get the namespaces from xml with python ElementTree

Question

I use python 2.7 with the lib ElementTree.

I can't use lxml lib.

I need to get the namespaces in a string namespace_string. In order to fill my namespace dictionary.

my xml:

<?xml version="1.0" encoding="UTF-8"?>
<AX_Bestandsdatenauszug
    xmlns="http://www.adv-online.de/namespaces/adv/gid/6.0"
    xmlns:adv="http://www.adv-online.de/namespaces/adv/gid/6.0"
    xmlns:gco="http://www.isotc211.org/2005/gco"
    xmlns:gmd="http://www.isotc211.org/2005/gmd"
    xmlns:gml="http://www.opengis.net/gml/3.2"
    xmlns:ows="http://www.opengis.net/ows"
    xmlns:wfs="http://www.adv-online.de/namespaces/adv/gid/wfs"
    xmlns:wfsext="http://www.adv-online.de/namespaces/adv/gid/wfsext"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema"
    xmlns:xlink="http://www.w3.org/1999/xlink"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:ogc="http://www.adv-online.de/namespaces/adv/gid/ogc"
    xsi:schemaLocation="http://www.adv-online.de/namespaces/adv/gid/6.0 NAS-Operationen.xsd">

    <enthaelt>
            <gml:featureMember>
            <xmlstuff>....a lot of xml stuff....</xmlstuff>
            </gml:featureMember>
    </enthaelt>
</AX_Bestandsdatenauszug>

code:

import clr
import sys

clr.AddReference('ProtoGeometry')
from Autodesk.DesignScript.Geometry import *
sys.path.append("C:\Program Files (x86)\IronPython 2.7\Lib")
import xml.etree.ElementTree as ET
from io import StringIO


xml="file.xml"

tree = ET.parse(xml)
root = tree.getroot()


my_schema = "namespace_string"

my_namespaces = dict([node for _, node in ET.iterparse(StringIO(my_schema), events=['start-ns'])])

The code for the dictionary is from this answer:https://stackoverflow.com/a/37409050/7317684

I tryed namespace_string=root.tag but this get me only ="{http://www.adv-online.de/namespaces/adv/gid/6.0}AX_Bestandsdatenauszug"

Found only lxml solutions:(

Any help would be great!

mzjn · Answer 1 · 2017-02-22T10:04:08.407

9

The code for creating a dictionary with all the declared namespaces can be made quite simple. This is all that is needed:

import xml.etree.ElementTree as ET

my_namespaces = dict([node for _, node in ET.iterparse('file.xml',
                                                        events=['start-ns'])])

You don't need to use StringIO or open(). Just provide the XML filename as an argument to iterparse().

Each item provided by iterparse() is an (event, (prefix, namespace-uri)) tuple. The start-ns event is not described in the Python 2.7 documentation of iterparse (but it is mentioned in the corresponding Python 3 documentation).

Note: the code above works in CPython and Jython, but not in IronPython. See https://github.com/IronLanguages/main/issues/968.

edited Feb 22 '17 at 10:04

answered Feb 21 '17 at 16:10

mzjn

48,958
13
128
248

I forgot to mention, that i use IronPython 2.7. I didn't know thats this was important. I got a error that say: IronPython don't support `iterparse`. But oddly that was not the case with the code of **saurabhsuman** the error did not occur. – Yuli Feb 22 '17 at 09:09
It should work with IronPython 2.7.9. See https://github.com/IronLanguages/ironpython2/issues/370. – mzjn Oct 23 '18 at 15:27

saurabhsuman4797 · Answer 2 · 2017-02-20T11:18:48.597

3

You should pass the contents of the xml file in ET.iterparse() instead of string my_schema.

Change your code to:

from io import StringIO
import xml.etree.ElementTree as ET

xml = "file.xml"
f = open(xml, "r")
xml_data = unicode(f.read() , "utf-8") 
my_namespaces = dict([node for _, node in ET.iterparse(StringIO(xml_data), events=['start-ns'])])

from pprint import pprint
pprint(my_namespaces)

Output:

{'': 'http://www.adv-online.de/namespaces/adv/gid/6.0',
 u'adv': 'http://www.adv-online.de/namespaces/adv/gid/6.0',
 u'gco': 'http://www.isotc211.org/2005/gco',
 u'gmd': 'http://www.isotc211.org/2005/gmd',
 u'gml': 'http://www.opengis.net/gml/3.2',
 u'ogc': 'http://www.adv-online.de/namespaces/adv/gid/ogc',
 u'ows': 'http://www.opengis.net/ows',
 u'wfs': 'http://www.adv-online.de/namespaces/adv/gid/wfs',
 u'wfsext': 'http://www.adv-online.de/namespaces/adv/gid/wfsext',
 u'xlink': 'http://www.w3.org/1999/xlink',
 u'xsd': 'http://www.w3.org/2001/XMLSchema',
 u'xsi': 'http://www.w3.org/2001/XMLSchema-instance'}

edited Feb 20 '17 at 11:18

answered Feb 20 '17 at 07:04

saurabhsuman4797

71
1
7

Thx for your help, but i got a `ValueError: write to closed file` in this line: `my_namespaces = dict([node for _, node in ET.iterparse(StringIO(xml_data), events=['start-ns'])])`. – Yuli Feb 20 '17 at 10:21
can you check now with the edited code, the line `my_namespaces = dict([node for _, node in ET.iterparse(StringIO(xml_data), events=['start-ns'])])` should be within with block. – saurabhsuman4797 Feb 20 '17 at 10:26
The same error in the same line appears with the codeline in the block. – Yuli Feb 20 '17 at 10:36
can you check now with the edited code, it is working on my side – saurabhsuman4797 Feb 20 '17 at 11:17
Can you post the stack trace – saurabhsuman4797 Feb 20 '17 at 11:31
Im working with Dynamo for Revit, The hole Errormessage is: `Warning: IronPythonEvaluator.EvaluateIronPythonScript operation failed. Traceback (most recent call last): File "", line 20, in ValueError: write to closed file` – Yuli Feb 20 '17 at 12:14

get the namespaces from xml with python ElementTree

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