fix: disable cache on config route

ref: #35

Signed-off-by: A. Ottr <alex@otter.foo>

Author: aottr

backend/src/config/config.controller.ts

@@ -22,8 +22,10 @@ import { ConfigDTO } from "./dto/config.dto";
 import { TestEmailDTO } from "./dto/testEmail.dto";
 import UpdateConfigDTO from "./dto/updateConfig.dto";
 import { LogoService } from "./logo.service";
+import { NoCacheInterceptor } from "./interceptor/no-cache.interceptor";
 
 @Controller("configs")
+@UseInterceptors(NoCacheInterceptor)
 export class ConfigController {
   constructor(
     private configService: ConfigService,

backend/src/config/interceptor/no-cache.interceptor.ts

@@ -0,0 +1,28 @@
+import {
+  CallHandler,
+  ExecutionContext,
+  Injectable,
+  NestInterceptor,
+} from "@nestjs/common";
+import { Observable } from "rxjs";
+import { tap } from "rxjs/operators";
+
+@Injectable()
+export class NoCacheInterceptor implements NestInterceptor {
+  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
+    const response = context.switchToHttp().getResponse();
+
+    return next.handle().pipe(
+      tap(() => {
+        // Set headers to prevent caching by reverse proxies
+        response.setHeader(
+          "Cache-Control",
+          "no-store, no-cache, must-revalidate, private",
+        );
+        response.setHeader("Pragma", "no-cache");
+        response.setHeader("Expires", "0");
+      }),
+    );
+  }
+}
+