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 *  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
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 *
 */

package org.apache.tools.ant.taskdefs;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.Date;
import java.util.zip.GZIPInputStream;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.MagicNames;
import org.apache.tools.ant.Main;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.types.Mapper;
import org.apache.tools.ant.types.Resource;
import org.apache.tools.ant.types.ResourceCollection;
import org.apache.tools.ant.types.resources.Resources;
import org.apache.tools.ant.types.resources.URLProvider;
import org.apache.tools.ant.types.resources.URLResource;
import org.apache.tools.ant.util.FileNameMapper;
import org.apache.tools.ant.util.FileUtils;

/**
 * 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 int NUMBER_RETRIES = 3;
    private static final int DOTS_PER_LINE = 50;
    private static final int BIG_BUFFER_SIZE = 100 * 1024;
    private static final FileUtils FILE_UTILS = FileUtils.getFileUtils();
    private static final int REDIRECT_LIMIT = 25;
    // HttpURLConnection doesn't have a constant for this in Java5 and
    // what it calls HTTP_MOVED_TEMP would better be FOUND
    private static final int HTTP_MOVED_TEMP = 307;

    private static final String HTTP = "http";
    private static final String HTTPS = "https";

    private static final String DEFAULT_AGENT_PREFIX = "Apache Ant";
    private static final String GZIP_CONTENT_ENCODING = "gzip";

    private final Resources sources = new Resources();
    private File destination; // required
    private boolean verbose = false;
    private boolean quiet = false;
    private boolean useTimestamp = false; //off by default
    private boolean ignoreErrors = false;
    private String uname = null;
    private String pword = null;
    private long maxTime = 0;
    private int numberRetries = NUMBER_RETRIES;
    private boolean skipExisting = false;
    private boolean httpUseCaches = true; // on by default
    private boolean tryGzipEncoding = false;
    private Mapper mapperElement = null;
    private String userAgent =
        System.getProperty(MagicNames.HTTP_AGENT_PROPERTY,
                           DEFAULT_AGENT_PREFIX + "/"
                           + Main.getShortAntVersion());

    /**
     * Does the work.
     *
     * @exception BuildException Thrown in unrecoverable error.
     */
    @Override
    public void execute() throws BuildException {
        checkAttributes();

        for (final Resource r : sources) {
            final URLProvider up = r.as(URLProvider.class);
            final URL source = up.getURL();

            File dest = destination;
            if (destination.isDirectory()) {
                if (mapperElement == null) {
                    String path = source.getPath();
                    if (path.endsWith("/")) {
                        path = path.substring(0, path.length() - 1);
                    }
                    final int slash = path.lastIndexOf("/");
                    if (slash > -1) {
                        path = path.substring(slash + 1);
                    }
                    dest = new File(destination, path);
                } else {
                    final FileNameMapper mapper = mapperElement.getImplementation();
                    final String[] d = mapper.mapFileName(source.toString());
                    if (d == null) {
                        log("skipping " + r + " - mapper can't handle it",
                            Project.MSG_WARN);
                        continue;
                    } else if (d.length == 0) {
                        log("skipping " + r + " - mapper returns no file name",
                            Project.MSG_WARN);
                        continue;
                    } else if (d.length > 1) {
                        log("skipping " + r + " - mapper returns multiple file"
                            + " names", Project.MSG_WARN);
                        continue;
                    }
                    dest = new File(destination, d[0]);
                }
            }

            //set up logging
            final int logLevel = Project.MSG_INFO;
            DownloadProgress progress = null;
            if (verbose) {
                progress = new VerboseProgress(System.out);
            }

            //execute the get
            try {
                doGet(source, dest, logLevel, progress);
            } catch (final 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.
     * @deprecated only gets the first configured resource
     */
    @Deprecated
    public boolean doGet(final int logLevel, final DownloadProgress progress)
            throws IOException {
        checkAttributes();
        for (final Resource r : sources) {
            final URLProvider up = r.as(URLProvider.class);
            final URL source = up.getURL();
            return doGet(source, destination, logLevel, progress);
        }
        /*NOTREACHED*/
        return false;
    }

