com.nabla.dc.server.ImageService.java Source code

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Here is the source code for com.nabla.dc.server.ImageService.java

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/**
 Copyright 2012 nabla
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
* 
*/
package com.nabla.dc.server;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.text.MessageFormat;
import java.util.Calendar;
import java.util.Date;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.google.inject.Inject;
import com.google.inject.Singleton;
import com.nabla.wapp.server.database.IDatabase;
import com.nabla.wapp.server.database.IReadOnlyDatabase;
import com.nabla.wapp.server.database.StatementFormat;
import com.nabla.wapp.shared.dispatch.InternalErrorException;

/**
 * @author FNorais
 *
 */
@Singleton
public class ImageService extends HttpServlet {

    private static final int DEFAULT_BUFFER_SIZE = 10240; // 10KB
    private static final long serialVersionUID = 1L;
    private static final Log log = LogFactory.getLog(ImageService.class);
    private final IDatabase db;

    @Inject
    public ImageService(@IReadOnlyDatabase final IDatabase db) {
        this.db = db;
    }

    @Override
    public void doGet(final HttpServletRequest request, final HttpServletResponse response) throws IOException {
        final String imageId = request.getParameter("id");
        if (imageId == null || imageId.isEmpty()) {
            if (log.isTraceEnabled())
                log.trace("missing image ID");
            response.sendError(HttpServletResponse.SC_NOT_FOUND);
        } else {
            try {
                if (exportImage(imageId, response)) {
                    //   response.setStatus(HttpServletResponse.SC_OK);
                } else
                    response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            } catch (final SQLException e) {
                if (log.isErrorEnabled())
                    log.error("SQL error " + e.getErrorCode() + "-" + e.getSQLState(), e);
                response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            } catch (final Throwable e) {
                if (log.isErrorEnabled())
                    log.error("unexpected error", e);
                response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            }
        }
    }

    private boolean exportImage(final String imageId, final HttpServletResponse response)
            throws IOException, SQLException, InternalErrorException {
        final Connection conn = db.getConnection();
        try {
            final PreparedStatement stmt = StatementFormat.prepare(conn, "SELECT * FROM image WHERE id=?;",
                    imageId);
            try {
                final ResultSet rs = stmt.executeQuery();
                try {
                    if (!rs.next()) {
                        if (log.isDebugEnabled())
                            log.debug("failed to find report ID= " + imageId);
                        return false;
                    }
                    if (log.isTraceEnabled())
                        log.trace("exporting image " + imageId);
                    response.reset();
                    response.setBufferSize(DEFAULT_BUFFER_SIZE);
                    response.setContentType(rs.getString("content_type"));
                    response.setHeader("Content-Length", String.valueOf(rs.getInt("length")));
                    response.setHeader("Content-Disposition",
                            MessageFormat.format("inline; filename=\"{0}\"", rs.getString("name")));
                    // to prevent images to be downloaded every time user hovers one image
                    final Calendar cal = Calendar.getInstance();
                    cal.setTime(new Date());
                    cal.add(Calendar.MONTH, 2);
                    response.setDateHeader("Expires", cal.getTime().getTime());
                    final BufferedInputStream input = new BufferedInputStream(rs.getBinaryStream("content"),
                            DEFAULT_BUFFER_SIZE);
                    try {
                        final BufferedOutputStream output = new BufferedOutputStream(response.getOutputStream(),
                                DEFAULT_BUFFER_SIZE);
                        try {
                            final byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
                            int length;
                            while ((length = input.read(buffer)) > 0)
                                output.write(buffer, 0, length);
                        } finally {
                            output.close();
                        }
                    } finally {
                        input.close();
                    }
                } finally {
                    rs.close();
                }
            } finally {
                stmt.close();
            }
        } finally {
            conn.close();
        }
        return true;
    }

}