org.codice.ddf.platform.email.impl.SmtpClientImpl.java Source code

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Here is the source code for org.codice.ddf.platform.email.impl.SmtpClientImpl.java

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/**
 * Copyright (c) Codice Foundation
 *
 * <p>This is free software: you can redistribute it and/or modify it under the terms of the GNU
 * Lesser General Public License as published by the Free Software Foundation, either version 3 of
 * the License, or any later version.
 *
 * <p>This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details. A copy of the GNU Lesser General Public
 * License is distributed along with this program and can be found at
 * <http://www.gnu.org/licenses/lgpl.html>.
 */
package org.codice.ddf.platform.email.impl;

import static org.apache.commons.lang.Validate.isTrue;
import static org.apache.commons.lang.Validate.notEmpty;
import static org.apache.commons.lang.Validate.notNull;

import ddf.security.common.audit.SecurityLogger;
import java.util.Arrays;
import java.util.Properties;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import javax.annotation.Nullable;
import javax.mail.Authenticator;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import org.apache.commons.lang.StringUtils;
import org.codice.ddf.platform.email.SmtpClient;
import org.codice.ddf.platform.util.StandardThreadFactoryBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Supports unauthenticated connections to a mail server and username/password authenticated
 * connections over TLS. If the username is not blank and the password is not empty, then auth/tls
 * will be used.
 *
 * <p>The method {@link #send(Message)} will exceute asynchronously in a single thread. The number
 * of operations awaiting execution is unbounded.
 *
 * <p>
 *
 * <p><b> This code is experimental. While this interface is functional and tested, it may change or
 * be removed in a future version of the library. </b>
 */
public class SmtpClientImpl implements SmtpClient {

    private static final Logger LOGGER = LoggerFactory.getLogger(SmtpClientImpl.class);

    private static final String SMTP_HOST_PROPERTY = "mail.smtp.host";

    private static final String SMTP_PORT_PROPERTY = "mail.smtp.port";

    private static final String SMTP_AUTH_PROPERTY = "mail.smtp.auth";

    private static final String SMTP_START_TLS_ENABLE_PROPERTY = "mail.smtp.starttls.enable";

    private static final String TRUE = Boolean.TRUE.toString();

    private static final String FALSE = Boolean.FALSE.toString();

    private final ExecutorService executorService = Executors.newFixedThreadPool(1,
            StandardThreadFactoryBuilder.newThreadFactory("smtpClientImplThread"));

    private String hostName;

    private Integer portNumber;

    private String userName;

    private String password;

    /**
     * Set the username for the email server.
     *
     * @param userName the username of the email server
     */
    public void setUserName(@Nullable String userName) {
        this.userName = userName;
    }

    /**
     * Set the password for the email server.
     *
     * @param password the password for the email server
     */
    public void setPassword(@Nullable String password) {
        this.password = password;
    }

    /** @param hostName must be non-empty */
    public void setHostName(String hostName) {
        notEmpty(hostName, "hostName must be non-empty");
        this.hostName = hostName;
    }

    /** @param portNumber must be non-null and >0 */
    public void setPortNumber(Integer portNumber) {
        notNull(portNumber, "portNumber must be non-null");
        isTrue(portNumber > 0, "portNumber must be >0");
        this.portNumber = portNumber;
    }

    @Override
    public Session createSession() {

        Properties properties = new Properties();

        if (hostName == null) {
            throw new IllegalArgumentException("Hostname cannot be null for smtp client.");
        }

        properties.setProperty(SMTP_HOST_PROPERTY, hostName);
        properties.setProperty(SMTP_PORT_PROPERTY, portNumber.toString());

        if (StringUtils.isNotBlank(userName)) {
            properties.put(SMTP_AUTH_PROPERTY, TRUE);
            properties.put(SMTP_START_TLS_ENABLE_PROPERTY, TRUE);

            return Session.getInstance(properties, createAuthenticator());
        } else {
            properties.setProperty(SMTP_AUTH_PROPERTY, FALSE);
            return Session.getInstance(properties);
        }
    }

    @Override
    public Future<Void> send(Message message) {
        notNull(message, "message must be non-null");
        return executorService.submit(() -> {
            try {
                Transport.send(message);
            } catch (MessagingException e) {
                LOGGER.debug("Could not send message {}", message, e);
                return null;
            }

            SecurityLogger.audit("Sent an email: recipient={} subject={}",
                    Arrays.toString(message.getAllRecipients()), message.getSubject());
            return null;
        });
    }

    Authenticator createAuthenticator() {
        return new Authenticator() {
            @Override
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(userName, password);
            }
        };
    }
}