GuzzleRetryMiddleware - Code Metrics - Inspection of "X-Retry-Counter header" - caseyamcl/guzzle_retry_middleware - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#5)

unknown

created 2018-06-06 12:22 UTC

GuzzleRetryMiddleware B

↳ Parent: Project

Complexity

Total Complexity

Size/Duplication

Total Lines	318
Duplicated Lines	0 %

Coupling/Cohesion

Components	1
Dependencies	3

Test Coverage

Coverage

99.02%

Importance

Changes

Metric	Value
wmc	38
lcom	1
cbo	3
dl	0
loc	318
ccs	101
cts	102
cp	0.9902
rs	8.3999
c	0
b	0
f	0

12 Methods

Rating	Name	Size	Complexity
A	returnResponse()	10	3
A	factory()	6	1
A	__construct()	5	1
A	__invoke()	18	2
A	onFulfilled()	8	2
B	onRejected()	20	5
B	shouldRetryConnectException()	18	6
B	shouldRetryHttpResponse()	20	5
A	countRemainingRetries()	10	3
B	doRetry()	26	2
B	determineDelayTimeout()	22	5
A	deriveTimeoutFromHeader()	12	3

<?php
/**
 * Guzzle Retry Middleware Library
 *
 * @license http://opensource.org/licenses/MIT
 * @link https://github.com/caseyamcl/guzzle_retry_middleware
 * @version 2.0
 * @package caseyamcl/guzzle_retry_middleware
 * @author Casey McLaughlin <[email protected]>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 *
 * ------------------------------------------------------------------
 */

namespace GuzzleRetry;

use GuzzleHttp\Exception\BadResponseException;
use GuzzleHttp\Exception\ConnectException;
use GuzzleHttp\Promise\Promise;
use Psr\Http\Message\RequestInterface;
use Psr\Http\Message\ResponseInterface;

/**
 * Retry After Middleware
 *
 * Guzzle 6 middleware that retries requests when encountering responses
 * with certain conditions (429 or 503).  This middleware also respects
 * the `RetryAfter` header
 *
 * @author Casey McLaughlin <[email protected]>
 */
class GuzzleRetryMiddleware
{
    // HTTP date format
    const DATE_FORMAT = 'D, d M Y H:i:s T';

    const HEADER = 'X-Retry-Counter';

    /**
     * @var array
     */
    private $defaultOptions = [

        // Retry enabled.  Toggle retry on or off per request
        'retry_enabled'                    => true,

        // If server doesn't provide a Retry-After header, then set a default back-off delay
        // NOTE: This can either be a float, or it can be a callable that returns a (accepts count and response|null)
        'default_retry_multiplier'         => 1.5,

        // Set a maximum number of attempts per request
        'max_retry_attempts'               => 10,

        // Set this to TRUE to retry only if the HTTP Retry-After header is specified
        'retry_only_if_retry_after_header' => false,

        // Only retry when status is equal to these response codes
        'retry_on_status'                  => ['429', '503'],

        // Callback to trigger when delay occurs (accepts count, delay, request, response, options)
        'on_retry_callback'                => null,

        // Retry on connect timeout?
        'retry_on_timeout'                 => false,

        // Add the number of retries to an X-Header
        'expose_header'                    => false,

        // The header key
        'header'                           => self::HEADER
    ];

    /**
     * @var callable
     */
    private $nextHandler;

    /**
     * Provides a closure that can be pushed onto the handler stack
     *
     * Example:
     * <code>$handlerStack->push(GuzzleRetryMiddleware::factory());</code>
     *
     * @param array $defaultOptions
     * @return \Closure
     */
    public static function factory(array $defaultOptions = [])
    {
        return function (callable $handler) use ($defaultOptions) {
            return new static($handler, $defaultOptions);
        };
    }

    /**
     * GuzzleRetryMiddleware constructor.
     *
     * @param callable $nextHandler
     * @param array $defaultOptions
     */
    public function __construct(callable $nextHandler, array $defaultOptions = [])
    {
        $this->nextHandler = $nextHandler;
        $this->defaultOptions = array_replace($this->defaultOptions, $defaultOptions);
    }

