Add refresh content docs

docs/docs/environment-variables.md

@@ -134,9 +134,7 @@ Gatsby also allows you to specify another environment variable when running the
 
 - `ENABLE_GATSBY_REFRESH_ENDPOINT`
 
-If set to true, this will expose a `/__refresh` webhook that is able to receive `POST` requests to _refresh_ the sourced content. This exposed webhook can be triggered whenever remote data changes, which means you can update your data without re-launching the development server.
-
-You can trigger this endpoint locally, for example, on Unix-based operating systems (like Ubuntu and macOS) using `curl -X POST http://localhost:8000/__refresh`.
+This allows you to refresh your sourced content. See [Refreshing content](/docs/content-and-data/refreshing-content).
 
 ## Build Variables
 

docs/docs/refreshing-content.md

@@ -0,0 +1,13 @@
+---
+title: Refreshing Content
+---
+
+During local development it can be useful to refresh sourced content without restarting the development server. To faciliate this Gatsby exposes an environmental variable `ENABLE_GATSBY_REFRESH_ENDPOINT`.
+
+If set to true, this will expose a /\_\_refresh webhook that is able to receive POST requests to refresh the sourced content. This exposed webhook can be triggered whenever remote data changes.
+
+You can trigger this endpoint locally, for example, on Unix-based operating systems (like Ubuntu and macOS) using curl -X POST http://localhost:8000/__refresh.
+
+Additionally, the sourced content can also be refreshed through the GraphiQL explorer.
+
+Securing the refresh endpoint is possible by supplying a value for the environmental variable `GATSBY_REFRESH_TOKEN`, which will cause Gatsby to only accept requests with a matching authorization header. For example `GATSBY_REFRESH_TOKEN=12345` would require a request with header: `authorization: 12345`.

www/src/data/sidebars/doc-links.yaml

@@ -228,6 +228,8 @@
             - title: Sourcing Content from JSON or YAML
               link: /docs/sourcing-content-from-json-or-yaml/
               breadcrumbTitle: JSON or YAML
+            - title: Refreshing Content
+              link: /docs/refreshing-content/
         - title: Querying Your Data with GraphQL
           link: /docs/graphql/
           breadcrumbTitle: Querying with GraphQL