As described here (http://craigipedia.blogspot.com/2013/02/linking-drafts-day-one-and-textexpander.html) this script provides the glue between Drafts, TextExpander, Pythonista, and Day One on iOS to bring TextExpander fill-in support to a workflow.

Expander.py

#!/usr/bin/env python

#############################################################################
#
# Fill-in Expander
# (c) 2013 Craig A. Pearlman
# code@craig.blackfog.net
#
# This code is licensed under a Creative Commons Attribution 3.0 Unported
# license (http://creativecommons.org/licenses/by/3.0/). Attribution is not
# required, but it would be a nice gesture.
#
# This is my first (real) python script. Please make corrections. I know it's
# a tad clumsy.
#
#############################################################################
#
# Call from Drafts with a custom URL action as follows:
#
# pythonista://fillin_expander?action=run&argv=[urlencoded snippet]
#
# Essentially, fill in the form in Drafts with the proper values. You will
# need to expand the snippet in Drafts, as well. If you want the action to
# fire off Day One at the end, you will need to enable firing actions from
# URL support in Drafts' settings.
#
# When done, this will return the filled-in snippet back to Drafts and then
# automatically shove it off to Day One (you can modify this behavior to suit
# your needs).
#
#############################################################################
# NOTE: this does not currently support "optional sections" (don't use 'em)
# TODO: See if there's a way to do this more graphically


### REQUIREMENTS ###

import console
import re
import sys
import urllib
import webbrowser


### FUNCTIONS ###


def parse_fillin(parts):
    properties = dict()
    last_key = 'type'

    for part in parts:
        components = re.split('=', part)

        if 'type' in properties and \
            properties['type'] == 'fillpopup' and \
            'options' not in properties:
            properties['options'] = []

        if (len(components) == 1):
            if last_key == 'options':
                properties['options'].append(components[0])
            else:
                properties[last_key] = components[0]
                last_key = 'options'
        else:
            if components[0] == 'default':
                properties['default'] = components[1]
                if 'options' in properties and 'default' in properties:
                    properties['options'].append(properties['default'])
            else:
                properties[ components[0] ] = components[1]

    return properties


def prompt_text(properties):
    prompt = 'TEXT (' + properties['name'] + ')'

    if 'default' in properties:
        prompt += ' [' + properties['default'] + ']: '
    else:
        prompt += ': '

    sys.stdout.write(prompt)
    data = sys.stdin.readline().rstrip()

    if data == '' and 'default' in properties:
        data = properties['default']

    return data


# separate from TEXT in case we decide to handle it differently
def prompt_area(properties):
    prompt = 'AREA (' + properties['name'] + ')'

    if 'default' in properties:
        prompt += ' [' + properties['default'] + ']: '
    else:
        prompt += ': '

    sys.stdout.write(prompt)
    data = sys.stdin.readline().rstrip()

    if data == '' and 'default' in properties:
        data = properties['default']

    return data


def prompt_popup(properties):
    sys.stdout.write('MENU (' + properties['name'] + ')')

    if 'default' in properties:
        sys.stdout.write(' [' + properties['default'] + ']: ')
    else:
        sys.stdout.write(': ')

    sys.stdout.write("\n")

    # there's something wonky in the indices here; prolly don't understand
    # something about one of the functions (but it works)
    for i in range(1, len(properties['options']) + 1):
        print('  [' + str(i) + '] ' + properties['options'][i - 1])

    sys.stdout.write('=> ')

    data = sys.stdin.readline().rstrip()

    if (data == '' or not data.isdigit()) and 'default' in properties:
        data = properties['options'].index(properties['default'])
    else:
        data = int(data) - 1

    return properties['options'][int(data)]


def do_replacements(fillin):
    trimmed = re.sub('^%|%$', '', fillin)
    parts   = re.split(':', trimmed)

    properties = parse_fillin(parts)

    if properties['type'] == 'filltext':
        return prompt_text(properties)
    elif properties['type'] == 'fillpopup':
        return prompt_popup(properties)
    elif properties['type'] == 'fillarea':
        return prompt_area(properties)
    else:
        raise Exception('Unsupported fillin type: ' + properties['type'])


### MAIN ###

console.clear()

# need to change to urllib.parse.x in 3.x (Apple, wherefore 2.x?)
snippet = urllib.unquote_plus(sys.argv[1])
fillins = re.findall('%[^%]+%', snippet)

for fillin in fillins:
    replacement = do_replacements(fillin)
    #print(fillin.rstrip() + ': ' + replacement)
    snippet = re.sub(fillin, replacement, snippet)

# need to change to urllib.parse.x in 3.x (Apple, wherefore 2.x?)
encoded_snippet = urllib.quote(snippet)

webbrowser.open('drafts://x-callback-url/create?text=' + encoded_snippet + \
                '&action=' + urllib.quote('Send to Day One'))

# END