Parsing Google Base XML with PHP XMLReader

Question

I'm trying to import a number of google base xml files into a single database, but alas, while I assumed the the Google Base XML would be a standardised format it seems that different sources create files with different structures.

Therefore, my import that can process the XML file from source A fails when applied to source B.

Is there are standard or common way to transform various Google Base XML documents into a single format?

For example, source A uses a

 <description>

tag while source B uses a

<summary>

tag.

Source A specifies the product link as

<link href="http://..."></link>

while source B uses

<link>http://...</link>