[Zope-PAS] plugin webservice

[javi lopez]

hello i want to do a plugin to webservice:

I put this in my class class ValidatePlugin(BasePlugin, Cacheable):

     meta_type = 'ValidaPlugin'
    security = ClassSecurityInfo()

    def __init__(self, id, title=None):
        self._id = self.id = id
        self.title = title

    security.declarePrivate('authenticateCredentials')
    def authenticateCredentials(self, credentials):


        user_id = credentials.get( 'user_id' )
        if user_id is None:
            return None
        return user_id, user_id

    security.declarePrivate('extractCredentials')
    def extractCredentials(self, request):


        creds = {}
        userid = request.get(self.uservar)
        if userid:
            creds.update({'user_id':userid})
        return creds


but it don´t work, i want validate user of plone to webservice with
that product, but i don´t know. Can you help me?? thanks