xref: /webtrees/app/Http/Middleware/CompressResponse.php (revision c4943cff72f95a28fbb9404e3c20b169ff098e5c) 
1<?php
2
3/**
4 * webtrees: online genealogy
5 * Copyright (C) 2021 webtrees development team
6 * This program is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <https://www.gnu.org/licenses/>.
16 */
17
18declare(strict_types=1);
19
20namespace Fisharebest\Webtrees\Http\Middleware;
21
22use Psr\Http\Message\RequestInterface;
23use Psr\Http\Message\ResponseInterface;
24use Psr\Http\Message\ServerRequestInterface;
25use Psr\Http\Message\StreamFactoryInterface;
26use Psr\Http\Server\MiddlewareInterface;
27use Psr\Http\Server\RequestHandlerInterface;
28
29use function extension_loaded;
30use function gzdeflate;
31use function gzencode;
32use function in_array;
33use function str_contains;
34use function strlen;
35use function strstr;
36use function strtolower;
37use function strtr;
38
39/**
40 * Middleware to compress (gzip or deflate) a response.
41 */
42class CompressResponse implements MiddlewareInterface
43{
44    // Non-text responses that will benefit from compression.
45    protected const MIME_TYPES = [
46        'application/javascript',
47        'application/json',
48        'application/pdf',
49        'application/vnd.geo+json',
50        'application/xml',
51        'image/svg+xml',
52    ];
53
54    protected StreamFactoryInterface $stream_factory;
55
56    /**
57     * CompressResponse constructor.
58     *
59     * @param StreamFactoryInterface $stream_factory
60     */
61    public function __construct(StreamFactoryInterface $stream_factory)
62    {
63        $this->stream_factory = $stream_factory;
64    }
65
66    /**
67     * @param ServerRequestInterface  $request
68     * @param RequestHandlerInterface $handler
69     *
70     * @return ResponseInterface
71     */
72    public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
73    {
74        $response = $handler->handle($request);
75
76        $method = $this->compressionMethod($request);
77
78        if ($method !== null && $this->isCompressible($response)) {
79            $content = (string) $response->getBody();
80
81            switch ($method) {
82                case 'deflate':
83                    $content = gzdeflate($content);
84                    break;
85
86                case 'gzip':
87                    $content = gzencode($content);
88                    break;
89            }
90
91            if ($content === false) {
92                return $response;
93            }
94
95            $stream = $this->stream_factory->createStream($content);
96
97            return $response
98                ->withBody($stream)
99                ->withHeader('content-encoding', $method)
100                ->withHeader('content-length', (string) strlen($content))
101                ->withHeader('vary', 'accept-encoding');
102        }
103
104        return $response;
105    }
106
107    /**
108     * @param RequestInterface $request
109     *
110     * @return string|null
111     */
112    protected function compressionMethod(RequestInterface $request): ?string
113    {
114        $accept_encoding = strtolower($request->getHeaderLine('accept-encoding'));
115        $zlib_available  = extension_loaded('zlib');
116
117        if ($zlib_available) {
118            if (str_contains($accept_encoding, 'gzip')) {
119                return 'gzip';
120            }
121
122            if (str_contains($accept_encoding, 'deflate')) {
123                return 'deflate';
124            }
125        }
126
127        return null;
128    }
129
130    /**
131     * @param ResponseInterface $response
132     *
133     * @return bool
134     */
135    protected function isCompressible(ResponseInterface $response): bool
136    {
137        // Already encoded?
138        if ($response->hasHeader('content-encoding')) {
139            return false;
140        }
141
142        $content_type = $response->getHeaderLine('content-type');
143        $content_type = strtr($content_type, [' ' => '']);
144        $content_type = strstr($content_type, ';', true) ?: $content_type;
145        $content_type = strtolower($content_type);
146
147        if (str_starts_with($content_type, 'text/')) {
148            return true;
149        }
150
151        return in_array($content_type, static::MIME_TYPES, true);
152    }
153}
154