Add instructions on how to reverse proxy

README.md

@@ -27,6 +27,29 @@ pip install -r requirements.txt
 PREVIEW_HOMESERVER=https://example.com python3 server.py
 ```
 
+### With a reverse proxy
+You should use a reverse proxy to handle routing the request to this server. An example with caddy
+(ripped from my config file for matrix.nexy7574.co.uk)is below:
+
+```caddy
+matrix.example.com {
+    # Add cache control, CSP, and CORP:
+    header /_matrix/media/*/thumbnail/*/* Cache-Control 'max-age=172800,stale-while-revalidate=86400'
+    header /_matrix/media/*/download/*/* Cache-Control 'max-age=172800,stale-while-revalidate=86400'
+    header /_matrix/media/* Content-Security-Policy "sandbox; default-src 'none'; script-src 'none'; plugin-types application/pdf; style-src 'unsafe-inline'; object-src 'self';"
+    header /_matrix/media/* Cross-Origin-Resource-Policy 'cross-origin'
+
+    # Send all requests for URL previews to the DIP server
+    rewrite /_matrix/media/*/preview_url /preview_url
+    reverse_proxy /preview_url localhost:2226
+    
+    # Send all other requests to the homeserver
+    reverse_proxy localhost:8008
+}
+```
+
+You can most likely figure out how to do this with your chosen reverse proxy server if you aren't using Caddy.
+
 ### Example docker-compose.yml
 ```yaml
 version: "3"