xml2json.py

"""
	xml2json.py
	Kailash Nadh, http://nadh.in
	December 2012
	
	License:        MIT License
	Documentation:    http://nadh.in/code/xmlutils.py
"""

import codecs
import xml.etree.ElementTree as et
import json


def elem2list(elem):
	"""
	Convert an ElementTree element to a list
	"""
	block = {}

	# get the element's children
	children = elem.getchildren()

	if children:
		cur = map(elem2list, children)

		# create meaningful lists
		scalar = False
		try:
			if elem[0].tag != elem[1].tag:  # [{a: 1}, {b: 2}, {c: 3}] => {a: 1, b: 2, c: 3}
				cur = dict(zip(
					map(lambda e: e.keys()[0], cur),
					map(lambda e: e.values()[0], cur)
				))
			else:
				scalar = True
		except Exception as e:  # [{a: 1}, {a: 2}, {a: 3}] => {a: [1, 2, 3]}
			scalar = True

		if scalar:
			if len(cur) > 1:
				cur = {elem[0].tag: [e.values()[0] for e in cur if e.values()[0] is not None]}
			else:
				cur = {elem[0].tag: cur[0].values()[0] }

		block[elem.tag] = cur
	else:
		val = None
		if elem.text:
			val = elem.text.strip()
			val = val if len(val) > 0 else None

		block[elem.tag] = val 
	
	return block


def xml2json(elem, pretty=True):
	"""
	Convert an ElementTree Element (root) to json
	"""
	# if the given Element is not the root element, find it
	if hasattr(elem, 'getroot'):
		elem = elem.getroot()

	return json.dumps(elem2list(elem), indent=(4 if pretty else None))


def xml2json_file(input_file, output=None, pretty=True, encoding='utf-8'):
	"""
	Convert xml file to json
	"""
	context = et.iterparse(input_file, events=("start", "end"))
	context = iter(context)
	event, root = context.next()

	json = xml2json(root, pretty)

	# if an output filename is given, write to it, otherwise, return json
	if output is not None:
		output = codecs.open(output, "w", encoding)
		output.write(json)
	else:
		return json