class LoginForm(rend.Page):
    """ Minimalist Login Page"""
    addSlash = True
    docFactory = loaders.stan(
        T.html[
            T.head[
                T.title["Please Login"]
            ],
            T.body[
                T.form(action=guard.LOGIN_AVATAR, method="post")[
                    T.table[
                        T.tr[
                            T.td[ "Username:" ],
                            T.td[ T.input(type='text', name='username') ],
                        ],
                        T.tr[
                            T.td[ "Password:" ],
                            T.td[ T.input(type='password', name='password') ],
                        ]
                    ],
                    T.input(type='submit'),
                ]
            ]
        ])
class opsviewWebChecker:
    implements(checkers.ICredentialsChecker)
    credentialInterfaces = (IUsernamePassword)

    def __init__(self):
        pass

    def requestAvatarId(self, credentials):
        uname = credentials.username
        passwd = credentials.password
        sub = subscriber.addSubscriber(uname, passwd)
        auth_result = sub.authenticateNodes()
        if auth_result:
            return defer.succeed(uname)
        else:
            return defer.fail(credError.UnauthorizedLogin("Incorrect Login"))


class opsviewRealm(object):
    implements(IRealm)

    def __init__(self, pageResource):
        self.pageResource = pageResource

    def requestAvatar(self, avatarId, mind, *interfaces):
        for iface in interfaces:
            if avatarId is checkers.ANONYMOUS:
                resc = LoginForm()
                resc.realm = self
                return (inevow.IResource, resc, lambda: None)
            else:
                resc = self.pageResource
                resc.realm = self
                return (inevow.IResource, resc, lambda: None)
        raise NotImplementedError()

class RootPage(rend.Page):

    def __init__(self, *args, **kwargs):
        rend.Page.__init__(self, *args, **kwargs)

    addSlash = True
    docFactory = loaders.stan(
        T.html[
            T.head[
                T.title["Main Page"]
            ],
            T.body["logged in!"]
        ]
    )

def wrapAuthorized(site):
    site = inevow.IResource(site)
    realmObject = opsviewRealm(site)
    portalObject = Portal(realmObject)
    myChecker = opsviewWebChecker()
    #Allow anonymous access to the login page
    portalObject.registerChecker(
        checkers.AllowAnonymousAccess(), IAnonymous
    )
    #Allow authenticated users to the main page
    portalObject.registerChecker(myChecker)
    site = appserver.NevowSite(resource=guard.SessionWrapper(portalObject))
    return site

site = wrapAuthorized(RootPage())

def getService():
    service = internet.TCPServer(httpport, site)
    service.setName("WEBService")
    return service


--------------------


<type 'exceptions.AttributeError'>: 'str' object has no attribute 'providedBy'
/usr/local/lib/python2.7/site-packages/Twisted-11.0.0-py2.7-linux-x86_64.egg/twisted/internet/defer.py, line 133 in maybeDeferred
131    """
132    try:
133        result = f(*args, **kw)
134    except:
Locals
args    (PageContext(tag=<nevow.guard.SessionWrapper object at 0x14ea7510>), ('__login__',))
kw  {}
f   <bound method SessionWrapper.locateChild of <nevow.guard.SessionWrapper object at 0x14ea7510>>
/usr/local/lib/python2.7/site-packages/Nevow-0.10.0-py2.7.egg/nevow/guard.py, line 314 in locateChild
312            #                 ^ we are this getChild
313            # with or without a session
314            return self._delegate(ctx, segments)
315
Locals
ctx PageContext(tag=<nevow.guard.SessionWrapper object at 0x14ea7510>)
segments    ('__login__',)
self    <nevow.guard.SessionWrapper object at 0x14ea7510>
/usr/local/lib/python2.7/site-packages/Nevow-0.10.0-py2.7.egg/nevow/guard.py, line 332 in _delegate
330            if sessionKey in self.sessions:
331                session = self.sessions[sessionKey]
332                return self.checkLogin(ctx, session, segments)
333        # without a session
Locals
session <nevow.guard.GuardSession instance at 0x15128638>
segments    ('__login__',)
ctx PageContext(tag=<nevow.guard.SessionWrapper object at 0x14ea7510>)
sessionKey  'b6f82dcba56ff793c96b54b43e055fb3'
self    <nevow.guard.SessionWrapper object at 0x14ea7510>
/usr/local/lib/python2.7/site-packages/Nevow-0.10.0-py2.7.egg/nevow/guard.py, line 461 in checkLogin
459                    u = u.child(seg)
460                return u, ()
461            return self.login(request, session, self.getCredentials(request), subSegments).addCallback(
462                unmangleURL).addErrback(
Locals
subSegments ()
request <POST /__login__ HTTP/1.1>
session <nevow.guard.GuardSession instance at 0x15128638>
unmangleURL <function unmangleURL at 0x16eff938>
self    <nevow.guard.SessionWrapper object at 0x14ea7510>
/usr/local/lib/python2.7/site-packages/Nevow-0.10.0-py2.7.egg/nevow/guard.py, line 529 in login
527        mind = self.mindFactory(request, credentials)
528        session.mind = mind
529        return self.portal.login(credentials, mind, self.credInterface).addCallback(
530            self._cbLoginSuccess, session, segments
Locals
session <nevow.guard.GuardSession instance at 0x15128638>
credentials <twisted.cred.credentials.UsernamePassword instance at 0x16fd6a28>
mind    None
segments    ()
request <POST /__login__ HTTP/1.1>
self    <nevow.guard.SessionWrapper object at 0x14ea7510>
/usr/local/lib/python2.7/site-packages/Twisted-11.0.0-py2.7-linux-x86_64.egg/twisted/cred/portal.py, line 114 in login
112        """
113        for i in self.checkers:
114            if i.providedBy(credentials):
115                return maybeDeferred(self.checkers[i].requestAvatarId, credentials
Locals
i   'checkPassword'
credentials <twisted.cred.credentials.UsernamePassword instance at 0x16fd6a28>
self    <twisted.cred.portal.Portal instance at 0x14ea8320>
Globals
providedBy  <built-in function providedBy>
maybeDeferred   <function maybeDeferred at 0x143ef1b8>
<type 'exceptions.AttributeError'>: 'str' object has no attribute 'providedBy'