PHP Command Line Application

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”.

Further Material

• 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.

Dependency Management

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": "^2.4"
    },
    "require-dev": {
        "phpunit/phpunit": "^6.3"
    }
}

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.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.

Testing Tools

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.

Directory Structure

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 bin directory.

We provided a working example of a minimal project on github.com/vanilla-project/php-command-line.

• src
• tests
• bin
• composer.json
• composer.lock

Naming Conventions

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 index.php.

Tests match their production code file names with a Test suffix, e.g. tests for code in src/Vanilla.php should be written in test/VanillaTest.php.

Example Project

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.php is the main executable that instantiates and runs:
  • src/Example/Greeting.php contains the main application.

Running the Tests

All tests can be run by executing

vendor/phpunit/phpunit/phpunit

phpunit will automatically find all tests inside the tests directory and run them based on the configuration in the phpunit.xml file.

Testing Approach

The test for class Greeting is only verifying the return value of one method.

Running the Application

To run the application execute bin/hello.php or php bin/hello.php. You should see the text “Hello” being printed.

$: bin/hello.php
Hello