    /**
     * make a get request, with the supplied progress and logging info.
     *
     * All the other config parameters like ignoreErrors are set at
     * the task level.
     * @param source the URL to get
     * @param dest the target file
     * @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.
     * @since Ant 1.8.0
     */
    public boolean doGet(final URL source, final File dest, final int logLevel,
                         DownloadProgress progress)
        throws IOException {

        if (dest.exists() && skipExisting) {
            log("Destination already exists (skipping): "
                + dest.getAbsolutePath(), logLevel);
            return true;
        }

        //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) {
                final Date t = new Date(timestamp);
                log("local file date : " + t.toString(), logLevel);
            }
            hasTimestamp = true;
        }

        final GetThread getThread = new GetThread(source, dest,
                                            hasTimestamp, timestamp, progress,
                                            logLevel, userAgent);
        getThread.setDaemon(true);
        getProject().registerThreadTask(getThread, this);
        getThread.start();
        try {
            getThread.join(maxTime * 1000);
        } catch (final InterruptedException ie) {
            log("interrupted waiting for GET to finish",
                Project.MSG_VERBOSE);
        }

        if (getThread.isAlive()) {
            final String msg = "The GET operation took longer than " + maxTime
                + " seconds, stopping it.";
            if (ignoreErrors) {
                log(msg);
            }
            getThread.closeStreams();
            if (!ignoreErrors) {
                throw new BuildException(msg);
            }
            return false;
        }

        return getThread.wasSuccessful();
    }

    @Override
    public void log(final String msg, final int msgLevel) {
        if (!quiet || msgLevel <= Project.MSG_ERR) {
            super.log(msg, msgLevel);
        }
    }

    /**
     * Check the attributes.
     */
    private void checkAttributes() {

        if (userAgent == null || userAgent.trim().length() == 0) {
            throw new BuildException("userAgent may not be null or empty");
        }

        if (sources.size() == 0) {
            throw new BuildException("at least one source is required",
                                     getLocation());
        }
        for (final Resource r : sources) {
            final URLProvider up = r.as(URLProvider.class);
            if (up == null) {
                throw new BuildException("Only URLProvider resources are"
                                         + " supported", getLocation());
            }
        }

        if (destination == null) {
            throw new BuildException("dest attribute is required", getLocation());
        }

        if (destination.exists() && sources.size() > 1
            && !destination.isDirectory()) {
            throw new BuildException("The specified destination is not a"
                                     + " directory",
                                     getLocation());
        }

        if (destination.exists() && !destination.canWrite()) {
            throw new BuildException("Can't write to "
                                     + destination.getAbsolutePath(),
                                     getLocation());
        }

        if (sources.size() > 1 && !destination.exists()) {
            destination.mkdirs();
        }
    }

    /**
     * Set an URL to get.
     *
     * @param u URL for the file.
     */
    public void setSrc(final URL u) {
        add(new URLResource(u));
    }

    /**
     * Adds URLs to get.
     * @since Ant 1.8.0
     */
    public void add(final ResourceCollection rc) {
        sources.add(rc);
    }

    /**
     * Where to copy the source file.
     *
     * @param dest Path to file.
     */
    public void setDest(final File dest) {
        this.destination = dest;
    }

    /**
     * If true, show verbose progress information.
     *
     * @param v if "true" then be verbose
     */
    public void setVerbose(final boolean v) {
        verbose = v;
    }

    /**
     * If true, set default log level to Project.MSG_ERR.
     *
     * @param v if "true" then be quiet
     * @since Ant 1.9.4
     */
    public void setQuiet(final boolean v){
        this.quiet = 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(final boolean v) {
        ignoreErrors = v;
    }

    /**
     * If true, conditionally download a file based on the timestamp
     * of the local copy.
     *
     * 

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.

* *

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.

