在 PHP 中将文件流式传输到 html5 而无需将文件写入文件系统

Question

我对 PHP 还很陌生，对流媒体视频也很陌生。

我将 mp4 视频存储在我的 SQL SERVER 的文件流列中，我想将它们流式传输到 HTML5 视频。

我已经设法使用以下流类 (http://codesamplez.com/programming/php-html5-video-streaming-tutorial)，通过“file_put_contents($filePath, $queryresult)”为其提供一个临时文件，但必须依赖于写入然后清理中间文件文件系统到底有问题。

我是否遗漏了一个关键概念，该概念允许我将文件直接从数据库流式传输到视频“src”，而无需在两者之间写入文件？

提前致谢！

Answer 1

如果您自己创建临时文件然后将其删除。然后你可以通过使用 PHP 的内置来改进这个过程 tempfile()哪个

在读写 (w+) 模式下创建一个具有唯一名称的临时文件并返回一个文件句柄。该文件在关闭时自动删除（例如，通过调用 fclose()，或者当没有剩余对tmpfile()) 或脚本结束时返回的文件句柄。

private function open()
{
    if ( !($this->stream = tmpfile()) ) {
        fwrite($this->stream, $videodata);
        rewind($this->stream);
        die('Could not open stream for reading');
    }
    // now your temp file is ready to be read.
} 

所以现在你没有温度的责任。删除 PHP 将为您处理。如果您需要自定义临时。文件名或获取详细信息，您可以使用此http://php.net/manual/en/function.sys-get-temp-dir.php

如果您根本不想使用文件，而是想纯粹使用内存解决方案，那么您可以尝试使用内存流

private function open()
{
    if ( !($this->stream = fopen('php://memory', 'wb+') ) ) {
        fwrite($this->stream, $videodata);
        rewind($this->stream);
        die('Could not open stream for reading');
    }
    // now your in-memory file is ready to be read.
} 

您可以在内存流上 fread、fwrite、file_get_contents 或使用 tcp 流将其扔到网络上。但我必须说，第二种解决方案有点占用内存，因此不适合流式传输大文件。

Answer 2

编写临时文件对我来说似乎是一种临时解决方法。当您从数据库中获取流并且需要向客户端提供流时，根本不需要将数据存储在硬盘上。

您需要做的就是替换链接示例中从文件读取的部分（并将二进制内容回显到客户端）并改为从 sql 读取。

在您链接的示例函数 stream() 中，替换这部分

    while(!feof($this->stream) && $i <= $this->end) {
        $bytesToRead = $this->buffer;
        if(($i+$bytesToRead) > $this->end) {
            $bytesToRead = $this->end - $i + 1;
        }
        $data = fread($this->stream, $bytesToRead);
        echo $data;
        flush();
        $i += $bytesToRead;
    }

替换成这样的：

/* Execute the query. */  
$stmt = sqlsrv_query($conn, $tsql, $params);  
if( $stmt === false )  
{  
     echo "Error in statement execution.</br>";  
     die( print_r( sqlsrv_errors(), true));  
}  

/* Retrieve and display the data.  
The return data is retrieved as a binary stream. */  
if ( sqlsrv_fetch( $stmt ) )  
{  
   $videostream = sqlsrv_get_field( $stmt, 0,   
                      SQLSRV_PHPTYPE_STREAM(SQLSRV_ENC_BINARY));  
   //header("Content-Type: image/jpg");  
   fpassthru($videostream );  
}  
else  
{  
     echo "Error in retrieving data.</br>";  
     die(print_r( sqlsrv_errors(), true));  
}  

Answer 3

为了后代，这是我的最终结果，它似乎在不需要临时文件的情况下运行良好。

不确定是否将查询包含在类中并将 $MediaFileID 传递给类是否更有意义，但这是按原样工作的，所以现在我已经离开了。

整个修改后的课程都包含在其原始信用信息中：

function ExecutereadMediaSP($MediaFileID){

    try{

    $connection = ConnectToDB();

    ini_set('memory_limit', '-1');

    // logs basic info about media viewer.  Mainly for a basic hit counter.
    LogMediaRequest($connection, $MediaFileID);

    //Selects binary data from SQL Server based on MediaFileID.  Passes this to Stream Class.  May be able to make further improvements later.
    $sql = "SELECT ... data from FILESTREAM column based on file ID ...";   

    $rst = $connection->prepare($sql);
    $rst->execute();
    $rst->bindColumn(1, $filecontent, PDO::PARAM_LOB, 0, PDO::SQLSRV_ENCODING_BINARY);

