org.ambraproject.wombat.service.FreemarkerMailServiceImpl.java Source code

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Here is the source code for org.ambraproject.wombat.service.FreemarkerMailServiceImpl.java

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/*
 * Copyright (c) 2017 Public Library of Science
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

package org.ambraproject.wombat.service;

import freemarker.template.Configuration;
import freemarker.template.Template;
import freemarker.template.TemplateException;
import org.ambraproject.wombat.config.site.Site;
import org.apache.http.entity.ContentType;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.mail.MailPreparationException;
import org.springframework.ui.Model;
import org.springframework.web.servlet.view.freemarker.FreeMarkerConfig;

import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.mail.BodyPart;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMultipart;
import java.io.BufferedWriter;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.Objects;

public class FreemarkerMailServiceImpl implements FreemarkerMailService {

    @Autowired
    private FreeMarkerConfig freeMarkerConfig;

    private Configuration getConfiguration() {
        return freeMarkerConfig.getConfiguration();
    }

    private Template getEmailTemplate(Site site, String type, String filename) throws IOException {
        String path = String.format("%s/ftl/email/%s/%s.ftl", site, type, filename);
        return getConfiguration().getTemplate(path);
    }

    @Override
    public Multipart createContent(Site site, String templateFilename, Model context)
            throws IOException, MessagingException {
        Template textTemplate = getEmailTemplate(site, "txt", templateFilename);
        Template htmlTemplate = getEmailTemplate(site, "html", templateFilename);

        // Create a "text" Multipart message
        Multipart mp = createPartForMultipart(textTemplate, context, "alternative", ContentType.TEXT_PLAIN);

        // Create a "HTML" Multipart message
        Multipart htmlContent = createPartForMultipart(htmlTemplate, context, "related", ContentType.TEXT_HTML);

        BodyPart htmlPart = new MimeBodyPart();
        htmlPart.setContent(htmlContent);
        mp.addBodyPart(htmlPart);

        return mp;
    }

    private Multipart createPartForMultipart(Template htmlTemplate, Model context, String multipartType,
            ContentType contentType) throws IOException, MessagingException {
        Multipart multipart = new MimeMultipart(multipartType);
        multipart.addBodyPart(createBodyPart(contentType, htmlTemplate, context));
        return multipart;
    }

    private BodyPart createBodyPart(ContentType contentType, Template htmlTemplate, Model context)
            throws IOException, MessagingException {
        BodyPart htmlPage = new MimeBodyPart();
        String encoding = getConfiguration().getDefaultEncoding();
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream(0x100);
        Writer writer = new BufferedWriter(new OutputStreamWriter(outputStream, encoding));

        htmlTemplate.setOutputEncoding(encoding);
        htmlTemplate.setEncoding(encoding);

        try {
            htmlTemplate.process(context, writer);
        } catch (TemplateException e) {
            throw new MailPreparationException("Can't generate " + contentType.getMimeType() + " subscription mail",
                    e);
        }

        htmlPage.setDataHandler(createBodyPartDataHandler(outputStream.toByteArray(),
                contentType.toString() + "; charset=" + getConfiguration().getDefaultEncoding()));

        return htmlPage;
    }

    private static DataHandler createBodyPartDataHandler(byte[] data, String contentType) {
        Objects.requireNonNull(data);
        Objects.requireNonNull(contentType);
        return new DataHandler(new DataSource() {
            @Override
            public InputStream getInputStream() throws IOException {
                return new ByteArrayInputStream(data);
            }

            @Override
            public OutputStream getOutputStream() throws IOException {
                throw new IOException("Read-only data");
            }

            @Override
            public String getContentType() {
                return contentType;
            }

            @Override
            public String getName() {
                return "main";
            }
        });
    }

}