Hi, On Sun, Jan 30, 2022 at 1:15 AM Eran Kornblau <eran.kornb...@kaltura.com> wrote:
> > > > -----Original Message----- > > From: Eran Kornblau > > Sent: Wednesday, 19 January 2022 9:14 > > To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org> > > Subject: RE: [FFmpeg-devel] http: honor response headers in redirect > caching > > > > > > > > > > > Hi, > > > > > > On Mon, Jan 17, 2022 at 7:10 AM Ronald S. Bultje <rsbul...@gmail.com> > wrote: > > > > > > > Hi, > > > > > > > > On Tue, Jan 11, 2022 at 9:43 AM Eran Kornblau > > > > <eran.kornb...@kaltura.com> > > > > wrote: > > > > > > > >> Hi all, > > > >> > > > >> Recently I’ve submitted a patch that adds a config option to > > > >> disable the caching of http redirects. > > > >> We planned this as a workaround to the fact there’s a limit on the > > > >> expiration that can be set on S3 pre-signed URLs. > > > >> The idea was to have a service that generates signed S3 URLs and > > > >> redirects to them, ffmpeg would hit this service on every > > > >> seek/disconnect, and get a fresh S3 URL. > > > >> > > > >> We found that in some cases, ffmpeg seeks on every frame (probably > > > >> due to some gap between the positions of video/audio frames in the > > > >> file). In these cases, completely disabling the redirect caching > > > >> becomes quite inefficient - our S3 signing service gets called ~20 > > > >> times/sec by a single encoding task. > > > >> > > > >> The attached patch provides a more complete/correct implementation > > > >> of redirect caching – the decision whether to cache/for how long is > > > >> now determined according to the response from the server - status > > > >> code (e.g. 301 vs 302), expires header & cache-control header. The > > > >> behavior (detailed in the comment of the commit) is more aligned > > > >> with how browsers handle it. > > > >> > > > >> In high level, these are the changes that were implemented in the > > > >> patch – > > > >> > > > >> 1. Added a dictionary on HTTPContext for keeping the cache – > > > >> since I need to save both the target URL and the expiration, I’m > > > >> formatting them together on a single string > > > >> (“expiry;target-url”) > > > >> 2. Added a string on HTTPContext to save the value of the > > > >> location header – this makes the existing flags > > > >> new_location/location_changed redundant, and they were removed > > > >> 3. Added functions for parsing Cache-Control/Expires – for > > > >> Expires I used the existing function for parsing cookie expiration > > > >> time. The result is saved on a new integer on HTTPContent - a zero > > > >> value means that no such header was encountered yet, a negative > > > >> value means the response should not be cached. > > > >> Once this patch is merged, IMHO we can remove the flag that I added > > > >> in the previous patch (=always treat it as 0, and have the caching > > > >> work based on the new dictionary). I will happily submit another > > > >> patch for this. > > > >> > > > >> Thank you! > > > >> > > > > > > > > Will merge this in 1-2 days if there's no further comments. > > > > > > > > > > Merged. > > > > > > Ronald > > > > Ronald, thank you for your continued support on this one! > > > > As promised, sending another patch to remove the `cache_redirect` > option, as it seems to be no longer needed. > > > > Thanks > > > > Eran > > Ping > Got it, will apply this later today. I realize this is an API change but since the option only existed for 2 weeks, it should be OK. Ronald _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
