anz.casclient 1.1.1

=====================
anz.casclient README
=====================

:author: jiangdongjin
:contact: eastxing@gmail.com
:date: 2010/09/25
:abstract: This is a Zope PAS plugin that authenticates users against a
CAS (Central Authentication Service) server.

.. contents::
.. sectnum::

Introduction
============
anz.casclient is a PAS plugin that authenticates users against a CAS
(Central Authentication Service) server.

Overview
========
anz.casclient implement a new PAS plugin 'Anz CAS Client'. It enabling you
to integrate your Zope sites into your CAS SSO solutions.

Credits
========
Thanks to those guys who developed the following products, without your
works anz.casclient will never happen.

- CAS_
- `JA-SIG CAS Client for Java 3.1`_
- CAS4PAS_

.. _CAS: http://www.jasig.org/cas
.. _`JA-SIG CAS Client for Java 3.1`: https://wiki.jasig.org/display/CASC/CAS+Client+for+Java+3.1
.. _CAS4PAS: http://plone.org/products/cas4pas

Comparison with CAS4PAS
=======================
CAS4PAS is the first(if not the only)CAS client used in Zope world, but it
has only implemented partial CAS
`protocol <http://www.jasig.org/cas/protocol>`_, so comes anz.casclient.

anz.casclient have some advantages:

- anz.casclient provides full CAS 1.0/2.0 protocol implementation.
- anz.casclient implemented Single-Sign-Out.
- anz.casclient provides a framework that similar as the official java
client implementation, this will make it easy to follow the evolution of
CAS client.

Requirements
============
- Plone 3 or Plone 4
- ZODB3>=3.8.3 (test under 3.8.3 only)
- zope.proxy>=3.4.1 (test under 3.4.1 only)
- zope.bforest

Installation
============
To install anz.casclient into the global Python environment (or a
workingenv), using a traditional Zope 2 instance, you can do this:

* When you're reading this you have probably already run
``easy_install anz.casclient``. Find out how to install setuptools
(and EasyInstall) here:
http://peak.telecommunity.com/DevCenter/EasyInstall

* Create a file called ``anz.casclient-configure.zcml`` in the
``/path/to/instance/etc/package-includes`` directory. The file
should only contain this::

<include package="anz.casclient" />

Alternatively, if you are using zc.buildout and the
plone.recipe.zope2instance recipe to manage your project, you can do this:

* Add ``anz.casclient`` to the list of eggs to install, e.g.:

::

[buildout]
...
eggs =
...
anz.casclient

* Tell the plone.recipe.zope2instance recipe to install a ZCML slug:

::

[instance]
recipe = plone.recipe.zope2instance
...
zcml =
anz.casclient

* Re-run buildout, e.g. with:

::

$ ./bin/buildout

You can skip the ZCML slug if you are going to explicitly include the
package from another package's configure.zcml file.

How to use anz.casclient
========================

Create 'Anz CAS Client' plugin
------------------------------
Go into ZMI, {your plone site}\acl_users, add an 'Anz CAS Client' instance,
choose any Id you like, we input 'anz_casclient' for example.

Configure 'Anz CAS Client' plugin
---------------------------------
Go into {your plone site}\acl_users\anz_casclient, in 'Active' tab active
all four interface.

Click 'Authentication' to configure 'Authentication Plugins', move
'anz_casclient' to the top.

Click 'Challenge' to configure 'Challenge Plugins', move 'anz_casclient'
to the top.

Click 'Extraction' to configure 'Extraction Plugins', move 'anz_casclient'
to the top.

Go into 'Properties' tab to configure CAS related properties.

