php获取远程图片大小函数示例

2. //用法 echo remote_filesize($url,$user='',$pw='');
3. $url = "http://www.aa.com/librarys/images/random/rand_11.jpg";//图片地址
4. echo remote_filesize($url,$user='',$pw='');
5. function remote_filesize($uri,$user='',$pw='')
6. {
7. // start output buffering
8. ob_start();
9. // initialize curl with given uri
10. $ch = curl_init($uri); // make sure we get the header
11. curl_setopt($ch, CURLOPT_HEADER, 1); // make it a http HEAD request
12. curl_setopt($ch, CURLOPT_NOBODY, 1); // if auth is needed, do it here
13. if (!empty($user) && !empty($pw))
14. {
15. $headers = array('Authorization: Basic ' . base64_encode($user.':'.$pw));
16. curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
17. }
18. $okay = curl_exec($ch);
19. curl_close($ch); // get the output buffer
20. $head = ob_get_contents(); // clean the output buffer and return to previous // buffer settings
21. ob_end_clean(); // gets you the numeric value from the Content-Length // field in the http header
22. $regex = '/Content-Length:\s([0-9].+?)\s/';
23. $count = preg_match($regex, $head, $matches); // if there was a Content-Length field, its value // will now be in $matches[1]
24. if (isset($matches[1]))
25. {
26. $size = $matches[1];
27. }
28. else
29. {
30. $size = 'unknown';
31. }
32. $last_mb = round($size/(1024*1024),3);
33. $last_kb = round($size/1024,3);
34. return $last_kb . 'KB / ' . $last_mb.' MB';
35. }

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实现思路： 先CURL获取图片到缓冲区，然后正则获取图片的Content-Length信息，即实现了获取远程图片大小的功能。