Setting pgNumType property in python-docx is without effect

Question

I'm trying to set page numbers in a word document using python-docx. I found an attribute pgNumType (pageNumberType), which I'm setting with this code:

document = Document()
section = document.add_section(WD_SECTION.CONTINUOUS)
sections = document.sections

sectPr = sections[0]._sectPr

pgNumType = OxmlElement('w:pgNumType')
pgNumType.set(qn('w:fmt'), 'decimal')
pgNumType.set(qn('w:start'), '1')

sectPr.append(pgNumType)

This code does nothing, no page numbers are in the output document. I did the same with a lnNumType attribute which is for line numbers and it worked fine. So what is it with the pgNumType attribute? The program executes without error, so the attribute exists. But anyone knows why it has no effect?

Answer 1

While your page style setting is fine, but it does not automatically insert a page number field anywhere in your document. Normally, page numbers appear in a header or a footer, but unfortunately, python-docx does not currently support headers, footers or fields. The former two appear to be an ongoing work in progress: https://github.com/python-openxml/python-docx/issues/104.

The linked issue mentions a number of workarounds. The one I have found to be most robust is to create an otherwise blank document with the headers and footers set up exactly the way you want in MS Word. You can then load and append to that document instead of the default template that docx.Document returns.

This technique is implied to be the suggested method for editing headers in the official documentation:

A lot of how a document looks is determined by the parts that are left when you delete all the content. Things like styles and page headers and footers are contained separately from the main content, allowing you to place a good deal of customization in your starting document that then appears in the document you produce.