Add Google FLoC opt-out header on web page requests. Closes #939

controllers/index.go

@@ -64,6 +64,9 @@ func IndexHandler(w http.ResponseWriter, r *http.Request) {
 	// Set a cache control max-age header
 	middleware.SetCachingHeaders(w, r)
 
+	// Opt-out of Google FLoC
+	middleware.DisableFloc(w)
+
 	http.ServeFile(w, r, path.Join(config.WebRoot, r.URL.Path))
 }
 

router/middleware/disableFloc.go

@@ -0,0 +1,8 @@
+package middleware
+
+import "net/http"
+
+// DisableFloc will tell Google to not use this response in their FLoC tracking.
+func DisableFloc(w http.ResponseWriter) {
+	w.Header().Set("Permissions-Policy", "interest-cohort=()")
+}