plausible-analytics / src / Client / lib / Lib / GuzzleHttp / RetryMiddleware.php

RetryMiddleware.php in Plausible Analytics trunk, at src/Client/lib/Lib/GuzzleHttp/RetryMiddleware.php

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1	<?php
2
3	namespace Plausible\Analytics\WP\Client\Lib\GuzzleHttp;
4
5	use Plausible\Analytics\WP\Client\Lib\GuzzleHttp\Promise as P;
6	use Plausible\Analytics\WP\Client\Lib\GuzzleHttp\Promise\PromiseInterface;
7	use Plausible\Analytics\WP\Client\Lib\Psr\Http\Message\RequestInterface;
8	use Plausible\Analytics\WP\Client\Lib\Psr\Http\Message\ResponseInterface;
9
10	/**
11	* Middleware that retries requests based on the boolean result of
12	* invoking the provided "decider" function.
13	*
14	* @final
15	*/
16	class RetryMiddleware
17	{
18	/**
19	* @var callable(RequestInterface, array): PromiseInterface
20	*/
21	private $nextHandler;
22
23	/**
24	* @var callable
25	*/
26	private $decider;
27
28	/**
29	* @var callable(int)
30	*/
31	private $delay;
32
33	/**
34	* @param callable $decider Function that accepts the number of retries,
35	* a request, [response], and [exception] and
36	* returns true if the request is to be
37	* retried.
38	* @param callable(RequestInterface, array): PromiseInterface $nextHandler Next handler to invoke.
39	* @param (callable(int): int)\|null $delay Function that accepts the number of retries
40	* and returns the number of
41	* milliseconds to delay.
42	*/
43	public function __construct( callable $decider, callable $nextHandler, ?callable $delay = null )
44	{
45	$this->decider = $decider;
46	$this->nextHandler = $nextHandler;
47	$this->delay = $delay ?: __CLASS__.'::exponentialDelay';
48	}
49
50	/**
51	* Default exponential backoff delay function.
52	*
53	* @return int milliseconds.
54	*/
55	public static function exponentialDelay(int $retries): int
56	{
57	return (int) 2 ** ($retries - 1) * 1000;
58	}
59
60	public function __invoke(RequestInterface $request, array $options): PromiseInterface
61	{
62	if (!isset($options['retries'])) {
63	$options['retries'] = 0;
64	}
65
66	$fn = $this->nextHandler;
67
68	return $fn($request, $options)
69	->then(
70	$this->onFulfilled($request, $options),
71	$this->onRejected($request, $options)
72	);
73	}
74
75	/**
76	* Execute fulfilled closure
77	*/
78	private function onFulfilled(RequestInterface $request, array $options): callable
79	{
80	return function ($value) use ($request, $options) {
81	if (!($this->decider)(
82	$options['retries'],
83	$request,
84	$value,
85	null
86	)) {
87	return $value;
88	}
89
90	return $this->doRetry($request, $options, $value);
91	};
92	}
93
94	/**
95	* Execute rejected closure
96	*/
97	private function onRejected(RequestInterface $req, array $options): callable
98	{
99	return function ($reason) use ($req, $options) {
100	if (!($this->decider)(
101	$options['retries'],
102	$req,
103	null,
104	$reason
105	)) {
106	return P\Create::rejectionFor($reason);
107	}
108
109	return $this->doRetry($req, $options);
110	};
111	}
112
113	private function doRetry( RequestInterface $request, array $options, ?ResponseInterface $response = null ): PromiseInterface
114	{
115	$options['delay'] = ($this->delay)(++$options['retries'], $response, $request);
116
117	return $this($request, $options);
118	}
119	}
120