Support hparams plugin via Tensorboard POST api handler.

jupyter_tensorboard/handlers.py

@@ -70,6 +70,59 @@ def get(self, name, path):
         else:
             raise web.HTTPError(404)
 
+    @web.authenticated
+    def post(self, name, path):
+
+        if path == "":
+            uri = self.request.path + "/"
+            if self.request.query:
+                uri += "?" + self.request.query
+            self.redirect(uri, permanent=True)
+            return
+
+        self.request.path = (
+            path if self.request.query
+            else "%s?%s" % (path, self.request.query))
+
+        manager = self.settings["tensorboard_manager"]
+        if name in manager:
+            tb_app = manager[name].tb_app
+            WSGIContainer(tb_app)(self.request)
+        else:
+            raise web.HTTPError(404)
+
+    def check_xsrf_cookie(self):
+        """Expand xsrf check exception for POST requests.
+
+        Expand xsrf_cookie exceptions, normally only applied to GET and HEAD
+        requests, to POST requests for tensorboard api.
+
+        Provides support for hparams plugin, which uses POST to retrieve
+        experiment information but can't be trivially extended to include xsrf
+        information in these POST requests.
+
+        """
+
+        try:
+            return super(TensorboardHandler, self).check_xsrf_cookie()
+        except web.HTTPError:
+            if self.request.method in {"GET", "POST", "HEAD"}:
+                # Consider Referer a sufficient cross-origin check for GET
+                # requests, mirrors logic in IPythonHandler.check_xsrf_cookie.
+                # Extended to POST for Tensorboard API.
+                if not self.check_referer():
+                    referer = self.request.headers.get("Referer")
+                    if referer:
+                        msg = (
+                            "Blocking Cross Origin request from {}."
+                            .format(referer)
+                        )
+                    else:
+                        msg = "Blocking request from unknown origin"
+                    raise web.HTTPError(403, msg)
+            else:
+                raise
+
 
 class TensorboardErrorHandler(IPythonHandler):
     pass