PHP code which supports byte-range downloads (for iPhone)

[tomjones]

Hi.

 

I am attempting to enable byte-range support on my Media Temple grid service account to allow playback of audio and video files from an iPhone. They suggested the following php script, but it does not provide any instructions on how to use it. Would someone be able to explain how to install this file? I've copied it to a directory as index.php, but an mp3 served to an iPhone from that directory still results in a non-specific error in the iPhone's browser.

 

http://dev.mobi/article/content-delivery-mobile-devices

I am referencing Appendix A: Streaming for Apple iPhone

 

Thank you for your time.

 

Tom

 

[tomjones]

bump.

[jonsjava]

following their example, this should do it for you. To use it, you simply add this content into a php file, then call it as such:

http://example.com/folder_name/file_name.php?file=filename.ext (file=filename.ext is the important thing: change filename.ext to the file you want to download)

<?php
$directory = "./"; //change this to the relative path to the application. it's asking for the directory your music is stored
$file1 = $_GET['file']; //FORMAT:  filename.php?file=example.oog or whatever the files name is.
$file = $directory.$file1;
if (is_file($file))
{
        header("Content-type: $mime_type");

        if (isset($_SERVER['HTTP_RANGE'])) // do it for any device that supports byte-ranges not only iPhone
        {
                rangeDownload($file);
        }
        else
        {
                header("Content-Length: ".filesize($file));
                readfile($file);
        }
} 
else
{
        // some error...
}


function rangeDownload($file)
{
        $fp = @fopen($file, 'rb');

        $size   = filesize($file); // File size
        $length = $size;           // Content length
        $start  = 0;               // Start byte
        $end    = $size - 1;       // End byte
        // Now that we've gotten so far without errors we send the accept range header
        /* At the moment we only support single ranges.
         * Multiple ranges requires some more work to ensure it works correctly
         * and comply with the spesifications: http://www.w3.org/Protocols/rfc2616/rfc2616-sec19.html#sec19.2
         *
         * Multirange support annouces itself with:
         * header('Accept-Ranges: bytes');
         *
         * Multirange content must be sent with multipart/byteranges mediatype,
         * (mediatype = mimetype)
         * as well as a boundry header to indicate the various chunks of data.
         */
        header("Accept-Ranges: 0-$length");
        // header('Accept-Ranges: bytes');
        // multipart/byteranges
        // http://www.w3.org/Protocols/rfc2616/rfc2616-sec19.html#sec19.2
        if (isset($_SERVER['HTTP_RANGE']))
        {
                $c_start = $start;
                $c_end   = $end;
                // Extract the range string
                list(, $range) = explode('=', $_SERVER['HTTP_RANGE'], 2);
                // Make sure the client hasn't sent us a multibyte range
                if (strpos($range, ',') !== false)
                {
                        // (?) Shoud this be issued here, or should the first
                        // range be used? Or should the header be ignored and
                        // we output the whole content?
                        header('HTTP/1.1 416 Requested Range Not Satisfiable');
                        header("Content-Range: bytes $start-$end/$size");
                        // (?) Echo some info to the client?
                        exit;
                }
                // If the range starts with an '-' we start from the beginning
                // If not, we forward the file pointer
                // And make sure to get the end byte if spesified
                if ($range{0} == '-')
                {
                        // The n-number of the last bytes is requested
                        $c_start = $size - substr($range, 1);
                }
                else
                {
                        $range  = explode('-', $range);
                        $c_start = $range[0];
                        $c_end   = (isset($range[1]) && is_numeric($range[1])) ? $range[1] : $size;
                }
                /* Check the range and make sure it's treated according to the specs.
                 * http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
                 */
                // End bytes can not be larger than $end.
                $c_end = ($c_end > $end) ? $end : $c_end;
                // Validate the requested range and return an error if it's not correct.
                if ($c_start > $c_end || $c_start > $size - 1 || $c_end >= $size)
                {
                        header('HTTP/1.1 416 Requested Range Not Satisfiable');
                        header("Content-Range: bytes $start-$end/$size");
                        // (?) Echo some info to the client?
                        exit;
                }
                $start  = $c_start;
                $end    = $c_end;
                $length = $end - $start + 1; // Calculate new content length
                fseek($fp, $start);
                header('HTTP/1.1 206 Partial Content');
        }
        // Notify the client the byte range we'll be outputting
        header("Content-Range: bytes $start-$end/$size");
        header("Content-Length: $length");

        // Start buffered download
        $buffer = 1024 * 8;
        while(!feof($fp) && ($p = ftell($fp)) <= $end)
        {
                if ($p + $buffer > $end)
                {
                        // In case we're only outputtin a chunk, make sure we don't
                        // read past the length
                        $buffer = $end - $p + 1;
                }
                set_time_limit(0); // Reset time limit for big files
                echo fread($fp, $buffer);
                flush(); // Free up memory. Otherwise large files will trigger PHP's memory limit.
        }

        fclose($fp);
}                  

?>