allow OPTIONS requests for api endpoints (to enable CORS)

jupyter_notebook/services/kernels/handlers.py

@@ -48,7 +48,7 @@ class MainKernelHandler(IPythonHandler):
 
 class KernelHandler(IPythonHandler):
 
-    SUPPORTED_METHODS = ('DELETE', 'GET')
+    SUPPORTED_METHODS = ('DELETE', 'GET', 'OPTIONS')
 
     @web.authenticated
     @json_errors
@@ -66,6 +66,12 @@ class KernelHandler(IPythonHandler):
         self.set_status(204)
         self.finish()
 
+    @web.authenticated
+    @json_errors
+    def options(self, kernel_id):
+        self.set_header('Access-Control-Allow-Headers', 'accept, content-type')
+        self.finish()
+
 
 class KernelActionHandler(IPythonHandler):
 
@@ -83,6 +89,12 @@ class KernelActionHandler(IPythonHandler):
             self.write(json.dumps(model))
         self.finish()
 
+    @web.authenticated
+    @json_errors
+    def options(self, kernel_id, action):
+        self.set_header('Access-Control-Allow-Headers', 'accept, content-type')
+        self.finish()
+
 
 class ZMQChannelsHandler(AuthenticatedZMQStreamHandler):
     

jupyter_notebook/services/kernelspecs/handlers.py

@@ -41,7 +41,7 @@ def kernelspec_model(handler, name):
     return d
 
 class MainKernelSpecHandler(IPythonHandler):
-    SUPPORTED_METHODS = ('GET',)
+    SUPPORTED_METHODS = ('GET', 'OPTIONS')
 
     @web.authenticated
     @json_errors
@@ -61,6 +61,11 @@ class MainKernelSpecHandler(IPythonHandler):
         self.set_header("Content-Type", 'application/json')
         self.finish(json.dumps(model))
 
+    @web.authenticated
+    @json_errors
+    def options(self):
+        self.finish()
+
 
 class KernelSpecHandler(IPythonHandler):
     SUPPORTED_METHODS = ('GET',)

jupyter_notebook/services/sessions/handlers.py

@@ -65,6 +65,12 @@ class SessionRootHandler(IPythonHandler):
         self.set_status(201)
         self.finish(json.dumps(model, default=date_default))
 
+    @web.authenticated
+    @json_errors
+    def options(self):
+        self.set_header('Access-Control-Allow-Headers', 'accept, content-type')
+        self.finish()
+
 class SessionHandler(IPythonHandler):
 
     SUPPORTED_METHODS = ('GET', 'PATCH', 'DELETE')