Move middlewares to web/middleware (#14480)

Co-authored-by: 6543 <6543@obermui.de>

modules/web/middleware/flash.go

@@ -0,0 +1,68 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package middleware
+
+import "net/url"
+
+// flashes enumerates all the flash types
+const (
+	SuccessFlash = "SuccessMsg"
+	ErrorFlash   = "ErrorMsg"
+	WarnFlash    = "WarningMsg"
+	InfoFlash    = "InfoMsg"
+)
+
+var (
+	// FlashNow FIXME:
+	FlashNow bool
+)
+
+// Flash represents a one time data transfer between two requests.
+type Flash struct {
+	DataStore
+	url.Values
+	ErrorMsg, WarningMsg, InfoMsg, SuccessMsg string
+}
+
+func (f *Flash) set(name, msg string, current ...bool) {
+	if f.Values == nil {
+		f.Values = make(map[string][]string)
+	}
+	isShow := false
+	if (len(current) == 0 && FlashNow) ||
+		(len(current) > 0 && current[0]) {
+		isShow = true
+	}
+
+	if isShow {
+		f.GetData()["Flash"] = f
+	} else {
+		f.Set(name, msg)
+	}
+}
+
+// Error sets error message
+func (f *Flash) Error(msg string, current ...bool) {
+	f.ErrorMsg = msg
+	f.set("error", msg, current...)
+}
+
+// Warning sets warning message
+func (f *Flash) Warning(msg string, current ...bool) {
+	f.WarningMsg = msg
+	f.set("warning", msg, current...)
+}
+
+// Info sets info message
+func (f *Flash) Info(msg string, current ...bool) {
+	f.InfoMsg = msg
+	f.set("info", msg, current...)
+}
+
+// Success sets success message
+func (f *Flash) Success(msg string, current ...bool) {
+	f.SuccessMsg = msg
+	f.set("success", msg, current...)
+}