org.cryptomator.frontend.webdav.jackrabbitservlet.DavFileWithRange.java Source code

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Here is the source code for org.cryptomator.frontend.webdav.jackrabbitservlet.DavFileWithRange.java

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/*******************************************************************************
 * Copyright (c) 2016 Sebastian Stenzel and others.
 * This file is licensed under the terms of the MIT license.
 * See the LICENSE.txt file for more info.
 *
 * Contributors:
 *     Sebastian Stenzel - initial API and implementation
 *******************************************************************************/
package org.cryptomator.frontend.webdav.jackrabbitservlet;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.channels.Channels;
import java.util.Objects;

import org.apache.commons.lang3.tuple.ImmutablePair;
import org.apache.commons.lang3.tuple.Pair;
import org.apache.jackrabbit.webdav.DavServletResponse;
import org.apache.jackrabbit.webdav.DavSession;
import org.apache.jackrabbit.webdav.io.OutputContext;
import org.apache.jackrabbit.webdav.lock.LockManager;
import org.cryptomator.filesystem.ReadableFile;
import org.cryptomator.filesystem.jackrabbit.FileLocator;
import org.eclipse.jetty.http.HttpHeader;

import com.google.common.io.ByteStreams;

/**
 * Delivers only the requested range of bytes from a file.
 * 
 * @see {@link https://tools.ietf.org/html/rfc7233#section-4}
 */
class DavFileWithRange extends DavFile {

    private final Pair<String, String> requestRange;

    public DavFileWithRange(FilesystemResourceFactory factory, LockManager lockManager, DavSession session,
            FileLocator node, Pair<String, String> requestRange) {
        super(factory, lockManager, session, node);
        this.requestRange = Objects.requireNonNull(requestRange);
    }

    @Override
    public void spool(OutputContext outputContext) throws IOException {
        outputContext.setModificationTime(node.lastModified().toEpochMilli());
        if (!outputContext.hasStream()) {
            return;
        }
        final long contentLength = node.size();
        final Pair<Long, Long> range = getEffectiveRange(contentLength);
        if (range.getLeft() < 0 || range.getLeft() > range.getRight() || range.getRight() > contentLength) {
            outputContext.setProperty(HttpHeader.CONTENT_RANGE.asString(), "bytes */" + contentLength);
            throw new UncheckedDavException(DavServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE,
                    "Valid Range would be in [0, " + contentLength + "]");
        }
        final Long rangeLength = range.getRight() - range.getLeft() + 1;
        outputContext.setContentLength(rangeLength);
        outputContext.setProperty(HttpHeader.CONTENT_RANGE.asString(),
                contentRangeResponseHeader(range.getLeft(), range.getRight(), contentLength));
        outputContext.setContentType(CONTENT_TYPE_VALUE);
        outputContext.setProperty(CONTENT_DISPOSITION_HEADER, CONTENT_DISPOSITION_VALUE);
        outputContext.setProperty(X_CONTENT_TYPE_OPTIONS_HEADER, X_CONTENT_TYPE_OPTIONS_VALUE);
        try (ReadableFile src = node.openReadable(); OutputStream out = outputContext.getOutputStream()) {
            src.position(range.getLeft());
            InputStream limitedIn = ByteStreams.limit(Channels.newInputStream(src), rangeLength);
            ByteStreams.copy(limitedIn, out);
        }
    }

    private String contentRangeResponseHeader(long firstByte, long lastByte, long completeLength) {
        return String.format("bytes %d-%d/%d", firstByte, lastByte, completeLength);
    }

    private Pair<Long, Long> getEffectiveRange(long contentLength) {
        try {
            final Long lower = requestRange.getLeft().isEmpty() ? null : Long.valueOf(requestRange.getLeft());
            final Long upper = requestRange.getRight().isEmpty() ? null : Long.valueOf(requestRange.getRight());
            if (lower == null && upper == null) {
                return new ImmutablePair<Long, Long>(0l, contentLength - 1);
            } else if (lower == null) {
                return new ImmutablePair<Long, Long>(contentLength - upper, contentLength - 1);
            } else if (upper == null) {
                return new ImmutablePair<Long, Long>(lower, contentLength - 1);
            } else {
                return new ImmutablePair<Long, Long>(lower, Math.min(upper, contentLength - 1));
            }
        } catch (NumberFormatException e) {
            throw new IllegalArgumentException("Invalid byte range: " + requestRange, e);
        }
    }

}