Properly escape template variables

dev_mode/templates/partial.html

@@ -1,12 +1,14 @@
-  <script id="jupyter-config-data" type="application/json">{
-    {% for key, value in page_config.items() -%}
-    "{{ key }}": "{{ value }}",
-    {% endfor -%}
-    "baseUrl": "{{ base_url }}",
-    "wsUrl": "{{ ws_url }}"
-  }</script>
+{# Copy so we do not modify the page_config with updates. #}
+{% set page_config_full = page_config.copy() %}
+
+{# Set a dummy variable - we just want the side effect of the update. #}
+{% set _ = page_config_full.update(baseUrl=base_url, wsUrl=ws_url) %}
+
+  <script id="jupyter-config-data" type="application/json">
+    {{ page_config_full | tojson }}
+  </script>
 
   {% block favicon %}
-  <link rel="icon" type="image/x-icon" href="{{ base_url }}static/base/images/favicon.ico" class="idle favicon">
-  <link rel="" type="image/x-icon" href="{{ base_url }}static/base/images/favicon-busy-1.ico" class="busy favicon">
+  <link rel="icon" type="image/x-icon" href="{{ base_url | urlencode }}static/base/images/favicon.ico" class="idle favicon">
+  <link rel="" type="image/x-icon" href="{{ base_url | urlencode }}static/base/images/favicon-busy-1.ico" class="busy favicon">
   {% endblock %}