add JupyterHub.public_url config

When specified, removes all guesses based on the request,
which aren't always correct in proxy situations (especially Host and protocol)

jupyterhub/apihandlers/auth.py

@@ -110,14 +110,20 @@ class OAuthHandler:
         redirect_uri = self.get_argument('redirect_uri')
         if not redirect_uri or not redirect_uri.startswith('/'):
             return uri
+
         # make absolute local redirects full URLs
         # to satisfy oauthlib's absolute URI requirement
-        redirect_uri = (
-            get_browser_protocol(self.request)
-            + "://"
-            + self.request.host
-            + redirect_uri
-        )
+
+        public_url = self.settings.get("public_url")
+        if public_url:
+            proto = public_url.scheme
+            host = public_url.netloc
+        else:
+            # guess from request
+            proto = get_browser_protocol(self.request)
+            host = self.request.host
+        redirect_uri = f"{proto}://{host}{redirect_uri}"
+
         parsed_url = urlparse(uri)
         query_list = parse_qsl(parsed_url.query, keep_blank_values=True)
         for idx, item in enumerate(query_list):

jupyterhub/app.py

@@ -704,6 +704,21 @@ class JupyterHub(Application):
         proto = 'https' if self.ssl_cert else 'http'
         return proto + '://:8000'
 
+    public_url = Unicode(
+        "",
+        config=True,
+        help="""Set the public URL of JupyterHub
+
+        This will skip any detection of URL and protocol from requests,
+        which isn't always correct when JupyterHub is behind
+        multiple layers of proxies, etc.
+        Usually the failure is detecting http when it's really https.
+
+        Should include the full, public URL of JupyterHub,
+        including the public-facing base_url prefix.
+        """,
+    )
+
     subdomain_host = Unicode(
         '',
         help="""Run single-user servers on subdomains of this host.
@@ -2755,6 +2770,7 @@ class JupyterHub(Application):
             spawner_class=self.spawner_class,
             base_url=self.base_url,
             default_url=self.default_url,
+            public_url=urlparse(self.public_url) if self.public_url else "",
             cookie_secret=self.cookie_secret,
             cookie_max_age_days=self.cookie_max_age_days,
             redirect_to_server=self.redirect_to_server,

jupyterhub/handlers/base.py

@@ -569,10 +569,15 @@ class BaseHandler(RequestHandler):
         # tornado <4.2 have a bug that consider secure==True as soon as
         # 'secure' kwarg is passed to set_secure_cookie
         kwargs = {'httponly': True}
-        if self.request.protocol == 'https':
-            kwargs['secure'] = True
-        if self.subdomain_host:
-            kwargs['domain'] = self.domain
+        public_url = self.settings.get("public_url")
+        if public_url:
+            if public_url.scheme == 'https':
+                kwargs['secure'] = True
+        else:
+            if self.request.protocol == 'https':
+                kwargs['secure'] = True
+            if self.subdomain_host:
+                kwargs['domain'] = self.domain
 
         kwargs.update(self.settings.get('cookie_options', {}))
         kwargs.update(overrides)
@@ -654,8 +659,15 @@ class BaseHandler(RequestHandler):
         next_url = self.get_argument('next', default='')
         # protect against some browsers' buggy handling of backslash as slash
         next_url = next_url.replace('\\', '%5C')
-        proto = get_browser_protocol(self.request)
-        host = self.request.host
+        public_url = self.settings.get("public_url")
+        if public_url:
+            proto = public_url.scheme
+            host = public_url.netloc
+        else:
+            # guess from request
+            proto = get_browser_protocol(self.request)
+            host = self.request.host
+
         if next_url.startswith("///"):
             # strip more than 2 leading // down to 2
             # because urlparse treats that as empty netloc,

jupyterhub/services/auth.py

@@ -37,7 +37,7 @@ import uuid
 import warnings
 from http import HTTPStatus
 from unittest import mock
-from urllib.parse import urlencode
+from urllib.parse import urlencode, urlparse
 
 from tornado.httpclient import AsyncHTTPClient, HTTPRequest
 from tornado.httputil import url_concat
@@ -891,8 +891,13 @@ class HubOAuth(HubAuth):
             # OAuth that doesn't complete shouldn't linger too long.
             'max_age': 600,
         }
-        if get_browser_protocol(handler.request) == 'https':
-            kwargs['secure'] = True
+        public_url = os.getenv("JUPYTERHUB_PUBLIC_URL")
+        if public_url:
+            if urlparse(public_url).scheme == 'https':
+                kwargs['secure'] = True
+        else:
+            if get_browser_protocol(handler.request) == 'https':
+                kwargs['secure'] = True
         # load user cookie overrides
         kwargs.update(self.cookie_options)
         handler.set_secure_cookie(cookie_name, b64_state, **kwargs)