programmatic creation of SetExpression fields in OpenOffice.org Writer

Question

I'm trying to define "variables" in an openoffice document, and I must be doing something wrong because when I try to display the value of the variable using a field, I only get an empty string.

Here's the code I'm using (using the Python UNO bridge). The interesting bit is the second function.

import time
import subprocess
import logging
import os
import sys
import uno
from com.sun.star.text.SetVariableType import STRING

def get_uno_model(): # helper function to connect to OOo. Only interesting 
                     # if you want to reproduce the issue locally, 
                     # don't spend time on this one
    try:
        model = XSCRIPTCONTEXT.getDocument()
    except NameError:
        pass # we are not running in a macro
    # get the uno component context from the PyUNO runtime
    localContext = uno.getComponentContext()

    # create the UnoUrlResolver
    resolver = localContext.ServiceManager.createInstanceWithContext(
                                    "com.sun.star.bridge.UnoUrlResolver", localContext )

    # connect to the running office
    try:
        ctx = resolver.resolve("uno:socket,host=localhost,port=2002;"
                               "urp;StarOffice.ComponentContext")
    except:
        cmd = ['soffice', '--writer', '-accept=socket,host=localhost,port=2002;urp;']
        popen = subprocess.Popen(cmd)
        time.sleep(1)
        ctx = resolver.resolve("uno:socket,host=localhost,port=2002;"
                               "urp;StarOffice.ComponentContext")
    smgr = ctx.ServiceManager

    # get the central desktop object
    desktop = smgr.createInstanceWithContext("com.sun.star.frame.Desktop", ctx)

    # access the current writer document
    model = desktop.getCurrentComponent()
    return model

def build_variable(model, name, value):
    # find or create a TextFieldMaster with the correct name
    master_prefix = u"com.sun.star.text.fieldmaster.SetExpression"
    variable_names = set([_name.split('.')[-1] 
                          for _name in model.TextFieldMasters.ElementNames
                          if _name.startswith(master_prefix)])
    master_name = u'%s.%s' % (master_prefix, name)
    if name not in variable_names:
        master = model.createInstance(master_prefix)
        master.Name = name
    else:
        master = model.TextFieldMasters.getByName(master_name)

    # create the SetExpression field
    field = model.createInstance(u'com.sun.star.text.textfield.SetExpression')
    field.attachTextFieldMaster(master)
    field.IsVisible = True
    field.IsInput = False
    field.SubType = STRING
    field.Content = value
    return field

model = get_uno_model() # local function to connect to OpenOffice
text = model.Text
field = build_variable(model, u'Toto', 'nice variable')
text.insertTextContent(text.getEnd(), field, False)

This code works somehow (unless I removed too much), but if I manually insert a field to display the value of Toto I don't get the 'nice variable' string that I expect, and the field which is inserted has no value

Answer 1

The code is missing setting the SubType property of the master field to STRING after the creation of the master field.