interface Evaluating variables Adding logical expressions Comparisons The “and” and “or” operators Conditions Working with structured data Working with objects Optimizing the interpreter by adding a compiler Verifying performance improvements [ iv ]
An introduction to observables Introduction to event loop and ReactiveX delay defer Scheduler recursive-scheduler map and flatMap reduce toArray merge do scan zip Parsing logs through a Reactive scheduler Event queues with ReactiveX Summary
Preface PHP is a great language for developing web applications. It is essentially a server-side scripting language that is also used for general-purpose programming. PHP 7 is the latest version, which provides major backward-compatibility breaks and focuses on providing improved performance and speed. With the rise in demand for high performance, this newest version contains everything you need to build efficient applications. PHP 7 provides improved engine execution, better memory usage, and a better set of tools allowing you to maintain high traffic on your websites with low-cost hardware and servers
through a multithreading web server.
What this book covers Chapter 1, Create a User Profile System and use the Null Coalesce Operator, we'll discover new
PHP 7 features and build app for storing user profiles.
Chapter 2, Build a Database Class and Simple Shopping Cart, we'll create a simple database
layer library which will help us access our database. We'll cover some tips on making our queries secure, and how to make our coding simpler and more succinct with PHP 7. Chapter 3, Building a Social Newsletter Service, we'll be building a social newsletter service,
which will have a way for users to sign in using their social login and allow them to register to a newsletter. We'll also make a simple admin system for managing the newsletters. Chapter 4, Build a Simple Blog with Search Capability using Elasticsearch, you will learn how to
create a blog system, experiment with ElasticSearch and how to apply it in your code. Also, you will learn how to create a simple blog application and store data into MySQL. Chapter 5, Creating a RESTful Web Service, shows you how create a RESTful web service
that can be used to manage user profiles. The service will be implemented using the Slim micro framework and use a MongoDB database for persistence. The chapter also covers the basics of RESTful web services, most importantly the common HTTP request and response methods, the PSR-7 standard and PHP 7’s new mongodb extension.
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Preface Chapter 6, Building a Chat Application, describes the implementation of a real-time chat
application using WebSockets. You will learn how to use the Ratchet framework to build stand-alone WebSocket and HTTP servers with PHP and how to connect to WebSocket servers in a JavaScript client application. We will also discuss how you can implement authentication for WebSocket applications and how to deploy them in a production environment. Chapter 7, Building an Asynchronous Microservice Architecture, covers the implementation of
a (small) microservice architecture. Instead of RESTful web services, you will use ZeroMQ in this chapter for network communication, an alternative communication protocol that focuses on asynchronicity, loose coupling and high performance. Chapter 8, Building a Parser and Interpreter for a Custom Language, describes how to use the
PHP-PEG library to define a grammar and implement a parser for a custom expression language that can be used to add end-user development features to enterprise applications. Chapter 9, Reactive Extensions in PHP, here we'll look into the Reactive extensions library
for PHP, and and try to build a simple scheduled app.
What you need for this book You’ll need to download and install PHP 7 from the official PHP website. You’ll also need to install a Webserver such as Apache or Nginx configured to run PHP 7 by default. If you are experienced with virtual machines, you can also use Docker containers and/or Vagrant to build an environment with PHP 7 installed.
Who this book is for The book is for web developers, PHP consultants, and anyone who is working on multiple projects with PHP. Basic knowledge of PHP programming is assumed.
Conventions In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning. Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "Let's create a simple UserProfile class." [2]
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Preface
A block of code is set as follows: function fetch_one($id) { $link = mysqli_connect(''); $query = "SELECT * from ". $this->table . " WHERE `id` =' " . $results = mysqli_query($link, $query); }
$id "'";
When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold: 'credit_card' => $credit_card, 'items' => //<all the items and prices>//, 'total' => $total,
Any command-line input or output is written as follows: mysql> source insert_profiles.sql
New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "Simply click on Allow access and then click on OK." Warnings or important notes appear in a box like this.
Tips and tricks appear like this.
