[Standards] Chat Markers vs. Delivery receipts
sam at samwhited.com
Mon Jan 18 15:26:36 UTC 2016
On Sat, Jan 16, 2016 at 4:00 PM, Daniele Ricci <daniele.athome at gmail.com> wrote:
> My question is: considering that my server stores delivery receipts
> too, what is the real advantage of chat markers over delivery
> receipts, besides supporting two more states (displayed, acked)? Am I
> missing something from the XEP?
> Also, I was surprised when I read "Chat Markers MAY be used alongside
> Delivery Receipts", since they actually overlap, right?
Chat markers and delivery receipts are orthogonal concepts. Chat
markers are meant for determining if a client has viewed the current
chat (or performed some action, eg. composing a message), while
delivery receipts only show that a message has been delivered to your
contacts client (and don't make any guarantees that they've actually
seen the message).
To be able to make the most accurate determination about whether or
not your contact has read a given message, eg. for read-state
tracking, you'll need to use both.
To illustrate, imagine you send a message that gets lost (but no error
is returned) and is never delivered to your contact. Then they bring
their conversation with you to the foreground and start composing a
message. If you're only using chat markers, it will appear as if your
contact has read your last message, but in reality it was never
delivered to them.
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