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.

"All to do with NETCONF <hello> messages"

from xml.etree import cElementTree as ET

from ncclient.glue import Listener

from ncclient.content import TreeBuilder, BASE_NS

from ncclient.content import qualify as _

from ncclient.content import unqualify as __

def build(capabilities, encoding='utf-8'):

    "Given a list of capability URI's returns encoded <hello> message"

    spec = {

        'tag': _('hello', BASE_NS),

        'children': [{

            'tag': 'capabilities',

            'children': # this is fun :-)

                [{ 'tag': 'capability', 'text': uri} for uri in capabilities]

            }]

        }

    return TreeBuilder(spec).to_string(encoding)

def parse(raw):

    "Returns tuple of (session-id, ['capability_uri', ...])"

    sid, capabilities = 0, []

    root = ET.fromstring(raw)

    for child in root.getchildren():

        if __(child.tag) == 'session-id':

            sid = child.text

        elif __(child.tag) == 'capabilities':

            for cap in child.getiterator(_('capability', BASE_NS)):

                capabilities.append(cap.text)

            # cisco doesn't namespace hello message

            for cap in child.getiterator('capability'): 

                capabilities.append(cap.text)

    return sid, capabilities

class HelloListener(Listener):

    def __init__(self, init_cb, error_cb):

        self._init_cb, self._error_cb = init_cb, error_cb

    def __str__(self):

        return 'HelloListener'

    def callback(self, root, raw):

        if __(root[0]) == 'hello':

            try:

                id, capabilities = parse(raw)

            except Exception as e:

                self._error_cb(e)

            else:

                self._init_cb(id, capabilities)

    def errback(self, err):

        self._error_cb(err)