JSON to XML

Let’s say you want to fetch a JSON object from a URL and convert it into XML. Here’s how you can do that:

>>> import json
>>> import urllib
>>> import dicttoxml2
>>> page = urllib.urlopen('http://quandyfactory.com/api/example')
>>> content = page.read()
>>> obj = json.loads(content)
>>> print(obj)
{u'mylist': [u'foo', u'bar', u'baz'], u'mydict': {u'foo': u'bar', u'baz': 1}, u'ok': True}
>>> xml = dicttoxml2.dicttoxml(obj)
>>> print(xml)
<?xml version="1.0" encoding="UTF-8" ?><root><mylist><item type="str">foo</item><item type="str">bar</item><item type="str">baz</item></mylist><mydict><foo type="str">bar</foo><baz type="int">1</baz></mydict><ok type="bool">true</ok></root>

It’s that simple.

Disable Type Attributes

By default, dicttoxml includes a type attribute for each element. Starting in version 1.4, you can turn this off by passing an optional attr_type=False argument to the dicttoxml method.

Using our example:

>>> xml = dicttoxml2.dicttoxml(obj, attr_type=False)
>>> print(xml)
<?xml version="1.0" encoding="UTF-8" ?><root><mydict><foo>bar</foo><baz>1</baz></mydict><mylist><item>foo</item><item>bar</item><item>baz</item></mylist><ok>true</ok></root>

As you can see, the only difference is that the type attributes are now absent.

Custom Root

By default, dicttoxml wraps all the elements in a <root> … </root> element. Starting in version 1.5, you can change the name of the root element to something else by passing an optional custom_root=some_custom_root argument to the dicttoxml method.

Using our example:

>>> xml = dicttoxml2.dicttoxml(obj, custom_root='some_custom_root')
>>> print(xml)
<?xml version="1.0" encoding="UTF-8" ?><some_custom_root><mydict><foo>bar</foo><baz>1</baz></mydict><mylist><item>foo</item><item>bar</item><item>baz</item></mylist><ok>true</ok></some_custom_root>

As you can see, the name of the root element has changed to some_custom_root.

XML Snippet

You can also create an XML snippet for inclusion into another XML document, rather than a full XML document itself.

Continuing with the example from above:

>>> xml_snippet = dicttoxml2.dicttoxml(obj, root=False)
>>> print(xml_snippet)
<mylist><item type="str">foo</item><item type="str">bar</item><item type="str">baz</item></mylist><mydict><foo type="str">bar</foo><baz type="int">1</baz></mydict><ok type="bool">true</ok>

With the optional root argument set to False, the method converts the dict into XML without including an <?xml> prolog or a <root> element to enclose all the other elements.

Pretty-Printing

As they say, Python comes with batteries included. You can easily syntax-check and pretty-print your XML using Python’s xml.dom.minidom module.

Again, continuing with our example:

>>> from xml.dom.minidom import parseString
>>> dom = parseString(xml)
>>> print(dom.toprettyxml())
<?xml version="1.0" ?>
<root>
    <mylist type="list">
        <item type="str">foo</item>
        <item type="str">bar</item>
        <item type="str">baz</item>
    </mylist>
    <mydict type="dict">
        <foo type="str">bar</foo>
        <baz type="int">1</baz>
    </mydict>
    <ok type="bool">true</ok>
</root>

This makes the XML easier to read. If it is not well-formed, the xml parser will raise an exception.

Unique ID Attributes

Starting in version 1.1, you can set an optional ids parameter so that dicttoxml gives each element a unique id attribute.

With the ids flag on, the function generates a unique randomly-generated ID for each element based on the parent element in the form parent_unique. For list items, the id is in the form parent_unique_index.

