這篇文章是作爲ServerFault(https://serverfault.com/questions/131156/user-receiving-partial-downloads)的一個問題開始的,但我確定我們的php腳本是罪魁禍首。所以我在這裏發佈一個更新的問題,關於我認爲的實際問題。PHP文件服務腳本:不可靠的下載?
我正在使用php腳本來驗證權限,然後爲我的網站的用戶提供文件下載。大多數情況下,這是有效的,但最近有一位用戶發現下載量更大的問題。對於大於100MB的文件,他只獲得〜80%的下載量。此外,此腳本的所有下載都無法報告文件大小。此外,測試表明,如果給定直接鏈接(報告文件大小),相同的用戶可以可靠地下載每個失敗的文件。
這裏的代碼中的相關片段,我們使用的服務文件:
header("Content-type:$contenttype");
$len = filesize($filename);
header("Content-Length: $len");
header("Content-Disposition: attachment; filename=".$title.".".$ext);
readfile($filename);
注意$的contentType,$文件名,$ title和$ EXT都設置正確,纔來到這裏。這些已經過三重檢查。他們都不是問題。另外,$ len確實提供了正確的文件大小。
雖然研究這個問題,我遇到了這個帖子:Content-Length header always zero
看來,我遇到了同樣的問題。當我使用腳本時,我在文件上獲得了分塊編碼,並且沒有爲內容長度設置大小。我假設在大量下載中出現問題,導致他在文件結束之前得到一個零長度的塊。
這裏頭是什麼樣子的直接請求:
http://www.grinderschool.com/videos/zfff5061b65ae00e8b21/KillsAids021.wmv
GET /videos/zfff5061b65ae00e8b21/KillsAids021.wmv HTTP/1.1
Host: www.grinderschool.com
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3 (.NET CLR 3.5.30729)
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Connection: keep-alive
Referer: http://www.grinderschool.com/phpBB3/viewtopic.php?f=14&p=29468
Cookie: style_cookie=printonly; phpbb3_7c544_u=2; phpbb3_7c544_k=44b832912e5f887d; phpbb3_7c544_sid=e8852df42e08cc1b2250300c2897f78f; __utma=174624884.2719561324781918700.1251850714.1270986325.1270989003.575; __utmz=174624884.1264524375.411.12.utmcsr=google|utmccn=(organic)|utmcmd=organic|utmctr=low%20stakes%20poker%20videos; phpbb3_cmviy_k=; phpbb3_cmviy_u=2; phpbb3_cmviy_sid=d8df5c0943863004ca40ef9c392d371d; __utmb=174624884.4.10.1270989003; __utmc=174624884
Pragma: no-cache
Cache-Control: no-cache
HTTP/1.1 200 OK
Date: Sun, 11 Apr 2010 12:57:41 GMT
Server: Apache/2.2.14 (Unix) mod_ssl/2.2.14 OpenSSL/0.9.8l DAV/2 mod_auth_passthrough/2.1 FrontPage/5.0.2.2635
Last-Modified: Sun, 04 Apr 2010 12:51:06 GMT
Etag: "eb42d6-7d9b843-48368aa6dc280"
Accept-Ranges: bytes
Content-Length: 131708995
Keep-Alive: timeout=10, max=30
Connection: Keep-Alive
Content-Type: video/x-ms-wmv
而這裏就是他們的樣子供我的腳本回答請求:
http://www.grinderschool.com/download_video_test.php?t=KillsAids021&format=wmv
GET /download_video_test.php?t=KillsAids021&format=wmv HTTP/1.1
Host: www.grinderschool.com
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3 (.NET CLR 3.5.30729)
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Connection: keep-alive
Cookie: style_cookie=printonly; phpbb3_7c544_u=2; phpbb3_7c544_k=44b832912e5f887d; phpbb3_7c544_sid=e8852df42e08cc1b2250300c2897f78f; __utma=174624884.2719561324781918700.1251850714.1270986325.1270989003.575; __utmz=174624884.1264524375.411.12.utmcsr=google|utmccn=(organic)|utmcmd=organic|utmctr=low%20stakes%20poker%20videos; phpbb3_cmviy_k=; phpbb3_cmviy_u=2; phpbb3_cmviy_sid=d8df5c0943863004ca40ef9c392d371d; __utmb=174624884.4.10.1270989003; __utmc=174624884
HTTP/1.1 200 OK
Date: Sun, 11 Apr 2010 12:58:02 GMT
Server: Apache/2.2.14 (Unix) mod_ssl/2.2.14 OpenSSL/0.9.8l DAV/2 mod_auth_passthrough/2.1 FrontPage/5.0.2.2635
X-Powered-By: PHP/5.2.11
Content-Disposition: attachment; filename=KillsAids021.wmv
Vary: Accept-Encoding
Content-Encoding: gzip
Keep-Alive: timeout=10, max=30
Connection: Keep-Alive
Transfer-Encoding: chunked
Content-Type: video/x-ms-wmv
所以,問題是...我能做些什麼來使腳本下載正常工作?同樣,對於99%的用戶來說,它的工作原理是這樣的(儘管現在我覺得它沒有報告文件大小,因此沒有時間估計可以計算下載)。
該行不在代碼中,因此我正在通過php.ini進行挖掘。如果你碰巧知道我應該尋找什麼,那會非常有幫助! – 2010-04-11 16:17:22
試試看:'zlib_output_compression'。它應該設置爲關。 – mattbasta 2010-04-11 16:41:34
我的不好:'zlib.output_compression = Off'和'zlib.output_handler = Off' – mattbasta 2010-04-11 16:42:24