php读取文件大小

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

1. <?php 
2. get_headers($url,true);
4. //返回结果
5. Array 
6. (
7. [0] => HTTP/1.1 200 OK
8. [Date] => Sat, 29 May 2004 12:28:14 GMT
9. [Server] => Apache/1.3.27 (Unix) (Red-Hat/Linux)
10. [Last-Modified] => Wed, 08 Jan 2003 23:11:55 GMT
11. [ETag] => "3f80f-1b6-3e1cb03b" 
12. [Accept-Ranges] => bytes
13. [Content-Length] => 438 
14. [Connection] => close
15. [Content-Type] => text/html
16. )
17. ?> 

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

1. function remote_filesize($uri,$user='',$pw='')
2. {
3. // start output buffering
4. ob_start();
5. // initialize curl with given uri
6. $ch = curl_init($uri);
7. // make sure we get the header
8. curl_setopt($ch, CURLOPT_HEADER, 1);
9. // make it a http HEAD request
10. curl_setopt($ch, CURLOPT_NOBODY, 1);
11. // if auth is needed, do it here
12. if (!emptyempty($user) && !emptyempty($pw))
13. {
14. $headers = array('Authorization: Basic ' . base64_encode($user.':'.$pw));
15. curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
16. }
17. $okay = curl_exec($ch);
18. curl_close($ch);
19. // get the output buffer
20. $head = ob_get_contents();
21. // clean the output buffer and return to previous
22. // buffer settings
23. ob_end_clean();
25. echo '<br>head-->'.$head.'<----end <br>';
27. // gets you the numeric value from the Content-Length
28. // field in the http header
29. $regex = '/Content-Length:s([0-9].+?)s/';
30. $count = preg_match($regex, $head, $matches);
32. // if there was a Content-Length field, its value
33. // will now be in $matches[1]
34. if (isset($matches[1]))
35. {
36. $size = $matches[1];
37. }
38. else 
39. {
40. $size = 'unknown';
41. }
42. //$last=round($size/(1024*1024),3);
43. //return $last.' MB';
44. return $size;
45. }

方法3:socket

1. function getFileSize($url)
2. {
3. $url = parse_url($url);
4. if($fp = @fsockopen($url['host'],emptyempty($url['port'])?80:$url['port'],$error))
5. {
6. fputs($fp,"GET ".(emptyempty($url['path'])?'/':$url['path'])." HTTP/1.1 ");
7. fputs($fp,"Host:$url[host] ");
8. while(!feof($fp))
9. {
10. $tmp = fgets($fp);
11. if(trim($tmp) == '')
12. {
13. break;
14. }
15. elseif(preg_match('/Content-Length:(.*)/si',$tmp,$arr))
16. {
17. return trim($arr[1]);
18. }
19. }
20. return null;
21. }
22. else 
23. {
24. return null;
25. }
26. }

方法4:file_get_contents

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