Use production mode (#904)

* Set NODE_ENV to production

* Disable the X-Powered-By HTTP header

* Explain what the different values do

* Add changelog file

Dockerfile

@@ -45,6 +45,8 @@ COPY --from=builder /src/lib ./
 COPY --from=builder /src/public ./public
 COPY --from=builder /src/assets ./assets
 
+ENV NODE_ENV="production"
+
 VOLUME /data
 EXPOSE 9993
 EXPOSE 7775

changelog.d/904.misc

@@ -0,0 +1 @@
+Switch expressjs to production mode for improved performance.

docs/setup.md

@@ -27,7 +27,12 @@ cd matrix-hookshot
 yarn # or npm i
 ```
 
-Starting the bridge (after configuring it), is a matter of running `yarn start`.
+Starting the bridge (after configuring it), is a matter of setting the `NODE_ENV` environment variable to `production` or `development`, depending if you want [better performance or more verbose logging](https://expressjs.com/en/advanced/best-practice-performance.html#set-node_env-to-production), and then running it:
+
+
+```bash
+NODE_ENV=production yarn start
+```
 
 ## Installation via Docker
 

src/ListenerService.ts

@@ -30,6 +30,7 @@ export class ListenerService {
         }
         for (const listenerConfig of config) {
             const app = expressApp();
+            app.set('x-powered-by', false);
             app.use(Handlers.requestHandler());
             this.listeners.push({
                 config: listenerConfig,