HttpCache::setLastModified() - Code Metrics - Inspection of "Porting http cache" - yiisoft/yii-web - Measure and Improve Code Quality continuously with Scrutinizer

Passed

Pull Request — master (#199)

by Rustam

created 2020-01-11 18:23 UTC

HttpCache::setLastModified() A

↳ Parent: HttpCache

Complexity

Conditions	1
Paths	1

Size

Total Lines	3
Code Lines	1

Duplication

Lines	0
Ratio	0 %

Importance

Changes	2
Bugs	0	Features	0

Metric	Value
cc	1
eloc	1
c	2
b	0
f	0
nc	1
nop	1
dl	0
loc	3
rs	10

<?php
namespace Yiisoft\Yii\Web\Middleware;

use Psr\Http\Message\ResponseFactoryInterface;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Server\MiddlewareInterface;
use Psr\Http\Server\RequestHandlerInterface;
use Yiisoft\Http\Method;

/**
 * HttpCache implements client-side caching by utilizing the `Last-Modified` and `ETag` HTTP headers.
 */
final class HttpCache implements MiddlewareInterface
{
    private const DEFAULT_HEADER = 'public, max-age=3600';

    /**
     * @var callable a PHP callback that returns the UNIX timestamp of the last modification time.
     * The callback's signature should be:
     *
     * ```php
     * function (ServerRequestInterface $request, $params): int
     * ```
     *
     * where `$request` is the {@see ServerRequestInterface} object that this filter is currently handling;
     * `$params` takes the value of {@see params}. The callback should return a UNIX timestamp.
     *
     * @see http://tools.ietf.org/html/rfc7232#section-2.2
     */
    private $lastModified;

    /**
     * @var callable a PHP callback that generates the ETag seed string.
     * The callback's signature should be:
     *
     * ```php
     * function (ServerRequestInterface $request, $params): string
     * ```
     *
     * where `$request` is the {@see ServerRequestInterface} object that this middleware is currently handling;
     * `$params` takes the value of {@see $params}. The callback should return a string serving
     * as the seed for generating an ETag.
     */
    private $etagSeed;

    /**
     * @var bool whether to generate weak ETags.
     *
     * Weak ETags should be used if the content should be considered semantically equivalent, but not byte-equal.
     *
     * @see http://tools.ietf.org/html/rfc7232#section-2.3
     */
    private bool $weakEtag = false;

    /**
     * @var mixed additional parameters that should be passed to the {@see $lastModified} and {@see etagSeed} callbacks.
     */
    private $params;

    /**
     * @var string the value of the `Cache-Control` HTTP header. If null, the header will not be sent.
     * @see http://tools.ietf.org/html/rfc2616#section-14.9
     */
    private ?string $cacheControlHeader = self::DEFAULT_HEADER;

    private ResponseFactoryInterface $responseFactory;

    public function __construct(ResponseFactoryInterface $responseFactory)
    {
        $this->responseFactory = $responseFactory;
    }

    public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
    {
        $method = $request->getMethod();
        if (
            !\in_array($method, [Method::GET, Method::HEAD])
            || ($this->lastModified === null && $this->etagSeed === null)
        ) {
            return $handler->handle($request);
        }

        $lastModified = $etag = null;
        if ($this->lastModified !== null) {
            $lastModified = call_user_func($this->lastModified, $request, $this->params);
        }

        if ($this->etagSeed !== null) {
            $seed = call_user_func($this->etagSeed, $request, $this->params);
            if ($seed !== null) {
                $etag = $this->generateEtag($seed);
            }
        }

        $cacheValid = $this->validateCache($request, $lastModified, $etag);
        if ($cacheValid) {
            $response = $this->responseFactory->createResponse(304);
            $response = $response->withHeader(
                'Last-Modified',
                gmdate('D, d M Y H:i:s', $lastModified) . ' GMT'
            );
            return $response;
        }

        $response = $handler->handle($request);
        if ($this->cacheControlHeader !== null) {
            $response = $response->withHeader('Cache-Control', $this->cacheControlHeader);
        }
        if ($etag !== null) {
            $response = $response->withHeader('Etag', $etag);
        }

