PHP is a general-purpose server-side scripting language primarily used in web development. Originally created by Rasmus Lerdorf in 1994, it is now by The PHP Development Team.
PHP originally stood for “Personal Home Page”, but now stands for “PHP: Hypertext Preprocessor”.
- Homepage: php.net
- Documentation: php.net/docs.php
- PHP: The Right Way: phptherightway.com
- Interactive PHP Tutorial: learn-php.org
Topics, Tools and Terms
PHP packages were traditionally installed via PEAR (PHP Extension and Application Repository), but more recently the standard package and dependency management tool is Composer.
Composer lets us run install commands to add packages to our system, for example
composer require phpunit would add the unit testing framework PHPUnit to our system.
For instructions on how to install Composer visit getcomposer.org.
Managing dependencies manually is time-consuming, fortunately Composer can automate this.
We can list our dependencies in a
composer.json file and run
composer install to bring these into our project.
composer.json file looks like this:
The “require” block tells Composer that the Twig templating package is required for production use and can install Twig with a version of 2.x.x (ie. up to, but not including, version 3).
The “require-dev” block tells Composer that PHPUnit is required in development, but not in production.
Dependencies can be added to
composer require author/package-name
Development dependencies can be added by
composer require author/package-name --dev
Dependencies can be updated to their latest maximum version by running
Composer will also generate a
composer.lock file on each
composer update and the initial
composer install. This is not meant to be edited directly, it tells Composer to use specific versions of packages - particularly useful when hyhou want your development dependencies to match what you will push to production.
There are a number of testing tools available for PHP. The most popular one is PHPUnit. PHPUnit follows the classic xUnit approach.
Behat is the most popular behaviour-driven development (BDD) testing framework.
Codeception is a framework combining BDD, unit testing, and integration testing, and is cross-compatible with PHPUnit.
In our guides we will be using PHPUnit as the default testing framework.
A typical directory structure for a PHP project consists of a
src directory that contains all source files and a
tests directory that includes all tests. For command-line applications the files to be executed to start your application (eg.
hello.php) would reside in a
We provided a working example of a minimal project on github.com/vanilla-project/php-command-line.
Directory names are in lower case. Class and interface files should be in upper case and match the class or interface names. Configuration, routes, and publically accessible files should be in lower case.
For example the class
Vanilla should be contained in file
Vanilla.php, the publically accessible route to the application should be
Tests match their production code file names with a
Test suffix, e.g. tests for code in
src/Vanilla.php should be written in
The repository for the example applications is available at github.com/vanilla-project/php-command-line.
The main application consists of basically two files:
bin/hello.phpis the main executable that instantiates and runs:
src/Example/Greeting.phpcontains the main application.
Running the Tests
All tests can be run by executing
phpunit will automatically find all tests inside the
tests directory and run them based on the configuration in the
The test for class
Greeting is only verifying the return value of one method.
Running the Application
To run the application execute
You should see the text “Hello” being printed.
$: bin/hello.php Hello