Bust the assets cache on modification.

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.24.0 - 2018-08-10
+## Added
+- Add a modified time query string to the assets included in the index in order to bust the cache. [#319](https://github.com/plotly/dash/pull/309)
+
 ## 0.23.1 - 2018-08-02
 ## Added
 - Add ie-compat meta tag to the index by default. [#316](https://github.com/plotly/dash/pull/316)

dash/dash.py

@@ -302,7 +302,8 @@ def _relative_url_path(relative_package_path='', namespace=''):
                 )
             elif 'asset_path' in resource:
                 static_url = flask.url_for('assets.static',
-                                           filename=resource['asset_path'])
+                                           filename=resource['asset_path'],
+                                           mod=resource['ts'])
                 srcs.append(static_url)
         return srcs
 
@@ -863,8 +864,8 @@ def _walk_assets_directory(self):
         walk_dir = self._assets_folder
         slash_splitter = re.compile(r'[\\/]+')
 
-        def add_resource(p):
-            res = {'asset_path': p}
+        def add_resource(p, filepath):
+            res = {'asset_path': p, 'filepath': filepath}
             if self.config.assets_external_path:
                 res['external_url'] = '{}{}'.format(
                     self.config.assets_external_path, path)
@@ -887,10 +888,13 @@ def add_resource(p):
                 else:
                     path = f
 
+                full = os.path.join(current, f)
+
                 if f.endswith('js'):
-                    self.scripts.append_script(add_resource(path))
+                    self.scripts.append_script(
+                        add_resource(path, full))
                 elif f.endswith('css'):
-                    self.css.append_css(add_resource(path))
+                    self.css.append_css(add_resource(path, full))
                 elif f == 'favicon.ico':
                     self._favicon = path
 

dash/resources.py

@@ -1,6 +1,7 @@
 from copy import copy
 import json
 import warnings
+import os
 
 from .development.base_component import Component
 
@@ -30,7 +31,9 @@ def _filter_resources(self, all_resources):
             elif 'absolute_path' in s:
                 filtered_resource['absolute_path'] = s['absolute_path']
             elif 'asset_path' in s:
+                info = os.stat(s['filepath'])
                 filtered_resource['asset_path'] = s['asset_path']
+                filtered_resource['ts'] = info.st_mtime
             elif self.config.serve_locally:
                 warnings.warn(
                     'A local version of {} is not available'.format(

dash/version.py

@@ -1 +1 @@
-__version__ = '0.23.1'
+__version__ = '0.24.0'