curl获取远程文件并同时强制下载

Question

我正在尝试获取远程文件并强制同时将其下载到用户.我无法粘贴代码,代码太长.但curl函数有效,但问题是它没有输出任何东西,直到它首先获取远程文件然后它强制下载到用户.

我用它来告诉curl返回一个回调

curl_setopt($ch, CURLOPT_READFUNCTION, 'readCallback');

现在在我的readCallback函数中我这样做:

function readCallback($curl, $stream, $maxRead){
    $read = fgets($stream, $maxRead);
    echo $read;
    return $read;
}

但它不会返回任何它等待直到获取远程文件完成.

Answer 1

试试这个,它将使用curl来获取文件的总大小然后下载代理它的文件的部分块给用户,这样就没有等待 curl首先下载它,我用avi,mp4,mp3测试了这个和一个exe,希望它有所帮助:

<?php
$file = 'http://example.com/somefile.mp3';
download($file,2000);

/*
Set Headers
Get total size of file
Then loop through the total size incrementing a chunck size
*/
function download($file,$chunks){
    set_time_limit(0);
    header('Content-Description: File Transfer');
    header('Content-Type: application/octet-stream');
    header('Content-disposition: attachment; filename='.basename($file));
    header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
    header('Expires: 0');
    header('Pragma: public');
    $size = get_size($file);
    header('Content-Length: '.$size);

    $i = 0;
    while($i<=$size){
        //Output the chunk
        get_chunk($file,(($i==0)?$i:$i+1),((($i+$chunks)>$size)?$size:$i+$chunks));
        $i = ($i+$chunks);
    }

}

//Callback function for CURLOPT_WRITEFUNCTION, This is what prints the chunk
function chunk($ch, $str) {
    print($str);
    return strlen($str);
}

//Function to get a range of bytes from the remote file
function get_chunk($file,$start,$end){
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $file);
    curl_setopt($ch, CURLOPT_RANGE, $start.'-'.$end);
    curl_setopt($ch, CURLOPT_BINARYTRANSFER, 1);
    curl_setopt($ch, CURLOPT_WRITEFUNCTION, 'chunk');
    $result = curl_exec($ch);
    curl_close($ch);
}

//Get total size of file
function get_size($url){
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_HEADER, true);
    curl_setopt($ch, CURLOPT_NOBODY, true);
    curl_exec($ch);
    $size = curl_getinfo($ch, CURLINFO_CONTENT_LENGTH_DOWNLOAD);
    return intval($size);
}
?>