protected boolean processAuthentication()

in geronimo-mail_2.1_impl/geronimo-mail_2.1_provider/src/main/java/org/apache/geronimo/mail/transport/smtp/SMTPConnection.java [1048:1149]
62 lines of code
16 McCabe index (conditional complexity)

    protected boolean processAuthentication() throws MessagingException {
        // no authentication defined?
        if (!props.getBooleanProperty(MAIL_SMTP_AUTH, false)) {
            return true;
        }

        // we need to authenticate, but we don't have userid/password
        // information...fail this
        // immediately.
        if (username == null || password == null) {
            return false;
        }

        // if unable to get an appropriate authenticator, just fail it.
        ClientAuthenticator authenticator = getSaslAuthenticator();
        if (authenticator == null) {
            throw new MessagingException("Unable to obtain SASL authenticator");
        }


        if (debug) {
            debugOut("Authenticating for user: " + username + " using " + authenticator.getMechanismName());
        }

        // if the authenticator has some initial data, we compose a command
        // containing the initial data.
        if (authenticator.hasInitialResponse()) {
            StringBuffer command = new StringBuffer();
            // the auth command initiates the handshaking.
            command.append("AUTH ");
            // and tell the server which mechanism we're using.
            command.append(authenticator.getMechanismName());
            command.append(" ");
            // and append the response data
            try {
                command.append(new String(Base64.encode(authenticator.evaluateChallenge(null)), "US-ASCII"));
            } catch (UnsupportedEncodingException e) {
            }
            // send the command now
            sendLine(command.toString());
        }
        // we just send an auth command with the command type.
        else {
            StringBuffer command = new StringBuffer();
            // the auth command initiates the handshaking.
            command.append("AUTH ");
            // and tell the server which mechanism we're using.
            command.append(authenticator.getMechanismName());
            // send the command now
            sendLine(command.toString());
        }

        // now process the challenge sequence. We get a 235 response back when
        // the server accepts the
        // authentication, and a 334 indicates we have an additional challenge.
        while (true) {
            // get the next line, and if it is an error response, return now.
            SMTPReply line;
            try {
                line = new SMTPReply(receiveLine());
            } catch (MalformedSMTPReplyException e) {
                throw new MessagingException(e.toString());
            } catch (MessagingException e) {
                throw e;
            }

            // if we get a completion return, we've passed muster, so give an
            // authentication response.
            if (line.getCode() == SMTPReply.AUTHENTICATION_COMPLETE) {
                debugOut("Successful SMTP authentication");
                return true;
            }
            // we have an additional challenge to process.
            else if (line.getCode() == SMTPReply.AUTHENTICATION_CHALLENGE) {
                // Does the authenticator think it is finished? We can't answer
                // an additional challenge,
                // so fail this.
                if (authenticator.isComplete()) {
                    return false;
                }

                try {
                    // we're passed back a challenge value, Base64 encoded.
                    byte[] challenge = Base64.decode(line.getMessage().getBytes("ISO8859-1"));

                    // have the authenticator evaluate and send back the encoded
                    // response.
                    sendLine(new String(Base64.encode(authenticator.evaluateChallenge(challenge)), "US-ASCII"));
                } catch (UnsupportedEncodingException e) {
                }
            }
            // completion or challenge are the only responses we know how to
            // handle. Anything else must
            // be a failure.
            else {
                if (debug) {
                    debugOut("Authentication failure " + line);
                }
                return false;
            }
        }
    }