/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you 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 org.elasticsearch.common.http.client;
import org.apache.lucene.util.IOUtils;
import org.elasticsearch.ElasticsearchTimeoutException;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.unit.TimeValue;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
/**
*
*/
public class HttpDownloadHelper {
private boolean useTimestamp = false;
private boolean skipExisting = false;
public boolean download(URL source, File dest, @Nullable DownloadProgress progress, TimeValue timeout) throws Exception {
if (dest.exists() && skipExisting) {
return true;
}
//don't do any progress, unless asked
if (progress == null) {
progress = new NullProgress();
}
//set the timestamp to the file date.
long timestamp = 0;
boolean hasTimestamp = false;
if (useTimestamp && dest.exists()) {
timestamp = dest.lastModified();
hasTimestamp = true;
}
GetThread getThread = new GetThread(source, dest, hasTimestamp, timestamp, progress);
try {
getThread.setDaemon(true);
getThread.start();
getThread.join(timeout.millis());
if (getThread.isAlive()) {
throw new ElasticsearchTimeoutException("The GET operation took longer than " + timeout + ", stopping it.");
}
}
catch (InterruptedException ie) {
return false;
} finally {
getThread.closeStreams();
}
return getThread.wasSuccessful();
}
/**
* Interface implemented for reporting
* progress of downloading.
*/
public interface DownloadProgress {
/**
* begin a download
*/
void beginDownload();
/**
* tick handler
*/
void onTick();
/**
* end a download
*/
void endDownload();
}
/**
* do nothing with progress info
*/
public static class NullProgress implements DownloadProgress {
/**
* begin a download
*/
public void beginDownload() {
}
/**
* tick handler
*/
public void onTick() {
}
/**
* end a download
*/
public void endDownload() {
}
}
/**
* verbose progress system prints to some output stream
*/
public static class VerboseProgress implements DownloadProgress {
private int dots = 0;
// CheckStyle:VisibilityModifier OFF - bc
PrintWriter writer;
// CheckStyle:VisibilityModifier ON
/**
* Construct a verbose progress reporter.
*
* @param out the output stream.
*/
public VerboseProgress(PrintStream out) {
this.writer = new PrintWriter(out);
}
/**
* Construct a verbose progress reporter.
*
* @param writer the output stream.
*/
public VerboseProgress(PrintWriter writer) {
this.writer = writer;
}
/**
* begin a download
*/
public void beginDownload() {
writer.print("Downloading ");
dots = 0;
}
/**
* tick handler
*/
public void onTick() {
writer.print(".");
if (dots++ > 50) {
writer.flush();
dots = 0;
}
}
/**
* end a download
*/
public void endDownload() {
writer.println("DONE");
writer.flush();
}
}
private class GetThread extends Thread {
private final URL source;
private final File dest;
private final boolean hasTimestamp;
private final long timestamp;
private final DownloadProgress progress;
private boolean success = false;
private IOException ioexception = null;
private InputStream is = null;
private OutputStream os = null;
private URLConnection connection;
private int redirections = 0;
GetThread(URL source, File dest, boolean h, long t, DownloadProgress p) {
this.source = source;
this.dest = dest;
hasTimestamp = h;
timestamp = t;
progress = p;
}
public void run() {
try {
success = get();
} catch (IOException ioex) {
ioexception = ioex;
}
}
private boolean get() throws IOException {
connection = openConnection(source);
if (connection == null) {
return false;
}
boolean downloadSucceeded = downloadFile();
//if (and only if) the use file time option is set, then
//the saved file now has its timestamp set to that of the
//downloaded file
if (downloadSucceeded && useTimestamp) {
updateTimeStamp();
}
return downloadSucceeded;
}
private boolean redirectionAllowed(URL aSource, URL aDest) throws IOException {
// Argh, github does this...
