| paulb@126 | 1 | #!/usr/bin/env python |
| paulb@126 | 2 | |
| paulb@126 | 3 | "An example login screen." |
| paulb@126 | 4 | |
| paulb@126 | 5 | import WebStack.Generic |
| paulb@126 | 6 | import md5 |
| paulb@126 | 7 | |
| paulb@126 | 8 | class LoginResource: |
| paulb@126 | 9 | |
| paulb@126 | 10 | "A resource providing a login screen." |
| paulb@126 | 11 | |
| paulb@126 | 12 | def __init__(self, authenticator): |
| paulb@126 | 13 | |
| paulb@126 | 14 | "Initialise the resource with an 'authenticator'." |
| paulb@126 | 15 | |
| paulb@126 | 16 | self.authenticator = authenticator |
| paulb@126 | 17 | |
| paulb@126 | 18 | def respond(self, trans): |
| paulb@126 | 19 | |
| paulb@126 | 20 | fields = trans.get_fields_from_body() |
| paulb@126 | 21 | redirect = "" |
| paulb@126 | 22 | |
| paulb@126 | 23 | if fields.has_key("redirect"): |
| paulb@126 | 24 | redirects = fields["redirect"] |
| paulb@126 | 25 | redirect = redirects[0] |
| paulb@126 | 26 | if self.authenticator.authenticate(trans): |
| paulb@126 | 27 | trans.set_header_value("Location", redirect) |
| paulb@126 | 28 | trans.set_response_code(307) |
| paulb@126 | 29 | return |
| paulb@126 | 30 | else: |
| paulb@126 | 31 | fields = trans.get_fields_from_path() |
| paulb@126 | 32 | if fields.has_key("redirect"): |
| paulb@126 | 33 | redirects = fields["redirect"] |
| paulb@126 | 34 | redirect = redirects[0] |
| paulb@126 | 35 | |
| paulb@126 | 36 | # When authentication fails or is yet to take place, show the login |
| paulb@126 | 37 | # screen. |
| paulb@126 | 38 | |
| paulb@126 | 39 | out = trans.get_response_stream() |
| paulb@126 | 40 | out.write(""" |
| paulb@126 | 41 | <html> |
| paulb@126 | 42 | <head> |
| paulb@126 | 43 | <title>Login Example</title> |
| paulb@126 | 44 | </head> |
| paulb@126 | 45 | <body> |
| paulb@126 | 46 | <h1>Login</h1> |
| paulb@126 | 47 | <form method="POST"> |
| paulb@126 | 48 | <p>Username: <input name="username" type="text" size="12"/></p> |
| paulb@126 | 49 | <p>Password: <input name="password" type="text" size="12"/></p> |
| paulb@126 | 50 | <p><input name="login" type="submit" value="Login"/></p> |
| paulb@126 | 51 | <input name="redirect" type="hidden" value="%s"/> |
| paulb@126 | 52 | </form> |
| paulb@126 | 53 | </body> |
| paulb@126 | 54 | </html> |
| paulb@126 | 55 | """ % redirect) |
| paulb@126 | 56 | |
| paulb@126 | 57 | class LoginAuthenticator: |
| paulb@126 | 58 | |
| paulb@130 | 59 | def __init__(self, secret_key, credentials, cookie_name=None): |
| paulb@126 | 60 | |
| paulb@130 | 61 | """ |
| paulb@130 | 62 | Initialise the authenticator with a 'secret_key', the authenticator's registry of |
| paulb@130 | 63 | 'credentials' and an optional 'cookie_name'. |
| paulb@126 | 64 | |
| paulb@130 | 65 | The 'credentials' must be an object which supports tests of the form |
| paulb@130 | 66 | '(username, password) in credentials'. |
| paulb@130 | 67 | """ |
| paulb@126 | 68 | |
| paulb@126 | 69 | self.secret_key = secret_key |
| paulb@130 | 70 | self.credentials = credentials |
| paulb@130 | 71 | self.cookie_name = cookie_name or "LoginAuthenticator" |
| paulb@126 | 72 | |
| paulb@126 | 73 | def authenticate(self, trans): |
| paulb@126 | 74 | |
| paulb@126 | 75 | # Process any supplied parameters. |
| paulb@126 | 76 | |
| paulb@126 | 77 | fields = trans.get_fields_from_body() |
| paulb@126 | 78 | |
| paulb@126 | 79 | if fields.has_key("username") and fields.has_key("password"): |
| paulb@126 | 80 | usernames, passwords = fields["username"], fields["password"] |
| paulb@126 | 81 | |
| paulb@126 | 82 | # Insist on only one username and password. |
| paulb@126 | 83 | |
| paulb@126 | 84 | if len(usernames) == 1 and len(passwords) == 1: |
| paulb@126 | 85 | username, password = usernames[0], passwords[0] |
| paulb@126 | 86 | |
| paulb@126 | 87 | # Check against the class's credentials. |
| paulb@126 | 88 | |
| paulb@126 | 89 | if (username, password) in self.credentials: |
| paulb@126 | 90 | |
| paulb@126 | 91 | # Make a special cookie token. |
| paulb@126 | 92 | # NOTE: This should be moved into a common library. |
| paulb@126 | 93 | |
| paulb@126 | 94 | trans.set_cookie_value( |
| paulb@130 | 95 | self.cookie_name, |
| paulb@126 | 96 | username + ":" + md5.md5(username + self.secret_key).hexdigest() |
| paulb@126 | 97 | ) |
| paulb@126 | 98 | |
| paulb@126 | 99 | return 1 |
| paulb@126 | 100 | |
| paulb@126 | 101 | return 0 |
| paulb@126 | 102 | |
| paulb@126 | 103 | # vim: tabstop=4 expandtab shiftwidth=4 |
