|
Matt Barnicle
mattb at wageslavery.org
Tue Sep 23 22:07:04 EDT 2008
> 2008/9/23 Matt Barnicle <mattb at wageslavery.org>: >> i'm having an issue with our site, which seems to be directly >> related to using req.sendfile. on our site, we have secure music >> downloads. the user has to go through a series of steps in order >> to >> gain access to the music (fyi, we run a legitimate service, not a >> pirate or warez site). just some background info.. basically we >> can't offer a direct download link or the security can be >> bypassed. >> so downloading is done through the handler, which runs the checks, >> and if everything looks good, the file is sent to the browser >> using >> req.sendfile with the local path to the file on disk. >> >> it works.. but the problem is, requests start backing up whenever >> a >> download is being sent. it looks like new requests are being sent >> to the apache process that is tied up sending the download file. >> i >> don't understand why this is happening though. i would think that >> while it's sending the file, no new requests would be queued in >> that >> process. i can verify this easily by downloading a file, and >> while >> it's downloading, clicking on a link on the site from the same >> window in which i downloaded in. the request will stay in the >> WAIT >> state (according to mod_status) until the download is finished, >> then >> the page will load and the queue will clear up. now if i change >> the >> download link to a static file, served directly by apache, this >> problem disappears. >> >> what can i do to fix this? it's a major issue right now. many >> times a day you can go to the site and it will hang for perhaps 1 >> to >> 3 minutes, then it will load, due to the above described >> situation. >> >> version notes: >> >> CentOS release 5 (Final) >> apache 2.2.3 >> mod_python 3.2 >> >> using prefork compiled into apache. misc apache configuration: >> >> KeepAlive Off >> >> <IfModule prefork.c> >> StartServers 8 >> MinSpareServers 5 >> MaxSpareServers 20 >> ServerLimit 256 >> MaxClients 256 >> MaxRequestsPerChild 4000 >> </IfModule> >> >> thank you for your time and consideration.. > > Are you setting a content length on the response before calling > req.sendfile()? > > How many concurrent requests for these files are you receiving and > how > long does it take to download a file? > > Graham yes, i believe so.. now that you mention it, i haven't verified the file size from the code below, i will do that to be sure. here is the code: file_path = self.conf.run.app_folder + 'public' + download.path file_stat = os.stat(file_path) file_size = str(file_stat.st_size) self.req.headers_out['Content-Length'] = file_size self.req.headers_out['Content-Disposition'] = 'attachment; filename=%s' % os.path.basename(file_path) bytes_sent = self.req.sendfile(file_path) - m@
|