        // https://tools.ietf.org/html/rfc7232#section-4.1
        if ($lastModified !== null && (!$cacheValid || ($cacheValid && $etag === null))) {
            $response = $response->withHeader(
                'Last-Modified',
                gmdate('D, d M Y H:i:s', $lastModified) . ' GMT'
            );
        }

        return $response;
    }

    /**
     * Validates if the HTTP cache contains valid content.
     * If both Last-Modified and ETag are null, returns false.
     * @param ServerRequestInterface $request
     * @param int|null $lastModified the calculated Last-Modified value in terms of a UNIX timestamp.
     * If null, the Last-Modified header will not be validated.
     * @param string|null $etag the calculated ETag value. If null, the ETag header will not be validated.
     * @return bool whether the HTTP cache is still valid.
     */
    private function validateCache(ServerRequestInterface $request, ?int $lastModified, ?string $etag): bool
    {
        if ($request->hasHeader('If-None-Match')) {
            // HTTP_IF_NONE_MATCH takes precedence over HTTP_IF_MODIFIED_SINCE
            // http://tools.ietf.org/html/rfc7232#section-3.3
            return $etag !== null && \in_array($etag, $this->getETags($request), true);
        }

        if ($request->hasHeader('If-Modified-Since')) {
            $header = $request->getHeaderLine('If-Modified-Since');
            return $lastModified !== null && @strtotime($header) >= $lastModified;
        }

        return false;
    }

    /**
     * Generates an ETag from the given seed string.
     * @param string $seed Seed for the ETag
     * @return string the generated ETag
     */
    private function generateEtag(string $seed): string
    {
        $etag = '"' . rtrim(base64_encode(sha1($seed, true)), '=') . '"';
        return $this->weakEtag ? 'W/' . $etag : $etag;
    }

    /**
     * Gets the Etags.
     *
     * @param ServerRequestInterface $request
     * @return array The entity tags
     */
    private function getETags(ServerRequestInterface $request): array
    {
        if ($request->hasHeader('If-None-Match')) {
            $header = $request->getHeaderLine('If-None-Match');
            $header = \str_replace('-gzip', '', $header);
            return \preg_split('/[\s,]+/', $header, -1, PREG_SPLIT_NO_EMPTY) ?: [];
        }

        return [];
    }

    public function setLastModified(callable $lastModified): void
    {
        $this->lastModified = $lastModified;
    }

    public function setEtagSeed(callable $etagSeed): void
    {
        $this->etagSeed = $etagSeed;
    }

    public function setWeakTag(bool $weakTag): void
    {
        $this->weakEtag = $weakTag;
    }

    public function setParams($params): void
    {
        $this->params = $params;
    }

    public function setCacheControlHeader(?string $header): void
    {
        $this->cacheControlHeader = $header;
    }
}


