php获取远程文件大小

获取本地文件大小filesize()就可以了,但是如何获取远程文件的大小呢? 这里介绍三个方法来获取远程文件的大小.

方法1:get_headers

<?php
get_headers($url,true);

//返回结果
Array
(
    [0] => HTTP/1.1 200 OK
    [Date] => Sat, 29 May 2004 12:28:14 GMT
    [Server] => Apache/1.3.27 (Unix)  (Red-Hat/Linux)
    [Last-Modified] => Wed, 08 Jan 2003 23:11:55 GMT
    [ETag] => "3f80f-1b6-3e1cb03b"
    [Accept-Ranges] => bytes
    [Content-Length] => 438
    [Connection] => close
    [Content-Type] => text/html
)
?>

 

此处可以直接根据Content-Length来获取到远程文件的大小了.

方法2:curl

function remote_filesize($uri,$user='',$pw='')
{
    // start output buffering
    ob_start();
    // initialize curl with given uri
    $ch = curl_init($uri);
    // make sure we get the header
    curl_setopt($ch, CURLOPT_HEADER, 1);
    // make it a http HEAD request
    curl_setopt($ch, CURLOPT_NOBODY, 1);
    // if auth is needed, do it here
    if (!emptyempty($user) && !emptyempty($pw))
    {
        $headers = array('Authorization: Basic ' . base64_encode($user.':'.$pw));
        curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    }
    $okay = curl_exec($ch);
    curl_close($ch);
    // get the output buffer
    $head = ob_get_contents();
    // clean the output buffer and return to previous
    // buffer settings
    ob_end_clean();

    echo '<br>head-->'.$head.'<----end <br>';

    // gets you the numeric value from the Content-Length
    // field in the http header
    $regex = '/Content-Length:\s([0-9].+?)\s/';
    $count = preg_match($regex, $head, $matches);

    // if there was a Content-Length field, its value
    // will now be in $matches[1]
    if (isset($matches[1]))
    {
        $size = $matches[1];
    }
    else
    {
        $size = 'unknown';
    }
    //$last=round($size/(1024*1024),3);
    //return $last.' MB';
    return $size;
}

 

方法3:socket

function getFileSize($url)
{
    $url = parse_url($url);
    if($fp = @fsockopen($url['host'],emptyempty($url['port'])?80:$url['port'],$error))
    {
        fputs($fp,"GET ".(emptyempty($url['path'])?'/':$url['path'])." HTTP/1.1\r\n");
        fputs($fp,"Host:$url[host]\r\n\r\n");
        while(!feof($fp))
        {
            $tmp = fgets($fp);
            if(trim($tmp) == '')
            {
                break;
            }
            elseif(preg_match('/Content-Length:(.*)/si',$tmp,$arr))
            {
                return trim($arr[1]);
            }
        }
        return null;
    }
    else
    {
        return null;
    }
}

 

方法4:file_get_contents

$fCont = file_get_contents("http://www.mg27.com/1.html");
echo strlen($fCont)/1024;

 

 

以上四种方法
curl > fsock > file_get_contents > getheader