Name
mod_changedpage
Synopsis
mod_changedpage
does for
RSS 1.0 what the cloud
element does for RSS 0.9x
— it introduces a form of Publish and Subscribe.
We’ll discuss
Publish and Subscribe in
detail in Chapter 12, but basically it enables a
system in which you can “subscribe”
to a feed and be notified when something new is published.
mod_changedpage
uses only one element, which
points to a changedPage server. Users wishing to
be told when the feed has updated send an HTTP POST request of a
certain format to this server. Upon updating, this server sends a
similar POST request back to the user. The user’s
client then knows about the update. Again, Chapter 12 examines this in detail.
Namespace
mod_changedpage
takes the namespace prefix
cp
: and is identified by the URI
http://my.theinfo.org/changed/1.0/rss/
. Hence, its
declaration looks like this:
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns="http://purl.org/rss/1.0/"
xmlns:cp="http://my.theinfo.org/changed/1.0/rss/">
Element
mod_changedpage
takes only one element, a
subelement of channel
:
-
<cp:server
rdf:resource="URL
"/>
The URL is the address of the changedPage server.
Example
Example 7-6. mod_changedpage in the channel
<?xml version="1.0" encoding="utf-8"?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns=http://purl.org/rss/1.0/
xmlns:cp="http://my.theinfo.org/changed/1.0/rss/" > <channel rdf:about="http://meerkat.oreillynet.com/?_fl=rss1.0"> <title>Meerkat</title> <link>http://meerkat.oreillynet.com</link> ...
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