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Return error when no MX records #44

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Return error when no MX records #44

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0dc0ce3
Return error when no MX records
milesfaciane May 31, 2024
ddd9be1
Update checkmail.go
milesfaciane Jun 3, 2024
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9 changes: 8 additions & 1 deletion checkmail.go
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,7 @@ const forceDisconnectAfter = time.Second * 5
var (
ErrBadFormat = errors.New("invalid format")
ErrUnresolvableHost = errors.New("unresolvable host")
ErrNoMXRecord = errors.New("host DNS does not have MX records")

emailRegexp = regexp.MustCompile(`(?m)^(((((((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?([A-Za-z0-9!#-'*+\/=?^_\x60{|}~-])+((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?)|(((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?"((\s? +)?(([!#-[\]-~])|(\\([ -~]|\s))))*(\s? +)?"))?)?(((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?<(((((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?(([A-Za-z0-9!#-'*+\/=?^_\x60{|}~-])+(\.([A-Za-z0-9!#-'*+\/=?^_\x60{|}~-])+)*)((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?)|(((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?"((\s? +)?(([!#-[\]-~])|(\\([ -~]|\s))))*(\s? +)?"))@((((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?(([A-Za-z0-9!#-'*+\/=?^_\x60{|}~-])+(\.([A-Za-z0-9!#-'*+\/=?^_\x60{|}~-])+)*)((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?)|(((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?\[((\s? +)?([!-Z^-~]))*(\s? +)?\]((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?)))>((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?))|(((((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?(([A-Za-z0-9!#-'*+\/=?^_\x60{|}~-])+(\.([A-Za-z0-9!#-'*+\/=?^_\x60{|}~-])+)*)((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?)|(((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?"((\s? +)?(([!#-[\]-~])|(\\([ -~]|\s))))*(\s? +)?"))@((((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?(([A-Za-z0-9!#-'*+\/=?^_\x60{|}~-])+(\.([A-Za-z0-9!#-'*+\/=?^_\x60{|}~-])+)*)((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?)|(((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?\[((\s? +)?([!-Z^-~]))*(\s? +)?\]((((\s? +)?(\(((\s? +)?(([!-'*-[\]-~]*)|(\\([ -~]|\s))))*(\s? +)?\)))(\s? +)?)|(\s? +))?))))$`)
)
Expand All @@ -47,8 +48,10 @@ func ValidateFormat(email string) error {
// ValidateMX validate if MX record exists for a domain.
func ValidateMX(email string) error {
_, host := split(email)
if _, err := net.LookupMX(host); err != nil {
if mx, err := net.LookupMX(host); err != nil {
return ErrUnresolvableHost
} else if len(mx) == 0 {
return ErrNoMXRecord
}

return nil
Expand All @@ -60,6 +63,8 @@ func ValidateHost(email string) error {
mx, err := net.LookupMX(host)
if err != nil {
return ErrUnresolvableHost
} else if len(mx) == 0 {
return ErrNoMXRecord
}
client, err := DialTimeout(fmt.Sprintf("%s:%d", mx[0].Host, 25), forceDisconnectAfter)
if err != nil {
Expand All @@ -78,6 +83,8 @@ func ValidateHostAndUser(serverHostName, serverMailAddress, email string) error
mx, err := net.LookupMX(host)
if err != nil {
return ErrUnresolvableHost
} else if len(mx) == 0 {
return ErrNoMXRecord
}
client, err := DialTimeout(fmt.Sprintf("%s:%d", mx[0].Host, 25), forceDisconnectAfter)
if err != nil {
Expand Down