Add httpmiddleware

Author: svarlamov

.drone.yml

@@ -50,3 +50,8 @@ pipeline:
     commands:
       - cd sqlkit
       - go build
+  httpmiddleware-build:
+    image: golang:1.9.2
+    commands:
+      - cd httpmiddleware
+      - go build

httpmiddleware/recover.go

@@ -0,0 +1,16 @@
+package httpmiddleware
+
+import "net/http"
+
+func RecoverInternalServerError(handler http.Handler) http.HandlerFunc {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		defer func() {
+			r := recover()
+			if r != nil {
+				w.WriteHeader(http.StatusInternalServerError)
+				w.Write([]byte("Internal server error"))
+			}
+		}()
+		handler.ServeHTTP(w, r)
+	})
+}

httpmiddleware/use.go

@@ -0,0 +1,12 @@
+package httpmiddleware
+
+import "net/http"
+
+// `Use` allows us to stack middleware to process the request
+// Example taken from https://github.com/gorilla/mux/pull/36#issuecomment-25849172
+func Use(handler http.HandlerFunc, mid ...func(http.Handler) http.HandlerFunc) http.HandlerFunc {
+	for _, m := range mid {
+		handler = m(handler)
+	}
+	return handler
+}