New subject: [lxml-dev] is there a lxml deb package ?

Sept. 15, 2005

      I've attached a piece of code that I wrote to make dealing with
namespaces a bit easier in lxml and ElementTree. You create a namespace
object with the short prefix and the URI of the namespace. You generate
fully qualified tag names through __getattr__ hackery (or __getitem__
hackery if the tag isn't a valid Python identifier).

  rdf = XMLNS('rdf', 'http://www.w3.org/1999/02/22-rdf-syntax-ns#')
  xsl = XMLNS('xsl', 'http://www.w3.org/1999/XSL/Transform')
  dc = XMLNS('dc', 'http://purl.org/dc/elements/1.1/')
  rdf.RDF == '{http://www.w3.org/1999/02/22-rdf-syntax-ns#}RDF'
  xsl['value-of'] == '{http://www.w3.org/1999/XSL/Transform}value-of'

Also, there's a convenience function nsmap(*args) which will create the
appropriate dictionary for passing to the nsmap keyword argument of
etree.Element(). E.g.

  etree.Element(rdf.RDF, nsmap=nsmap(rdf, dc))

I've found this to be quite handy.

-- 
Robert Kern
rkern@ucsd.edu

"In the fields of hell where the grass grows high
 Are the graves of dreams allowed to die."
  -- Richard Harter

#*****************************************************************************
#       Copyright (C) 2005 Robert Kern. All rights reserved.
#
#  Distributed under the terms of the BSD License.  The full license is in
#  the file COPYING, distributed as part of this software.
#*****************************************************************************

class XMLNS(object):
    """Convenience object for handling namespaced tag names in ElementTree-like
    APIs.

    ElementTree-like APIs use an inconvenient syntax for representing tags
    within namespaces. E.g.

        rdf:RDF -> {http://www.w3.org/1999/02/22-rdf-syntax-ns#}RDF
        dc:creator -> {http://purl.org/dc/elements/1.1/}creator

    Instances of XMLNS use __getattr__ magic to generate tags with this syntax.
    You can also use __getitem__ for those tags which are not valid Python
    identifiers.

        rdf = XMLNS('rdf', 'http://www.w3.org/1999/02/22-rdf-syntax-ns#')
        xsl = XMLNS('xsl', 'http://www.w3.org/1999/XSL/Transform')
        rdf.RDF == '{http://www.w3.org/1999/02/22-rdf-syntax-ns#}RDF'
        xsl['value-of'] == '{http://www.w3.org/1999/XSL/Transform}value-of'

    Constructor:
        XMLNS(prefix, url)
    """
    def __init__(self, prefix, url):
        self._url = url
        self._qname_prefix = u'{%s}'%url
        self._prefix = prefix

    def __getitem__(self, tag):
        return self._qname_prefix + tag
    __getattr__ = __getitem__

def nsmap(*args):
    """Create a dictionary mapping prefixes to namespace URLs from XMLNS
    instances.
    """
    d = {}
    for ns in args:
        d[ns._prefix] = ns._url
    return d

rdf = XMLNS('rdf', 'http://www.w3.org/1999/02/22-rdf-syntax-ns#')
dc = XMLNS('dc', 'http://purl.org/dc/elements/1.1/')
xsl = XMLNS('xsl', 'http://www.w3.org/1999/XSL/Transform')

[lxml-dev] Useful snippet: namespace objects

Robert Kern

Andrey Tatarinov

manatlan

Andrey Tatarinov

Olivier Grisel

manatlan

manatlan

manatlan

Olivier Grisel

manatlan

Martijn Faassen

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