============================== =========== ==============================
Property Required Note
serviceUrl False An identify of current service.
CAS will redirects to here
after login. Set this explicitly
but not determine it automatically
from request makes us get more
security assurance. See
`here <https://wiki.jasig.org/display/CASC/CASFilter>`_.
casServerUrlPrefix True The start of the CAS server URL.
useSession False Whether to store the Assertion
in session or not. If sessions
are not used, proxy granting
ticket will be required for
each request. Default set to True.
renew False If set to True, CAS will ask
user for credentials again to
authenticate, this may be used
for high-security applications.
Default set to False.
gateway False If set to True, CAS will not
ask the user for credentials.
If the user has a pre-existing
single sign-on session with CAS,
or if a single sign-on session
can be established through
non-interactive means(i.e.
trust authentication), CAS MAY
redirect the client to the URL
specified by the "service"
parameter, appending a valid
service ticket.(CAS also MAY
interpose an advisory page
informing the client that a CAS
authentication has taken place.)
If the client does not have a
single sign-on session with CAS,
and a non-interactive
authentication cannot be
established, CAS MUST redirect
the client to the URL specified
by the "service" parameter with
no "ticket" parameter appended
to the URL. If the "service"
parameter is not specified and
"gateway" is set, the behavior
of CAS is undefined. It is
RECOMMENDED that in this case,
CAS request credentials as if
neither parameter was specified.
This parameter is not compatible
with the "renew" parameter.
Behavior is undefined if both
are set to True. See details
`here_ <http://www.jasig.org/cas/client-integration/gateway>`_.
ticketValidationSpecification True Use which CAS protocol to
validate ticket.
one of ['CAS 1.0','CAS 2.0']
proxyCallbackUrlPrefix False The start of the proxy callback
url. You should set it point to
current plugin with protocol
'https'. The result url will be
'{proxyCallbackUrlPrefix}/proxyCallback'.
If set, it means this service
will be used as a proxier to
access back-end service on
behalf of a particular user.
acceptAnyProxy False Whether any proxy is OK.
Allowed Proxy Chains False Allowed proxy chains. Each
acceptable proxy chain should
include a space-separated list
of URLs. These URLs are
proxier's proxyCallbackUrl.
============================== =========== ==============================

Example configures:

- Set 'serviceUrl' to 'http://{my plone site domain}:{port}/plone'
- Set 'casServerUrlPrefix' to 'https://{my cas server domain}:{port}/cas'
- Set 'useSession' to True
- Set 'renew' to False
- Set 'gateway' to False
- Set 'ticketValidationSpecification' to 'CAS 2.0'
- Set 'proxyCallbackUrlPrefix' to 'https://{my plone site domain}:{port}/plone/acl_users/anz_casclient'
- Set 'acceptAnyProxy' to False
- Set 'Allowed Proxy Chains' to None

Configure 'CAS login' entrance
------------------------------
If you use 'Log in' link at the upper-right of the Plone page to login, you
should hide the stock Plone 'Log in' action first. Then add a new one named
'CAS log in' there, set URL(Expression) to
**'string:${globals_view/navigationRootUrl}/caslogin'**

Then add a Script(Python) named '**caslogin**' into 'portal_skins/custom',
its contents looks like:

::

## Script (Python) "caslogin"
##bind container=container
##bind context=context
##bind namespace=
##bind script=script
##bind subpath=traverse_subpath
##parameters=
##title=CAS Login
##
request = container.REQUEST

portal = context.portal_url.getPortalObject()
plugin = portal.acl_users.anz_casclient

if plugin.casServerUrlPrefix:
url = plugin.getLoginURL() + '?service=' + plugin.getService()
if plugin.renew:
url += '&renew=true'
if plugin.gateway:
url += '&gateway=true'

request.RESPONSE.redirect( url, lock=1 )

If you use 'login portlet' to login, you should remove the stock Plone
'login portlet' first so as not to confuse users. Then you should write a
new 'CAS login portlet' to authenticate users against CAS or customize
collective.castle_ to work with anz.casclient.

