xml2dict.py

"""
XML2Dict

Thunder Chen<nkchenz#gmail.com> 2007.9.1

revision131014 by fffonion <fffonion#gmail.com>
optimize memory usage
"""
from __future__ import print_function
try:
    import xml.etree.ElementTree as ET
except:
    import cElementTree as ET  # for 2.4

import re

__version__ = 1.1

"""
object_dict

nkchenz#gmail.com 2007

Provided as-is; use at your own risk; no warranty; no promises; enjoy!
"""

class object_dict(dict):
    """object view of dict, you can 
    >>> a = object_dict()
    >>> a.fish = 'fish'
    >>> a['fish']
    'fish'
    >>> a['water'] = 'water'
    >>> a.water
    'water'
    >>> a.test = {'value': 1}
    >>> a.test2 = object_dict({'name': 'test2', 'value': 2})
    >>> a.test, a.test2.name, a.test2.value
    (1, 'test2', 2)
    """
    def __init__(self, initd = None):
        if initd is None:
            initd = {}
        dict.__init__(self, initd)

    def __getattr__(self, item):
        d = self.__getitem__(item)
        # if value is the only key in object, you can omit it
        if isinstance(d, dict) and 'value' in d and len(d) == 1:
            return d['value']
        else:
            return d

    # def __iter__(self):
    #    yield self
    #    return

    def __setattr__(self, item, value):
        self.__setitem__(item, value)


class XML2Dict(object):
    @classmethod
    def _parse_node(self, node):
        node_tree = object_dict()
        # Save attrs and text, hope there will not be a child with same name
        if node.text:
            node_tree.value = node.text
        for (k, v) in node.attrib.items():
            k, v = self._namespace_split(k, object_dict({'value':v}))
            node_tree[k] = v
        # Save childrens
        for child in iter(node):
            tag, tree = self._namespace_split(child.tag, self._parse_node(child))
            if  tag not in node_tree:  # the first time, so store it in dict
                node_tree[tag] = tree
                continue
            old = node_tree[tag]
            if not isinstance(old, list):
                node_tree.pop(tag)
                node_tree[tag] = [old]  # multi times, so change old dict to a list
            node_tree[tag].append(tree)  # add the new one

        return  node_tree

    @classmethod
    def _namespace_split(self, tag, value):
        """
           Split the tag  '{http://cs.sfsu.edu/csc867/myscheduler}patients'
             ns = http://cs.sfsu.edu/csc867/myscheduler
             name = patients
        """
        result = re.compile("\{(.*)\}(.*)").search(tag)
        if result:
            # print(tag)
            value.namespace, tag = result.groups()
        return (tag, value)

    @classmethod
    def parse(self, file):
        """parse a xml file to a dict"""
        f = open(file, 'r')
        return self.fromstring(f.read())

    @classmethod
    def fromstring(self, s):
        """parse a string"""
        t = ET.fromstring(s)
        root_tag, root_tree = self._namespace_split(t.tag, self._parse_node(t))
        return object_dict({root_tag: root_tree})



if __name__ == '__main__':
    s = """<?xml version="1.0" encoding="utf-8" ?>
    <result>
        <count n="1">10</count>
        <data><id>491691</id><name>test</name></data>
        <data><id>491692</id><name>test2</name></data>
        <data><id>503938</id><name>hello, world</name></data>
    </result>"""

    xml = XML2Dict()
    r = xml.fromstring(s)
    from pprint import pprint
    pprint(r)
    print(r.result.count.value)
    print(r.result.count.n)

    for data in r.result.data:
        print(data.id, data.name)
    # pprint(xml.parse('a'))