/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.apache.tools.ant.taskdefs;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.util.FileUtils;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.Date;
/**
* Gets a particular file from a URL source.
* Options include verbose reporting, timestamp based fetches and controlling
* actions on failures. NB: access through a firewall only works if the whole
* Java runtime is correctly configured.
*
* @since Ant 1.1
*
* @ant.task category="network"
*/
public class Get extends Task {
private static final FileUtils FILE_UTILS = FileUtils.getFileUtils();
private URL source; // required
private File dest; // required
private boolean verbose = false;
private boolean useTimestamp = false; //off by default
private boolean ignoreErrors = false;
private String uname = null;
private String pword = null;
/**
* Does the work.
*
* @exception BuildException Thrown in unrecoverable error.
*/
public void execute() throws BuildException {
//set up logging
int logLevel = Project.MSG_INFO;
DownloadProgress progress = null;
if (verbose) {
progress = new VerboseProgress(System.out);
}
//execute the get
try {
doGet(logLevel, progress);
} catch (IOException ioe) {
log("Error getting " + source + " to " + dest);
if (!ignoreErrors) {
throw new BuildException(ioe, getLocation());
}
}
}
/**
* make a get request, with the supplied progress and logging info.
* All the other config parameters are set at the task level,
* source, dest, ignoreErrors, etc.
* @param logLevel level to log at, see {@link Project#log(String, int)}
* @param progress progress callback; null for no-callbacks
* @return true for a successful download, false otherwise.
* The return value is only relevant when {@link #ignoreErrors} is true, as
* when false all failures raise BuildExceptions.
* @throws IOException for network trouble
* @throws BuildException for argument errors, or other trouble when ignoreErrors
* is false.
*/
public boolean doGet(int logLevel, DownloadProgress progress)
throws IOException {
if (source == null) {
throw new BuildException("src attribute is required", getLocation());
}
if (dest == null) {
throw new BuildException("dest attribute is required", getLocation());
}
if (dest.exists() && dest.isDirectory()) {
throw new BuildException("The specified destination is a directory",
getLocation());
}
if (dest.exists() && !dest.canWrite()) {
throw new BuildException("Can't write to " + dest.getAbsolutePath(),
getLocation());
}
//dont do any progress, unless asked
if (progress == null) {
progress = new NullProgress();
}
log("Getting: " + source, logLevel);
log("To: " + dest.getAbsolutePath(), logLevel);
//set the timestamp to the file date.
long timestamp = 0;
boolean hasTimestamp = false;
if (useTimestamp && dest.exists()) {
timestamp = dest.lastModified();
if (verbose) {
Date t = new Date(timestamp);
log("local file date : " + t.toString(), logLevel);
}
hasTimestamp = true;
}
//set up the URL connection
URLConnection connection = source.openConnection();
//modify the headers
//NB: things like user authentication could go in here too.
if (hasTimestamp) {
connection.setIfModifiedSince(timestamp);
}
// prepare Java 1.1 style credentials
if (uname != null || pword != null) {
String up = uname + ":" + pword;
String encoding;
//we do not use the sun impl for portability,
//and always use our own implementation for consistent
//testing
Base64Converter encoder = new Base64Converter();
encoding = encoder.encode(up.getBytes());
connection.setRequestProperty ("Authorization",
"Basic " + encoding);
}
//connect to the remote site (may take some time)
connection.connect();
//next test for a 304 result (HTTP only)
if (connection instanceof HttpURLConnection) {
HttpURLConnection httpConnection
= (HttpURLConnection) connection;
long lastModified = httpConnection.getLastModified();
if (httpConnection.getResponseCode()
== 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
log("Not modified - so not downloaded", logLevel);
return false;
}
// test for 401 result (HTTP only)
if (httpConnection.getResponseCode()
== HttpURLConnection.HTTP_UNAUTHORIZED) {
String message = "HTTP Authorization failure";
if (ignoreErrors) {
log(message, logLevel);
return false;
} else {
throw new BuildException(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.
InputStream is = 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) {
log("Error opening connection " + ex, logLevel);
}
}
if (is == null) {
log("Can't get " + source + " to " + dest, logLevel);
if (ignoreErrors) {
return false;
}
throw new BuildException("Can't get " + source + " to " + dest,
getLocation());
}
FileOutputStream fos = new FileOutputStream(dest);
progress.beginDownload();
boolean finished = false;
try {
byte[] buffer = new byte[100 * 1024];
int length;
while ((length = is.read(buffer)) >= 0) {
fos.write(buffer, 0, length);
progress.onTick();
}
finished = true;
} finally {
FileUtils.close(fos);
FileUtils.close(is);
// we have started to (over)write dest, but failed.
// Try to delete the garbage we'd otherwise leave
// behind.
if (!finished) {
dest.delete();
}
}
progress.endDownload();
//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 (useTimestamp) {
long remoteTimestamp = connection.getLastModified();
if (verbose) {
Date t = new Date(remoteTimestamp);
log("last modified = " + t.toString()
+ ((remoteTimestamp == 0)
? " - using current time instead"
: ""), logLevel);
}
if (remoteTimestamp != 0) {
FILE_UTILS.setFileLastModified(dest, remoteTimestamp);
}
}
//successful download
return true;
}
/**
* Set the URL to get.
*
* @param u URL for the file.
*/
public void setSrc(URL u) {
this.source = u;
}
/**
* Where to copy the source file.
*
* @param dest Path to file.
*/
public void setDest(File dest) {
this.dest = dest;
}
/**
* If true, show verbose progress information.
*
* @param v if "true" then be verbose
*/
public void setVerbose(boolean v) {
verbose = v;
}
/**
* If true, log errors but do not treat as fatal.
*
* @param v if "true" then don't report download errors up to ant
*/
public void setIgnoreErrors(boolean v) {
ignoreErrors = v;
}
/**
* If true, conditionally download a file based on the timestamp
* of the local copy.
*
* <p>In this situation, the if-modified-since header is set so
* that the file is only fetched if it is newer than the local
* file (or there is no local file) This flag is only valid on
* HTTP connections, it is ignored in other cases. When the flag
* is set, the local copy of the downloaded file will also have
* its timestamp set to the remote file time.</p>
*
* <p>Note that remote files of date 1/1/1970 (GMT) are treated as
* 'no timestamp', and web servers often serve files with a
* timestamp in the future by replacing their timestamp with that
* of the current time. Also, inter-computer clock differences can
* cause no end of grief.</p>
* @param v "true" to enable file time fetching
*/
public void setUseTimestamp(boolean v) {
useTimestamp = v;
}
/**
* Username for basic auth.
*
* @param u username for authentication
*/
public void setUsername(String u) {
this.uname = u;
}
/**
* password for the basic authentication.
*
* @param p password for authentication
*/
public void setPassword(String p) {
this.pword = p;
}
/**
* Provide this for Backward Compatibility.
*/
protected static class Base64Converter
extends org.apache.tools.ant.util.Base64Converter {
}
/**
* Interface implemented for reporting
* progess 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
PrintStream out;
// CheckStyle:VisibilityModifier ON
/**
* Construct a verbose progress reporter.
* @param out the output stream.
*/
public VerboseProgress(PrintStream out) {
this.out = out;
}
/**
* begin a download
*/
public void beginDownload() {
dots = 0;
}
/**
* tick handler
*
*/
public void onTick() {
out.print(".");
if (dots++ > 50) {
out.flush();
dots = 0;
}
}
/**
* end a download
*/
public void endDownload() {
out.println();
out.flush();
}
}
}
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