.. _collective.castle: http://plone.org/products/collective.castle/

Configure 'CAS logout' entrance
-------------------------------
If you use 'Log out' link at the upper-right of the Plone page to logout,
you should hide the stock Plone 'Log out' action first. Then add a new one
named 'CAS log out' there, set URL(Expression) to
**'string:${globals_view/navigationRootUrl}/caslogout'**

Then add a Script(Python) named '**caslogout**' into 'portal_skins/custom',
its contents looks like:

::

## Script (Python) "caslogout"
##bind container=container
##bind context=context
##bind namespace=
##bind script=script
##bind subpath=traverse_subpath
##parameters=
##title=CAS Logout
##
from Products.CMFCore.utils import getToolByName

request = container.REQUEST
portal = context.portal_url.getPortalObject()
cas_client_plugin = portal.acl_users.anz_casclient

mt = getToolByName( context, 'portal_membership' )
mt.logoutUser( REQUEST=request )

request.RESPONSE.redirect( cas_client_plugin.casServerUrlPrefix + '/logout' )

How to use proxy authentication
===============================
Proxy authentication is added by CAS 2.0, for the reason why do we need
it, you can see the details `here. <http://www.jasig.org/cas/proxy-authentication>`_


1. Create two plone sites in one Zope instance, called them **plone** and
**backend**.
2. Create and configure 'Anz CAS Client' plugin on them(make sure both sites
can authenticate users against your CAS server).
3. anz.casclient carried a simple example to show how to use it, but it need
you to do a little customization. Open
**anz.casclient\anz\casclient\proxyauthexample\view.py** with your
favorite editor, find **__init__** method and modify it to suit your
situation:

::

def __init__( self, context, request ):
super(ProxyAuthExampleView, self).__init__( context, request )

# eg. http://xx.xx.xx.xx:8080/backend
self.BACK_END_SERVICE_URL = 'http://{domain of your zope instance}:{port}/backend'

# eg. /plone/acl_users/anz_casclient
self.PATH_TO_PROXIER_PLUGIN = '/plone/acl_users/anz_casclient'

# eg. /backend/acl_users/anz_casclient
self.PATH_TO_BACK_END_PLUGIN = '/backend/acl_users/anz_casclient'

4. After that restart your Zope, open a browser and login into site
**plone** ( suppose user name is **tom** ).
5. Modify location in your browser to
**http://{domain of your zope instance}:{port}/plone/@@proxyAuthExample/getUserInfoFromTargetService**
and click Enter, if all things goes well, you'll see:

::

Hello, tom!


SAML service ticket validation
==============================
From version 1.1, the server is able to connect to a CAS server 3.x and above
and validate the service ticket (ST) against the CAS server using SAML, in order
to retrieve the extra fields for the authenticated user that the CAS server may
be providing. To use his feature, it's required to configure the plugin to use
the SAML validation by configuring the **SAMLValidate** property to ``True``.

In order to do something with the retrieved properties an event
``ISAMLPropertiesExist`` is emmited for a subscriber to be hooked into it.


ToDo
====
* Add automation tests ( I really don't know how to automation test this
kind of package :) )

Changelog
=========

1.1.1 (2015-08-06)
----------------

- Fix release.


1.1 (2015-08-06)
----------------
- Fixed a problem in Plone 4.3 that forces to cast the resultant username to an
str before passing it to plone.session for session creation. It's needed to
cast username which is an unicode type to an str as plone.session does a
direct concatenation of unicode username and other string types that leads to
an UnicodeDecode error otherwise. It's needed to address plone.session to do
not so. Meanwhile, casting the username assumes that there are non ascii
chars in it [sneridagh]

- Fixed a problem when used in a Zope/ZEO environment with multiple Zope
clients. Make it work using the default Plone session factory solved the
problem. [sneridagh]

- Clean paster plugins in setup.py [sneridagh]

- Add an extra validation for CAS2.0 service ticket via SAML. This enables the
extraction of extra user properties. [sneridagh]

1.0.1
-----

- Update to support Plone4.

Note: When used under Plone3, please pin products version like this::

ZODB3==3.8.3
zope.proxy==3.4.1

1.0
---

- Initial release