docs: HTML embedding of charts/dashboards without authentication (apa…

…che#30032)

Co-authored-by: Sam Firke <sfirke@users.noreply.github.com>

docs/docs/configuration/networking-settings.mdx

@@ -1,3 +1,4 @@
+
 ---
 title: Network and Security Settings
 sidebar_position: 7
@@ -24,9 +25,65 @@ The following keys in `superset_config.py` can be specified to configure CORS:
 ## HTTP headers
 
 Note that Superset bundles [flask-talisman](https://pypi.org/project/talisman/)
-Self-descried as a small Flask extension that handles setting HTTP headers that can help
+Self-described as a small Flask extension that handles setting HTTP headers that can help
 protect against a few common web application security issues.
 
+
+## HTML Embedding of Dashboards and Charts
+
+There are two ways to embed a dashboard: Using the [SDK](https://www.npmjs.com/package/@superset-ui/embedded-sdk) or embedding a direct link. Note that in the latter case everybody who knows the link is able to access the dashboard.
+
+### Embedding a Public Direct Link to a Dashboard
+
+This works by first changing the content security policy (CSP) of [flask-talisman](https://github.com/GoogleCloudPlatform/flask-talisman) to allow for certain domains to display Superset content. Then a dashboard can be made publicly accessible, i.e. **bypassing authentication**. Once made public, the dashboard's URL can be added to an iframe in another website's HTML code.
+
+#### Changing flask-talisman CSP
+
+Add to `superset_config.py` the entire `TALISMAN_CONFIG` section from `config.py` and include a `frame-ancestors` section:
+```python
+TALISMAN_ENABLED = True
+TALISMAN_CONFIG = {
+    "content_security_policy": {
+    ...
+	"frame-ancestors": ["*.my-domain.com", "*.another-domain.com"],
+    ...
+```
+Restart Superset for this configuration change to take effect.
+
+#### Making a Dashboard Public
+
+1. Add the `'DASHBOARD_RBAC': True` [Feature Flag](https://github.com/apache/superset/blob/master/RESOURCES/FEATURE_FLAGS.md) to `superset_config.py`
+2. Add the `Public` role to your dashboard as described [here](https://superset.apache.org/docs/using-superset/creating-your-first-dashboard/#manage-access-to-dashboards)
+
+#### Embedding a Public Dashboard
+
+Now anybody can directly access the dashboard's URL. You can embed it in an iframe like so:
+
+```html
+<iframe
+  width="600"
+  height="400"
+  seamless
+  frameBorder="0"
+  scrolling="no"
+  src="https://superset.my-domain.com/superset/dashboard/10/?standalone=1&height=400"
+>
+</iframe>
+```
+#### Embedding a Chart
+
+A chart's embed code can be generated by going to a chart's edit view and then clicking at the top right on `...` > `Share` > `Embed code`
+
+### Enabling Embedding via the SDK
+
+Clicking on `...` next to `EDIT DASHBOARD` on the top right of the dashboard's overview page should yield a drop-down menu including the entry "Embed dashboard".
+
+To enable this entry, add the following line to the `.env` file:
+
+```text
+SUPERSET_FEATURE_EMBEDDED_SUPERSET=true
+```
+
 ## CSRF settings
 
 Similarly, [flask-wtf](https://flask-wtf.readthedocs.io/en/0.15.x/config/) is used manage