WIP Bound request queue (#28)

Bound request queue

Author: chriddyp

Diff for: CHANGELOG.md

@@ -2,6 +2,10 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## [0.11.1] - 2017-10-19
+### Fixed
+- :snail: :racehorse: Fixed a performance issue. In 0.11.0 we introduced an  internal request queue to fix some bugs. This request queue was boundless and in certain cases it could become really large and slow down the app. Now, we remove old requests from this queue when they are no longer needed, keeping its size under control. Originally reported in https://github.com/plotly/dash-renderer/issues/27
+
 ## [0.11.0] - 2017-09-28
 ### Fixed
 - 🐞 Previously, old requests could override new requests if their response was longer than the new one.

Diff for: dash_renderer/__init__.py

@@ -7,7 +7,8 @@
 # command in the dash_html_components package which printed out:
 # `dash_html_components.__init__: module references __file__`
 # TODO - Understand this better
-from .version import __version__
+# from .version import __version__
+__version__ = '0.11.1'
 __file__
 
 # Dash renderer's dependencies get loaded in a special order by the server:

Diff for: dash_renderer/version.py

@@ -1 +1 @@
-__version__ = '0.11.0'
+__version__ = '0.11.1'

Diff for: package.json

@@ -1,6 +1,6 @@
 {
   "name": "dash-renderer",
-  "version": "0.11.0",
+  "version": "0.11.1",
   "description": "render dash components in react",
   "main": "src/index.js",
   "scripts": {

Diff for: src/actions/index.js

@@ -397,6 +397,10 @@ export function notifyObservers(payload) {
                 const updateRequestQueue = rejected => {
                     const postRequestQueue = getState().requestQueue
                     const thisRequestIndex = getThisRequestIndex();
+                    if (thisRequestIndex === -1) {
+                        // It was already pruned away
+                        return;
+                    }
                     const updatedQueue = adjust(
                         merge(__, {
                             status: res.status,
@@ -406,15 +410,32 @@ export function notifyObservers(payload) {
                         thisRequestIndex,
                         postRequestQueue
                     );
+                    // We don't need to store any requests before this one
+                    const thisControllerId = postRequestQueue[
+                        thisRequestIndex].controllerId;
+                    const prunedQueue = updatedQueue.filter(
+                        (queueItem, index) => {
+                            return (
+                                queueItem.controllerId !== thisControllerId ||
+                                index >= thisRequestIndex
+                            );
+                        }
+                    );
 
-                    dispatch(setRequestQueue(updatedQueue));
+                    dispatch(setRequestQueue(prunedQueue));
                 }
 
                 const isRejected = () => {
                     const latestRequestIndex = findLastIndex(
                         propEq('controllerId', newRequestQueue[i].controllerId),
                         getState().requestQueue
                     );
+                    /*
+                     * Note that if the latest request is still `loading`
+                     * or even if the latest request failed,
+                     * we still reject this response in favor of waiting
+                     * for the latest request to finish.
+                     */
                     const rejected = latestRequestIndex > getThisRequestIndex();
                     return rejected;
                 }

Diff for: tests/test_render.py

@@ -462,7 +462,8 @@ def update_output(value):
         )
 
         self.request_queue_assertions(
-            expected_length=call_count.value, check_rejected=False)
+            expected_length=1,
+            check_rejected=False)
 
         assert_clean_console(self)
 
@@ -1535,5 +1536,4 @@ def update_output(n_clicks):
             'return window.store.getState().requestQueue'
         )
         self.assertFalse(request_queue[0]['rejected'])
-        self.assertTrue(request_queue[1]['rejected'])
-        self.assertFalse(request_queue[2]['rejected'])
+        self.assertEqual(len(request_queue), 1)