feat: add email sender

Signed-off-by: Kininaru <shiftregister233@outlook.com>

update go mod sum

Signed-off-by: Kininaru <shiftregister233@outlook.com>

object/email.go

@@ -0,0 +1,50 @@
+// Copyright 2021 The casbin Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// modified from https://github.com/casbin/casnode/blob/master/service/mail.go
+
+package object
+
+import (
+	"strconv"
+
+	"github.com/astaxie/beego"
+	"github.com/go-gomail/gomail"
+)
+
+var dialer *gomail.Dialer
+
+var mailConn = map[string]string{
+	"user": beego.AppConfig.String("mailUser"),
+	"pass": beego.AppConfig.String("mailPass"),
+	"host": beego.AppConfig.String("mailHost"),
+	"port": beego.AppConfig.String("mailPort"),
+}
+
+func InitDialer() {
+	port, _ := strconv.Atoi(mailConn["port"])
+	dialer = gomail.NewDialer(mailConn["host"], port, mailConn["user"], mailConn["pass"])
+}
+
+func SendEmail(title, content, dest, sender string) error {
+	message := gomail.NewMessage()
+	message.SetAddressHeader("From", beego.AppConfig.String("mailUser"), sender)
+	message.SetHeader("To", dest)
+	message.SetHeader("Subject", title)
+	message.SetBody("text/html", content)
+	if dialer == nil {
+		InitDialer()
+	}
+	return dialer.DialAndSend(message)
+}