    /**
     * @param RequestInterface $request
     * @param array $options
     * @return Promise
     */
    public function __invoke(RequestInterface $request, array $options)
    {
        // Combine options with defaults specified by this middleware
        $options = array_replace($this->defaultOptions, $options);

        // Set the retry count if not already set
        if (! isset($options['retry_count'])) {
            $options['retry_count'] = 0;
        }

        /** @var callable $next */
        $next = $this->nextHandler;
        return $next($request, $options)
            ->then(
                $this->onFulfilled($request, $options),
                $this->onRejected($request, $options)
            );
    }

    /**
     * No exceptions were thrown during processing
     *
     * Depending on where this middleware is in the stack, the response could still
     * be unsuccessful (e.g. 429 or 503), so check to see if it should be retried
     *
     * @param RequestInterface $request
     * @param array $options
     * @return callable
     */
    protected function onFulfilled(RequestInterface $request, array $options)
    {
        return function (ResponseInterface $response) use ($request, $options) {
            return ($this->shouldRetryHttpResponse($options, $response))
                ? $this->doRetry($request, $options, $response)
                : $this->returnResponse($options, $response);
        };
    }

    /**
     * An exception or error was thrown during processing
     *
     * If the reason is a BadResponseException exception, check to see if
     * the request can be retried.  Otherwise, pass it on.
     *
     * @param RequestInterface $request
     * @param array $options
     * @return callable
     */
    protected function onRejected(RequestInterface $request, array $options)
    {
        return function ($reason) use ($request, $options) {
            // If was bad response exception, test if we retry based on the response headers
            if ($reason instanceof BadResponseException) {
                if ($this->shouldRetryHttpResponse($options, $reason->getResponse())) {
/** @return stdClass|null */
function mayReturnNull() { }

function doesNotAcceptNull(stdClass $x) { }

// With potential error.
function withoutCheck() {
    $x = mayReturnNull();
    doesNotAcceptNull($x); // Potential error here.
}

// Safe - Alternative 1
function withCheck1() {
    $x = mayReturnNull();
    if ( ! $x instanceof stdClass) {
        throw new \LogicException('$x must be defined.');
    }
    doesNotAcceptNull($x);
}

// Safe - Alternative 2
function withCheck2() {
    $x = mayReturnNull();
    if ($x instanceof stdClass) {
        doesNotAcceptNull($x);
    }
}
                    return $this->doRetry($request, $options, $reason->getResponse());
                }
            // If this was a connection exception, test to see if we should retry based on connect timeout rules
            } elseif ($reason instanceof ConnectException) {
                // If was another type of exception, test if we should retry based on timeout rules
                if ($this->shouldRetryConnectException($reason, $options)) {
                    return $this->doRetry($request, $options);
                }
            }

            // If made it here, then we have decided not to retry the request
            return \GuzzleHttp\Promise\rejection_for($reason);
        };
    }

    protected function shouldRetryConnectException(ConnectException $e, array $options)
    {
        switch (true) {
            case $options['retry_enabled'] === false:
                return false;

            case $this->countRemainingRetries($options) == 0:
                return false;

            // Test if this was a connection or response timeout exception
            case isset($e->getHandlerContext()['errno']) && $e->getHandlerContext()['errno'] == 28:
                return isset($options['retry_on_timeout']) && $options['retry_on_timeout'] == true;

            // No conditions met, so return false
            default:
                return false;
        }
    }

    /**
     * Check to see if a request can be retried
     *
     * This checks two things:
     *
     * 1. The response status code against the status codes that should be retried
     * 2. The number of attempts made thus far for this request
     *
     * @param array $options
     * @param ResponseInterface|null $response
     * @return bool  TRUE if the response should be retried, FALSE if not
     */
    protected function shouldRetryHttpResponse(array $options, ResponseInterface $response)
    {
        $statuses = array_map('intval', (array) $options['retry_on_status']);

        switch (true) {
            case $options['retry_enabled'] === false:
                return false;

            case $this->countRemainingRetries($options) == 0:
                return false;

