From 844c5996ffc5121c4fc875f0ea3c8d96195b7202 Mon Sep 17 00:00:00 2001
From: Danny <dannyvankooten@gmail.com>
Date: Wed, 13 Jun 2018 11:15:18 +0200
Subject: [PATCH] set 'Tk: N' header on resources loaded by client. #65

---
 pkg/api/collect.go |  7 ++++++-
 pkg/api/routes.go  | 10 +++++++++-
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/pkg/api/collect.go b/pkg/api/collect.go
index 1d9389b..06c75dd 100644
--- a/pkg/api/collect.go
+++ b/pkg/api/collect.go
@@ -122,11 +122,16 @@ func (api *API) NewCollectHandler() http.Handler {
 			return err
 		}
 
-		// don't you cache this
+		// indicate that we're not tracking user data, see https://github.com/usefathom/fathom/issues/65
+		w.Header().Set("Tk", "N")
+
+		// headers to prevent caching
 		w.Header().Set("Content-Type", "image/gif")
 		w.Header().Set("Expires", "Mon, 01 Jan 1990 00:00:00 GMT")
 		w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
 		w.Header().Set("Pragma", "no-cache")
+
+		// response
 		w.WriteHeader(http.StatusOK)
 
 		// 1x1 px transparent GIF
diff --git a/pkg/api/routes.go b/pkg/api/routes.go
index 164d32c..f8fb537 100644
--- a/pkg/api/routes.go
+++ b/pkg/api/routes.go
@@ -29,10 +29,18 @@ func (api *API) Routes() *mux.Router {
 
 	// static assets & 404 handler
 	box := packr.NewBox("./../../assets/build")
-	r.Path("/tracker.js").Handler(serveFileHandler(&box, "js/tracker.js"))
+	r.Path("/tracker.js").Handler(serveTrackerFile(&box))
 	r.Path("/").Handler(serveFileHandler(&box, "index.html"))
 	r.PathPrefix("/assets").Handler(http.StripPrefix("/assets", http.FileServer(box)))
 	r.NotFoundHandler = NotFoundHandler(&box)
 
 	return r
 }
+
+func serveTrackerFile(box *packr.Box) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Tk", "N")
+		next := serveFile(box, "js/tracker.js")
+		next.ServeHTTP(w, r)
+	})
+}