From 3943897ae62cc82ab8e44eb55c330fd300eb6aba Mon Sep 17 00:00:00 2001
From: Achim Rohn <achim@rohn.eu>
Date: Wed, 13 Aug 2025 15:31:01 +0200
Subject: [PATCH] Add middleware that also gzips html content

---
 middleware.go | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 middleware.go

diff --git a/middleware.go b/middleware.go
new file mode 100644
index 0000000..7553b9c
--- /dev/null
+++ b/middleware.go
@@ -0,0 +1,58 @@
+package ersteller_lib
+
+import (
+	"compress/gzip"
+	"io"
+	"net/http"
+	"strings"
+)
+
+type gzipResponseWriter struct {
+	io.Writer
+	http.ResponseWriter
+}
+
+func (w gzipResponseWriter) Write(b []byte) (int, error) {
+	return w.Writer.Write(b)
+}
+
+// https://gist.github.com/the42/1956518
+func MakeGzipHandler(fn http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if !strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
+			fn.ServeHTTP(w, r)
+			return
+		}
+		w.Header().Set("Content-Encoding", "gzip")
+		gz := gzip.NewWriter(w)
+		defer gz.Close()
+		gzr := gzipResponseWriter{Writer: gz, ResponseWriter: w}
+		fn.ServeHTTP(gzr, r)
+	})
+}
+
+// https://www.jvt.me/posts/2023/09/01/golang-nethttp-global-middleware/
+func UseMiddleware(r *http.ServeMux, middlewares ...func(next http.Handler) http.Handler) http.Handler {
+	var s http.Handler
+	s = r
+
+	for _, mw := range middlewares {
+		s = mw(s)
+	}
+
+	return s
+}
+
+func LoggingMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		Debug("Path ", r.URL.String())
+		next.ServeHTTP(w, r)
+	})
+}
+
+func AcceptHeaderMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		Debug("Accept: %v", r.Header.Get("Accept"))
+		next.ServeHTTP(w, r)
+	})
+}