Question

从互联网上复制了一些代码，试图通过另一个PHP代码（基本上尝试流式传输图像）对图像进行HTTP推送。

但页面似乎根本没有显示任何图像。以下是从http://www.howtocreate.co.uk/php/dnld.php?file=6&action=1

获取的完整代码

function doServerPush($file,$type,$poll) {

    if( !file_exists($file) ) {
        //on first load, the file must exist, or it ends up sending a broken file
        header('Content-type: text/html',true,404);
    }

    @set_time_limit(0); //PHP must not terminate this script
    @ignore_user_abort(false); //do not ignore user aborts (may not be allowed, so status is checked in the loop)
    @ini_set( 'zlib.output_compression', 'off' );
    $poll *= 1000;

    //need a unique boundary
    //while it is possible to get a unique boundary for the current image data, it is possible that it will conflict
    //with future image data - can't help this, just have to live with it - might as well use a static string
    $separator = 'MTWJ_serverpush_boundary_';
    for( $i = 0, $randChars = Array('A','B'); $i < 20; $i++ ) {
        $separator .= $randChars[rand(0,1)];
    }

    header('Cache-Control: no-cache');
    header('Pragma: no-cache');
    //the header that makes server push work
    header("Content-Type: multipart/x-mixed-replace;boundary=$separator",true);
    $extrabreaks = '';

    do {
        //send one file starting with a multipart boundary
        $filelen = filesize($file);
        print "$extrabreaks--$separator\n";
        if( !$extrabreaks ) { $extrabreaks = "\n\n"; } //Safari needs exactly one blank line, no extra linebreaks on the first one
        print "Content-Type: $type\n";
        print "Content-Length: $filelen\n\n";
        readfile($file);
        //Safari needs 200+ bytes between headers - IE needs 256+ per flush, and this will also take care of that, when IE gets server push
        print str_pad('',200-$filelen); //whitespace here is ignored because of content-length
        $lastupdsate = filemtime($file);
        ob_flush();
        flush();
        $looptime = time();
        do {
            clearstatcache(); //need updated file info
            usleep($poll);
            if( time() - $looptime >= 10 ) {
                //every 10 seconds, force it to re-evaluate if the user has disconnected (connection_aborted does not know until this happens)
                //most use-cases will not need this protection because they will keep trying to send updates, but it is here just in case
                $looptime = time();
                print ' '; //whitespace is ignored at this specific point in the stream
                ob_flush();
                flush();
            }
            //poll the filesystem until the file changes, then send the update
            //the file may not always exist for the instant it is being replaced on the filesystem
            //nested loop and filemtime check inspired by http://web.they.org/software/php-push.php
        } while( !connection_aborted() && ( !file_exists($file) || ( $lastupdsate == filemtime($file) ) ) );
    } while( !connection_aborted() ); //if aborts are ignored, exit anyway to avoid endless threads
}
?>

调用代码的php文件如下：

require ("serverpush.php");

doServerPush("img.jpg",'image/jpeg',75);

，html如下：

<html>
    <head>
        <title>Streaming</title>

        <style type="text/css" media="screen">
            img
            {
                width: 200px;
                height: 200px;
                border: 2px solid #ABCDEF;
            }
        </style>
    </head>

    <body>

        <h1>Image stream test</h1>

        <img src="Stream.php" alt="Stream Image" />
    </body>
</html>

任何帮助都将得到赞赏。试图在Firefox和Chrome中运行代码

HTTP推送与multipart / x-mixed-replace php代码无法正常工作

0 个答案: