de.dentrassi.pm.storage.service.util.DownloadHelper.java Source code

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Here is the source code for de.dentrassi.pm.storage.service.util.DownloadHelper.java

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/*******************************************************************************
 * Copyright (c) 2014, 2015 IBH SYSTEMS GmbH.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBH SYSTEMS GmbH - initial API and implementation
 *******************************************************************************/
package de.dentrassi.pm.storage.service.util;

import java.io.IOException;
import java.util.function.Function;

import javax.servlet.http.HttpServletResponse;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.io.ByteStreams;

import de.dentrassi.pm.common.ArtifactInformation;
import de.dentrassi.pm.common.MetaKey;
import de.dentrassi.pm.storage.Artifact;
import de.dentrassi.pm.storage.service.StorageService;

public final class DownloadHelper {
    private final static Logger logger = LoggerFactory.getLogger(DownloadHelper.class);

    private DownloadHelper() {
    }

    public static final String APPLICATION_OCTET_STREAM = "application/octet-stream";

    public static void streamArtifact(final HttpServletResponse response, final StorageService storageService,
            final String artifactId, final String mimetype, final boolean download) throws IOException {
        streamArtifact(response, storageService, artifactId, mimetype, download, ArtifactInformation::getName);
    }

    public static void streamArtifact(final HttpServletResponse response, final StorageService storageService,
            final String artifactId, final String mimetype, final boolean download,
            final Function<ArtifactInformation, String> nameProvider) throws IOException {
        final Artifact artifact = storageService.getArtifact(artifactId);
        if (artifact == null) {
            response.setStatus(HttpServletResponse.SC_NOT_FOUND);
            response.setContentType("text/plain");
            response.getWriter().format("Artifact '%s' could not be found", artifactId);
            return;
        }

        streamArtifact(response, artifact, mimetype, download, nameProvider);
    }

    public static void streamArtifact(final HttpServletResponse response, final Artifact artifact,
            final String mimetype, final boolean download) throws IOException {
        streamArtifact(response, artifact, mimetype, download, ArtifactInformation::getName);
    }

    public static void streamArtifact(final HttpServletResponse response, final Artifact artifact,
            final String mimetype, final boolean download, final Function<ArtifactInformation, String> nameProvider)
            throws IOException {
        artifact.streamData((info, stream) -> {

            String mt = mimetype;
            if (mt == null) {
                mt = getMimeType(artifact);
            }

            response.setStatus(HttpServletResponse.SC_OK);
            response.setContentType(mt);
            response.setDateHeader("Last-Modified", info.getCreationTimestamp().getTime());

            try {
                response.setContentLengthLong(info.getSize());
                if (download) {
                    response.setHeader("Content-Disposition",
                            String.format("attachment; filename=%s", info.getName()));
                }
                final long size = ByteStreams.copy(stream, response.getOutputStream());
                logger.debug("Copyied {} bytes", size);
            } catch (final Exception e) {
                throw new RuntimeException(e);
            }
        });
    }

    private static String getMimeType(final Artifact artifact) {
        final String mimetype = artifact.getInformation().getMetaData().get(new MetaKey("mime", "type"));
        return mimetype == null ? APPLICATION_OCTET_STREAM : mimetype;
    }
}