xref: /webtrees/app/Http/Middleware/CompressResponse.php (revision 179fae3110cbb2a41e74e6ee6990077a6587169b) 
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    /** @var StreamFactoryInterface */
55    protected $stream_factory;
56
57    /**
58     * CompressResponse constructor.
59     *
60     * @param StreamFactoryInterface $stream_factory
61     */
62    public function __construct(StreamFactoryInterface $stream_factory)
63    {
64        $this->stream_factory = $stream_factory;
65    }
66
67    /**
68     * @param ServerRequestInterface  $request
69     * @param RequestHandlerInterface $handler
70     *
71     * @return ResponseInterface
72     */
73    public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
74    {
75        $response = $handler->handle($request);
76
77        $method = $this->compressionMethod($request);
78
79        if ($method !== null && $this->isCompressible($response)) {
80            $content = (string) $response->getBody();
81
82            switch ($method) {
83                case 'deflate':
84                    $content = gzdeflate($content);
85                    break;
86
87                case 'gzip':
88                    $content = gzencode($content);
89                    break;
90            }
91
92            if ($content === false) {
93                return $response;
94            }
95
96            $stream = $this->stream_factory->createStream($content);
97
98            return $response
99                ->withBody($stream)
100                ->withHeader('content-encoding', $method)
101                ->withHeader('content-length', (string) strlen($content))
102                ->withHeader('vary', 'accept-encoding');
103        }
104
105        return $response;
106    }
107
108    /**
109     * @param RequestInterface $request
110     *
111     * @return string|null
112     */
113    protected function compressionMethod(RequestInterface $request): ?string
114    {
115        $accept_encoding = strtolower($request->getHeaderLine('accept-encoding'));
116        $zlib_available  = extension_loaded('zlib');
117
118        if ($zlib_available) {
119            if (str_contains($accept_encoding, 'gzip')) {
120                return 'gzip';
121            }
122
123            if (str_contains($accept_encoding, 'deflate')) {
124                return 'deflate';
125            }
126        }
127
128        return null;
129    }
130
131    /**
132     * @param ResponseInterface $response
133     *
134     * @return bool
135     */
136    protected function isCompressible(ResponseInterface $response): bool
137    {
138        // Already encoded?
139        if ($response->hasHeader('content-encoding')) {
140            return false;
141        }
142
143        $content_type = $response->getHeaderLine('content-type');
144        $content_type = strtr($content_type, [' ' => '']);
145        $content_type = strstr($content_type, ';', true) ?: $content_type;
146        $content_type = strtolower($content_type);
147
148        if (str_starts_with($content_type, 'text/')) {
149            return true;
150        }
151
152        return in_array($content_type, static::MIME_TYPES, true);
153    }
154}
155