com.nabla.wapp.server.basic.general.ExportService.java Source code

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Here is the source code for com.nabla.wapp.server.basic.general.ExportService.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.wapp.server.basic.general;

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 java.util.GregorianCalendar;

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

import org.apache.commons.io.IOUtils;
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.Database;
import com.nabla.wapp.server.database.IDatabase;
import com.nabla.wapp.server.database.IReadWriteDatabase;
import com.nabla.wapp.server.database.StatementFormat;
import com.nabla.wapp.server.general.UserSession;
import com.nabla.wapp.server.general.Util;
import com.nabla.wapp.shared.dispatch.InternalErrorException;

@Singleton
public class ExportService extends HttpServlet {

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

    private final IDatabase db;

    @Inject
    public ExportService(@IReadWriteDatabase IDatabase db) {
        this.db = db;
    }

    @Override
    public void doGet(final HttpServletRequest request, final HttpServletResponse response) throws IOException {
        final String id = request.getParameter("id");
        if (id == null || id.isEmpty()) {
            if (log.isTraceEnabled())
                log.trace("missing file ID");
            response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            return;
        }
        final UserSession userSession = UserSession.load(request);
        if (userSession == null) {
            if (log.isTraceEnabled())
                log.trace("missing user session");
            response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            return;
        }
        try {
            if (exportFile(id, userSession, 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 exportFile(final String id, final UserSession userSession, final HttpServletResponse response)
            throws IOException, SQLException, InternalErrorException {
        final Connection conn = db.getConnection();
        try {
            final PreparedStatement stmt = StatementFormat.prepare(conn, "SELECT * FROM export WHERE id=?;", id);
            try {
                final ResultSet rs = stmt.executeQuery();
                try {
                    if (!rs.next()) {
                        if (log.isDebugEnabled())
                            log.debug("failed to find file ID= " + id);
                        return false;
                    }
                    if (!userSession.getSessionId().equals(rs.getString("userSessionId"))) {
                        if (log.isTraceEnabled())
                            log.trace("invalid user session ID");
                        return false;
                    }
                    if (log.isTraceEnabled())
                        log.trace("exporting file " + id);
                    response.reset();
                    response.setBufferSize(DEFAULT_BUFFER_SIZE);
                    response.setContentType(rs.getString("content_type"));
                    if (rs.getBoolean("output_as_file")) {
                        // IMPORTANT:
                        // MUST be done before calling getOutputStream() otherwise no SaveAs dialogbox
                        response.setHeader("Content-Disposition",
                                MessageFormat.format("attachment; filename=\"{0}\"", rs.getString("name")));
                    }
                    IOUtils.copy(rs.getBinaryStream("content"), response.getOutputStream());
                    /*   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();
                    try {
                        Database.executeUpdate(conn, "DELETE FROM export WHERE id=?;", id);
                    } catch (final SQLException e) {
                        if (log.isErrorEnabled())
                            log.error("failed to delete export record: " + e.getErrorCode() + "-" + e.getSQLState(),
                                    e);
                    }
                }
            } finally {
                stmt.close();
            }
        } finally {
            // remove any orphan export records i.e. older than 48h (beware of timezone!)
            final Calendar dt = Util.dateToCalendar(new Date());
            dt.add(GregorianCalendar.DATE, -2);
            try {
                Database.executeUpdate(conn, "DELETE FROM export WHERE created < ?;", Util.calendarToSqlDate(dt));
            } catch (final SQLException __) {
            }
            conn.close();
        }
        return true;
    }

}