Dependancy free

libs/cherrypy/lib/auth_basic.py

@@ -0,0 +1,87 @@
+# This file is part of CherryPy <http://www.cherrypy.org/>
+# -*- coding: utf-8 -*-
+# vim:ts=4:sw=4:expandtab:fileencoding=utf-8
+
+__doc__ = """This module provides a CherryPy 3.x tool which implements
+the server-side of HTTP Basic Access Authentication, as described in :rfc:`2617`.
+
+Example usage, using the built-in checkpassword_dict function which uses a dict
+as the credentials store::
+
+    userpassdict = {'bird' : 'bebop', 'ornette' : 'wayout'}
+    checkpassword = cherrypy.lib.auth_basic.checkpassword_dict(userpassdict)
+    basic_auth = {'tools.auth_basic.on': True,
+                  'tools.auth_basic.realm': 'earth',
+                  'tools.auth_basic.checkpassword': checkpassword,
+    }
+    app_config = { '/' : basic_auth }
+
+"""
+
+__author__ = 'visteya'
+__date__ = 'April 2009'
+
+import binascii
+from cherrypy._cpcompat import base64_decode
+import cherrypy
+
+
+def checkpassword_dict(user_password_dict):
+    """Returns a checkpassword function which checks credentials
+    against a dictionary of the form: {username : password}.
+
+    If you want a simple dictionary-based authentication scheme, use
+    checkpassword_dict(my_credentials_dict) as the value for the
+    checkpassword argument to basic_auth().
+    """
+    def checkpassword(realm, user, password):
+        p = user_password_dict.get(user)
+        return p and p == password or False
+
+    return checkpassword
+
+
+def basic_auth(realm, checkpassword, debug=False):
+    """A CherryPy tool which hooks at before_handler to perform
+    HTTP Basic Access Authentication, as specified in :rfc:`2617`.
+
+    If the request has an 'authorization' header with a 'Basic' scheme, this
+    tool attempts to authenticate the credentials supplied in that header.  If
+    the request has no 'authorization' header, or if it does but the scheme is
+    not 'Basic', or if authentication fails, the tool sends a 401 response with
+    a 'WWW-Authenticate' Basic header.
+
+    realm
+        A string containing the authentication realm.
+
+    checkpassword
+        A callable which checks the authentication credentials.
+        Its signature is checkpassword(realm, username, password). where
+        username and password are the values obtained from the request's
+        'authorization' header.  If authentication succeeds, checkpassword
+        returns True, else it returns False.
+    
+    """
+    
+    if '"' in realm:
+        raise ValueError('Realm cannot contain the " (quote) character.')
+    request = cherrypy.serving.request
+    
+    auth_header = request.headers.get('authorization')
+    if auth_header is not None:
+        try:
+            scheme, params = auth_header.split(' ', 1)
+            if scheme.lower() == 'basic':
+                username, password = base64_decode(params).split(':', 1)
+                if checkpassword(realm, username, password):
+                    if debug:
+                        cherrypy.log('Auth succeeded', 'TOOLS.AUTH_BASIC')
+                    request.login = username
+                    return # successful authentication
+        except (ValueError, binascii.Error): # split() error, base64.decodestring() error
+            raise cherrypy.HTTPError(400, 'Bad Request')
+    
+    # Respond with 401 status and a WWW-Authenticate header
+    cherrypy.serving.response.headers['www-authenticate'] = 'Basic realm="%s"' % realm
+    raise cherrypy.HTTPError(401, "You are not authorized to access that resource")
+