* @param v "true" to enable file time fetching */ public void setUseTimestamp(final boolean v) { useTimestamp = v; } /** * Username for basic auth. * * @param u username for authentication */ public void setUsername(final String u) { this.uname = u; } /** * password for the basic authentication. * * @param p password for authentication */ public void setPassword(final String p) { this.pword = p; } /** * The time in seconds the download is allowed to take before * being terminated. * * @since Ant 1.8.0 */ public void setMaxTime(final long maxTime) { this.maxTime = maxTime; } /** * The number of attempts to make for opening the URI, defaults to 3. * *

The name of the method is misleading as a value of 1 means * "don't retry on error" and a value of 0 meant don't even try to * reach the URI at all.

* * @param r number of attempts to make * * @since Ant 1.8.0 */ public void setRetries(final int r) { if (r <= 0) { log("Setting retries to " + r + " will make the task not even try to reach the URI at all", Project.MSG_WARN); } this.numberRetries = r; } /** * Skip files that already exist locally. * * @param s "true" to skip existing destination files * * @since Ant 1.8.0 */ public void setSkipExisting(final boolean s) { this.skipExisting = s; } /** * HTTP connections only - set the user-agent to be used * when communicating with remote server. if null, then * the value is considered unset and the behaviour falls * back to the default of the http API. * * @since Ant 1.9.3 */ public void setUserAgent(final String userAgent) { this.userAgent = userAgent; } /** * HTTP connections only - control caching on the * HttpUrlConnection: httpConnection.setUseCaches(); if false, do * not allow caching on the HttpUrlConnection. * *

Defaults to true (allow caching, which is also the * HttpUrlConnection default value.

* * @since Ant 1.8.0 */ public void setHttpUseCaches(final boolean httpUseCache) { this.httpUseCaches = httpUseCache; } /** * Whether to transparently try to reduce bandwidth by telling the * server ant would support gzip encoding. * *

Setting this to true also means Ant will uncompress * .tar.gz and similar files automatically.

