krz/vox-populi

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