            // No Retry-After header, and it is required?  Give up
            case (! $response->hasHeader('Retry-After') && $options['retry_only_if_retry_after_header']):
                return false;

            // Conditions met; see if status code matches one that can be retried
            default:
                return in_array($response->getStatusCode(), $statuses);
        }
    }

    /**
     * Count the number of retries remaining.  Always returns 0 or greater.
     * @param array $options
     * @return int
     */
    protected function countRemainingRetries(array $options)
    {
        $retryCount  = isset($options['retry_count']) ? (int) $options['retry_count'] : 0;

        $numAllowed  = isset($options['max_retry_attempts'])
            ? (int) $options['max_retry_attempts']
            : $this->defaultOptions['max_retry_attempts'];

        return max([$numAllowed - $retryCount, 0]);
    }

    /**
     * Retry the request
     *
     * Increments the retry count, determines the delay (timeout), executes callbacks, sleeps, and re-send the request
     *
     * @param RequestInterface $request
     * @param array $options
     * @param ResponseInterface|null $response
     * @return
     */
    protected function doRetry(RequestInterface $request, array $options, ResponseInterface $response = null)
    {
        // Increment the retry count
        ++$options['retry_count'];

        // Determine the delay timeout
        $delayTimeout = $this->determineDelayTimeout($options, $response);

        // Callback?
        if ($options['on_retry_callback']) {
            call_user_func(
                $options['on_retry_callback'],
                (int) $options['retry_count'],
                (float) $delayTimeout,
                $request,
                $options,
                $response
            );
        }

        // Delay!
        usleep($delayTimeout * 1000000);

        // Return
        return $this($request, $options);
    }

    protected function returnResponse(array $options, ResponseInterface $response)
    {
        if ($options['expose_header'] === false
            || $options['retry_count'] === 0
        ) {
            return $response;
        }

        return $response->withHeader($options['header'], $options['retry_count']);
    }

    /**
     * Determine the delay timeout
     *
     * Attempts to read and interpret the HTTP `Retry-After` header, or defaults
     * to a built-in incremental back-off algorithm.
     *
     * @param ResponseInterface $response
     * @param array $options
     * @return float  Delay timeout, in seconds
     */
    protected function determineDelayTimeout(array $options, ResponseInterface $response = null)
    {
        if (is_callable($options['default_retry_multiplier'])) {
            $defaultDelayTimeout = (float) call_user_func(
                $options['default_retry_multiplier'],
                $options['retry_count'],
                $response
            );
        } else {
            $defaultDelayTimeout = (float) $options['default_retry_multiplier'] * $options['retry_count'];
        }

        // Retry-After can be a delay in seconds or a date
        // (see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Retry-After)
        if ($response && $response->hasHeader('Retry-After')) {
            return
                $this->deriveTimeoutFromHeader($response->getHeader('Retry-After')[0])
                ?: $defaultDelayTimeout;
        } else {
            return $defaultDelayTimeout;
        }
    }

    /**
     * Attempt to derive the timeout from the HTTP `Retry-After` header
     *
     * The spec allows the header value to either be a number of seconds or a datetime.
     *
     * @param string $headerValue
     * @return float|null  The number of seconds to wait, or NULL if unsuccessful (invalid header)
     */
    protected function deriveTimeoutFromHeader($headerValue)
    {
        // The timeout will either be a number or a HTTP-formatted date,
        // or seconds (integer)
        if ((string) intval(trim($headerValue)) == $headerValue) {
            return intval(trim($headerValue));
        } elseif ($date = \DateTime::createFromFormat(self::DATE_FORMAT, trim($headerValue))) {
            return (int) $date->format('U') - time();
        } else {
            return null;
        }
    }
}


