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Merge pull request #28 from unapu-go/master
feat: add function ValidateHostAndUser to validate host and user preventing SPAN and BOT
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Original file line number | Diff line number | Diff line change |
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@@ -11,34 +11,42 @@ | |
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### 1. Format | ||
```go | ||
func main() { | ||
err := checkmail.ValidateFormat("ç$€§/[email protected]") | ||
if err != nil { | ||
fmt.Println(err) | ||
} | ||
} | ||
func main() { | ||
err := checkmail.ValidateFormat("ç$€§/[email protected]") | ||
if err != nil { | ||
fmt.Println(err) | ||
} | ||
} | ||
``` | ||
output: `invalid format` | ||
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### 2. Domain | ||
```go | ||
func main() { | ||
err := checkmail.ValidateHost("[email protected]") | ||
if err != nil { | ||
fmt.Println(err) | ||
} | ||
} | ||
func main() { | ||
err := checkmail.ValidateHost("[email protected]") | ||
if err != nil { | ||
fmt.Println(err) | ||
} | ||
} | ||
``` | ||
output: `unresolvable host` | ||
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### 3. User | ||
### 3. Host and User | ||
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If host is valid, requires valid SMTP `serverHostName` (see to [online validator](https://mxtoolbox.com/SuperTool.aspx)) and `serverMailAddress` to reverse validation | ||
for prevent SPAN and BOTS. | ||
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```go | ||
func main() { | ||
err := checkmail.ValidateHost("[email protected]") | ||
if smtpErr, ok := err.(checkmail.SmtpError); ok && err != nil { | ||
fmt.Printf("Code: %s, Msg: %s", smtpErr.Code(), smtpErr) | ||
} | ||
} | ||
func main() { | ||
var ( | ||
serverHostName = "smtp.myserver.com" // set your SMTP server here | ||
serverMailAddress = "[email protected]" // set your valid mail address here | ||
) | ||
err := checkmail.ValidateHostAndUser(serverHostName, serverMailAddress, "[email protected]") | ||
if smtpErr, ok := err.(checkmail.SmtpError); ok && err != nil { | ||
fmt.Printf("Code: %s, Msg: %s", smtpErr.Code(), smtpErr) | ||
} | ||
} | ||
``` | ||
output: `Code: 550, Msg: 550 5.1.1 The email account that you tried to reach does not exist.` | ||
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Original file line number | Diff line number | Diff line change |
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@@ -37,31 +37,50 @@ var ( | |
emailRegexp = regexp.MustCompile("^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$") | ||
) | ||
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func ValidateFormat(email string) error { | ||
if !emailRegexp.MatchString(email) { | ||
return ErrBadFormat | ||
} | ||
return nil | ||
} | ||
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// ValidateHost validate mail host. | ||
func ValidateHost(email string) error { | ||
_, host := split(email) | ||
mx, err := net.LookupMX(host) | ||
if err != nil { | ||
return ErrUnresolvableHost | ||
} | ||
client, err := DialTimeout(fmt.Sprintf("%s:%d", mx[0].Host, 25), forceDisconnectAfter) | ||
if err != nil { | ||
return NewSmtpError(err) | ||
} | ||
client.Close() | ||
return nil | ||
} | ||
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// ValidateHostAndUser validate mail host and user. | ||
// If host is valid, requires valid SMTP [1] serverHostName and serverMailAddress to reverse validation | ||
// for prevent SPAN and BOTS. | ||
// [1] https://mxtoolbox.com/SuperTool.aspx | ||
func ValidateHostAndUser(serverHostName, serverMailAddress, email string) error { | ||
_, host := split(email) | ||
mx, err := net.LookupMX(host) | ||
if err != nil { | ||
return ErrUnresolvableHost | ||
} | ||
client, err := DialTimeout(fmt.Sprintf("%s:%d", mx[0].Host, 25), forceDisconnectAfter) | ||
if err != nil { | ||
return NewSmtpError(err) | ||
} | ||
defer client.Close() | ||
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err = client.Hello("checkmail.me") | ||
err = client.Hello(serverHostName) | ||
if err != nil { | ||
return NewSmtpError(err) | ||
} | ||
err = client.Mail("[email protected]") | ||
err = client.Mail(serverMailAddress) | ||
if err != nil { | ||
return NewSmtpError(err) | ||
} | ||
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