1			<?php
2			namespace Yiisoft\Yii\Web\Middleware;
3
4			use Psr\Http\Message\ResponseFactoryInterface;
5			use Psr\Http\Message\ResponseInterface;
6			use Psr\Http\Message\ServerRequestInterface;
7			use Psr\Http\Server\MiddlewareInterface;
8			use Psr\Http\Server\RequestHandlerInterface;
9			use Yiisoft\Http\Method;
10
11			/**
12			* HttpCache implements client-side caching by utilizing the `Last-Modified` and `ETag` HTTP headers.
13			*/
14			final class HttpCache implements MiddlewareInterface
15			{
16			private const DEFAULT_HEADER = 'public, max-age=3600';
17
18			/**
19			* @var callable a PHP callback that returns the UNIX timestamp of the last modification time.
20			* The callback's signature should be:
21			*
22			* ```php
23			* function (ServerRequestInterface $request, $params): int
24			* ```
25			*
26			* where `$request` is the {@see ServerRequestInterface} object that this filter is currently handling;
27			* `$params` takes the value of {@see params}. The callback should return a UNIX timestamp.
28			*
29			* @see http://tools.ietf.org/html/rfc7232#section-2.2
30			*/
31			private $lastModified;
32
33			/**
34			* @var callable a PHP callback that generates the ETag seed string.
35			* The callback's signature should be:
36			*
37			* ```php
38			* function (ServerRequestInterface $request, $params): string
39			* ```
40			*
41			* where `$request` is the {@see ServerRequestInterface} object that this middleware is currently handling;
42			* `$params` takes the value of {@see $params}. The callback should return a string serving
43			* as the seed for generating an ETag.
44			*/
45			private $etagSeed;
46
47			/**
48			* @var bool whether to generate weak ETags.
49			*
50			* Weak ETags should be used if the content should be considered semantically equivalent, but not byte-equal.
51			*
52			* @see http://tools.ietf.org/html/rfc7232#section-2.3
53			*/
54			private bool $weakEtag = false;
55
56			/**
57			* @var mixed additional parameters that should be passed to the {@see $lastModified} and {@see etagSeed} callbacks.
58			*/
59			private $params;
60
61			/**
62			* @var string the value of the `Cache-Control` HTTP header. If null, the header will not be sent.
63			* @see http://tools.ietf.org/html/rfc2616#section-14.9
64			*/
65			private ?string $cacheControlHeader = self::DEFAULT_HEADER;
66
67			private ResponseFactoryInterface $responseFactory;
68
69			public function __construct(ResponseFactoryInterface $responseFactory)
70			{
71			$this->responseFactory = $responseFactory;
72			}
73
74			public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
75			{
76			$method = $request->getMethod();
77			if (
78			!\in_array($method, [Method::GET, Method::HEAD])
79			\|\| ($this->lastModified === null && $this->etagSeed === null)
80			) {
81			return $handler->handle($request);
82			}
83
84			$lastModified = $etag = null;
85			if ($this->lastModified !== null) {
86			$lastModified = call_user_func($this->lastModified, $request, $this->params);
87			}
88
89			if ($this->etagSeed !== null) {
90			$seed = call_user_func($this->etagSeed, $request, $this->params);
91			if ($seed !== null) {
92			$etag = $this->generateEtag($seed);
93			}
94			}
95
96			$cacheValid = $this->validateCache($request, $lastModified, $etag);
97			if ($cacheValid) {
98			$response = $this->responseFactory->createResponse(304);
99			$response = $response->withHeader(
100			'Last-Modified',
101			gmdate('D, d M Y H:i:s', $lastModified) . ' GMT'
102			);
103			return $response;
104			}
105
106			$response = $handler->handle($request);
107			if ($this->cacheControlHeader !== null) {
108			$response = $response->withHeader('Cache-Control', $this->cacheControlHeader);
109			}
110			if ($etag !== null) {
111			$response = $response->withHeader('Etag', $etag);
112			}
113
114			// https://tools.ietf.org/html/rfc7232#section-4.1
115			if ($lastModified !== null && (!$cacheValid \|\| ($cacheValid && $etag === null))) {
116			$response = $response->withHeader(
117			'Last-Modified',
118			gmdate('D, d M Y H:i:s', $lastModified) . ' GMT'
119			);
120			}
121
122			return $response;
123			}
124
125			/**
126			* Validates if the HTTP cache contains valid content.
127			* If both Last-Modified and ETag are null, returns false.
128			* @param ServerRequestInterface $request
129			* @param int\|null $lastModified the calculated Last-Modified value in terms of a UNIX timestamp.
130			* If null, the Last-Modified header will not be validated.
131			* @param string\|null $etag the calculated ETag value. If null, the ETag header will not be validated.
132			* @return bool whether the HTTP cache is still valid.
133			*/
134			private function validateCache(ServerRequestInterface $request, ?int $lastModified, ?string $etag): bool
135			{
136			if ($request->hasHeader('If-None-Match')) {
137			// HTTP_IF_NONE_MATCH takes precedence over HTTP_IF_MODIFIED_SINCE
138			// http://tools.ietf.org/html/rfc7232#section-3.3
139			return $etag !== null && \in_array($etag, $this->getETags($request), true);
140			}
141
142			if ($request->hasHeader('If-Modified-Since')) {
143			$header = $request->getHeaderLine('If-Modified-Since');
144			return $lastModified !== null && @strtotime($header) >= $lastModified;
145			}
146
147			return false;
148			}
149
150			/**
151			* Generates an ETag from the given seed string.
152			* @param string $seed Seed for the ETag
153			* @return string the generated ETag
154			*/
155			private function generateEtag(string $seed): string
156			{
157			$etag = '"' . rtrim(base64_encode(sha1($seed, true)), '=') . '"';
158			return $this->weakEtag ? 'W/' . $etag : $etag;
159			}
160
161			/**
162			* Gets the Etags.
163			*
164			* @param ServerRequestInterface $request
165			* @return array The entity tags
166			*/
167			private function getETags(ServerRequestInterface $request): array
168			{
169			if ($request->hasHeader('If-None-Match')) {
170			$header = $request->getHeaderLine('If-None-Match');
171			$header = \str_replace('-gzip', '', $header);
172			return \preg_split('/[\s,]+/', $header, -1, PREG_SPLIT_NO_EMPTY) ?: [];
173			}
174
175			return [];
176			}
177
178			public function setLastModified(callable $lastModified): void
179			{
180			$this->lastModified = $lastModified;
181			}
182
183			public function setEtagSeed(callable $etagSeed): void
184			{
185			$this->etagSeed = $etagSeed;
186			}
187
188			public function setWeakTag(bool $weakTag): void
189			{
190			$this->weakEtag = $weakTag;
191			}
192
193			public function setParams($params): void
194			{
195			$this->params = $params;
196			}
197
198			public function setCacheControlHeader(?string $header): void
199			{
200			$this->cacheControlHeader = $header;
201			}
202			}
203

yiisoft / yii-web

Pull Request — master (#199)

HttpCache::setLastModified() A

Complexity

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Duplication

Importance

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