blob: 11123d00797daf6a9431322ede176f7214136f9f [file] [log] [blame]
/*
* Copyright (C) 2010, Google Inc. and others
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0 which is available at
* https://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package org.eclipse.jgit.http.server;
import static org.eclipse.jgit.http.server.ServletUtils.acceptsGzipEncoding;
import static org.eclipse.jgit.util.HttpSupport.ENCODING_GZIP;
import static org.eclipse.jgit.util.HttpSupport.HDR_CONTENT_ENCODING;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.GZIPOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.eclipse.jgit.util.TemporaryBuffer;
/**
* Buffers a response, trying to gzip it if the user agent supports that.
* <p>
* If the response overflows the buffer, gzip is skipped and the response is
* streamed to the client as its produced, most likely using HTTP/1.1 chunked
* encoding. This is useful for servlets that produce mixed-mode content, where
* smaller payloads are primarily pure text that compresses well, while much
* larger payloads are heavily compressed binary data. {@link UploadPackServlet}
* is one such servlet.
*/
class SmartOutputStream extends TemporaryBuffer {
private static final int LIMIT = 32 * 1024;
private final HttpServletRequest req;
private final HttpServletResponse rsp;
private boolean compressStream;
private boolean startedOutput;
SmartOutputStream(final HttpServletRequest req,
final HttpServletResponse rsp,
boolean compressStream) {
super(LIMIT);
this.req = req;
this.rsp = rsp;
this.compressStream = compressStream;
}
/** {@inheritDoc} */
@Override
protected OutputStream overflow() throws IOException {
startedOutput = true;
OutputStream out = rsp.getOutputStream();
if (compressStream && acceptsGzipEncoding(req)) {
rsp.setHeader(HDR_CONTENT_ENCODING, ENCODING_GZIP);
out = new GZIPOutputStream(out);
}
return out;
}
/** {@inheritDoc} */
@Override
public void close() throws IOException {
super.close();
if (!startedOutput) {
// If output hasn't started yet, the entire thing fit into our
// buffer. Try to use a proper Content-Length header, and also
// deflate the response with gzip if it will be smaller.
if (256 < this.length() && acceptsGzipEncoding(req)) {
TemporaryBuffer gzbuf = new TemporaryBuffer.Heap(LIMIT);
try {
try (GZIPOutputStream gzip = new GZIPOutputStream(gzbuf)) {
this.writeTo(gzip, null);
}
if (gzbuf.length() < this.length()) {
rsp.setHeader(HDR_CONTENT_ENCODING, ENCODING_GZIP);
writeResponse(gzbuf);
return;
}
} catch (IOException err) {
// Most likely caused by overflowing the buffer, meaning
// its larger if it were compressed. Discard compressed
// copy and use the original.
}
}
writeResponse(this);
}
}
private void writeResponse(TemporaryBuffer out) throws IOException {
// The Content-Length cannot overflow when cast to an int, our
// hardcoded LIMIT constant above assures us we wouldn't store
// more than 2 GiB of content in memory.
rsp.setContentLength((int) out.length());
try (OutputStream os = rsp.getOutputStream()) {
out.writeTo(os, null);
os.flush();
}
}
}