Environment.php

<?php

class Environment {

	/**
	 * Current environment
	 *
	 * @var string
	 */
	static protected $env;


	/**
	 * Known environments
	 *
	 * @var array
	 */
	static protected $environments = array();


	/**
	 * Strict environments (only allow known environments to be used)
	 *
	 * @var bool
	 */
	static protected $strict = false;


	/**
	 * Strict environments (only allow known environments to be used)
	 *
	 * @var string
	 */
	static protected $htaccess_env = 'ENGINE_ENV';


	/**
	 * Default environment name
	 *
	 * @var string
	 */
	static protected $default_env = 'production';


	/**
	 * Magic method for testing environment. Does not work in PHP < 5.3. Causes fatal error
	 * ex: Environment::isLocal() === Environment::is('local')
	 *
	 * @param   $name
	 * @param   $arguments
	 * @return  bool
	 */
	static public function __callStatic($name, $arguments) {
		if (substr($name, 0, 2) == 'is') {
			$env = strtolower(substr($name, 2));

			$url = isset($arguments[0]) ? $arguments[0] : null;

			return self::is($env, $url);
		}
	}


	/**
	 * Set environment(s)
	 *
	 * @param   array|string    $env
	 * @param   string          $regex
	 * @return  bool
	 */
	static public function init($env = array(), $regex = '') {
		return self::add($env, $regex);
	}


	/**
	 * Add environment(s)
	 *
	 * @param   array|string    $env
	 * @param   string          $regex
	 * @return  bool
	 */
	static public function add($env = array(), $regex = '') {
		// Array of environments
		if (is_array($env)) {
			array_change_key_case($env, CASE_LOWER);
		}

		// Single environment
		else {
			$env = array(
				strtolower($env) => $regex
			);
		}

		// Combine the existing environments with the newly defined ones
		self::$environments = array_merge(self::$environments, $env);

		return true;
	}


	/**
	 * Strict environment
	 *
	 * @param   null|bool   $strict
	 * @return  bool
	 */
	static public function strict($strict = null) {
		// Value not set. Return the strict value
		if (is_null($strict)) {
			return self::$strict;
		}

		// Value set. If it is a boolean, set it. Otherwise, skip it
		if (is_bool($strict)) {
			self::$strict = $strict;
		}

		return self::$strict;
	}


	/**
	 * Environment var key from .htaccess file
	 *
	 * @param   string  $var
	 * @return  string
	 */
	static public function envVarKey($var = null) {
		// Value not set. Return the .htaccess environment var
		if (is_null($var)) {
			return self::$htaccess_env;
		}

		// Value set. If it is not empty, set it. Otherwise, skip it
		if ( ! empty($var)) {
			self::$htaccess_env = $var;
		}

		return self::$htaccess_env;
	}


	/**
	 * Environment var value from .htaccess file
	 *
	 * @param   mixed   $default
	 * @return  bool
	 */
	static public function envVar($default = null) {
		return (getenv(self::$htaccess_env)) ? strtolower(getenv(self::$htaccess_env)) : $default;
	}


	/**
	 * Get current environment
	 *
	 * @param   string  $url
	 * @return  string
	 */
	static public function get($url = null) {
		// .htaccess environment variable is set. Make that the current environment
		if ($getenv = self::envVar()) {
			return self::_setEnv($getenv);
		}

		$host = $_SERVER['SERVER_NAME'];

		// Prep the URL
		$url = self::_prepUrl($url);

		// URL is defined. Test environment against this URL instead of current URL
		if (self::_isUrl($url)) {
			$host = parse_url($url, PHP_URL_HOST);
		}

		foreach (self::$environments as $env => $regex) {
			if (preg_match($regex, $host)) {
				return self::_setEnv($env);
			}
		}

		return self::_setEnv(self::$default_env);
	}


	/**
	 * Check is specific environment
	 *
	 * @param   string  $env
	 * @param   string  $url
	 * @return  bool
	 */
	static public function is($env = null, $url = null) {
		// Current environment
		$current = self::get($url);

		// Environment to check for
		$env = strtolower($env);

		// Are they the same?
		return ($current === $env) ? true : false;
	}


	/**
	 * Is running through command line
	 *
	 * @return  bool
	 */
	static public function isCLI() {
		if ((defined('PHP_SAPI') && PHP_SAPI == 'cli') || (isset($_SERVER['argc']) && $_SERVER['argc'] >= 1)) {
			return true;
		}

		return false;
	}


	/**
	 * Is running on web (not command line )
	 *
	 * @return  bool
	 */
	static public function isWeb() {
		return ! self::isCLI();
	}


	/**
	 * Set environment
	 *
	 * @param   string  $env
	 * @return  string
	 */
	static private function _setEnv($env = null) {
		// Strict mode is on. Must be one of the known environments
		if ($env != self::$default_env && self::$strict && ! in_array($env, array_keys(self::$environments))) {
			$valid = array_merge((array) self::$default_env, (array) array_keys(self::$environments));

			die('Unable to get environment. Environment must be one of the following: '.implode(', ', $valid));
		}

		return $env;
	}


	/**
	 * Check if valid URL
	 *
	 * @param   string  $url
	 * @return  bool
	 */
	static private function _isUrl($url = '') {
		return (filter_var($url, FILTER_VALIDATE_URL)) ? true : false;
	}


	/**
	 * Prepare the URL in case it's not an actual URL
	 *
	 * @param   string  $url
	 * @return  string
	 */
	static private function _prepUrl($url = '') {
		$url = trim($url);

		if ($url) {
			if ( ! preg_match('/^https?:\/\//i', $url)) {
				$url = 'http://'.$url;
			}
		}

		return $url;
	}

}

environment_example.php

<?php

// Environments
$environments = array(
	'local'   => '/\.[local(host)?|dev|10?]+$/i',
	'staging' => '/\w\.(staging|branch)\.mywebsite\.com$/i'
);

// Initialize environments
Environment::init($environments);


var_dump( Environment::is('production') );
var_dump( Environment::is('staging') );
var_dump( Environment::is('foo') );
//var_dump( Environment::isProduction() ); // Does not work in PHP < 5.3. Causes fatal error
//var_dump( Environment::isLocal() ); // Does not work in PHP < 5.3. Causes fatal error
//var_dump( Environment::isFoo() ); // Does not work in PHP < 5.3. Causes fatal error

var_dump( Environment::is('production', 'something.com') );
var_dump( Environment::is('production', 'something.dev') );
var_dump( Environment::is('foo', 'something.com') );
var_dump( Environment::is('foo', 'something.dev') );

//var_dump( Environment::isProduction('something.dev') ); // Does not work in PHP < 5.3. Causes fatal error
//var_dump( Environment::isProduction('something.com') ); // Does not work in PHP < 5.3. Causes fatal error
//var_dump( Environment::isFoo('something.dev') ); // Does not work in PHP < 5.3. Causes fatal error
//var_dump( Environment::isFoo('something.com') ); // Does not work in PHP < 5.3. Causes fatal error


var_dump( Environment::envVarKey() );


var_dump( Environment::envVar() );


var_dump( Environment::strict() );
var_dump( Environment::strict(true) );
var_dump( Environment::strict(false) );


var_dump( Environment::get() );


var_dump( Environment::isCLI() );


var_dump( Environment::isWeb() );