de.whs.poodle.repositories.ImageRepository.java Source code

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Here is the source code for de.whs.poodle.repositories.ImageRepository.java

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/*
 * Copyright 2015 Westflische Hochschule
 *
 * This file is part of Poodle.
 *
 * Poodle is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Poodle 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with Poodle.  If not, see <http://www.gnu.org/licenses/>.
 */
package de.whs.poodle.repositories;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.servlet.http.HttpServletResponse;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.ResultSetExtractor;
import org.springframework.jdbc.support.GeneratedKeyHolder;
import org.springframework.jdbc.support.KeyHolder;
import org.springframework.stereotype.Repository;
import org.springframework.util.StreamUtils;

import de.whs.poodle.beans.UploadedImage;
import de.whs.poodle.repositories.exceptions.NotFoundException;

@Repository
public class ImageRepository {

    @Autowired
    private JdbcTemplate jdbc;

    @PersistenceContext
    private EntityManager em;

    /*
     * write the image into the database and return the generated object.
     */
    public void uploadImage(UploadedImage image, InputStream in, long length) {
        KeyHolder keyHolder = new GeneratedKeyHolder();
        jdbc.update(con -> {
            PreparedStatement ps = con.prepareStatement(
                    "INSERT INTO uploaded_image(filename,mimetype,data,instructor_id,course_id) VALUES(?,?,?,?,?)",
                    new String[] { "id" });

            ps.setString(1, image.getFilename());
            ps.setString(2, image.getMimeType());
            ps.setBinaryStream(3, in, length);
            ps.setInt(4, image.getInstructor().getId());
            ps.setInt(5, image.getCourseId());
            return ps;
        }, keyHolder);

        int id = keyHolder.getKey().intValue();
        image.setId(id);
    }

    public void writeImageToHttpResponse(int imageId, HttpServletResponse response) {
        jdbc.query("SELECT mimetype,data FROM uploaded_image WHERE id = ?", new Object[] { imageId },

                // use ResultSetExtractor so we can check whether a row even existed (NotFoundException)
                new ResultSetExtractor<Void>() {

                    @Override
                    public Void extractData(ResultSet rs) throws SQLException {
                        if (!rs.next()) // image doesn't exist
                            throw new NotFoundException();

                        String mimeType = rs.getString("mimetype");
                        response.setContentType(mimeType);

                        // write input stream from DB into http response
                        try (InputStream in = rs.getBinaryStream("data");
                                OutputStream out = response.getOutputStream();) {
                            StreamUtils.copy(in, out);
                            response.flushBuffer();
                        } catch (IOException e) {
                            throw new RuntimeException(e);
                        }

                        return null;
                    }

                });
    }

    public List<UploadedImage> getForCourse(int courseId) {
        return em.createQuery("FROM UploadedImage WHERE courseId = :courseId ORDER BY uploadedAt DESC",
                UploadedImage.class).setParameter("courseId", courseId).getResultList();
    }
}