/LoadEnv.php

<?php
/**
 * Created by PhpStorm.
 * User: marti
 * Date: 07-Mar-18
 * Time: 10:34
 */

namespace Bootstrap;

trait LoadEnv
{
    protected $_env;

    public function __construct($env)
    {
        $this->_env = $env;
    }

    public function loadEnvironment()
    {
        $lines =$this->readLinesFromFile();

        foreach($lines as $line){
            if(!$this->isComment($line) && $this->looksLikeSetter($line)){
                $this->setEnvironmentVariable($line);
            }
        }

        return $lines;
    }

    protected function readLinesFromFile()
    {
        // Read file into an array of lines with auto-detected line endings
        $autodetect = ini_get('auto_detect_line_endings');
        ini_set('auto_detect_line_endings', '1');
        $lines = file($this->_env, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
        ini_set('auto_detect_line_endings', $autodetect);

        return $lines;
    }

    protected function isComment($line)
    {
        return strpos(ltrim($line), '#') === 0;
    }

    protected function looksLikeSetter($line)
    {
        return strpos($line, "=") !== false;
    }

    public function setEnvironmentVariable($name, $value = null)
    {
        list($name, $value) = $this->normaliseVariable($name, $value);


        // If PHP is running as an Apache module and an existing
        // Apache environment variable exists, overwrite it
        if (function_exists('apache_getenv') && function_exists('apache_setenv') && apache_getenv($name)) {
            apache_setenv($name, $value);
        }

        if (function_exists('putenv')) {
            setenv($name, $value);
        }

        $_ENV[$name] = $value;
        $_SERVER[$name] = $value;
    }

    protected function normaliseVariable($name, $value)
    {
        list($name, $value) = $this->splitCompoundStringIntoParts($name, $value);
        list($name, $value) = $this->sanitiseVariableName($name, $value);
        list($name, $value) = $this->sanitiseVariableValue($name, $value);

        $value = $this->resolveNestedVariables($value);

        return array($name, $value);
    }

    protected function resolveNestedVariables($value)
    {
        if(strpos($value, '$') !== false){
            $loader = $this;

            $value = preg_replace_callback(
                '/\${([a-zA-Z0-9_]+)}/',
                function($matchedPatterns) use($loader){
                    $nestedVariable = $loader->getEnvirenmentVariable($matchedPatterns[1]);
                    if($nestedVariable === null){
                        return $matchedPatterns[0];
                    }else{
                        return $nestedVariable;
                    }
                },
                $value
            );
        }

        return $value;
    }

    public function getEnvironmentVariable($name)
    {
        switch(true){
            case array_key_exists($name, $_ENV):
                return $_ENV[$name];
            case array_key_exists($name, $_SERVER):
                return $_SERVER[$name];
            default:
                $value = getenv($name);
                return $value === false ? null : $value;
        }
    }

    protected function splitCompoundStringIntoParts($name, $value)
    {
        if(strpos($name, '=') !== false){
            list($name, $value) = array_map('trim', explode('=', $name, 2));
        }

        return array($name, $value);
    }

    protected function sanitiseVariableName($name, $value)
    {
        $name = trim(str_replace(['export', '\'', '"'], '', $name));

        return array($name, $value);
    }

    protected function sanitiseVariableValue($name, $value)
    {
        $value = trim($value);
        if (!$value) {
            return array($name, $value);
        }

        if ($this->beginsWithAQuote($value)) { // value starts with a quote
            $quote = $value[0];
            $regexPattern = sprintf(
                '/^
                %1$s          # match a quote at the start of the value
                (             # capturing sub-pattern used
                 (?:          # we do not need to capture this
                  [^%1$s\\\\] # any character other than a quote or backslash
                  |\\\\\\\\   # or two backslashes together
                  |\\\\%1$s   # or an escaped quote e.g \"
                 )*           # as many characters that match the previous rules
                )             # end of the capturing sub-pattern
                %1$s          # and the closing quote
                .*$           # and discard any string after the closing quote
                /mx',
                $quote
            );
            $value = preg_replace($regexPattern, '$1', $value);
            $value = str_replace("\\$quote", $quote, $value);
            $value = str_replace('\\\\', '\\', $value);
        } else {
            $parts = explode(' #', $value, 2);
            $value = trim($parts[0]);

            // Unquoted values cannot contain whitespace
            if (preg_match('/\s+/', $value) > 0) {
                throw new \Exception('Dotenv values containing spaces must be surrounded by quotes.');
            }
        }

        return array($name, trim($value));
    }
    protected function beginsWithAQuote($value)
    {
        return strpbrk($value[0], '"\'') !== false;
    }
}