ncclient:NETCONF Python client

# Copyright 2009 Shikhar Bhushan

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

#    http://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

"""The :mod:`xml_` module provides methods for creating, parsing, and dealing

with XML. It uses :mod:`~xml.etree.ElementTree`."""

from cStringIO import StringIO

from xml.etree import cElementTree as ET

from ncclient import NCClientError

class XMLError(NCClientError):

    pass

### Namespace-related

#: Base NETCONF namespace

BASE_NS_1_0 = 'urn:ietf:params:xml:ns:netconf:base:1.0'

#: Namespace for Tail-f core data model

TAILF_AAA_1_1 = 'http://tail-f.com/ns/aaa/1.1'

#: Namespace for Tail-f execd data model

TAILF_EXECD_1_1 = 'http://tail-f.com/ns/execd/1.1'

#: Namespace for Cisco data model

CISCO_CPI_1_0 = 'http://www.cisco.com/cpi_10/schema'

#: Namespace for Flowmon data model

FLOWMON_1_0 = 'http://www.liberouter.org/ns/netopeer/flowmon/1.0'

try:

    register_namespace = ET.register_namespace

except AttributeError:

    def register_namespace(prefix, uri):

        from xml.etree import ElementTree

        # cElementTree uses ElementTree's _namespace_map, so that's ok

        ElementTree._namespace_map[uri] = prefix

prefix_map = {

    BASE_NS_1_0: 'nc',

    TAILF_AAA_1_1: 'aaa',

    TAILF_EXECD_1_1: 'execd',

    CISCO_CPI_1_0: 'cpi',

    FLOWMON_1_0: 'fm',

}

for (ns, pre) in prefix_map.items():

    register_namespace(pre, ns)

qualify = lambda tag, ns=BASE_NS_1_0: tag if ns is None else '{%s}%s' % (ns, tag)

#unqualify = lambda tag: tag[tag.rfind('}')+1:]

def to_xml(ele, encoding="UTF-8"):

    """Convert an :class:`~xml.etree.ElementTree.Element` to XML.

    :arg ele: the :class:`~xml.etree.ElementTree.Element`

    :arg encoding: character encoding

    :rtype: :obj:`string`

    """

    xml = ET.tostring(ele, encoding)

    return xml if xml.startswith('<?xml') else '<?xml version="1.0" encoding="%s"?>%s' % (encoding, xml)

def to_ele(x):

    """Convert XML to :class:`~xml.etree.ElementTree.Element`.

    :type xml: :obj:`string`

    :rtype: :class:`~xml.etree.ElementTree.Element`

    """

    return x if iselement(x) else ET.fromstring(x)

iselement = ET.iselement

def parse_root(raw):

    """Efficiently parses the root element of an XML document.

    :arg raw: XML document

    :returns: a tuple of `(tag, attrib)`, where *tag* is the (qualified)

    name of the element and *attrib* is a dictionary of its attributes.

    :rtype: `tuple`

    """

    fp = StringIO(raw)

    for event, element in ET.iterparse(fp, events=('start',)):

        return (element.tag, element.attrib)

def validated_element(x, tags=None, attrs=None):

    """Checks if the root element of an XML document or

    :class:`~xml.etree.ElementTree.Element` meets the supplied criteria. Raises

    :exc:`XMLError` if it is not met.

    :arg x: the XML document or :class:`~xml.etree.ElementTree.Element` to validate

    :arg tags: tag name or a sequence of allowable tag names

    :arg attrs: sequence of required attribute names, each item may be a list of allowable alternatives

    :returns: validated element

    :rtype: :class:`~xml.etree.ElementTree.Element`

    """

    ele = to_ele(x)

    if tags:

        if isinstance(tags, basestring):

            tags = [tags]

        if ele.tag not in tags:

            raise XMLError("Element [%s] does not meet requirement" % ele.tag)

    if attrs:

        for req in attrs:

            if isinstance(req, basestring): req = [req]

            for alt in req:

                if alt in ele.attrib:

                    break

            else:

                raise XMLError("Element [%s] does not have required attributes" % ele.tag)

    return ele

def new_ele(tag, attrs={}, **extra):

    return ET.Element(tag, attrs, **extra)

def sub_ele(parent, tag, attrs={}, **extra):

    return ET.SubElement(parent, tag, attrs, **extra)