1<?php
2
3namespace GuzzleHttp\Psr7;
4
5use Psr\Http\Message\StreamInterface;
6
7/**
8 * Uses PHP's zlib.inflate filter to inflate deflate or gzipped content.
9 *
10 * This stream decorator skips the first 10 bytes of the given stream to remove
11 * the gzip header, converts the provided stream to a PHP stream resource,
12 * then appends the zlib.inflate filter. The stream is then converted back
13 * to a Guzzle stream resource to be used as a Guzzle stream.
14 *
15 * @link http://tools.ietf.org/html/rfc1952
16 * @link http://php.net/manual/en/filters.compression.php
17 *
18 * @final
19 */
20class InflateStream implements StreamInterface
21{
22    use StreamDecoratorTrait;
23
24    public function __construct(StreamInterface $stream)
25    {
26        // read the first 10 bytes, ie. gzip header
27        $header = $stream->read(10);
28        $filenameHeaderLength = $this->getLengthOfPossibleFilenameHeader($stream, $header);
29        // Skip the header, that is 10 + length of filename + 1 (nil) bytes
30        $stream = new LimitStream($stream, -1, 10 + $filenameHeaderLength);
31        $resource = StreamWrapper::getResource($stream);
32        stream_filter_append($resource, 'zlib.inflate', STREAM_FILTER_READ);
33        $this->stream = $stream->isSeekable() ? new Stream($resource) : new NoSeekStream(new Stream($resource));
34    }
35
36    /**
37     * @param StreamInterface $stream
38     * @param $header
39     *
40     * @return int
41     */
42    private function getLengthOfPossibleFilenameHeader(StreamInterface $stream, $header)
43    {
44        $filename_header_length = 0;
45
46        if (substr(bin2hex($header), 6, 2) === '08') {
47            // we have a filename, read until nil
48            $filename_header_length = 1;
49            while ($stream->read(1) !== chr(0)) {
50                $filename_header_length++;
51            }
52        }
53
54        return $filename_header_length;
55    }
56}
57