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Preface
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Preface
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1
Create a User Profile System and use the Null Coalesce Operator To begin this chapter, let's check out the new null coalesce in PHP 7. We'll also learn how to build a simple profiles page with listed users that you can click on, and create a simple CRUD-like system which will enable us to register new users to the system and delete users for banning purposes. We'll learn to use the PHP 7 null coalesce operator so that we can show data if there is any, or just display a simple message if there isn't any.
Let's create a simple UserProfile class. The ability to create classes has been available since PHP 5. A class in PHP starts with the word class, and the name of the class: class UserProfile { private $table = 'user_profiles'; } }
We've made the table private and added a private variable, where we define which table it will be related to.
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Create a User Profile System and use the Null Coalesce Operator
Let's add two functions, also known as a method, inside the class to simply fetch the data from the database: function fetch_one($id) { $link = mysqli_connect(''); $query = "SELECT * from ". $this->table . " WHERE `id` =' " . $results = mysqli_query($link, $query); }
$id "'";
function fetch_all() { $link = mysqli_connect('127.0.0.1', 'root','apassword','my_dataabase' ); $query = "SELECT * from ". $this->table . ";
$results = mysqli_query($link, $query); }
The null coalesce operator We can use PHP 7's null coalesce operator to allow us to check whether our results contain anything, or return a defined text which we can check on the views, this will be responsible for displaying any data. Let's put this in a file which will contain all the define statements, and call it: //definitions.php define('NO_RESULTS_MESSAGE', 'No results found'); require('definitions.php'); function fetch_all() { ...same lines ... $results = $results ?? NO_RESULTS_MESSAGE; return $message; }
On the client side, we'll need to come up with a template to show the list of user profiles. Let's create a basic HTML block to show that each profile can be a div element with several list item elements to output each table. In the following function, we need to make sure that all values have been filled in with at least the name and the age. Then we simply return the entire string when the function is called: function profile_template( $name, $age, $country ) { $name = $name ?? null; $age = $age ?? null;
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Create a User Profile System and use the Null Coalesce Operator if($name == null || $age === null) { return 'Name or Age need to be set'; } else { return '<div> <li>Name: ' . $name . ' </li> <li>Age: ' . $age . '</li> <li>Country:
' .
$country . ' </li>
</div>'; } }
Separation of Concerns In a proper MVC architecture, we need to separate the view from the models that get our data, and the controllers will be responsible for handling business logic. In our simple app, we will skip the controller layer since we just want to display the user profiles in one public facing page. The preceding function is also known as the template render part in an MVC architecture. While there are frameworks available for PHP that use the MVC architecture out of the box, for now we can stick to what we have and make it work. PHP frameworks can benefit a lot from the null coalesce operator. In some codes that I've worked with, we used to use the ternary operator a lot, but still had to add more checks to
ensure a value was not falsy. Furthermore, the ternary operator can get confusing, and takes some getting used to. The other alternative is to use the isSet function. However, due to the nature of the isSet function, some falsy values will be interpreted by PHP as being a set.
Creating views Now that we have our model complete, a template render function, we just need to create the view with which we can look at each profile.
