Mark Mark - 3 months ago 47
Python Question

lxml etree xmlparser remove unwanted namespace

I have an xml doc that I am trying to parse using Etree.lxml

<Envelope xmlns="http://www.example.com/zzz/yyy">
<Header>
<Version>1</Version>
</Header>
<Body>
some stuff
<Body>
<Envelope>


My code is:

path = "path to xml file"
from lxml import etree as ET
parser = ET.XMLParser(ns_clean=True)
dom = ET.parse(path, parser)
dom.getroot()


When I try to get dom.getroot() I get:

<Element {http://www.example.com/zzz/yyy}Envelope at 28adacac>


However I only want:

<Element Envelope at 28adacac>


When i do

dom.getroot().find("Body")


I get nothing returned. However, when I

dom.getroot().find("{http://www.example.com/zzz/yyy}Body")


I get a result.

I thought passing ns_clean=True to the parser would prevent this.

Any ideas?

Answer
import io
import lxml.etree as ET

content='''\
<Envelope xmlns="http://www.example.com/zzz/yyy">
  <Header>
    <Version>1</Version>
  </Header>
  <Body>
    some stuff
  </Body>
</Envelope>
'''    
dom = ET.parse(io.BytesIO(content))

You can find namespace-aware nodes using the xpath method:

body=dom.xpath('//ns:Body',namespaces={'ns':'http://www.example.com/zzz/yyy'})
print(body)
# [<Element {http://www.example.com/zzz/yyy}Body at 90b2d4c>]

If you really want to remove namespaces, you could use an XSL transformation:

# http://wiki.tei-c.org/index.php/Remove-Namespaces.xsl
xslt='''<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" indent="no"/>

<xsl:template match="/|comment()|processing-instruction()">
    <xsl:copy>
      <xsl:apply-templates/>
    </xsl:copy>
</xsl:template>

<xsl:template match="*">
    <xsl:element name="{local-name()}">
      <xsl:apply-templates select="@*|node()"/>
    </xsl:element>
</xsl:template>

<xsl:template match="@*">
    <xsl:attribute name="{local-name()}">
      <xsl:value-of select="."/>
    </xsl:attribute>
</xsl:template>
</xsl:stylesheet>
'''

xslt_doc=ET.parse(io.BytesIO(xslt))
transform=ET.XSLT(xslt_doc)
dom=transform(dom)

Here we see the namespace has been removed:

print(ET.tostring(dom))
# <Envelope>
#   <Header>
#     <Version>1</Version>
#   </Header>
#   <Body>
#     some stuff
#   </Body>
# </Envelope>

So you can now find the Body node this way:

print(dom.find("Body"))
# <Element Body at 8506cd4>