Continuing with our example:

>>> xml_with_ids = dicttoxml2.dicttoxml(obj, ids=True)
>>> print(parseString(xml_with_ids).toprettyxml())
<?xml version="1.0" ?>
<root>
        <mylist id="root_160980" type="list">
                <item id="mylist_609405_1" type="str">foo</item>
                <item id="mylist_609405_2" type="str">bar</item>
                <item id="mylist_609405_3" type="str">baz</item>
        </mylist>
        <mydict id="root_140407" type="dict">
                <foo id="mydict_260437" type="str">bar</foo>
                <baz id="mydict_111194" type="int">1</baz>
        </mydict>
        <ok id="root_612831" type="bool">true</ok>
</root>

Note that the default XML output remains the same as previous, so as not to break compatibility for existing uses.

Dict-Like and Iterable Objects

Starting in version 1.3, dicttoxml accepts dict-like objects that are derived from the dict base class and treats them like dicts. For example:

>>> import collections
>>> dictlike = collections.OrderedDict({'foo': 1, 'bar': 2, 'baz': 3})
>>> xml = dicttoxml.dicttoxml(dictlike)
>>> print(xml)
<?xml version="1.0" encoding="UTF-8" ?><root><baz type="int">3</baz><foo type="int">1</foo><bar type="int">2</bar></root>

Also starting in version 1.3, dicttoxml accepts iterable objects and treats them like lists. For example:

>>> myiterator = xrange(1,11)
>>> xml = dicttoxml.dicttoxml(myiterator)
>>> print(xml)
<?xml version="1.0" encoding="UTF-8" ?><root><item type="int">1</item><item type="int">2</item><item type="int">3</item><item type="int">4</item><item type="int">5</item><item type="int">6</item><item type="int">7</item><item type="int">8</item><item type="int">9</item><item type="int">10</item></root>

As always, this remains compatible with arbitrary nesting of objects and types.

Define Custom Item Names

Starting in version 1.7, if you don’t want item elements in a list to be called ‘item’, you can specify the element name using a function that takes the parent element name (i.e. the list name) as an argument.

>>> import dicttoxml2
>>> obj = {u'mylist': [u'foo', u'bar', u'baz'], u'mydict': {u'foo': u'bar', u'baz': 1}, u'ok': True}
>>> my_item_func = lambda x: 'list_item'
>>> xml = dicttoxml2.dicttoxml(obj, item_func=my_item_func)
>>> print(xml)
<?xml version="1.0" encoding="UTF-8" ?><root><mydict type="dict"><foo type="str">bar</foo><baz type="int">1</baz></mydict><mylist type="list"><list_item type="str">foo</list_item><list_item type="str">bar</list_item><list_item type="str">baz</list_item></mylist><ok type="bool">True</ok></root>

The benefit of taking the parent element name as an argument is that you can write the function to do something with it. Let’s say you have an object with some lists of specific items:

>>> obj = {'shrubs': ['abelia', 'aralia', 'aucuba', 'azalea', 'bamboo', 'barberry', 'bluebeard', 'boxwood', 'camellia', 'dogwood', 'elderberry', 'enkianthus', 'firethorn', 'fuchsia', 'hazel', 'heath', 'heather', 'holly', 'honeysuckle', 'hydrangea', 'laurel', 'lilac', 'mock orange', 'rhododendron', 'rose', 'rose of sharon', 'rosemary', 'smokebush', 'spirea', 'sweetbox', 'viburnum', 'weigela', 'yucca'], 'trees': ['ash', 'aspen', 'birch', 'butternut', 'cedar', 'cottonwood', 'elm', 'fir', 'hawthorn', 'larch', 'locust', 'maple', 'oak', 'pine', 'spruce', 'sycamore', 'willow']}

You can define each item name to be the singular of its parent name by returning all but the last character.

