Merge pull request #406 from plotly/default-favicon

Default favicon

Author: T4rk1n

Diff for: CHANGELOG.md

@@ -1,3 +1,11 @@
+## 0.28.0 - 2018-09-26
+## Added
+- Default favicon for dash apps. [#406](https://github.com/plotly/dash/pull/406#issuecomment-424821743)
+- Bust the cache of the assets favicon.
+
+## Fixed
+- Remove the first and last blank lines from the HTML index string. [#403](https://github.com/plotly/dash/pull/403)
+
 ## 0.27.0 - 2018-09-20
 ## Added
 - Added support for serving dev bundles from the components suite, enable with `app.run_server(dev_tools_serve_dev_bundles=True)` [#369](https://github.com/plotly/dash/pull/369)

Diff for: MANIFEST.in

@@ -1,2 +1,3 @@
 include README.md
 include LICENSE
+include dash/favicon.ico

Diff for: dash/dash.py

@@ -214,6 +214,9 @@ def add_url(name, view_func, methods=('GET',)):
             '{}<path:path>'.format(self.config['routes_pathname_prefix']),
             self.index)
 
+        add_url('{}_favicon.ico'.format(self.config['routes_pathname_prefix']),
+                self._serve_default_favicon)
+
         self.server.before_first_request(self._setup_server)
 
         self._layout = None
@@ -459,11 +462,22 @@ def index(self, *args, **kwargs):  # pylint: disable=unused-argument
         config = self._generate_config_html()
         metas = self._generate_meta_html()
         title = getattr(self, 'title', 'Dash')
+
         if self._favicon:
-            favicon = '<link rel="icon" type="image/x-icon" href="{}">'.format(
-                self.get_asset_url(self._favicon))
+            favicon_mod_time = os.path.getmtime(
+                os.path.join(self._assets_folder, self._favicon))
+            favicon_url = self.get_asset_url(self._favicon) + '?m={}'.format(
+                favicon_mod_time
+            )
         else:
-            favicon = ''
+            favicon_url = '{}_favicon.ico'.format(
+                self.config.requests_pathname_prefix)
+
+        favicon = _format_tag('link', {
+            'rel': 'icon',
+            'type': 'image/x-icon',
+            'href': favicon_url
+        }, opened=True)
 
         index = self.interpolate_index(
             metas=metas, title=title, css=css, config=config,
@@ -973,6 +987,15 @@ def add_resource(p, filepath):
     def _invalid_resources_handler(self, err):
         return err.args[0], 404
 
+    def _serve_default_favicon(self):
+        headers = {
+            'Cache-Control': 'public, max-age={}'.format(
+                self.config.components_cache_max_age)
+        }
+        return flask.Response(pkgutil.get_data('dash', 'favicon.ico'),
+                              headers=headers,
+                              content_type='image/x-icon')
+
     def get_asset_url(self, path):
         asset = _get_asset_path(
             self.config.requests_pathname_prefix,

Diff for: dash/favicon.ico

@@ -1 +1 @@
-__version__ = '0.27.0'
+__version__ = '0.28.0'