go-mail/senderror.go

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// SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
//
// SPDX-License-Identifier: MIT
package mail
import (
"errors"
"strings"
)
// List of SendError reasons
const (
// ErrGetSender is returned if the Msg.GetSender method fails during a Client.Send
ErrGetSender SendErrReason = iota
// ErrGetRcpts is returned if the Msg.GetRecipients method fails during a Client.Send
ErrGetRcpts
// ErrSMTPMailFrom is returned if the Msg delivery failed when sending the MAIL FROM command
// to the sending SMTP server
ErrSMTPMailFrom
// ErrSMTPRcptTo is returned if the Msg delivery failed when sending the RCPT TO command
// to the sending SMTP server
ErrSMTPRcptTo
// ErrSMTPData is returned if the Msg delivery failed when sending the DATA command
// to the sending SMTP server
ErrSMTPData
// ErrSMTPDataClose is returned if the Msg delivery failed when trying to close the
// Client data writer
ErrSMTPDataClose
// ErrSMTPReset is returned if the Msg delivery failed when sending the RSET command
// to the sending SMTP server
ErrSMTPReset
// ErrWriteContent is returned if the Msg delivery failed when sending Msg content
// to the Client writer
ErrWriteContent
// ErrConnCheck is returned if the Msg delivery failed when checking if the SMTP
// server connection is still working
ErrConnCheck
// ErrNoUnencoded is returned if the Msg delivery failed when the Msg is configured for
// unencoded delivery but the server does not support this
ErrNoUnencoded
// ErrAmbiguous is a generalized delivery error for the SendError type that is
// returned if the exact reason for the delivery failure is ambiguous
ErrAmbiguous
)
// SendError is an error wrapper for delivery errors of the Msg
type SendError struct {
Reason SendErrReason
isTemp bool
errlist []error
rcpt []string
}
// SendErrReason represents a comparable reason on why the delivery failed
type SendErrReason int
// Error implements the error interface for the SendError type
func (e *SendError) Error() string {
if e.Reason > 10 {
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return "unknown reason"
}
var errMessage strings.Builder
errMessage.WriteString(e.Reason.String())
if len(e.errlist) > 0 {
errMessage.WriteRune(':')
for i := range e.errlist {
errMessage.WriteRune(' ')
errMessage.WriteString(e.errlist[i].Error())
if i != len(e.errlist)-1 {
errMessage.WriteString(", ")
}
}
}
if len(e.rcpt) > 0 {
errMessage.WriteString(", affected recipient(s): ")
for i := range e.rcpt {
errMessage.WriteString(e.rcpt[i])
if i != len(e.rcpt)-1 {
errMessage.WriteString(", ")
}
}
}
return errMessage.String()
}
// Is implements the errors.Is functionality and compares the SendErrReason
func (e *SendError) Is(errType error) bool {
var t *SendError
if errors.As(errType, &t) && t != nil {
return e.Reason == t.Reason && e.isTemp == t.isTemp
}
return false
}
// IsTemp returns true if the delivery error is of temporary nature and can be retried
func (e *SendError) IsTemp() bool {
if e == nil {
return false
}
return e.isTemp
}
// String implements the Stringer interface for the SendErrReason
func (r SendErrReason) String() string {
switch r {
case ErrGetSender:
return "getting sender address"
case ErrGetRcpts:
return "getting recipient addresses"
case ErrSMTPMailFrom:
return "sending SMTP MAIL FROM command"
case ErrSMTPRcptTo:
return "sending SMTP RCPT TO command"
case ErrSMTPData:
return "sending SMTP DATA command"
case ErrSMTPDataClose:
return "closing SMTP DATA writer"
case ErrSMTPReset:
return "sending SMTP RESET command"
case ErrWriteContent:
return "sending message content"
case ErrConnCheck:
return "checking SMTP connection"
case ErrNoUnencoded:
return ErrServerNoUnencoded.Error()
case ErrAmbiguous:
return "ambiguous reason, check Msg.SendError for message specific reasons"
}
return "unknown reason"
}
// isTempError checks the given SMTP error and returns true if the given error is of temporary nature
// and should be retried
func isTempError(err error) bool {
return err.Error()[0] == '4'
}