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.

"Methods for creating, parsing, and dealing with XML and ElementTree objects."

from cStringIO import StringIO

from xml.etree import cElementTree as ET

# in case problems occur include the ElementTree file from the parent dir

# import ElementTree 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"

#: Namespace for Juniper 9.6R4

JUNIPER_1_1 = "http://xml.juniper.net/xnm/1.1/xnm"

#

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

register_namespace.func_doc = "ElementTree's namespace map determines the prefixes for namespace URI's when serializing to XML. This method allows modifying this map to specify a prefix for a namespace URI."

for (ns, pre) in {

    BASE_NS_1_0: 'nc',

    TAILF_AAA_1_1: 'aaa',

    TAILF_EXECD_1_1: 'execd',

    CISCO_CPI_1_0: 'cpi',

    FLOWMON_1_0: 'fm',

    JUNIPER_1_1: 'junos',

}.items(): 

    register_namespace(pre, ns)

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

"""Qualify a *tag* name with a *namespace*, in :mod:`~xml.etree.ElementTree` fashion i.e. *{namespace}tagname*."""

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

    "Convert and return the XML for an *ele* (:class:`~xml.etree.ElementTree.Element`) with specified *encoding*."

    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 and return the :class:`~xml.etree.ElementTree.Element` for the XML document *x*. If *x* is already an :class:`~xml.etree.ElementTree.Element` simply returns that."

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

def parse_root(raw):

    "Efficiently parses the root element of a *raw* XML document, returning a tuple of its qualified name and attribute dictionary."

    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 Element meets the supplied criteria.

    *tags* if specified is either a single allowable tag name or sequence of allowable alternatives

    *attrs* if specified is a sequence of required attributes, each of which may be a sequence of several allowable alternatives

    Raises :exc:`XMLError` if the requirements are not met.

    """

    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

new_ele = lambda tag, attrs={}, **extra: ET.Element(qualify(tag), attrs, **extra)

sub_ele = lambda parent, tag, attrs={}, **extra: ET.SubElement(parent, qualify(tag), attrs, **extra)