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Create a User Profile System and use the Null Coalesce Operator
Our view will be put inside a foreach block, and we'll use the template we wrote to render the right values: //listprofiles.php <html> <!doctype html> <head> href=" />"> </head> <body> foreach($results as $item) { echo profile_template($item->name, $item->age, $item->country;
} ?> </body> </html>
Let's put the code above into index.php . While we may install the Apache server, configure it to run PHP, install new virtual hosts and the other necessary features, and put our PHP code into an Apache folder, this will take time. So, for the purposes of testing this out, we can just run PHP's server for development. To run the built-in PHP server (read more at
we will use the folder
we are running, inside a terminal: php -S localhost:8000
If we open up our browser, we should see nothing yet, No results found. This means we need to populate our database. If you have an error with your database connection, be sure to replace the correct database credentials we supplied into each of the mysql_connect calls that we made. 1. To supply data to our database, we can create a simple SQL script like this: INSERT INTO user_profiles ('Chin Wu', 30, 'Mongolia'); INSERT INTO user_profiles ('Erik Schmidt', 22, 'Germany'); INSERT INTO user_profiles ('Rashma Naru', 33, 'India');
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Create a User Profile System and use the Null Coalesce Operator
2. Let's save it in a file such as insert_profiles.sql. In the same directory as the SQL file, log on to the MySQL client by using the following command: mysql -u root -p
3. Then type use <name of database>: mysql>
use <database>;
4. Import the script by running the source command: mysql> source insert_profiles.sql
Now our user profiles page should show the following:
Create a profile input form Now let's create the HTML form for users to enter their profile data. Our profiles app would be no use if we didn't have a simple way for a user to enter their user profile details. We'll create the profile input form like this: //create_profile.php <html> <body> <form action="post_profile.php" method="POST"> <label>Name</label><input name="name">
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Create a User Profile System and use the Null Coalesce Operator <label>Age</label><input name="age"> <label>Country</label><input name="country"> </form> </body> </html>
In this profile post, we'll need to create a PHP script to take care of anything the user posts. It will create an SQL statement from the input values and output whether or not they were inserted. We can use the null coalesce operator again to verify that the user has inputted all values and left nothing undefined or null: $name = $_POST['name'] ?? ""; $age = $_POST['country'] ?? ""; $country = $_POST['country'] ?? "";
This prevents us from accumulating errors while inserting data into our database. First, let's create a variable to hold each of the inputs in one array: $input_values = [ 'name' => $name, 'age' => $age, 'country' => $country ];
The preceding code is a new PHP 5.4+ way to write arrays. In PHP 5.4+, it is no longer necessary to put an actual array(); the author personally likes the new syntax better.
We should create a new method in our UserProfile class to accept these values: Class UserProfile { public function insert_profile($values)
Create a User Profile System and use the Null Coalesce Operator
Instead of creating a parameter in our function to hold each argument as we did with our profile template render function, we can simply use an array to hold our values. This way, if a new field needs to be inserted into our database, we can just add another field to the SQL insert statement. While we are at it, let's create the edit profile section. For now, we'll assume that whoever is using this edit profile is the administrator of the site. We'll need to create a page where, provided the $_GET['id'] has been set, that the user that we will be fetching from the database and displaying on the form. Here is how that
code will look like: require('class/userprofile.php');//contains the class UserProfile into $id = $_GET['id'] ?? 'No ID'; //if id was a string, i.e. "No ID", this would go into the if block if(is_numeric($id)) { $profile = new UserProfile(); //get data from our database $results = $user->fetch_id($id); if($results && $results->num_rows > 0 ) { while($obj = $results->fetch_object()) { $name = $obj->name; $age = $obj->age; $country = $obj->country; } //display form with a hidden field containing the value of the ID ?> <form action="post_update_profile.php" method="post"> <label>Name</label>
exit;
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Create a User Profile System and use the Null Coalesce Operator }
Notice that we're using what is known as the shortcut echo statement in the form. It makes our code simpler and easier to read. Since we're using PHP 7, this feature should come out of the box. Once someone submits the form, it goes into our $_POST variable and we'll create a new Update function in our UserProfile class.
Admin system Let's finish off by creating a simple grid for an admin dashboard portal that will be used with our user profiles database. Our requirement for this is simple: we can just set up a table-based layout that displays each user profile in rows. From the grid, we will add the links to be able to edit the profile, or delete it, if we want to. The code to display a table in our HTML view would look like this: <table> <tr> <td>John Doe</td> <td>21</td> <td>USA</td> <td><a href="edit_profile.php?id=1">Edit</a></td> <td><a href="profileview.php?id=1">View</a>
<td><a href="delete_profile.php?id=1">Delete</a> </tr> </table> This script to this is the following: //listprofiles.php $sql = "SELECT * FROM userprofiles LIMIT $start, $limit "; $rs_result = mysqli_query ($sql); //run the query while($row = mysqli_fetch_assoc($rs_result) { ?> <tr> <td><?=$row['name'];?></td> <td><?=$row['age'];?></td> <td><?=$row['country'];?></td> <td><td>-->
