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package sasl
import (
"bytes"
"errors"
)
// The PLAIN mechanism name.
const Plain = "PLAIN"
type plainClient struct {
Identity string
Username string
Password string
}
func (a *plainClient) Start() (mech string, ir []byte, err error) {
mech = "PLAIN"
ir = []byte(a.Identity + "\x00" + a.Username + "\x00" + a.Password)
return
}
func (a *plainClient) Next(challenge []byte) (response []byte, err error) {
return nil, ErrUnexpectedServerChallenge
}
// A client implementation of the PLAIN authentication mechanism, as described
// in RFC 4616. Authorization identity may be left blank to indicate that it is
// the same as the username.
func NewPlainClient(identity, username, password string) Client {
return &plainClient{identity, username, password}
}
// Authenticates users with an identity, a username and a password. If the
// identity is left blank, it indicates that it is the same as the username.
// If identity is not empty and the server doesn't support it, an error must be
// returned.
type PlainAuthenticator func(identity, username, password string) error
type plainServer struct {
done bool
authenticate PlainAuthenticator
}
func (a *plainServer) Next(response []byte) (challenge []byte, done bool, err error) {
if a.done {
err = ErrUnexpectedClientResponse
return
}
// No initial response, send an empty challenge
if response == nil {
return []byte{}, false, nil
}
a.done = true
parts := bytes.Split(response, []byte("\x00"))
if len(parts) != 3 {
err = errors.New("Invalid response")
return
}
identity := string(parts[0])
username := string(parts[1])
password := string(parts[2])
err = a.authenticate(identity, username, password)
done = true
return
}
// A server implementation of the PLAIN authentication mechanism, as described
// in RFC 4616.
func NewPlainServer(authenticator PlainAuthenticator) Server {
return &plainServer{authenticate: authenticator}
}
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