Add: Message Id header to avoid spam mails

1. Add: Message Id header to avoid spam mails

notificationmdl/email/email.go

@@ -7,6 +7,8 @@ import (
 	"strings"
 	"sync"
 
+	"corelab.mkcl.org/MKCLOS/coredevelopmentplatform/corepkgv2/utiliymdl/guidmdl"
+
 	"gopkg.in/gomail.v2"
 
 	"corelab.mkcl.org/MKCLOS/coredevelopmentplatform/corepkgv2/configmdl"
@@ -51,6 +53,7 @@ type Email struct {
 	subject     string
 	attachments []string
 	body        string
+	plainBody   string
 }
 
 func NewEmail(to, cc, bcc, attachments []string, from, subject, body string) *Email {
@@ -127,13 +130,21 @@ func (email *Email) parseTemplateText(templateText string, templateData interfac
 
 // Send -send email
 func (email *Email) Send() error {
+	domain, domainErr := getSenderDomain(email.from)
+	if domainErr != nil {
+		loggermdl.LogError("error getting domain address: ", domainErr)
+		return domainErr
+	}
 	message := gomail.NewMessage()
 	message.SetHeader("From", email.from)
 	message.SetHeader("To", email.to...)
 	message.SetHeader("Cc", email.cc...)
 	message.SetHeader("Bcc", email.bcc...)
 	message.SetHeader("Subject", email.subject)
-	message.SetBody("text/html", email.body)
+	message.SetBody("text/plain", email.plainBody)
+	message.SetHeader("Message-ID", getMSGIDHeader(domain, guidmdl.GetGUID()))
+	message.AddAlternative("text/html", email.body)
+
 	for _, attachment := range email.attachments {
 		message.Attach(attachment) // attach whatever you want
 	}
@@ -146,6 +157,19 @@ func (email *Email) Send() error {
 	return nil
 }
 
+func getMSGIDHeader(domain, guid string) string {
+	return "<" + guid + "@" + domain + ">"
+}
+
+func getSenderDomain(from string) (string, error) {
+	s := strings.Split(from, "@")
+	if len(s) != 2 {
+		return "", errormdl.Wrap("invalid email id for sender")
+	}
+
+	return s[1], nil
+}
+
 // SendMailSMTP - send email service sends email as per the given html template and data using smtp
 // func (email *Email) SendMailSMTP(templateFilePath string, templateData interface{}) error {
 // 	err := email.parseTemplate(templateFilePath, templateData)