SMTP Client
To create an SMTP client program in Go, you need to create a few files: main.go for the main logic and optionally, a client.go file for the client functionality. Here is a step-by-step guide:
Step 1: Initialize the Go Module
First, create a new directory for your project and initialize the Go module.
mkdir smtpclient
cd smtpclient
go mod init github.com/username/smtpclient
Step 2: Create the client.go File
Create a client.go file to handle the SMTP client functionality.
// client.go
package main
import (
"crypto/tls"
"fmt"
"log"
"net/smtp"
)
// SendEmail sends an email using the specified SMTP server.
func SendEmail(server, port, user, password, from, to, subject, body string) error {
auth := smtp.PlainAuth("", user, password, server)
msg := []byte("To: " + to + "\r\n" +
"Subject: " + subject + "\r\n" +
"\r\n" + body + "\r\n")
addr := server + ":" + port
tlsconfig := &tls.Config{
InsecureSkipVerify: true,
ServerName: server,
}
conn, err := tls.Dial("tcp", addr, tlsconfig)
if err != nil {
return err
}
defer conn.Close()
c, err := smtp.NewClient(conn, server)
if err != nil {
return err
}
defer c.Quit()
if err = c.Auth(auth); err != nil {
return err
}
if err = c.Mail(from); err != nil {
return err
}
if err = c.Rcpt(to); err != nil {
return err
}
w, err := c.Data()
if err != nil {
return err
}
_, err = w.Write(msg)
if err != nil {
return err
}
err = w.Close()
if err != nil {
return err
}
return c.Quit()
}
Step 3: Create the main.go File
Create a main.go file to use the client functionality.
// main.go
package main
import (
"fmt"
"os"
)
func main() {
if len(os.Args) != 9 {
fmt.Println("Usage: smtpclient <server> <port> <user> <password> <from> <to> <subject> <body>")
os.Exit(1)
}
server := os.Args[1]
port := os.Args[2]
user := os.Args[3]
password := os.Args[4]
from := os.Args[5]
to := os.Args[6]
subject := os.Args[7]
body := os.Args[8]
err := SendEmail(server, port, user, password, from, to, subject, body)
if err != nil {
fmt.Printf("Failed to send email: %v\n", err)
os.Exit(1)
}
fmt.Println("Email sent successfully")
}
Step 4: Run the Program
Run the program using the go run command.
go run main.go smtp.example.com 587 username password from@example.com to@example.com "Subject" "Email body"
This will send an email using the specified SMTP server.
Last modified: 19 December 2024