Add Authenticator.auto_login

Simplifies login URL, handler login

- all login redirects go to `settings['login_url']`
- `login_url` is unconditionally `/hub/login`
- `/hub/login` renders form page or 'login with...' button
- enabling auto_login redirects from /hub/login to Authenticator.login_url()

jupyterhub/app.py

@@ -1173,10 +1173,12 @@ class JupyterHub(Application):
         db.commit()
 
     def init_oauth(self):
+        base_url = self.hub.server.base_url
         self.oauth_provider = make_provider(
             self.session_factory,
-            url_prefix=url_path_join(self.hub.server.base_url, 'api/oauth2'),
-            login_url=self.authenticator.login_url(self.hub.server.base_url),
+            url_prefix=url_path_join(base_url, 'api/oauth2'),
+            login_url=url_path_join(base_url, 'login')
+,
         )
 
     def init_proxy(self):
@@ -1307,7 +1309,7 @@ class JupyterHub(Application):
             **jinja_options
         )
 
-        login_url = self.authenticator.login_url(base_url)
+        login_url = url_path_join(base_url, 'login')
         logout_url = self.authenticator.logout_url(base_url)
 
         # if running from git, disable caching of require.js

jupyterhub/auth.py

@@ -31,7 +31,7 @@ class Authenticator(LoggingConfigurable):
         help="""
         Set of users that will have admin rights on this JupyterHub.
 
-        Admin users have extra privilages:
+        Admin users have extra privileges:
          - Use the admin panel to see list of users logged in
          - Add / remove users in some authenticators
          - Restart / halt the hub
@@ -250,10 +250,23 @@ class Authenticator(LoggingConfigurable):
         """
         self.whitelist.discard(user.name)
 
+    auto_login = Bool(False, config=True,
+        help="""Automatically begin the login process
+
+        rather than starting with a "Login with..." link at `/hub/login`
+
+        To work, `.login_url()` must give a URL other than the default `/hub/login`,
+        such as an oauth handler or another automatic login handler,
+        registered with `.get_handlers()`.
+
+        .. versionadded:: 0.8
+        """
+    )
+
     def login_url(self, base_url):
         """Override this when registering a custom login handler
 
-        Generally used by authenticators that do not use simple form based authentication.
+        Generally used by authenticators that do not use simple form-based authentication.
 
         The subclass overriding this is responsible for making sure there is a handler
         available to handle the URL returned from this method, using the `get_handlers`

jupyterhub/handlers/login.py

@@ -7,8 +7,8 @@ from urllib.parse import urlparse
 
 from tornado.escape import url_escape
 from tornado import gen
+from tornado.httputil import url_concat
 
-from ..utils import url_path_join
 from .base import BaseHandler
 
 
@@ -23,8 +23,10 @@ class LogoutHandler(BaseHandler):
                 self.clear_login_cookie(name)
             user.other_user_cookies = set([])
             self.statsd.incr('logout')
-
-        self.redirect(url_path_join(self.hub.server.base_url, 'login'), permanent=False)
+        if self.authenticator.auto_login:
+            self.render('logout.html')
+        else:
+            self.redirect(self.settings['login_url'], permanent=False)
 
 
 class LoginHandler(BaseHandler):
@@ -37,6 +39,7 @@ class LoginHandler(BaseHandler):
                 login_error=login_error,
                 custom_html=self.authenticator.custom_html,
                 login_url=self.settings['login_url'],
+                authenticator_login_url=self.authenticator.login_url(self.hub.server.base_url),
         )
 
     def get(self):
@@ -60,6 +63,16 @@ class LoginHandler(BaseHandler):
             self.set_login_cookie(self.get_current_user())
             self.redirect(next_url, permanent=False)
         else:
+            if self.authenticator.auto_login:
+                auto_login_url = self.authenticator.login_url(self.hub.server.base_url)
+                if auto_login_url == self.settings['login_url']:
+                    self.authenticator.auto_login = False
+                    self.log.warning("Authenticator.auto_login cannot be used without a custom login_url")
+                else:
+                    if next_url:
+                        auto_login_url = url_concat(auto_login_url, {'next': next_url})
+                    self.redirect(auto_login_url)
+                    return
             username = self.get_argument('username', default='')
             self.finish(self._render(username=username))
 

jupyterhub/handlers/pages.py

@@ -53,7 +53,7 @@ class RootHandler(BaseHandler):
                 url = url_path_join(self.hub.server.base_url, 'home')
                 self.log.debug("User is not running: %s", url)
         else:
-            url = url_path_join(self.hub.server.base_url, 'login')
+            url = self.settings['login_url']
         self.redirect(url)
 
 

share/jupyter/hub/templates/login.html

@@ -11,7 +11,7 @@
 {{ custom_html }}
 {% elif login_service %}
 <div class="service-login">
-  <a class='btn btn-jupyter btn-lg' href='{{login_url}}'>
+  <a class='btn btn-jupyter btn-lg' href='{{authenticator_login_url}}'>
     Sign in with {{login_service}}
   </a>
 </div>

share/jupyter/hub/templates/logout.html

@@ -0,0 +1,9 @@
+{% extends "page.html" %}
+{% block main %}
+<div id="logout-main" class="container">
+  <p>
+    Successfully logged out.
+  </p>
+</div>
+{% endblock %}
+