server/protocols/protocols-lmtp/src/main/java/org/apache/james/lmtpserver/MailetContainerHandler.java

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package org.apache.james.lmtpserver;

import java.util.Collection;

import javax.inject.Inject;

import org.apache.james.core.MailAddress;
import org.apache.james.mailetcontainer.api.MailProcessor;
import org.apache.james.protocols.api.Response;
import org.apache.james.protocols.lmtp.LMTPMultiResponse;
import org.apache.james.protocols.smtp.SMTPResponse;
import org.apache.james.protocols.smtp.SMTPRetCode;
import org.apache.james.protocols.smtp.SMTPSession;
import org.apache.james.protocols.smtp.core.AbstractHookableCmdHandler;
import org.apache.james.protocols.smtp.dsn.DSNStatus;
import org.apache.james.protocols.smtp.hook.HookResult;
import org.apache.james.protocols.smtp.hook.HookReturnCode;
import org.apache.james.smtpserver.DataLineJamesMessageHookHandler;
import org.apache.mailet.Mail;

import com.github.steveash.guavate.Guavate;
import com.google.common.collect.ImmutableList;

public class MailetContainerHandler extends DataLineJamesMessageHookHandler {
    private final MailProcessor mailProcessor;

    @Inject
    public MailetContainerHandler(MailProcessor mailProcessor) {
        this.mailProcessor = mailProcessor;
    }

    @Override
    protected Response processExtensions(SMTPSession session, Mail mail) {
        Collection<MailAddress> recipients = ImmutableList.copyOf(mail.getRecipients());
        try {
            super.processExtensions(session, mail);

            if (recipients.size() == 0) {
                // Return 503 see https://datatracker.ietf.org/doc/html/rfc2033#section-4.2
                AbstractHookableCmdHandler.calcDefaultSMTPResponse(HookResult.builder()
                    .hookReturnCode(HookReturnCode.ok())
                    .smtpReturnCode(SMTPRetCode.MAIL_OK)
                    .smtpDescription(DSNStatus.getStatus(DSNStatus.SUCCESS, DSNStatus.CONTENT_OTHER) + " Message received")
                    .build());
            }

            mailProcessor.service(mail);

            return LMTPMultiResponse.of(
                recipients.stream()
                    .map(recipient -> AbstractHookableCmdHandler.calcDefaultSMTPResponse(HookResult.builder()
                        .hookReturnCode(HookReturnCode.ok())
                        .smtpReturnCode(SMTPRetCode.MAIL_OK)
                        .smtpDescription(DSNStatus.getStatus(DSNStatus.SUCCESS, DSNStatus.CONTENT_OTHER) + " Message received <" + recipient.asString() + ">")
                        .build()))
                    .collect(Guavate.toImmutableList()));

        } catch (Exception e) {
            return LMTPMultiResponse.of(
                recipients.stream()
                    .map(recipient -> new SMTPResponse(SMTPRetCode.LOCAL_ERROR, DSNStatus.getStatus(DSNStatus.TRANSIENT, DSNStatus.UNDEFINED_STATUS) + " Temporary error deliver message <" + recipient.asString() + ">"))
                    .collect(Guavate.toImmutableList()));
        }
    }
}