server address verification

simple Email address check for from & to
default port=25 for server address

net/gsmtp/gsmtp.go

@@ -18,6 +18,7 @@ import (
 	"strings"
 )
 
+// SMTP is the structure for smtp connection
 type SMTP struct {
 	Address  string
 	Username string
@@ -38,35 +39,45 @@ func New(address, username, password string) *SMTP {
 // and then sends an email from address from, to addresses to, with
 // message msg.
 func (s *SMTP) SendMail(from, tos, subject, body string, contentType ...string) error {
-	if s.Address == "" {
-		return fmt.Errorf("address is necessary")
-	}
+	server := ""
+	address := ""
 
 	hp := strings.Split(s.Address, ":")
-	if len(hp) != 2 {
-		return fmt.Errorf("address format error")
-	}
-
-	arr := strings.Split(tos, ";")
-	count := len(arr)
-	safeArr := make([]string, 0, count)
-	for i := 0; i < count; i++ {
-		if arr[i] == "" {
-			continue
+	if (s.Address == "") || (len(hp) > 2) {
+		return fmt.Errorf("Server address is either empty or incorrect: %s", s.Address)
+	} else if len(hp) == 1 {
+		server = s.Address
+		address = server + ":25"
+	} else if len(hp) == 2 {
+		if (hp[0] == "") || (hp[1] == "") {
+			return fmt.Errorf("Server address is either empty or incorrect: %s", s.Address)
 		}
-		safeArr = append(safeArr, arr[i])
+		server = hp[0]
+		address = s.Address
 	}
 
-	if len(safeArr) == 0 {
-		return fmt.Errorf("tos invalid")
+	tosArr := []string{}
+	arr := strings.Split(tos, ";")
+	for _, to := range arr {
+		// TODO: replace with regex
+		if strings.Contains(to, "@") {
+			tosArr = append(tosArr, to)
+		}
+	}
+
+	if len(tosArr) == 0 {
+		return fmt.Errorf("tos if invalid: %s", tos)
+	}
+
+	if !strings.Contains(from, "@") {
+		return fmt.Errorf("from is invalid: %s", from)
 	}
 
-	tos = strings.Join(safeArr, ";")
 	b64 := base64.NewEncoding("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
 
 	header := make(map[string]string)
 	header["From"] = from
-	header["To"] = tos
+	header["To"] = strings.Join(tosArr, ";")
 	header["Subject"] = fmt.Sprintf("=?UTF-8?B?%s?=", b64.EncodeToString([]byte(subject)))
 	header["MIME-Version"] = "1.0"
 
@@ -84,6 +95,6 @@ func (s *SMTP) SendMail(from, tos, subject, body string, contentType ...string)
 	}
 	message += "\r\n" + b64.EncodeToString([]byte(body))
 
-	auth := smtp.PlainAuth("", s.Username, s.Password, hp[0])
-	return smtp.SendMail(s.Address, auth, from, strings.Split(tos, ";"), []byte(message))
+	auth := smtp.PlainAuth("", s.Username, s.Password, server)
+	return smtp.SendMail(address, auth, from, tosArr, []byte(message))
 }