I was having some problems the other day using mt.setPostCategories to set the category on my first test post using the XML-RPC API that MovableType provides. I found some info over at d2r, the code for mt.setPostCategories is just wrong - not even valid xml - and that ID in <name>categoryID</name> should be Id (arg!). So, I decided to learn more about XML-RPC and dug out some books and poked and proded until setting my category occurred without fault.

I still think that adding the primary category as part of the metaWeblog.newPost struct would be cool. It’s kinda crazy to post, set categories, republish. I’ve got a post in over at the MT forums asking this.

So now my little VB app works - just sends the XML-RPC raw - now to get into more of the XML document creation. (Why am I doing this? Just cuz I think XML is cool and have being playing around with the MSXML control a lot.)

Here’s the proper XML-RPC code for mt.setPostCategories: (I replaced tabs with spaces to make it look a little nicer on the web.)

<?xml version="1.0"?>
<methodCall>
<!-- The name of the method to call. -->
<methodName>mt.setPostCategories</methodName>
<params>
<param>
<value>
<!-- Entry ID. -->
<string>[MT ID of Entry]</string>
</value>
</param>
<param>
<value>
<!-- The username to post this entry under. -->
<string>[username]</string>
</value>
</param>
<param>
<value>
<!-- The password for the username supplied above. -->
<string>[password]</string>
</value>
</param>
<param>
<value>
<array>
<data>
<struct>
<member>
<name>categoryId</name>
<value>
<string>[MT ID of category]</string>
</value>
</member>
<member>
<name>isPrimary</name>
<value>
<boolean>true</boolean>
</value>
</member>
</struct>
</data>
</array>
</value>
</param>
</params>
</methodCall>