    $row = $rst->fetch(PDO::FETCH_ASSOC);//sql can only return one row due to unique identifier

    //Stream file 
    $stream = new VideoStream($filecontent);
    $stream->start();

    //Clean up.
    $rst->closeCursor();
    unset($rst);
    $connection = null;

    } catch (Exception $e) {
        error_log("Error in getting video\n".$e->getMessage(),0);
    }

}


/**
 * VideoStream - PHP class that supports (adaptive) streaming of files
 *
 * @author Rana
 * modified by HazCod to use stream_get_contents and correct session shutoff
 * https://github.com/HazCod
 * @link http://codesamplez.com/programming/php-html5-video-streaming-tutorial
 */
class VideoStream
{
    private $path = "";
    private $stream = "";
    private $buffer = 102400;
    private $start  = -1;
    private $end    = -1;
    private $size   = 0;

    function __construct($filecontent) 
    {


        try{

        // Opens file handle resource to replace use of actual file in the file system.
        $file_handle = fopen('php://memory', 'r+', false, stream_context_create()); 

        // Writes data from SQL Query to file wrapper.
        fwrite($file_handle, $filecontent);

        // Moves pointer to beginning of file.
        fseek($file_handle, 0);

        // Gets info on the "file."  Required to get filesize.
        $fstat = array();

        // gather statistics
        $fstat = fstat($file_handle);

        //Set File Size for Stream Class.
        $this->size  = $fstat['size'];

        // Define Stream as "File."
        $this->stream = $file_handle;

        } catch (PDOException $e) {
            error_log("Error in getting video\n".$e->getMessage(),0);
        }

    }

    /**
     * Set proper header to serve the video content
     */
    private function setHeader()
    {   
        ob_get_clean();
        header("Content-Type: video/mp4");
        header("Cache-Control: max-age=2592000, public");
        header("Expires: ".gmdate('D, d M Y H:i:s', time()+2592000) . ' GMT');
      //  header("Last-Modified: ".gmdate('D, d M Y H:i:s', @filemtime($this->path)) . ' GMT' );
        $this->start = 0;

        $this->end   = $this->size - 1;
       // header("Accept-Ranges: 0-".$this->end);

        if (isset($_SERVER['HTTP_RANGE'])) {

            $c_start = $this->start;
            $c_end = $this->end;

            list(, $range) = explode('=', $_SERVER['HTTP_RANGE'], 2);
            if (strpos($range, ',') !== false) {
                header('HTTP/1.1 416 Requested Range Not Satisfiable');
                header("Content-Range: bytes $this->start-$this->end/$this->size");
                exit;
            }
            if ($range == '-') {
                $c_start = $this->size - substr($range, 1);
            }else{
                $range = explode('-', $range);
                $c_start = $range[0];

                $c_end = (isset($range[1]) && is_numeric($range[1])) ? $range[1] : $c_end;
            }
            $c_end = ($c_end > $this->end) ? $this->end : $c_end;
            if ($c_start > $c_end || $c_start > $this->size - 1 || $c_end >= $this->size) {
                header('HTTP/1.1 416 Requested Range Not Satisfiable');
                header("Content-Range: bytes $this->start-$this->end/$this->size");
                exit;
            }
            $this->start = $c_start;
            $this->end = $c_end;
            $length = $this->end - $this->start + 1;
            fseek($this->stream, $this->start);
            header('HTTP/1.1 206 Partial Content');
            header("Content-Length: ".$length);
            header("Content-Range: bytes $this->start-$this->end/".$this->size);
        }
        else
        {
            header("Content-Length: ".$this->size);
        }  

    }

    /**
     * close curretly opened stream
     */
    private function end()
    {
        fclose($this->stream);
        exit;
    }

    /**
     * perform the streaming of calculated range
     */
    private function stream()
    {
        $i = $this->start;
        set_time_limit(0);
        while(!feof($this->stream) && $i <= $this->end && connection_aborted() == 0) {
            $bytesToRead = $this->buffer;
            if(($i+$bytesToRead) > $this->end) {
                $bytesToRead = $this->end - $i + 1;
            }
            $data = stream_get_contents($this->stream, $bytesToRead);
            echo $data;
            flush();
            $i += $bytesToRead;
        }
    }

    /**
     * Start streaming video content
     */
    function start()
    {
        session_write_close(); //ensure our session is written away before streaming, else we cannot use it elsewhere
        $this->setHeader();
        $this->stream();
        $this->end();
    }
}