1		<?php
2		/**
3		* Guzzle Retry Middleware Library
4		*
5		* @license http://opensource.org/licenses/MIT
6		* @link https://github.com/caseyamcl/guzzle_retry_middleware
7		* @version 2.0
8		* @package caseyamcl/guzzle_retry_middleware
9		* @author Casey McLaughlin <[email protected]>
10		*
11		* For the full copyright and license information, please view the LICENSE
12		* file that was distributed with this source code.
13		*
14		* ------------------------------------------------------------------
15		*/
16
17		namespace GuzzleRetry;
18
19		use GuzzleHttp\Exception\BadResponseException;
20		use GuzzleHttp\Exception\ConnectException;
21		use GuzzleHttp\Promise\Promise;
22		use Psr\Http\Message\RequestInterface;
23		use Psr\Http\Message\ResponseInterface;
24
25		/**
26		* Retry After Middleware
27		*
28		* Guzzle 6 middleware that retries requests when encountering responses
29		* with certain conditions (429 or 503). This middleware also respects
30		* the `RetryAfter` header
31		*
32		* @author Casey McLaughlin <[email protected]>
33		*/
34		class GuzzleRetryMiddleware
35		{
36		// HTTP date format
37		const DATE_FORMAT = 'D, d M Y H:i:s T';
38
39		const HEADER = 'X-Retry-Counter';
40
41		/**
42		* @var array
43		*/
44		private $defaultOptions = [
45
46		// Retry enabled. Toggle retry on or off per request
47		'retry_enabled' => true,
48
49		// If server doesn't provide a Retry-After header, then set a default back-off delay
50		// NOTE: This can either be a float, or it can be a callable that returns a (accepts count and response\|null)
51		'default_retry_multiplier' => 1.5,
52
53		// Set a maximum number of attempts per request
54		'max_retry_attempts' => 10,
55
56		// Set this to TRUE to retry only if the HTTP Retry-After header is specified
57		'retry_only_if_retry_after_header' => false,
58
59		// Only retry when status is equal to these response codes
60		'retry_on_status' => ['429', '503'],
61
62		// Callback to trigger when delay occurs (accepts count, delay, request, response, options)
63		'on_retry_callback' => null,
64
65		// Retry on connect timeout?
66		'retry_on_timeout' => false,
67
68		// Add the number of retries to an X-Header
69		'expose_header' => false,
70
71		// The header key
72		'header' => self::HEADER
73		];
74
75		/**
76		* @var callable
77		*/
78		private $nextHandler;
79
80		/**
81		* Provides a closure that can be pushed onto the handler stack
82		*
83		* Example:
84		* <code>$handlerStack->push(GuzzleRetryMiddleware::factory());</code>
85		*
86		* @param array $defaultOptions
87		* @return \Closure
88		*/
89	66	public static function factory(array $defaultOptions = [])
90		{
91		return function (callable $handler) use ($defaultOptions) {
92	66	return new static($handler, $defaultOptions);
93	66	};
94		}
95
96		/**
97		* GuzzleRetryMiddleware constructor.
98		*
99		* @param callable $nextHandler
100		* @param array $defaultOptions
101		*/
102	69	public function __construct(callable $nextHandler, array $defaultOptions = [])
103		{
104	69	$this->nextHandler = $nextHandler;
105	69	$this->defaultOptions = array_replace($this->defaultOptions, $defaultOptions);
106	69	}
107
108		/**
109		* @param RequestInterface $request
110		* @param array $options
111		* @return Promise
112		*/
113	66	public function __invoke(RequestInterface $request, array $options)
114		{
115		// Combine options with defaults specified by this middleware
116	66	$options = array_replace($this->defaultOptions, $options);
117
118		// Set the retry count if not already set
119	66	if (! isset($options['retry_count'])) {
120	66	$options['retry_count'] = 0;
121	44	}
122
123		/** @var callable $next */
124	66	$next = $this->nextHandler;
125	66	return $next($request, $options)
126	66	->then(
127	66	$this->onFulfilled($request, $options),
128	66	$this->onRejected($request, $options)
129	44	);
130		}
131
132		/**
133		* No exceptions were thrown during processing
134		*
135		* Depending on where this middleware is in the stack, the response could still
136		* be unsuccessful (e.g. 429 or 503), so check to see if it should be retried
137		*
138		* @param RequestInterface $request
139		* @param array $options
140		* @return callable
141		*/
