Question

I have a Solace JMS Messaging Box which I am automating the administration of, and the device uses lots of very small XML posts to configure. Since the device has so very many commands in its XML spec, I need a way to create arbitrary XML requests.

The XML looks like:

<rpc semp-version="soltr/5_5">
<create>
<message-vpn>
<vpn-name>developer.testvpn</vpn-name>
</message-vpn>
</create>
</rpc>

And a second call to change a setting might look like this:

<rpc semp-version="soltr/5_5">
<message-vpn>
<vpn-name>developer.testvpn</vpn-name>
<export-policy>
<no>
<export-subscriptions/>
</no>
</export-policy>
</message-vpn>
</rpc>

Since there are many commands in the XML spec, I’m looking for a way to create them freely from something like dot name space. eg:

mycall = SolaceXML()
mycall.create.message_vpn.vpn_name="developer.testvpn"
mycall.message_vpn.vpn_name='developer.testvpn'
mycall.message_vpn.export_policy.no.export_subscription

UPDATE
I have posted my solution below. Its not as small as I’d like it but it works for me.

K

Answer 1

I have found a solution in the mean time. Hopefully this helps someone else. This solution builds nested dictionary objects from dot name space calls, and then converts it to XML.

from xml.dom.minidom import Document
import copy
import re
from collections import OrderedDict

class d2x:
    ''' Converts Dictionary to XML '''
    def __init__(self, structure):
        self.doc = Document()
        if len(structure) == 1:
            rootName = str(structure.keys()[0])
            self.root = self.doc.createElement(rootName)
            self.doc.appendChild(self.root)
            self.build(self.root, structure[rootName])

    def build(self, father, structure):
        if type(structure) == dict:
            for k in structure:
                tag = self.doc.createElement(k)
                father.appendChild(tag)
                self.build(tag, structure[k])
        elif type(structure) == OrderedDict:
            for k in structure:
                tag = self.doc.createElement(k)
                father.appendChild(tag)
                self.build(tag, structure[k])

        elif type(structure) == list:
            grandFather = father.parentNode
            tagName = father.tagName
            grandFather.removeChild(father)
            for l in structure:
                tag = self.doc.createElement(tagName)
                self.build(tag, l)
                grandFather.appendChild(tag)

        else:
            data = str(structure)
            tag = self.doc.createTextNode(data)
            father.appendChild(tag)

    def display(self):
        # I render from the root instead of doc to get rid of the XML header
        #return self.root.toprettyxml(indent="  ")
        return self.root.toxml()

class SolaceNode:
    ''' a sub dictionary builder '''
    def __init__(self):
        self.__dict__ = OrderedDict()
    def __getattr__(self, name):
        name = re.sub("_", "-", name)
        try:
            return self.__dict__[name]
        except:
            self.__dict__[name] = SolaceNode()
            return self.__dict__[name]
    def __str__(self):
        return str(self.__dict__)
    def __repr__(self):
        return str(self.__dict__)
    def __call__(self, *args, **kwargs):
        return self.__dict__
    def __setattr__(self, name, value):
        name = re.sub("_", "-", name)
        self.__dict__[name] = value

class SolaceXMLBuilder(object):
    ''' main dictionary builder

    Any dot-name-space like calling of a instance of SolaceXMLBuilder will create
    nested dictionary keys. These are converted to XML whenever the instance 
    representation is called ( __repr__ ) 

    Example

    a=SolaceXMLBuilder()
    a.foo.bar.baz=2
    str(a)
    '<rpc semp-version="soltr/5_5">\n<foo><bar><baz>2</baz></bar></foo></rpc>'

    '''
    def __init__(self):
        self.__dict__ = OrderedDict()
        self.__setattr__ = None
    def __getattr__(self, name):
        name = re.sub("_", "-", name)
        try:
            return self.__dict__[name]
        except:
            self.__dict__[name] = SolaceNode()
            return self.__dict__[name]
    def __repr__(self):
        # Show XML
        myxml = d2x(eval(str(self.__dict__)))
        # I had to conjur up my own header cause solace doesnt like </rpc> to have attribs
        #return str('<rpc semp-version="soltr/5_5">\n%s</rpc>' % myxml.display())
        return str('<rpc semp-version="soltr/5_5">\n%s</rpc>' % myxml.display())
    def __call__(self, *args, **kwargs):
        return self.__dict__
    # def __setattr__(self, name, value):
    #   raise Exception('no you cant create assignments here, only on sub-elements')



if __name__ == '__main__':
    x = SolaceXMLBuilder()
    x.create.message_vpn.vpn_name='NEWVPN'
    print(x)

    # <?xml version="1.0" ?>
    # <rpc semp-version="soltr/5_5">
    #   <create>
    #     <message-vpn>
    #       <vpn-name>
    #         NEWVPN
    #       </vpn-name>
    #     </message-vpn>
    #   </create>
    # </rpc semp-version="soltr/5_5">   

    x=SolaceXMLBuilder()
    x.message_vpn.vpn_name='NEWVPN'
    x.message_vpn.no.feature_X
    print(x)

    # <?xml version="1.0" ?>
    # <rpc semp-version="soltr/5_5">
    #   <message-vpn>
    #     <vpn-name>
    #       NEWVPN
    #     </vpn-name>
    #     <no>
    #       <feature-X/>
    #     </no>
    #   </message-vpn>
    # </rpc semp-version="soltr/5_5">


    # >>> client = SolaceAPI('pt1')
    # >>> xml = SolaceXMLBuilder()
    # >>> xml.create.message_vpn.vpn_name='NEWVPN'
    # >>> client.rpc(str(xml))
    # {u'rpc-reply': {u'execute-result': {u'@code': u'ok'}, u'@semp-version': u'soltr/5_5'}}