Golang SMTP发送空电子邮件

Question

Why when I try to send email i'm received empty email?

    func contactHandler(w http.ResponseWriter, r *http.Request) {
        if r.Method == "GET" {
            t, _ := template.ParseFiles("template/static/contact.html")
            t.Execute(w, nil)
        } else if r.Method == "POST" {
            r.ParseForm()
            msg := "Name: " + r.Form["name"][0] + ", Email: " + r.Form["email"][0] + ", Message: " + r.Form["message"][0]
            println("out ", msg)
            smtp.SendMail("smtp.gmail.com:587", smtp.PlainAuth("", "login", "password", "smtp.gmail.com"), "[e-mail]", []string{"[e-mail]"}, []byte(msg))
            http.Redirect(w, r, "/", 301)
        }
    }

But if I change []byte(msg) to []byte("TEST") I received email with TEST word

Answer 1

You can't make up the email header format as you please. The email header must follow a specific format defined in RFC2822. Try to build your variable 'msg' by using this format:

from := fmt.Sprintf("From: <%s>
", "[e-mail]")
to := fmt.Sprintf("To: <%s>
", "[e-mail]")
subject := "Subject: This is the subject
"
body := "This is the email body.
Bye
"

msg := from+to+subject+"
"+body

See details in https://tools.ietf.org/html/rfc2822