JBoss.orgCommunity Documentation
XCAP
stands for Extensible Markup Language (
XML
)
Configuration Access Protocol. It is used to read, write and modify documents published on
XCAP
enabled servers. Such servers maintain said documents along with list of clients subscribed to the changes. Each change
to document on
server requires server to notify registered( subscribed ) clients. In simplest scenario, client, after it has been
notified,
rereads whole
document from server with
XCAP
call. However this is inefficient since documents may be big, client may be interested only
in part of the document - in particular cases
change to that part may not happen. Moreover, frequent
pulls on
XCAP
resources, increase dramatically amount and size of network traffic.
To counter this problem
xcap-diff
has been created. It is augmented version of
XML Diff
. In general
, diff function allows server to generate difference patch and send to clients only changed content, and only in cases when
client is interested in change.
This approach
reduces not only traffic content size, but also number of messages exchanged between server
and registered clients.
The
xcap-diff
generates minimal difference patch between two documents or their elements based on part to which client subscribed.
Generated patch can be
applied to not changed document(ie. at client side) in order to have identical document as one from which patch has been generated.