Utility to replace variables enclosed in square brackets with the given value in Microsoft Word docx files. Based upon the following blog post. http://virantha.com/2013/08/16/reading-and-writing-microsoft-word-docx-files-with-python/

docx.py

import os, re, zipfile, shutil, tempfile
from lxml import etree


class docx():
    def __init__(self, docx_filename):
        self.filename = docx_filename

        with open(self.filename) as f:
          self.zipfile = zipfile.ZipFile(f)
          self.xml_content = self.zipfile.read('word/document.xml')

        self.xml_tree = self._get_xml_tree(self.xml_content)
        self._join_tags(self.xml_tree)


    def _get_xml_tree(self, xml_string):
        return etree.fromstring(xml_string)

    def _check_element_is(self, element, type_char):
        word_schema = 'http://schemas.openxmlformats.org/wordprocessingml/2006/main'
        return element.tag == '{%s}%s' % (word_schema, type_char)

    def _itertext(self, tree):
        for node in tree.iter(tag=etree.Element):
            if self._check_element_is(node, 't'):
                yield (node, node.text)

    def _join_tags(self, tree):
        chars = []
        openbrac = False
        inside_openbrac_node = False

        for node, text in self._itertext(tree):
            # Scan through every node with text
            for i, c in enumerate(text):
                # Go through each node's text character by character
                if c == '[':
                    openbrac = True # Within a tag
                    inside_openbrac_node = True # Tag was opened in this node
                    openbrac_node = node # Save ptr to open bracket containing node
                    chars = []
                elif c== ']':
                    assert openbrac
                    if inside_openbrac_node:
                        # Open and close inside same node, no need to do anything
                        pass
                    else:
                        # Open bracket in earlier node, now it's closed
                        # So append all the chars we've encountered since the openbrac_node '['
                        # to the openbrac_node
                        chars.append(']')
                        openbrac_node.text += ''.join(chars)
                        # Also, don't forget to remove the characters seen so far from current node
                        node.text = text[i+1:] 
                    openbrac = False
                    inside_openbrac_node = False
                else:
                    # Normal text character
                    if openbrac and inside_openbrac_node:
                        # No need to copy text
                        pass
                    elif openbrac and not inside_openbrac_node:
                        chars.append(c)
                    else:
                        # outside of a open/close
                        pass
            if openbrac and not inside_openbrac_node:
                # Went through all text that is part of an open bracket/close bracket
                # in other nodes
                # need to remove this text completely
                node.text = ""
            inside_openbrac_node = False

    def replace(self, variable, value):
        var = '[%s]' % variable.lower()

        for node, text in self._itertext(self.xml_tree):
            if var in text.lower():
                regex = re.compile(re.escape(var), re.IGNORECASE)
                node.text = regex.sub(value, text)

    def save_as(self, output_filename):
        tmp_dir = tempfile.mkdtemp()
        with open(self.filename) as f:
            self.zipfile = zipfile.ZipFile(f)
            self.zipfile.extractall(tmp_dir)

        with open(os.path.join(tmp_dir,'word/document.xml'), 'w') as f:
            xmlstr = etree.tostring(self.xml_tree, pretty_print=True)
            f.write(xmlstr)

        filenames = self.zipfile.namelist()
        
        zip_copy_filename = output_filename
        with zipfile.ZipFile(zip_copy_filename, "w") as docx:
            for filename in filenames:
                docx.write(os.path.join(tmp_dir, filename), filename)

        # Clean up the temp dir
        shutil.rmtree(tmp_dir)


if __name__ == "__main__":
    doc = docx('test.docx')

    doc.replace('variable', 'value')
    doc.replace('another_variable', 'another value')

    doc.save_as('test_result.docx')

Search for the required text the same way I am searching/replacing variables with values in the function replace.