Merged changes from cce branch (r3727:HEAD/4008); the branch is now in sync with trunk

1 files changed, 81 insertions, 0 deletions

diff --git a/paste/auth/multi.py b/paste/auth/multi.py
new file mode 100644
index 0000000..1b593ae
--- /dev/null
+++ b/paste/auth/multi.py
@@ -0,0 +1,81 @@
+# (c) 2005 Clark C. Evans
+# This module is part of the Python Paste Project and is released under
+# the MIT License: http://www.opensource.org/licenses/mit-license.php
+# This code was written with funding by http://prometheusresearch.com
+"""
+Multi Authentication 
+
+In some environments, the choice of authentication method to be used
+depends upon the environment and is not "fixed".  This middleware 
+allows N authentication methods to be registered along with a goodness
+function which determines which method should be used.
+
+Strictly speaking this is not limited to authentication, but it is a
+common requirement in that domain; this is why it isn't named
+AuthMultiHandler (for now).
+"""
+
+class MultiHandler:
+    """ This middleware provides two othogonal facilities:
+          (a) a way to register any number of middlewares
+          (b) a way to register predicates which cause one of
+              the registered middlewares to be used
+        If none of the predicates returns True, then the
+        application is invoked directly without middleware
+    """
+    def __init__(self, application):
+        self.application = application
+        self.default = application
+        self.binding = {}
+        self.predicate = []
+    def add_method(self, name, factory, *args, **kwargs):
+        self.binding[name] = factory(self.application, *args, **kwargs)
+    def add_predicate(self, name, checker):
+        self.predicate.append((checker,self.binding[name]))
+    def set_default(self, name):
+        """ 
+        This method sets the default middleware to be executed, 
+        if none of the rules apply. 
+        """
+        self.default = self.binding[name]
+    def set_query_argument(self, name, key = '*authmeth', value = None):
+        """
+        This method indicates that the named middleware component should
+        be executed if the given key/value pair occurs in the query args.
+        """
+        lookfor = "%s=%s" % (key, value or name)
+        self.add_predicate(name, 
+            lambda environ: lookfor in environ.get('QUERY_STRING',''))
+    def __call__(self, environ, start_response):
+        for (checker,binding) in self.predicate:
+            if checker(environ):
+                return binding(environ, start_response)
+        return self.default(environ, start_response)
+
+middleware = MultiHandler
+
+__all__ = ['MultiHandler']
+
+if '__main__' == __name__:
+    import basic, digest, cas, cookie, form
+    from paste.httpexceptions import *
+    from paste.wsgilib import dump_environ
+    from paste.util.baseserver import serve
+    multi = MultiHandler(dump_environ)
+    multi.add_method('basic',basic.middleware,
+                     'tag:clarkevans.com,2005:basic',
+                     lambda n,p: n == p )
+    multi.set_query_argument('basic')
+    multi.add_method('digest',digest.middleware,
+                     'tag:clarkevans.com,2005:digest',
+                     lambda r,u: digest.digest_password(u,r,u))
+    multi.set_query_argument('digest')
+    multi.add_method('form',lambda ap: cookie.middleware(
+                                           form.middleware(ap,
+                                               lambda n,p: n == p)))
+    multi.set_query_argument('form')
+    #authority = "https://secure.its.yale.edu/cas/servlet/"
+    #multi.add_method('cas',lambda ap: cookie.middleware(
+    #                                      cas.middleware(ap,authority)))
+    #multi.set_default('cas')
+    serve(HTTPExceptionHandler(multi))