- Can use R2 for storage without site being a domain/zone in Cloudflare
- Made change to XenForo's attachment data entity to be more efficient (normally XenForo checks if an attachment exists before making an additional call to actually get it). This will reduce an API call for every attachment view because we don't need to check if the attachment exists (we know it does already because we have a record of it in attachment data).
- Added new option: Use presigned URLs for attachments stored in R2 (allows attachments stored in R2 to be viewed directly by the user, rather than you server needing to download the attachment to pass it through to the user)
The presigned URL thing is particularly interesting... a remote storage system like R2 has your server checking user permissions to see if a user can view something, then it makes an API call to fetch the file/object and then passes that through to the user.
As an example, if you have a 10MB attachment, your server first needs to download 10MB and then it sends that 10MB to the end user (so there's the time it takes to download the attachment from R2 and as well as 20MB total bandwidth happening on your server... 10MB in, then 10MB out). With presigned URLs, your server does the permission check and then if the user has permission to view the attachment, the user is redirected to a unique URL that expires in 60 seconds to fetch the attachment. This means attachments are viewed faster for end-users and your server isn't wasting bandwidth passing it through to the user.
Presigned URLs that expire and can't be changed by users is done with cryptographic signing (hence the name, presigned URLs).
