Add external_js/css_urls to dash ctor, support for external only urls

dash/dash.py

@@ -61,7 +61,7 @@
 
 
 # pylint: disable=too-many-instance-attributes
-# pylint: disable=too-many-arguments
+# pylint: disable=too-many-arguments, too-many-locals
 class Dash(object):
     def __init__(
             self,
@@ -75,6 +75,8 @@ def __init__(
             compress=True,
             meta_tags=None,
             index_string=_default_index,
+            external_script_urls=None,
+            external_css_urls=None,
             **kwargs):
 
         # pylint-disable: too-many-instance-attributes
@@ -128,6 +130,10 @@ def _handle_error(error):
         # static files from the packages
         self.css = Css()
         self.scripts = Scripts()
+
+        self._external_scripts_urls = external_script_urls or []
+        self._external_css_urls = external_css_urls or []
+
         self.registered_paths = {}
 
         # urls
@@ -302,7 +308,8 @@ def _relative_url_path(relative_package_path='', namespace=''):
     def _generate_css_dist_html(self):
         links = self._collect_and_register_resources(
             self.css.get_all_css()
-        )
+        ) + self._external_css_urls
+
         return '\n'.join([
             '<link rel="stylesheet" href="{}">'.format(link)
             for link in links
@@ -324,7 +331,7 @@ def _generate_scripts_html(self):
             self.scripts._resources._filter_resources(
                 dash_renderer._js_dist
             )
-        )
+        ) + self._external_scripts_urls
 
         return '\n'.join([
             '<script src="{}"></script>'.format(src)

tests/test_integration.py

@@ -434,4 +434,26 @@ def will_raise():
         self.assertTrue('{%config%}' in exc_msg)
         self.assertTrue('{%scripts%}' in exc_msg)
         time.sleep(0.5)
-        print('invalid index string')
+
+    def test_external_files_init(self):
+        js_files = [
+            'https://www.google-analytics.com/analytics.js',
+            'https://cdn.polyfill.io/v2/polyfill.min.js'
+        ]
+        css_files = [
+            'https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css',
+            'https://codepen.io/chriddyp/pen/bWLwgP.css'
+        ]
+
+        app = dash.Dash(
+            external_script_urls=js_files, external_css_urls=css_files)
+
+        app.layout = html.Div()
+
+        self.startServer(app)
+        time.sleep(0.5)
+
+        for fmt, url in itertools.chain(
+                (("//script[@src='{}']", x) for x in js_files),
+                (("//link[@href='{}']", x) for x in css_files)):
+            self.driver.find_element_by_xpath(fmt.format(url))