>>> my_item_func = lambda x: x[:-1]
>>> xml = dicttoxml.dicttoxml(obj, item_func=my_item_func)
>>> print(xml)
<?xml version="1.0" encoding="UTF-8" ?><root><shrubs type="list"><shrub type="str">abelia</shrub><shrub type="str">aralia</shrub><shrub type="str">aucuba</shrub><shrub type="str">azalea</shrub><shrub type="str">bamboo</shrub><shrub type="str">barberry</shrub><shrub type="str">bluebeard</shrub><shrub type="str">boxwood</shrub><shrub type="str">camellia</shrub><shrub type="str">dogwood</shrub><shrub type="str">elderberry</shrub><shrub type="str">enkianthus</shrub><shrub type="str">firethorn</shrub><shrub type="str">fuchsia</shrub><shrub type="str">hazel</shrub><shrub type="str">heath</shrub><shrub type="str">heather</shrub><shrub type="str">holly</shrub><shrub type="str">honeysuckle</shrub><shrub type="str">hydrangea</shrub><shrub type="str">laurel</shrub><shrub type="str">lilac</shrub><shrub type="str">mock orange</shrub><shrub type="str">rhododendron</shrub><shrub type="str">rose</shrub><shrub type="str">rose of sharon</shrub><shrub type="str">rosemary</shrub><shrub type="str">smokebush</shrub><shrub type="str">spirea</shrub><shrub type="str">sweetbox</shrub><shrub type="str">viburnum</shrub><shrub type="str">weigela</shrub><shrub type="str">yucca</shrub></shrubs><trees type="list"><tree type="str">ash</tree><tree type="str">aspen</tree><tree type="str">birch</tree><tree type="str">butternut</tree><tree type="str">cedar</tree><tree type="str">cottonwood</tree><tree type="str">elm</tree><tree type="str">fir</tree><tree type="str">hawthorn</tree><tree type="str">larch</tree><tree type="str">locust</tree><tree type="str">maple</tree><tree type="str">oak</tree><tree type="str">pine</tree><tree type="str">spruce</tree><tree type="str">sycamore</tree><tree type="str">willow</tree></trees></root>

Of course, this can be combined with other optional arguments, like disabling type attributes or custom root element names.

CDATA

Starting in version 1.7.1, you can wrap values in CDATA by setting the optional cdata argument to True.

>>> import dicttoxml2
>>> obj = {u'mylist': [u'foo', u'bar', u'baz'], u'mydict': {u'foo': u'bar', u'baz': 1}, u'ok': True}
>>> xml = dicttoxml2.dicttoxml(obj, cdata=True)
>>> print(xml)
<?xml version="1.0" encoding="UTF-8" ?><root><mydict type="dict"><foo type="str"><![CDATA[bar]]></foo><baz type="int"><![CDATA[1]]></baz></mydict><mylist type="list"><item type="str"><![CDATA[foo]]></item><item type="str"><![CDATA[bar]]></item><item type="str"><![CDATA[baz]]></item></mylist><ok type="bool"><![CDATA[True]]></ok></root>

If you do not set cdata to True, the default value is False and values are not wrapped.

Debugging

You can enable debugging information.

>>> import dicttoxml2
>>> dicttoxml2.set_debug()
Debug mode is on. Events are logged at: dicttoxml.log
>>> xml = dicttoxml.dicttoxml(some_dict)

By default, debugging information is logged to dicttoxml.log, but you can change this:

>>> dicttoxml2.set_debug(filename='some_other_filename.log')
Debug mode is on. Events are logged at: some_other_filename.log

To turn debug mode off, just call set_debug with an argument of False:

>>> dicttoxml2.set_debug(False)
Debug mode is off.

If you encounter any errors in the code, please file an issue on github: [https://github.com/Ousret/dicttoxml/issues](https://github.com/Ousret/dicttoxml/issues).

List Folding

You may want to make list folding act differently. To do so, please set the parameter fold_list=False.

Example:

{‘book’: [{‘title’: ‘Python Programming’, ‘license’: ‘GPL’, ‘author’: [‘Adam’, ‘Benny’, ‘Charlie’]}, {‘license’: ‘Apache 2.0’, ‘title’: ‘Business Modelling’}]}

Code:

>>> dicttoxml2.dicttoxml(payload, fold_list=False, attr_type=False)

Output:

<?xml version="1.0" encoding="UTF-8" ?> <root>

<book>

<title>Python Programming</title> <license>GPL</license> <author>Adam</author> <author>Benny</author> <author>Charlie</author>

</book> <book>

<license>Apache 2.0</license> <title>Business Modelling</title>

</book>

</root>