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. 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".
