/*
* Copyright (C) 2009-2010, Google Inc.
* and other copyright owners as documented in the project's IP log.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Distribution License v1.0 which
* accompanies this distribution, is reproduced below, and is
* available at http://www.eclipse.org/org/documents/edl-v10.php
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* - Neither the name of the Eclipse Foundation, Inc. nor the
* names of its contributors may be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.eclipse.jgit.http.server;
import static javax.servlet.http.HttpServletResponse.SC_PARTIAL_CONTENT;
import static javax.servlet.http.HttpServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE;
import static org.eclipse.jgit.util.HttpSupport.HDR_ACCEPT_RANGES;
import static org.eclipse.jgit.util.HttpSupport.HDR_CONTENT_LENGTH;
import static org.eclipse.jgit.util.HttpSupport.HDR_CONTENT_RANGE;
import static org.eclipse.jgit.util.HttpSupport.HDR_IF_RANGE;
import static org.eclipse.jgit.util.HttpSupport.HDR_RANGE;
import java.io.EOFException;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.text.MessageFormat;
import java.util.Enumeration;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.eclipse.jgit.lib.ObjectId;
/**
* Dumps a file over HTTP GET (or its information via HEAD).
* <p>
* Supports a single byte range requested via {@code Range} HTTP header. This
* feature supports a dumb client to resume download of a larger object file.
*/
final class FileSender {
private final File path;
private final RandomAccessFile source;
private final long lastModified;
private final long fileLen;
private long pos;
private long end;
FileSender(final File path) throws FileNotFoundException {
this.path = path;
this.source = new RandomAccessFile(path, "r");
try {
this.lastModified = path.lastModified();
this.fileLen = source.getChannel().size();
this.end = fileLen;
} catch (IOException e) {
try {
source.close();
} catch (IOException closeError) {
// Ignore any error closing the stream.
}
final FileNotFoundException r;
r = new FileNotFoundException(MessageFormat.format(HttpServerText.get().cannotGetLengthOf, path));
r.initCause(e);
throw r;
}
}
void close() {
try {
source.close();
} catch (IOException e) {
// Ignore close errors on a read-only stream.
}
}
long getLastModified() {
return lastModified;
}
String getTailChecksum() throws IOException {
final int n = 20;
final byte[] buf = new byte[n];
source.seek(fileLen - n);
source.readFully(buf, 0, n);
return ObjectId.fromRaw(buf).getName();
}
void serve(final HttpServletRequest req, final HttpServletResponse rsp,
final boolean sendBody) throws IOException {
if (!initRangeRequest(req, rsp)) {
rsp.sendError(SC_REQUESTED_RANGE_NOT_SATISFIABLE);
return;
}
rsp.setHeader(HDR_ACCEPT_RANGES, "bytes");
rsp.setHeader(HDR_CONTENT_LENGTH, Long.toString(end - pos));
if (sendBody) {
final OutputStream out = rsp.getOutputStream();
try {
final byte[] buf = new byte[4096];
source.seek(pos);
while (pos < end) {
final int r = (int) Math.min(buf.length, end - pos);
final int n = source.read(buf, 0, r);
if (n < 0) {
throw new EOFException(MessageFormat.format(HttpServerText.get().unexpectedeOFOn, path));
}
out.write(buf, 0, n);
pos += n;
}
out.flush();
} finally {
out.close();
}
}
}
private boolean initRangeRequest(final HttpServletRequest req,
final HttpServletResponse rsp) throws IOException {
final Enumeration<String> rangeHeaders = getRange(req);
if (!rangeHeaders.hasMoreElements()) {
// No range headers, the request is fine.
return true;
}
final String range = rangeHeaders.nextElement();
if (rangeHeaders.hasMoreElements()) {
// To simplify the code we support only one range.
return false;
}
final int eq = range.indexOf('=');
final int dash = range.indexOf('-');
if (eq < 0 || dash < 0 || !range.startsWith("bytes=")) {
return false;
}
final String ifRange = req.getHeader(HDR_IF_RANGE);
if (ifRange != null && !getTailChecksum().equals(ifRange)) {
// If the client asked us to verify the ETag and its not
// what they expected we need to send the entire content.
return true;
}
try {
if (eq + 1 == dash) {
// "bytes=-500" means last 500 bytes
pos = Long.parseLong(range.substring(dash + 1));
pos = fileLen - pos;
} else {
// "bytes=500-" (position 500 to end)
// "bytes=500-1000" (position 500 to 1000)
pos = Long.parseLong(range.substring(eq + 1, dash));
if (dash < range.length() - 1) {
end = Long.parseLong(range.substring(dash + 1));
end++; // range was inclusive, want exclusive
}
}
} catch (NumberFormatException e) {
// We probably hit here because of a non-digit such as
// "," appearing at the end of the first range telling
// us there is a second range following. To simplify
// the code we support only one range.
return false;
}
if (end > fileLen) {
end = fileLen;
}
if (pos >= end) {
return false;
}
rsp.setStatus(SC_PARTIAL_CONTENT);
rsp.setHeader(HDR_CONTENT_RANGE, "bytes " + pos + "-" + (end - 1) + "/"
+ fileLen);
source.seek(pos);
return true;
}
@SuppressWarnings("unchecked")
private static Enumeration<String> getRange(final HttpServletRequest req) {
return req.getHeaders(HDR_RANGE);
}
}