Meter.php

<?php
/**
 * Rate limit meter.
 *
 * @package Cedaro\WPRESTCop
 * @since 1.0.0
 * @copyright Copyright (c) 2015 Cedaro, LLC
 * @license GPL-2.0+
 */
 
namespace Cedaro\WPRESTCop;
 
/**
 * Meter class.
 *
 * @package Cedaro\WPRESTCop
 * @since 1.0.0
 */
class Meter implements \jsonSerializable {
/**
 * Unique meter identifier.
 *
 * @since 1.0.0
 * @var string|int
 */
protected $id;
 
/**
 * Number of requests allowed per interval.
 *
 * @since 1.0.0
 * @var int
 */
protected $limit;
 
/**
 * Seconds per interval.
 *
 * @since 1.0.0
 * @var int
 */
protected $interval;
 
/**
 * Number of remaining ticks allowed in the interval.
 *
 * @since 1.0.0
 * @var int
 */
protected $remaining;
 
/**
 * The interval start time.
 *
 * @since 1.0.0
 * @var int
 */
protected $start;
 
/**
 * Constructor method.
 *
 * @since 1.0.0
 *
 * @param string|int $id Unique key to identify the current client.
 * @param int $limit Number of ticks allowed per interval.
 * @param int $interval Seconds per interval.
 */
public function __construct( $id, $limit, $interval ) {
$this->id = $id;
$this->interval = $interval;
$this->limit = $limit;
$this->remaining = $this->limit;
$this->start = time();
}
 
/**
 * Retrieve the meter identifier.
 *
 * @since 1.0.0
 *
 * @return string
 */
public function get_id() {
return $this->id;
}
 
/**
 * Retrieve rate limit headers.
 *
 * @since 1.0.0
 *
 * @return array
 */
public function get_headers() {
$headers = [
'X-RateLimit-Limit' => $this->get_limit(),
'X-RateLimit-Remaining' => $this->get_remaining(),
'X-RateLimit-Reset' => $this->get_reset(),
];
 
if ( $this->is_limit_exceeded() ) {
$headers['Retry-After'] = $this->get_reset();
$headers['X-RateLimit-Remaining'] = 0;
}
 
return $headers;
}
 
/**
 * Retrieve the number of ticks allowed in the interval.
 *
 * @since 1.0.0
 *
 * @return int
 */
public function get_limit() {
return $this->limit;
}
 
/**
 * Whether the limit has been exceeded.
 *
 * @since 1.0.0
 *
 * @return bool
 */
public function is_limit_exceeded() {
return 0 > $this->get_remaining();
}
 
/**
 * Retrieve the number of ticks allowed before the limit is reached.
 *
 * @since 1.0.0
 *
 * @return int
 */
public function get_remaining() {
return $this->remaining;
}
 
/**
 * Retrieve the number of seconds until the meter resets.
 *
 * @since 1.0.0
 *
 * @return int
 */
public function get_reset() {
return $this->start + $this->interval - time();
}
 
/**
 * Update the counter.
 *
 * @since 1.0.0
 *
 * @param int $tick The number of hits.
 * @return $this
 */
public function tick( $tick = 1 ) {
$this->remaining -= $tick;
return $this;
}
 
/**
 * Convert the meter to an array.
 *
 * @since 1.0.0
 *
 * @return array
 */
public function to_array() {
return [
'limit' => $this->get_limit(),
'remaining' => $this->is_limit_exceeded() ? 0 : $this->get_remaining(),
'reset' => $this->get_reset(),
];
}
 
/**
 * Serialize for JSON.
 *
 * @since 1.0.0
 *
 * @return array
 */
public function jsonSerialize() {
return $this->to_array();
}
}