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package smtp
import (
"io"
)
var (
ErrAuthRequired = &SMTPError{
Code: 502,
EnhancedCode: EnhancedCode{5, 7, 0},
Message: "Please authenticate first",
}
ErrAuthUnsupported = &SMTPError{
Code: 502,
EnhancedCode: EnhancedCode{5, 7, 0},
Message: "Authentication not supported",
}
)
// A SMTP server backend.
type Backend interface {
NewSession(c *Conn) (Session, error)
}
type BodyType string
const (
Body7Bit BodyType = "7BIT"
Body8BitMIME BodyType = "8BITMIME"
BodyBinaryMIME BodyType = "BINARYMIME"
)
// MailOptions contains custom arguments that were
// passed as an argument to the MAIL command.
type MailOptions struct {
// Value of BODY= argument, 7BIT, 8BITMIME or BINARYMIME.
Body BodyType
// Size of the body. Can be 0 if not specified by client.
Size int
// TLS is required for the message transmission.
//
// The message should be rejected if it can't be transmitted
// with TLS.
RequireTLS bool
// The message envelope or message header contains UTF-8-encoded strings.
// This flag is set by SMTPUTF8-aware (RFC 6531) client.
UTF8 bool
// The authorization identity asserted by the message sender in decoded
// form with angle brackets stripped.
//
// nil value indicates missing AUTH, non-nil empty string indicates
// AUTH=<>.
//
// Defined in RFC 4954.
Auth *string
}
// Session is used by servers to respond to an SMTP client.
//
// The methods are called when the remote client issues the matching command.
type Session interface {
// Discard currently processed message.
Reset()
// Free all resources associated with session.
Logout() error
// Authenticate the user using SASL PLAIN.
AuthPlain(username, password string) error
// Set return path for currently processed message.
Mail(from string, opts *MailOptions) error
// Add recipient for currently processed message.
Rcpt(to string) error
// Set currently processed message contents and send it.
//
// r must be consumed before Data returns.
Data(r io.Reader) error
}
// LMTPSession is an add-on interface for Session. It can be implemented by
// LMTP servers to provide extra functionality.
type LMTPSession interface {
// LMTPData is the LMTP-specific version of Data method.
// It can be optionally implemented by the backend to provide
// per-recipient status information when it is used over LMTP
// protocol.
//
// LMTPData implementation sets status information using passed
// StatusCollector by calling SetStatus once per each AddRcpt
// call, even if AddRcpt was called multiple times with
// the same argument. SetStatus must not be called after
// LMTPData returns.
//
// Return value of LMTPData itself is used as a status for
// recipients that got no status set before using StatusCollector.
LMTPData(r io.Reader, status StatusCollector) error
}
// StatusCollector allows a backend to provide per-recipient status
// information.
type StatusCollector interface {
SetStatus(rcptTo string, err error)
}
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