get attribute from xml-node with specific value

Question

I have an XSD-file where I need to get a namespace as defined in the root-tag:

<schema xmlns="http://www.w3.org/2001/XMLSchema" xmlns:abw="http://www.liegenschaftsbestandsmodell.de/ns/abw/1.0.1.0" xmlns:adv="http://www.adv-online.de/namespaces/adv/gid/6.0" xmlns:bfm="http://www.liegenschaftsbestandsmodell.de/ns/bfm/1.0" xmlns:gml="http://www.opengis.net/gml/3.2" xmlns:sc="http://www.interactive-instruments.de/ShapeChange/AppInfo" elementFormDefault="qualified" targetNamespace="http://www.liegenschaftsbestandsmodell.de/ns/abw/1.0.1.0" version="1.0.1.0">
  <!-- elements -->
</schema>

Now as the targetNamespace of this schema-definition is "http://www.liegenschaftsbestandsmodell.de/ns/abw/1.0.1.0" I need to get the short identifier for this namespace - which is abw. To get this identifier I have to get that attribute from the root-tag that has the exact same value as my targetNamespace (I can´t rely on the identifier beeing part of the targetNamespace-string allready, this may change in the future).

On this question How to extract xml attribute using Python ElementTree I found how to get the value of an attribute given by its name. However I don´t know the attributes name, only its value, so what can I do when I have a value and want to select the attribute having this value?

I think of something like this:

for key in root.attrib.keys():
    if(root.attrib[key] == targetNamespace):
        return root.attrib[key]

but root.attrib only contains elementFormDefault, targetNamespace and version, but not xmlns:abw.

do you want to search name spaces

Hisham Karam
– Hisham Karam

2016-10-19 07:58:07 +00:00
Commented Oct 19, 2016 at 7:58 — Hisham Karam
– Hisham Karam, Commented Oct 19, 2016 at 7:58

Hisham Karam · Accepted Answer · 2016-10-19 07:39:40Z

1

string must be Unicode else error will appear

Traceback (most recent call last):
  File "<pyshell#62>", line 1, in <module>
    it = etree.iterparse(StringIO(xml))
TypeError: initial_value must be unicode or None, not str

code:

>>> from io import StringIO
>>> from xml.etree import ElementTree
>>> xml=u"""<schema xmlns="http://www.w3.org/2001/XMLSchema" xmlns:abw="http://www.liegenschaftsbestandsmodell.de/ns/abw/1.0.1.0" xmlns:adv="http://www.adv-online.de/namespaces/adv/gid/6.0" xmlns:bfm="http://www.liegenschaftsbestandsmodell.de/ns/bfm/1.0" xmlns:gml="http://www.opengis.net/gml/3.2" xmlns:sc="http://www.interactive-instruments.de/ShapeChange/AppInfo" elementFormDefault="qualified" targetNamespace="http://www.liegenschaftsbestandsmodell.de/ns/abw/1.0.1.0" version="1.0.1.0">
  <!-- elements -->
</schema>"""
>>> ns = dict([
    node for _, node in ElementTree.iterparse(
        StringIO(xml), events=['start-ns']
    )
])
>>> for k,v in ns.iteritems():
    if v=='http://www.liegenschaftsbestandsmodell.de/ns/abw/1.0.1.0':
        print k

output:

abw

edited Oct 19, 2016 at 7:39

answered Oct 19, 2016 at 6:57

Hisham Karam

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3 Comments

MakePeaceGreatAgain Over a year ago

This seems to work, however I don´t understand the dictionaries definition using the for-loop node for _, node in ...

Hisham Karam Over a year ago

@HimBromBeere look at name space section link

Hisham Karam Over a year ago

@HimBromBeere iterparse return the event and element i ignored event . element as tupel containing namespace and value the i converted the result into dict for easy search

MakePeaceGreatAgain · Accepted Answer · 2016-10-19 08:19:10Z

0

Using minidom instead of ETree did it:

import xml.dom.minidom as DOM
tree = DOM.parse(myFile)
root = tree.documentElement
targetNamespace = root.getAttribute("targetNamespace")

d = dict(root.attributes.items())
for key in d:
    if d[key] == targetNamespace: return key

This will return either targetNamespace or xmlns:abw depending on what comes first in the xsd. Of course we should ignore the first case, but this goes out of scope of this question.

edited Oct 19, 2016 at 8:19

answered Oct 19, 2016 at 7:59

MakePeaceGreatAgain

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3 Comments

Hisham Karam Over a year ago

Traceback (most recent call last):   File "<pyshell#154>", line 1, in <module>     targetNamespace = root.getattribute("targetNamespace") AttributeError: Element instance has no attribute 'getattribute'

Hisham Karam Over a year ago

getAttribute instead of getattribute

MakePeaceGreatAgain Over a year ago

@HishamKaram Thank you for the hint, updated accordingly.

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