Environment abstractions for PHP

README.md

Draft for a simple PSR providing a trivial abstraction of the local system environment.

Why? So we can stop using hacks to work around dependencies on system state - so that these dependencies can be made visible as (constructor) dependencies, and so we can mock the implementations under test.

environment.php

<?php

namespace Psr\Environment;

/**
 * This abstraction represents the local system's internal hardware clock.
 */
interface SystemClock
{
    /**
     * Get the current time measured in seconds since the Unix Epoch (January 1 1970 00:00:00 GMT)
     *
     * @return int time in seconds
     */
    public function getTime(): int;
    
    /**
     * Get the current time measured in seconds since the Unix Epoch (January 1 1970 00:00:00 GMT)
     * with as many fractions of precision as possible under the current 
     * 
     * @return float time in seconds (with fractions)
     */
    public function getExactTime(): float;
}

/**
 * This abstraction provides access to local environment variables (set by the operating system or `putenv`) 
 */
interface SystemVars
{
    /**
     * Get the value of a specified local environment variable.
     *
     * @return string environment variable value
     * 
     * @throws OutOfBoundsException if the specified variable has not been set
     */
    public function getVar(string $name): string;
    
    /**
     * Check if a specified local environment variable is set.
     *
     * @return bool TRUE, if the specified variable is set
     */
    public function hasVar(string $name): bool;
}