This post originated from an RSS feed registered with Python Buzz by Phillip Pearson. Original Post: How do you send blog posts with complicated RSS over the metaWeblog API? Feed Title: Second p0st Feed URL: http://www.myelin.co.nz/post/rss.xml Feed Description: Tech notes and web hackery from the guy that brought you bzero, Python Community Server, the Blogging Ecosystem and the Internet Topic Exchange Latest Python Buzz Posts Latest Python Buzz Posts by Phillip Pearson Latest Posts From Second p0st

An item in an RSS 2.0 feed looks like this:

<item>
    <title>title</title>
    <link>http://example.com/path/to/post</link>
    <guid>http://example.com/path/to/post</guid>
    <description>an rss2 item looks like this:
 
&lt;item&gt;
&nbsp;&nbsp;&nbsp; &lt;title&gt;title&lt;/title&gt;...</description>
</item>

title, link, guid and description are all part of the spec.  You can put in other things if you like, as long as you put them in a namespace.  Say, if you want to categorise this item under the Topic Exchange's Software channel, you could say that this way:

<item xmlns:ent="http://purl.org/NET/ENT/1.0/">
    <title>title</title>
    <link>http://example.com/path/to/post</link>
    <guid>http://example.com/path/to/post</guid>
    <description>an rss2 item looks like this:
 
&lt;item&gt;
&nbsp;&nbsp;&nbsp; &lt;title&gt;title&lt;/title&gt;...</description>
    <ent:cloud ent:href="http://topicexchange.com/topics">
        <ent:topic ent:id="software" ent:href="http://topicexchange.com/t/software/">software</ent:topic>
    </ent:cloud>
</item>

ent:cloud and ent:topic, as well as the attributes ent:href and ent:id are all defined in the ENT spec.

If you wanted to make this item into a book review, still in the same channel, you could say it like this.

<item xmlns:ent="http://purl.org/NET/ENT/1.0/" xmlns:rvw="http://purl.org/NET/RVW/0.1/">
    <title>title</title>
    <link>http://example.com/path/to/post</link>
    <guid>http://example.com/path/to/post</guid>
    <description>an rss2 item looks like this:
 
&lt;item&gt;
&nbsp;&nbsp;&nbsp; &lt;title&gt;title&lt;/title&gt;...</description>
    <ent:cloud ent:href="http://topicexchange.com/topics">
        <ent:topic ent:id="software" ent:href="http://topicexchange.com/t/software/">software</ent:topic>
    </ent:cloud>
    <rvw:item>
        <rvw:link>http://www.amazon.com/exec/obidos/ASIN/0156027321/</rvw:link>
        <dc:identifier>ASIN:0156027321</dc:identifier>
        <dc:type>Text</dc:type>
        <dc:title>Life of Pi</dc:title>
        <dc:creator>Yann Martel</dc:creator>
        <dc:publisher>Harvest Books</dc:publisher>
        <dc:date>2003-05</dc:date>
        <ent:cloud ent:href="http://www.pmbrowser.info/rvw/">
            <ent:topic ent:href="http://www.pmbrowser.info/rvw/types.xtm#book" ent:id="book">Book</ent:topic>  
        </ent:cloud>
        <rvw:rating>
            <rvw:minimum>0</rvw:minimum>
            <rvw:maximum>10</rvw:maximum>
        <rvw:value>7</rvw:value>
        </rvw:rating>
    </rvw:item>
</item>

All the rvw elements are defined in the RVW spec.

Now, if you want to post something like this to a weblog, what are your options?  Basically, you can use the metaWeblog API or make up your own one.  If you use the existing API, you will be compatible with many existing blogging tools, and if you make up your own one, you won't.

In Python, the call to post a normal blog post looks like this:

import xmlrpclib
s = xmlrpclib.Server('http://127.0.0.1:5335/RPC2')
s.metaWeblog.newPost(BLOGID, LOGIN, PASSWORD, {
    'title': TITLE,
    'link': LINK,
    'description': DESCRIPTION,
})

BLOGID, for Radio, is 'home'.  LOGIN and PASSWORD are the values you configure here.  TITLE, LINK and DESCRIPTION are the values that show in the title, link and description elements in the resulting RSS.

If you want to include the ENT classification, it gets a bit trickier.  I think this is how it should work:

s.metaWeblog.newPost(BLOGID, LOGIN, PASSWORD, {
    'title': TITLE,
    'link': LINK,
    'description': DESCRIPTION,
    'http://purl.org/NET/ENT/1.0/': {
        'cloud': {
            'href': "http://www.pmbrowser.info/rvw/",
            '_value': {
                'topic': {
                    'href': "http://www.pmbrowser.info/rvw/types.xtm#book",
                    'id': "book",
                    '_value': "Book",
                },
            },
        },
    },
})

I've never seen any code using this, but there are hooks in Radio (see radio.weblog.metaWeblog.* and weblogData.callbacks.*) for plugins to handle extra values, so it's likely that someone is using it somewhere.  The spec isn't clear as to whether namespaces have to be re-specified for attributes (e.g. the ent:href under the ent:cloud) or sub-elements (e.g. the ent:topic under the ent:cloud), so this looks a little weird.

Does anybody know of any real-life examples of this sort of thing?  I'd be very interested to hear from you, as I'm not at all sure if I got the above example correct.

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