Change mail settings for smtps

docker-compose.yml

@@ -2,7 +2,7 @@ version: "3.5"
 
 services:
   database:
-    image: postgres
+    image: postgres:14.7
     restart: always
     environment:
       - POSTGRES_USER=postgres

mail/service.go

@@ -1,11 +1,12 @@
 package mail
 
 import (
+	"crypto/tls"
 	"fmt"
 	"net/smtp"
 	"strings"
 	"time"
-	"text/template" 
+
 	"github.com/sirupsen/logrus"
 )
 
@@ -16,41 +17,23 @@ type Mail struct {
 }
 
 func (mail *Mail) BuildMessage() []byte {
-
-	type TemplateData struct {
-		To      []string
-		Subject string
-		Body    string
-	}
-
-	var message strings.Builder
-
-	msg := "MIME-version: 1.0;\nContent-Type: text/html; charset=\"UTF-8\";\r\n"
-	msg += fmt.Sprintf("From: Recruitment Automation System IITK<%s>\r\n", sender)
-	msg += fmt.Sprintf("Subject: %s\r\n", mail.Subject)
+	message := "MIME-version: 1.0;\nContent-Type: text/html; charset=\"UTF-8\";\r\n"
+	message += fmt.Sprintf("From: Recruitment Automation System IITK<%s>\r\n", sender)
+	message += fmt.Sprintf("Subject: %s | Recruitment Automation System\r\n", mail.Subject)
 
 	// If mass mailing, BCC all the users
 	if len(mail.To) == 1 {
-		msg += fmt.Sprintf("To: %s\r\n\r\n", mail.To[0])
+		message += fmt.Sprintf("To: %s\r\n\r\n", mail.To[0])
 	} else {
-		msg += fmt.Sprintf("To: Undisclosed Recipients<%s>\r\n\r\n", webteam)
+		message += fmt.Sprintf("To: Undisclosed Recipients<%s>\r\n\r\n", webteam)
 	}
 
-	message.WriteString(msg)
+	message += strings.Replace(mail.Body, "\n", "<br>", -1)
+	message += "<br><br>--<br>Recruitment Automation System<br>"
+	message += "Indian Institute of Technology Kanpur<br><br>"
+	message += "<small>This is an auto-generated email. Please do not reply.</small>"
 
-	bodyWithLineBreaks := strings.ReplaceAll(mail.Body, "\n", "<br>")
-
-	tmpl := template.Must(template.New("Template").Parse(DefaultTemplate))
-	err := tmpl.Execute(&message, TemplateData{
-		Subject: mail.Subject,
-		Body:    bodyWithLineBreaks,
-	})
-	if err != nil {
-		logrus.Errorf("Error executing email template: %v", err)
-		return nil
-	}
-
-	return []byte(message.String())
+	return []byte(message)
 }
 
 func batchEmails(to []string, batch int) [][]string {
@@ -69,19 +52,67 @@ func batchEmails(to []string, batch int) [][]string {
 }
 
 func Service(mailQueue chan Mail) {
-	addr := fmt.Sprintf("%s:%s", host, port)
-	auth := smtp.PlainAuth("", user, pass, host)
-
-	for mail := range mailQueue {
-		message := mail.BuildMessage()
-		to := append(mail.To, webteam)
-		batches:= batchEmails(to, batch); 
-		for _, emailBatch:= range batches {
-			if err := smtp.SendMail(addr, auth, sender, emailBatch, message); err != nil {
-				logrus.Errorf("Error sending mail: %v", emailBatch)
-				logrus.Errorf("Error: %v", err)
+		addr := fmt.Sprintf("%s:%s", host, port)
+		auth := smtp.PlainAuth("", user, pass, host)
+
+		tlsConfig := &tls.Config{
+			InsecureSkipVerify: true, // Change this to verify server certificate in production
+		}
+		conn, err := tls.Dial("tcp", addr, tlsConfig)
+		if err != nil {
+			logrus.Errorf("Error dialing SMTPS server: %v", err)
+		}
+
+		client, err := smtp.NewClient(conn, host)
+		if err != nil {
+			logrus.Errorf("Error creating SMTP client: %v", err)
+		}
+
+
+		if err := client.Auth(auth); err != nil {
+			logrus.Errorf("Error authenticating: %v", err)
+		}
+
+		for mail := range mailQueue {
+			message := mail.BuildMessage()
+			to := append(mail.To, webteam)
+			batches := batchEmails(to, batch)
+			for _, emailBatch := range batches {
+
+				// if err := client.StartTLS(tlsConfig); err != nil {
+				// 	logrus.Errorf("Error starting TLS: %v", err)
+				// 	continue
+				// }
+				if err := client.Mail(sender); err != nil {
+					logrus.Errorf("Error setting sender: %v", err)
+				}
+
+				for _, recipient := range emailBatch {
+					if err := client.Rcpt(recipient); err != nil {
+						logrus.Errorf("Error setting recipient %s: %v", recipient, err)
+						continue
+					}
+				}
+
+				// Send the email body
+				w, err := client.Data()
+				if err != nil {
+					logrus.Errorf("Error creating data writer: %v", err)
+					continue
+				}
+				_, err = w.Write(message)
+				if err != nil {
+					logrus.Errorf("Error writing email body: %v", err)
+				}
+				err = w.Close()
+				if err != nil {
+					logrus.Errorf("Error closing data writer: %v", err)
+				}
+				time.Sleep(1 * time.Second)
 			}
-			time.Sleep(1 * time.Second)
 		}
-	}
+
+		if err := client.Quit(); err != nil {
+			logrus.Errorf("Error closing connection: %v", err)
+		}
 }