135 lines
		
	
	
		
			4.3 KiB
		
	
	
	
		
			PHP
		
	
	
	
			
		
		
	
	
			135 lines
		
	
	
		
			4.3 KiB
		
	
	
	
		
			PHP
		
	
	
	
<?php
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namespace BookStack\Http;
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use BookStack\Util\WebSafeMimeSniffer;
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use Illuminate\Http\Request;
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/**
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 * Helper wrapper for range-based stream response handling.
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 * Much of this used symfony/http-foundation as a reference during build.
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 * URL: https://github.com/symfony/http-foundation/blob/v6.0.20/BinaryFileResponse.php
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 * License: MIT license, Copyright (c) Fabien Potencier.
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 */
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class RangeSupportedStream
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{
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    protected string $sniffContent = '';
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    protected array $responseHeaders = [];
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    protected int $responseStatus = 200;
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    protected int $responseLength = 0;
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    protected int $responseOffset = 0;
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    public function __construct(
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        protected $stream,
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        protected int $fileSize,
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        Request $request,
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    ) {
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        $this->responseLength = $this->fileSize;
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        $this->parseRequest($request);
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    }
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    /**
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     * Sniff a mime type from the stream.
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     */
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    public function sniffMime(string $extension = ''): string
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    {
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        $offset = min(2000, $this->fileSize);
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        $this->sniffContent = fread($this->stream, $offset);
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        return (new WebSafeMimeSniffer())->sniff($this->sniffContent, $extension);
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    }
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    /**
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     * Output the current stream to stdout before closing out the stream.
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     */
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    public function outputAndClose(): void
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    {
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        // End & flush the output buffer, if we're in one, otherwise we still use memory.
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        // Output buffer may or may not exist depending on PHP `output_buffering` setting.
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        // Ignore in testing since output buffers are used to gather a response.
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        if (!empty(ob_get_status()) && !app()->runningUnitTests()) {
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            ob_end_clean();
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        }
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        $outStream = fopen('php://output', 'w');
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        $sniffLength = strlen($this->sniffContent);
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        $bytesToWrite = $this->responseLength;
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        if ($sniffLength > 0 && $this->responseOffset < $sniffLength) {
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            $sniffEnd = min($sniffLength, $bytesToWrite + $this->responseOffset);
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            $sniffOutLength = $sniffEnd - $this->responseOffset;
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            $sniffOutput = substr($this->sniffContent, $this->responseOffset, $sniffOutLength);
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            fwrite($outStream, $sniffOutput);
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            $bytesToWrite -= $sniffOutLength;
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        } else if ($this->responseOffset !== 0) {
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            fseek($this->stream, $this->responseOffset);
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        }
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        stream_copy_to_stream($this->stream, $outStream, $bytesToWrite);
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        fclose($this->stream);
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        fclose($outStream);
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    }
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    public function getResponseHeaders(): array
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    {
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        return $this->responseHeaders;
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    }
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    public function getResponseStatus(): int
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    {
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        return $this->responseStatus;
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    }
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    protected function parseRequest(Request $request): void
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    {
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        $this->responseHeaders['Accept-Ranges'] = $request->isMethodSafe() ? 'bytes' : 'none';
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        $range = $this->getRangeFromRequest($request);
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        if ($range) {
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            [$start, $end] = $range;
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            if ($start < 0 || $start > $end) {
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                $this->responseStatus = 416;
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                $this->responseHeaders['Content-Range'] = sprintf('bytes */%s', $this->fileSize);
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            } else {
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                $this->responseLength = $end < $this->fileSize ? $end - $start + 1 : -1;
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                $this->responseOffset = $start;
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                $this->responseStatus = 206;
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                $this->responseHeaders['Content-Range'] = sprintf('bytes %s-%s/%s', $start, $end, $this->fileSize);
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                $this->responseHeaders['Content-Length'] = $end - $start + 1;
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            }
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        }
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        if ($request->isMethod('HEAD')) {
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            $this->responseLength = 0;
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        }
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    }
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    protected function getRangeFromRequest(Request $request): ?array
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    {
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        $range = $request->headers->get('Range');
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        if (!$range || !$request->isMethod('GET') || !str_starts_with($range, 'bytes=')) {
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            return null;
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        }
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        if ($request->headers->has('If-Range')) {
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            return null;
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        }
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        [$start, $end] = explode('-', substr($range, 6), 2) + [0];
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        $end = ('' === $end) ? $this->fileSize - 1 : (int) $end;
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        if ('' === $start) {
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            $start = $this->fileSize - $end;
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            $end = $this->fileSize - 1;
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        } else {
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            $start = (int) $start;
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        }
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        $end = min($end, $this->fileSize - 1);
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        return [$start, $end];
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    }
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}
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