subaddressing support, closes #61

utils/mail.go

@@ -1,14 +1,56 @@
 package utils
 
-import "strings"
+import (
+	"strings"
+
+	"github.com/mcnijman/go-emailaddress"
+)
 
 // Mailbox returns mailbox part from email address
 func Mailbox(email string) string {
-	index := strings.LastIndex(email, "@")
-	if index == -1 {
-		return email
+	mailbox, _, _ := EmailParts(email)
+	return mailbox
+}
+
+// Subaddress returns sub address part form email address
+func Subaddress(email string) string {
+	_, sub, _ := EmailParts(email)
+	return sub
+}
+
+// Hostname returns hostname part from email address
+func Hostname(email string) string {
+	_, _, hostname := EmailParts(email)
+	return hostname
+}
+
+// EmailParts parses email address into mailbox, subaddress, and hostname
+func EmailParts(email string) (string, string, string) {
+	var mailbox, hostname string
+	address, err := emailaddress.Parse(email)
+	if err == nil {
+		mailbox = address.LocalPart
+		hostname = address.Domain
+	} else {
+		mailbox = email
+		hostname = email
+		mIdx := strings.Index(email, "@")
+		hIdx := strings.LastIndex(email, "@")
+		if mIdx != -1 {
+			mailbox = email[:mIdx]
+		}
+		if hIdx != -1 {
+			hostname = email[hIdx+1:]
+		}
 	}
-	return email[:index]
+
+	var sub string
+	idx := strings.Index(mailbox, "+")
+	if idx != -1 {
+		sub = strings.ReplaceAll(mailbox[idx:], "+", "")
+		mailbox = strings.ReplaceAll(mailbox[:idx], "+", "")
+	}
+	return mailbox, sub, hostname
 }
 
 // EmailsList returns human-readable list of mailbox's emails for all available domains
@@ -34,8 +76,3 @@ func EmailsList(mailbox string, domain string) string {
 
 	return msg.String()
 }
-
-// Hostname returns hostname part from email address
-func Hostname(email string) string {
-	return email[strings.LastIndex(email, "@")+1:]
-}