25 Apr
2026
25 Apr
'26
8:09 a.m.
I'd like to add that SFS does have:
- Source attaching (allows clients to put a shared file in the correct
time in the message history if upload is slow, also means clients can
already display file metadata and thumbnail while the file is still
uploading), backwards compatible (legacy clients would see the file
upload delayed). This is implemented in multiple clients
- Sending of multiple files in a single message (e.g. to send photo
galleries), backwards compatible (legacy clients would see this as
multiple messages). This is implemented at least in Kaidan, WIP in
Dino.
- Extension for proper E2EE (XEP-0448) when using SCE-alike encryption
schemes (OX, OMEMO2), also backwards compatible (it's possible to send
a file in a chat where some clients only do siacs-OMEMO such that
OMEMO2+XEP-0448 clients see a proper SFS file transfer with metadata
and legacy siacs-OMEMO+XEP-0454 clients get the "aesgcm" link, but both
download and decrypt the same HTTP upload, so the file doesn't need to
be uploaded twice). This is implemented at least in Kaidan.
These are major improvements over SIMS in practice. Of course
technically one could have done incompatible changes to XEP-0385 to
reach them in SIMS, but then it also wouldn't be SIMS compatible
anymore and would need a new namespace, so what's the point.
Marvin
On Fri, 2026-04-24 at 16:44 +0200, Thilo Molitor wrote:
This seems
backwards to me. SFS is just a shallow clone of SIMS but
with
less namespace reuse after all. Why would we lend legitimacy to
something
like that?
Are you sure you are talking about the same XEP here?
XEP-0447 says in its introduction:
This is a reiteration on Stateless Inline Media Sharing (XEP-0385)
[1] with
some significant changes:
- No focus on media, generic for every file type.
- Body can be used for fallback.
- Using File metadata element (XEP-0446) [2].
- Using XML for structured data instead of URIs when possible, adding
further
extensibility (like providing proper means of sharing encrypted files
on http
servers).
- Not relying on underspecified usage of References (XEP-0372) [3].
Especially using the file metadata element seems like a better
namespace reuse
to me, no?
It also is generic and can be used for all types of file, not just
for media.
That's a clear advantage compared to SIMS.
-tmolitor