Comparing documents with OpenOffice and Python

I'm finally able to focus on something other than reading and playing Tales of Symphonia, and I've decided I need some actions before I look at making an action registry in KnowledgeTree.

I've been interested in automatic document conversion, and I've got recipes for OpenOffice.org and Office to generate PDF from word processor documents (obviously OO.org can do more source formats).

But what really seemed cool was the ability to generate diffs between documents, which OpenOffice.org does rather nicely. But it seems that no-one has a simple working example of using this via the OpenOffice.org UNO/URP. But reading up from multiple sources was enough to come up with a short example prototype. You need OpenOffice.org running with the remote socket (such as: /usr/lib/openoffice2/program/soffice.bin -headless -invisible '-accept=socket,host=localhost,port=2002;urp;'), and the Python UNO bridge module. OpenOffice.org v1 seems to not generate a proper PDF, I tested on a OpenOffice.org 2 beta.

#!/usr/bin/env python

import uno
from com.sun.star.beans import PropertyValue

url = uno.systemPathToFileUrl('/home/nbm/360survey-changed.doc')
url_original = uno.systemPathToFileUrl('/home/nbm/360survey-original.doc')
url_save = uno.systemPathToFileUrl('/home/nbm/360survey-diffs.pdf')

### Get Service Manager
context = uno.getComponentContext()
resolver = context.ServiceManager.createInstanceWithContext("com.sun.star.bridge.UnoUrlResolver", context)
ctx = resolver.resolve("uno:socket,host=localhost,port=2002;urp;StarOffice.ComponentContext")
smgr = ctx.ServiceManager

### Load document

properties = []
p = PropertyValue()
p.Name = "Hidden"
p.Value = True
properties.append(p)
properties = tuple(properties)

desktop = smgr.createInstanceWithContext("com.sun.star.frame.Desktop", ctx)
doc = desktop.loadComponentFromURL(url, "_blank", 0, properties)

### Compare with original document
properties = []
p = PropertyValue()
p.Name = "URL"
p.Value = url_original
properties.append(p)
properties = tuple(properties)

dispatch_helper = smgr.createInstanceWithContext("com.sun.star.frame.DispatchHelper", ctx)
dispatch_helper.executeDispatch(doc.getCurrentController().getFrame(), ".uno:CompareDocuments", "", 0, properties)

### Save File
properties = []
p = PropertyValue()
p.Name = "Overwrite"
p.Value = True
properties.append(p)
p = PropertyValue()
p.Name = "FilterName"
p.Value = 'writer_pdf_Export'
properties.append(p)
properties = tuple(properties)

doc.storeToURL(url_save, properties)
doc.dispose()