142	66	protected function onFulfilled(RequestInterface $request, array $options)
143		{
144		return function (ResponseInterface $response) use ($request, $options) {
145	54	return ($this->shouldRetryHttpResponse($options, $response))
146	49	? $this->doRetry($request, $options, $response)
147	54	: $this->returnResponse($options, $response);
148	66	};
149		}
150
151		/**
152		* An exception or error was thrown during processing
153		*
154		* If the reason is a BadResponseException exception, check to see if
155		* the request can be retried. Otherwise, pass it on.
156		*
157		* @param RequestInterface $request
158		* @param array $options
159		* @return callable
160		*/
161		protected function onRejected(RequestInterface $request, array $options)
162		{
163	66	return function ($reason) use ($request, $options) {
164		// If was bad response exception, test if we retry based on the response headers
165	18	if ($reason instanceof BadResponseException) {
166	3	if ($this->shouldRetryHttpResponse($options, $reason->getResponse())) {
		0 ignored issues – show Bug introduced 2017-10-01 14:35 UTC by Report Bug Copy Issue Report It seems like `$reason->getResponse()` can be `null`; however, `shouldRetryHttpResponse()` does not accept `null`, maybe add an additional type check? Unless you are absolutely sure that the expression can never be null because of other conditions, we strongly recommend to add an additional type check to your code: /** @return stdClass\|null */ function mayReturnNull() { } function doesNotAcceptNull(stdClass $x) { } // With potential error. function withoutCheck() { $x = mayReturnNull(); doesNotAcceptNull($x); // Potential error here. } // Safe - Alternative 1 function withCheck1() { $x = mayReturnNull(); if ( ! $x instanceof stdClass) { throw new \LogicException('$x must be defined.'); } doesNotAcceptNull($x); } // Safe - Alternative 2 function withCheck2() { $x = mayReturnNull(); if ($x instanceof stdClass) { doesNotAcceptNull($x); } } Loading history...
167	3	return $this->doRetry($request, $options, $reason->getResponse());
168		}
169		// If this was a connection exception, test to see if we should retry based on connect timeout rules
170	15	} elseif ($reason instanceof ConnectException) {
171		// If was another type of exception, test if we should retry based on timeout rules
172	12	if ($this->shouldRetryConnectException($reason, $options)) {
173	6	return $this->doRetry($request, $options);
174		}
175	6	}
176
177		// If made it here, then we have decided not to retry the request
178	12	return \GuzzleHttp\Promise\rejection_for($reason);
179	66	};
180		}
181
182	12	protected function shouldRetryConnectException(ConnectException $e, array $options)
183		{
184	8	switch (true) {
185	12	case $options['retry_enabled'] === false:
186		return false;
187
188	12	case $this->countRemainingRetries($options) == 0:
189	3	return false;
190
191		// Test if this was a connection or response timeout exception
192	12	case isset($e->getHandlerContext()['errno']) && $e->getHandlerContext()['errno'] == 28:
193	9	return isset($options['retry_on_timeout']) && $options['retry_on_timeout'] == true;
194
195		// No conditions met, so return false
196	2	default:
197	3	return false;
198	2	}
199		}
200
201		/**
202		* Check to see if a request can be retried
203		*
204		* This checks two things:
205		*
206		* 1. The response status code against the status codes that should be retried
207		* 2. The number of attempts made thus far for this request
208		*
209		* @param array $options
210		* @param ResponseInterface\|null $response
211		* @return bool TRUE if the response should be retried, FALSE if not
212		*/
213	54	protected function shouldRetryHttpResponse(array $options, ResponseInterface $response)
214		{
215	54	$statuses = array_map('intval', (array) $options['retry_on_status']);
216
217	36	switch (true) {
218	54	case $options['retry_enabled'] === false:
219	3	return false;
220
221	54	case $this->countRemainingRetries($options) == 0:
222	12	return false;
223
224		// No Retry-After header, and it is required? Give up
225	54	case (! $response->hasHeader('Retry-After') && $options['retry_only_if_retry_after_header']):
226	3	return false;
227
