more hooks for authenticators

Allow authenticators to:

- register custom handlers
- change login and logout URLs
- replace the entire login form

This appears to be enough to get oauth working.

jupyterhub/app.py

@@ -210,7 +210,8 @@ class JupyterHubApp(Application):
     def _cookie_secret_default(self):
         return os.environ.get('JPY_COOKIE_SECRET', random_hex(64))
     
-    authenticator_class = Type("jupyterhub.auth.PAMAuthenticator", config=True,
+    authenticator_class = Type(PAMAuthenticator, Authenticator,
+        config=True,
         help="""Class for authenticating users.
         
         This should be a class with the following form:
@@ -224,12 +225,14 @@ class JupyterHubApp(Application):
           and `data` is the POST form data from the login page.
         """
     )
+    
     authenticator = Instance(Authenticator)
     def _authenticator_default(self):
         return self.authenticator_class(config=self.config)
 
     # class for spawning single-user servers
-    spawner_class = Type("jupyterhub.spawner.LocalProcessSpawner", config=True,
+    spawner_class = Type(LocalProcessSpawner, Spawner,
+        config=True,
         help="""The class to use for spawning single-user servers.
         
         Should be a subclass of Spawner.
@@ -323,6 +326,8 @@ class JupyterHubApp(Application):
         h = []
         h.extend(handlers.default_handlers)
         h.extend(apihandlers.default_handlers)
+        # load handlers from the authenticator
+        h.extend(self.authenticator.get_handlers(self))
 
         self.handlers = self.add_url_prefix(self.hub_prefix, h)
 
@@ -534,13 +539,16 @@ class JupyterHubApp(Application):
     
     def init_tornado_settings(self):
         """Set up the tornado settings dict."""
-        base_url = self.base_url
+        base_url = self.hub.server.base_url
         template_path = os.path.join(self.data_files_path, 'templates'),
         jinja_env = Environment(
             loader=FileSystemLoader(template_path),
             **self.jinja_environment_options
         )
         
+        login_url = self.authenticator.login_url(base_url)
+        logout_url = self.authenticator.logout_url(base_url)
+        
         settings = dict(
             config=self.config,
             log=self.log,
@@ -550,9 +558,10 @@ class JupyterHubApp(Application):
             admin_users=self.admin_users,
             authenticator=self.authenticator,
             spawner_class=self.spawner_class,
-            base_url=base_url,
+            base_url=self.base_url,
             cookie_secret=self.hub.server.cookie_secret,
-            login_url=url_path_join(self.hub.server.base_url, 'login'),
+            login_url=login_url,
+            logout_url=logout_url,
             static_path=os.path.join(self.data_files_path, 'static'),
             static_url_prefix=url_path_join(self.hub.server.base_url, 'static/'),
             template_path=template_path,

jupyterhub/auth.py

@@ -9,6 +9,8 @@ import simplepam
 from IPython.config import LoggingConfigurable
 from IPython.utils.traitlets import Unicode, Set
 
+from .utils import url_path_join
+
 class Authenticator(LoggingConfigurable):
     """A class for authentication.
     
@@ -22,6 +24,7 @@ class Authenticator(LoggingConfigurable):
         If empty, allow any user to attempt login.
         """
     )
+    custom_html = Unicode('')
     
     @gen.coroutine
     def authenticate(self, handler, data):
@@ -32,6 +35,22 @@ class Authenticator(LoggingConfigurable):
         and return None on failed authentication.
         """
     
+    def login_url(self, base_url):
+        """Override to register a custom login handler"""
+        return url_path_join(base_url, 'login')
+    
+    def logout_url(self, base_url):
+        """Override to register a custom logout handler"""
+        return url_path_join(base_url, 'logout')
+    
+    def get_handlers(self, app):
+        """Return any custom handlers the authenticator needs to register
+        
+        (e.g. for OAuth)
+        """
+        return []
+
+
 class PAMAuthenticator(Authenticator):
     encoding = Unicode('utf8', config=True,
         help="""The encoding to use for PAM """

jupyterhub/handlers/base.py

@@ -206,6 +206,7 @@ class BaseHandler(RequestHandler):
             base_url=self.hub.server.base_url,
             user=user,
             login_url=self.settings['login_url'],
+            logout_url=self.settings['logout_url'],
             static_url=self.static_url,
         )
 

jupyterhub/handlers/login.py

@@ -25,6 +25,7 @@ class LoginHandler(BaseHandler):
                 next=url_escape(self.get_argument('next', default='')),
                 username=username,
                 message=message,
+                custom_html=self.authenticator.custom_html,
         )
     
     def get(self):

share/jupyter/templates/login.html

@@ -6,6 +6,9 @@
 {% block main %}
 
 <div id="login-main" class="container">
+{% if custom_html %}
+{{custom_html}}
+{% else %}
   <form action="{{login_url}}?next={{next}}" method="post" role="form">
         <div class="input-group">
           <span class="input-group-addon">Username:</span>
@@ -24,6 +27,7 @@
     </div>
   </div>
   {% endif %}
+{% endif %}
 <div/>
 
 {% endblock %}

share/jupyter/templates/page.html

@@ -83,9 +83,9 @@
 
     <span id="login_widget">
       {% if user %}
-        <a id="logout" class="btn navbar-btn btn-default pull-right" href="{{base_url}}logout">Logout</a>
+        <a id="logout" class="btn navbar-btn btn-default pull-right" href="{{logout_url}}">Logout</a>
       {% else %}
-        <a id="login" class="btn navbar-btn btn-default pull-right" href="{{base_url}}login">Login</a>
+        <a id="login" class="btn navbar-btn btn-default pull-right" href="{{login_url}}">Login</a>
       {% endif %}
     </span>