Phase 1 MVP — echo bot factory

middleware.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"crypto/subtle"
+	"log"
+	"net/http"
+	"runtime/debug"
+	"time"
+)
+
+func chain(h http.Handler, mws ...func(http.Handler) http.Handler) http.Handler {
+	for i := len(mws) - 1; i >= 0; i-- {
+		h = mws[i](h)
+	}
+	return h
+}
+
+func recoverMW(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		defer func() {
+			if rec := recover(); rec != nil {
+				log.Printf("panic %s %s: %v\n%s", r.Method, r.URL.Path, rec, debug.Stack())
+				http.Error(w, "internal error", http.StatusInternalServerError)
+			}
+		}()
+		next.ServeHTTP(w, r)
+	})
+}
+
+type statusRecorder struct {
+	http.ResponseWriter
+	status int
+}
+
+func (sr *statusRecorder) WriteHeader(code int) {
+	sr.status = code
+	sr.ResponseWriter.WriteHeader(code)
+}
+
+func accessLogMW(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		start := time.Now()
+		sr := &statusRecorder{ResponseWriter: w, status: http.StatusOK}
+		next.ServeHTTP(sr, r)
+		log.Printf("%s %s %d %s", r.Method, r.URL.Path, sr.status, time.Since(start))
+	})
+}
+
+func verifyTelegramSecret(provided, expected string) bool {
+	if expected == "" {
+		return false
+	}
+	return subtle.ConstantTimeCompare([]byte(provided), []byte(expected)) == 1
+}