// if (!(aSource.getProtocol().equals(aDest.getProtocol()) || ("http"
// .equals(aSource.getProtocol()) && "https".equals(aDest
// .getProtocol())))) {
// String message = "Redirection detected from "
// + aSource.getProtocol() + " to " + aDest.getProtocol()
// + ". Protocol switch unsafe, not allowed.";
// throw new IOException(message);
// }
redirections++;
if (redirections > 5) {
String message = "More than " + 5 + " times redirected, giving up";
throw new IOException(message);
}
return true;
}
private URLConnection openConnection(URL aSource) throws IOException {
// set up the URL connection
URLConnection connection = aSource.openConnection();
// modify the headers
// NB: things like user authentication could go in here too.
if (hasTimestamp) {
connection.setIfModifiedSince(timestamp);
}
if (connection instanceof HttpURLConnection) {
((HttpURLConnection) connection).setInstanceFollowRedirects(false);
((HttpURLConnection) connection).setUseCaches(true);
((HttpURLConnection) connection).setConnectTimeout(5000);
}
// connect to the remote site (may take some time)
connection.connect();
// First check on a 301 / 302 (moved) response (HTTP only)
if (connection instanceof HttpURLConnection) {
HttpURLConnection httpConnection = (HttpURLConnection) connection;
int responseCode = httpConnection.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_MOVED_PERM ||
responseCode == HttpURLConnection.HTTP_MOVED_TEMP ||
responseCode == HttpURLConnection.HTTP_SEE_OTHER) {
String newLocation = httpConnection.getHeaderField("Location");
String message = aSource
+ (responseCode == HttpURLConnection.HTTP_MOVED_PERM ? " permanently"
: "") + " moved to " + newLocation;
URL newURL = new URL(newLocation);
if (!redirectionAllowed(aSource, newURL)) {
return null;
}
return openConnection(newURL);
}
// next test for a 304 result (HTTP only)
long lastModified = httpConnection.getLastModified();
if (responseCode == HttpURLConnection.HTTP_NOT_MODIFIED
|| (lastModified != 0 && hasTimestamp && timestamp >= lastModified)) {
// not modified so no file download. just return
// instead and trace out something so the user
// doesn't think that the download happened when it
// didn't
return null;
}
// test for 401 result (HTTP only)
if (responseCode == HttpURLConnection.HTTP_UNAUTHORIZED) {
String message = "HTTP Authorization failure";
throw new IOException(message);
}
}
//REVISIT: at this point even non HTTP connections may
//support the if-modified-since behaviour -we just check
//the date of the content and skip the write if it is not
//newer. Some protocols (FTP) don't include dates, of
//course.
return connection;
}
private boolean downloadFile() throws FileNotFoundException, IOException {
IOException lastEx = null;
for (int i = 0; i < 3; i++) {
// this three attempt trick is to get round quirks in different
// Java implementations. Some of them take a few goes to bind
// property; we ignore the first couple of such failures.
try {
is = connection.getInputStream();
break;
} catch (IOException ex) {
lastEx = ex;
}
}
if (is == null) {
throw new IOException("Can't get " + source + " to " + dest, lastEx);
}
os = new FileOutputStream(dest);
progress.beginDownload();
boolean finished = false;
try {
byte[] buffer = new byte[1024 * 100];
int length;
while (!isInterrupted() && (length = is.read(buffer)) >= 0) {
os.write(buffer, 0, length);
progress.onTick();
}
finished = !isInterrupted();
} finally {
if (!finished) {
// we have started to (over)write dest, but failed.
// Try to delete the garbage we'd otherwise leave
// behind.
IOUtils.closeWhileHandlingException(os, is);
IOUtils.deleteFilesIgnoringExceptions(dest.toPath());
} else {
IOUtils.close(os, is);
}
}
progress.endDownload();
return true;
}
private void updateTimeStamp() {
long remoteTimestamp = connection.getLastModified();
if (remoteTimestamp != 0) {
dest.setLastModified(remoteTimestamp);
}
}
/**
* Has the download completed successfully?
* <p/>
* <p>Re-throws any exception caught during executaion.</p>
*/
boolean wasSuccessful() throws IOException {
if (ioexception != null) {
throw ioexception;
}
return success;
}
/**
* Closes streams, interrupts the download, may delete the
* output file.
*/
void closeStreams() throws IOException {
interrupt();
if (success) {
IOUtils.close(is, os);
} else {
IOUtils.closeWhileHandlingException(is, os);
if (dest != null && dest.exists()) {
IOUtils.deleteFilesIgnoringExceptions(dest.toPath());
}
}
}
}
}