recv & send

client.go

@@ -0,0 +1,123 @@
+package main
+
+import (
+	"bytes"
+	"crypto/tls"
+	"fmt"
+	"io"
+	"net/smtp"
+	"net/textproto"
+
+	"github.com/flashmob/go-guerrilla/mail"
+	"github.com/pkg/errors"
+)
+
+type closeable interface {
+	Close() error
+}
+
+// sendMail sends the contents of the envelope to a SMTP server.
+func sendMail(e *mail.Envelope, config *mailRelayConfig) error {
+	server := fmt.Sprintf("%s:%d", config.Server, config.Port)
+	to := getTo(e)
+
+	var msg bytes.Buffer
+	msg.Write(e.Data.Bytes())
+	msg.WriteString("\r\n")
+
+	fmt.Println("==== Starting email send ====")
+	defer fmt.Println("==== Finished email send ====")
+	var err error
+	var conn *tls.Conn
+	var client *smtp.Client
+	var writer io.WriteCloser
+
+	tlsconfig := &tls.Config{
+		InsecureSkipVerify: true,
+		ServerName:         config.Server,
+	}
+
+	if conn, err = tls.Dial("tcp", server, tlsconfig); err != nil {
+		return errors.Wrap(err, "dial error")
+	}
+
+	if client, err = smtp.NewClient(conn, config.Server); err != nil {
+		close(conn, "conn")
+		return errors.Wrap(err, "newclient error")
+	}
+	shouldCloseClient := true
+	defer func(shouldClose *bool) {
+		if *shouldClose {
+			close(client, "client")
+		}
+	}(&shouldCloseClient)
+
+	auth := smtp.PlainAuth("", config.Username, config.Password, config.Server)
+	if err = client.Auth(auth); err != nil {
+		return errors.Wrap(err, "auth error")
+	}
+
+	if err = client.Mail(e.MailFrom.String()); err != nil {
+		return errors.Wrap(err, "mail error")
+	}
+
+	for _, addy := range to {
+		if err = client.Rcpt(addy); err != nil {
+			return errors.Wrap(err, "rcpt error")
+		}
+	}
+
+	if writer, err = client.Data(); err != nil {
+		return errors.Wrap(err, "data error")
+	}
+	_, err = writer.Write(msg.Bytes())
+	close(writer, "writer")
+	if err != nil {
+		return errors.Wrap(err, "write error")
+	}
+
+	if err = client.Quit(); isQuitError(err) {
+		return errors.Wrap(err, "quit error")
+	}
+	// We only need to close client if some other error prevented us
+	// from getting to `client.Quit`
+	shouldCloseClient = false
+	return nil
+}
+
+func close(c closeable, what string) {
+	err := c.Close()
+	if err != nil {
+		fmt.Printf("!!!!! Error closing %s: %v\n", what, err)
+	}
+}
+
+func isQuitError(err error) bool {
+	if err == nil {
+		return false
+	}
+	e, ok := err.(*textproto.Error)
+	if ok {
+		// SMTP codes 221 or 250 are acceptable here
+		if e.Code == 221 || e.Code == 250 {
+			return false
+		}
+	}
+	return true
+}
+
+// getTo returns the array of email addresses in the envelope.
+func getTo(e *mail.Envelope) []string {
+	var ret []string
+	for _, addy := range e.RcptTo {
+		ret = append(ret, addy.String())
+	}
+	return ret
+}
+
+func display(b []byte) {
+	s := string(b)
+	fmt.Println("################################")
+	fmt.Printf("%s\n", s)
+	fmt.Println("################################")
+}