xref: /webtrees/app/Http/Middleware/CompressResponse.php (revision 1ff45046fabc22237b5d0d8e489c96f031fc598d) 
1<?php
2
3/**
4 * webtrees: online genealogy
5 * Copyright (C) 2023 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 strstr;
35use function strtolower;
36use function strtr;
37
38/**
39 * Middleware to compress (gzip or deflate) a response.
40 */
41class CompressResponse implements MiddlewareInterface
42{
43    // Non-text responses that will benefit from compression.
44    protected const MIME_TYPES = [
45        'application/javascript',
46        'application/json',
47        'application/pdf',
48        'application/vnd.geo+json',
49        'application/xml',
50        'image/svg+xml',
51    ];
52
53    protected StreamFactoryInterface $stream_factory;
54
55    /**
56     * @param StreamFactoryInterface $stream_factory
57     */
58    public function __construct(StreamFactoryInterface $stream_factory)
59    {
60        $this->stream_factory = $stream_factory;
61    }
62
63    /**
64     * @param ServerRequestInterface  $request
65     * @param RequestHandlerInterface $handler
66     *
67     * @return ResponseInterface
68     */
69    public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
70    {
71        $response = $handler->handle($request);
72
73        $method = $this->compressionMethod($request);
74
75        if ($method !== null && $this->isCompressible($response)) {
76            $content = (string) $response->getBody();
77
78            switch ($method) {
79                case 'deflate':
80                    $content = gzdeflate($content);
81                    break;
82
83                case 'gzip':
84                    $content = gzencode($content);
85                    break;
86            }
87
88            if ($content === false) {
89                return $response;
90            }
91
92            $stream = $this->stream_factory->createStream($content);
93
94            return $response
95                ->withBody($stream)
96                ->withHeader('content-encoding', $method)
97                ->withHeader('vary', 'accept-encoding');
98        }
99
100        return $response;
101    }
102
103    protected function compressionMethod(RequestInterface $request): string|null
104    {
105        $accept_encoding = strtolower($request->getHeaderLine('accept-encoding'));
106        $zlib_available  = extension_loaded('zlib');
107
108        if ($zlib_available) {
109            if (str_contains($accept_encoding, 'gzip')) {
110                return 'gzip';
111            }
112
113            if (str_contains($accept_encoding, 'deflate')) {
114                return 'deflate';
115            }
116        }
117
118        return null;
119    }
120
121    /**
122     * @param ResponseInterface $response
123     *
124     * @return bool
125     */
126    protected function isCompressible(ResponseInterface $response): bool
127    {
128        // Already encoded?
129        if ($response->hasHeader('content-encoding')) {
130            return false;
131        }
132
133        $content_type = $response->getHeaderLine('content-type');
134        $content_type = strtr($content_type, [' ' => '']);
135        $content_type = strstr($content_type, ';', true) ?: $content_type;
136        $content_type = strtolower($content_type);
137
138        if (str_starts_with($content_type, 'text/')) {
139            return true;
140        }
141
142        return in_array($content_type, static::MIME_TYPES, true);
143    }
144}
145