228		// Conditions met; see if status code matches one that can be retried
229	34	default:
230	51	return in_array($response->getStatusCode(), $statuses);
231	34	}
232		}
233
234		/**
235		* Count the number of retries remaining. Always returns 0 or greater.
236		* @param array $options
237		* @return int
238		*/
239	63	protected function countRemainingRetries(array $options)
240		{
241	63	$retryCount = isset($options['retry_count']) ? (int) $options['retry_count'] : 0;
242
243	63	$numAllowed = isset($options['max_retry_attempts'])
244	63	? (int) $options['max_retry_attempts']
245	63	: $this->defaultOptions['max_retry_attempts'];
246
247	63	return max([$numAllowed - $retryCount, 0]);
248		}
249
250		/**
251		* Retry the request
252		*
253		* Increments the retry count, determines the delay (timeout), executes callbacks, sleeps, and re-send the request
254		*
255		* @param RequestInterface $request
256		* @param array $options
257		* @param ResponseInterface\|null $response
258		* @return
259		*/
260	48	protected function doRetry(RequestInterface $request, array $options, ResponseInterface $response = null)
261		{
262		// Increment the retry count
263	48	++$options['retry_count'];
264
265		// Determine the delay timeout
266	48	$delayTimeout = $this->determineDelayTimeout($options, $response);
267
268		// Callback?
269	48	if ($options['on_retry_callback']) {
270	39	call_user_func(
271	39	$options['on_retry_callback'],
272	39	(int) $options['retry_count'],
273	39	(float) $delayTimeout,
274	39	$request,
275	39	$options,
276	13	$response
277	26	);
278	26	}
279
280		// Delay!
281	48	usleep($delayTimeout * 1000000);
282
283		// Return
284	48	return $this($request, $options);
285		}
286
287	54	protected function returnResponse(array $options, ResponseInterface $response)
288		{
289	54	if ($options['expose_header'] === false
290	54	\|\| $options['retry_count'] === 0
291	36	) {
292	51	return $response;
293		}
294
295	3	return $response->withHeader($options['header'], $options['retry_count']);
296		}
297
298		/**
299		* Determine the delay timeout
300		*
301		* Attempts to read and interpret the HTTP `Retry-After` header, or defaults
302		* to a built-in incremental back-off algorithm.
303		*
304		* @param ResponseInterface $response
305		* @param array $options
306		* @return float Delay timeout, in seconds
307		*/
308	48	protected function determineDelayTimeout(array $options, ResponseInterface $response = null)
309		{
310	48	if (is_callable($options['default_retry_multiplier'])) {
311	3	$defaultDelayTimeout = (float) call_user_func(
312	3	$options['default_retry_multiplier'],
313	3	$options['retry_count'],
314	1	$response
315	2	);
316	2	} else {
317	45	$defaultDelayTimeout = (float) $options['default_retry_multiplier'] * $options['retry_count'];
318		}
319
320		// Retry-After can be a delay in seconds or a date
321		// (see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Retry-After)
322	48	if ($response && $response->hasHeader('Retry-After')) {
323		return
324	9	$this->deriveTimeoutFromHeader($response->getHeader('Retry-After')[0])
325	9	?: $defaultDelayTimeout;
326		} else {
327	39	return $defaultDelayTimeout;
328		}
329		}
330
331		/**
332		* Attempt to derive the timeout from the HTTP `Retry-After` header
333		*
334		* The spec allows the header value to either be a number of seconds or a datetime.
335		*
336		* @param string $headerValue
337		* @return float\|null The number of seconds to wait, or NULL if unsuccessful (invalid header)
338		*/
339	9	protected function deriveTimeoutFromHeader($headerValue)
340		{
341		// The timeout will either be a number or a HTTP-formatted date,
342		// or seconds (integer)
343	9	if ((string) intval(trim($headerValue)) == $headerValue) {
344	3	return intval(trim($headerValue));
345	6	} elseif ($date = \DateTime::createFromFormat(self::DATE_FORMAT, trim($headerValue))) {
346	3	return (int) $date->format('U') - time();
347		} else {
348	3	return null;
349		}
350		}
351		}
352

caseyamcl / guzzle_retry_middleware

Pull Request — master (#5)

GuzzleRetryMiddleware B

Complexity

Size/Duplication

Coupling/Cohesion

Test Coverage

Importance

12 Methods

Duplication Side-by-Side

Filter issues like