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
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.
An example composer.json
file looks like this:
{
"name": "example-project",
"require": {
"twig/twig": "^3.0"
},
"require-dev": {
"phpunit/phpunit": "^8.4"
}
}
The "require" block tells Composer that the Twig templating package is required for production use and can install Twig with a version of 3.x.x (ie. up to, but not including, version 4).
The "require-dev" block tells Composer that PHPUnit is required in development, but not in production.
Dependencies can be added to composer.json
by
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 update
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 this guide we will be using PHPUnit as the 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 web applications the publicly accessible files (eg. index.php
) would reside in a public
directory which would then be your webservers document root.
Another common convention is having a bin
directory that may contain executable files to start your application.
- src/
- test/
- public/
- composer.json
- composer.lock
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 publicly accessible files should be in lower case.
For example the class Example
should be contained in file Example.php
, the publicly accessible route to the application should be index.php
.
Tests match their production code file names with a Test
suffix, e.g. tests for code in src/Example.php
should be written in test/ExampleTest.php
.
The main application consists of basically two files:
public/example.php
is the main executable that instantiates and runs:src/Example/Greeting.php
contains the main application.
All tests can be run by executing
vendor/phpunit/phpunit/phpunit
phpunit
will automatically find all tests inside the test
directory and run them based on the configuration in the phpunit.xml
file.
The test for the class Greeting
verifies that the return value of the sayHello
method returns the string "Hello {name}", where {name} is the value passed through to the constructor.
PHP has an in-built server for local development. To run this change into the directory public
and run
php -S localhost:8000
Then open your browser at http://localhost:8000/example.php
You should see the text "Hello Ada Lovelace" being printed.