* * @since Ant 1.9.5 */ public void setTryGzipEncoding(boolean b) { tryGzipEncoding = b; } /** * Define the mapper to map source to destination files. * @return a mapper to be configured. * @exception BuildException if more than one mapper is defined. * @since Ant 1.8.0 */ public Mapper createMapper() throws BuildException { if (mapperElement != null) { throw new BuildException("Cannot define more than one mapper", getLocation()); } mapperElement = new Mapper(getProject()); return mapperElement; } /** * Add a nested filenamemapper. * @param fileNameMapper the mapper to add. * @since Ant 1.8.0 */ public void add(final FileNameMapper fileNameMapper) { createMapper().add(fileNameMapper); } /** * Provide this for Backward Compatibility. */ protected static class Base64Converter extends org.apache.tools.ant.util.Base64Converter { } /** * 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 PrintStream out; // CheckStyle:VisibilityModifier ON /** * Construct a verbose progress reporter. * @param out the output stream. */ public VerboseProgress(final PrintStream out) { this.out = out; } /** * begin a download */ public void beginDownload() { dots = 0; } /** * tick handler * */ public void onTick() { out.print("."); if (dots++ > DOTS_PER_LINE) { out.flush(); dots = 0; } } /** * end a download */ public void endDownload() { out.println(); out.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 final int logLevel; private boolean success = false; private IOException ioexception = null; private BuildException exception = null; private InputStream is = null; private OutputStream os = null; private URLConnection connection; private int redirections = 0; private String userAgent = null; GetThread(final URL source, final File dest, final boolean h, final long t, final DownloadProgress p, final int l, final String userAgent) { this.source = source; this.dest = dest; hasTimestamp = h; timestamp = t; progress = p; logLevel = l; this.userAgent = userAgent; } @Override public void run() { try { success = get(); } catch (final IOException ioex) { ioexception = ioex; } catch (final BuildException bex) { exception = bex; } } private boolean get() throws IOException, BuildException { connection = openConnection(source); if (connection == null) { return false; } final 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(final URL aSource, final URL aDest) { if (!(aSource.getProtocol().equals(aDest.getProtocol()) || (HTTP .equals(aSource.getProtocol()) && HTTPS.equals(aDest .getProtocol())))) { final String message = "Redirection detected from " + aSource.getProtocol() + " to " + aDest.getProtocol() + ". Protocol switch unsafe, not allowed."; if (ignoreErrors) { log(message, logLevel); return false; } else { throw new BuildException(message); } } redirections++; if (redirections > REDIRECT_LIMIT) { final String message = "More than " + REDIRECT_LIMIT + " times redirected, giving up"; if (ignoreErrors) { log(message, logLevel); return false; } else { throw new BuildException(message); } } return true; } private URLConnection openConnection(final URL aSource) throws IOException { // set up the URL connection final URLConnection connection = aSource.openConnection(); // modify the headers // NB: things like user authentication could go in here too. if (hasTimestamp) { connection.setIfModifiedSince(timestamp); } // Set the user agent connection.addRequestProperty("User-Agent", this.userAgent); // prepare Java 1.1 style credentials if (uname != null || pword != null) { final String up = uname + ":" + pword; String encoding; // we do not use the sun impl for portability, // and always use our own implementation for consistent // testing final Base64Converter encoder = new Base64Converter(); encoding = encoder.encode(up.getBytes()); connection.setRequestProperty("Authorization", "Basic " + encoding); } if (tryGzipEncoding) { connection.setRequestProperty("Accept-Encoding", GZIP_CONTENT_ENCODING); } if (connection instanceof HttpURLConnection) { ((HttpURLConnection) connection) .setInstanceFollowRedirects(false); ((HttpURLConnection) connection) .setUseCaches(httpUseCaches); } // connect to the remote site (may take some time) try { connection.connect(); } catch (final NullPointerException e) { //bad URLs can trigger NPEs in some JVMs throw new BuildException("Failed to parse " + source.toString(), e); } // First check on a 301 / 302 (moved) response (HTTP only) if (connection instanceof HttpURLConnection) { final HttpURLConnection httpConnection = (HttpURLConnection) connection; final int responseCode = httpConnection.getResponseCode(); if (isMoved(responseCode)) { final String newLocation = httpConnection.getHeaderField("Location"); final String message = aSource + (responseCode == HttpURLConnection.HTTP_MOVED_PERM ? " permanently" : "") + " moved to " + newLocation; log(message, logLevel); final URL newURL = new URL(aSource, newLocation); if (!redirectionAllowed(aSource, newURL)) { return null; } return openConnection(newURL); } // next test for a 304 result (HTTP only) final 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 log("Not modified - so not downloaded", logLevel); return null; } // test for 401 result (HTTP only) if (responseCode == HttpURLConnection.HTTP_UNAUTHORIZED) { final String message = "HTTP Authorization failure"; if (ignoreErrors) { log(message, logLevel); return null; } 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. return connection; } private boolean isMoved(final int responseCode) { return responseCode == HttpURLConnection.HTTP_MOVED_PERM || responseCode == HttpURLConnection.HTTP_MOVED_TEMP || responseCode == HttpURLConnection.HTTP_SEE_OTHER || responseCode == HTTP_MOVED_TEMP; } private boolean downloadFile() throws FileNotFoundException, IOException { for (int i = 0; i < numberRetries; i++) { // this three attempt trick is to get round quirks in different // Java implementations. Some of them take a few goes to bind // properly; we ignore the first couple of such failures. try { is = connection.getInputStream(); break; } catch (final 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()); } if (tryGzipEncoding && GZIP_CONTENT_ENCODING.equals(connection.getContentEncoding())) { is = new GZIPInputStream(is); } os = new FileOutputStream(dest); progress.beginDownload(); boolean finished = false; try { final byte[] buffer = new byte[BIG_BUFFER_SIZE]; int length; while (!isInterrupted() && (length = is.read(buffer)) >= 0) { os.write(buffer, 0, length); progress.onTick(); } finished = !isInterrupted(); } finally { FileUtils.close(os); 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(); return true; } private void updateTimeStamp() { final long remoteTimestamp = connection.getLastModified(); if (verbose) { final 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); } } /** * Has the download completed successfully? * *

Re-throws any exception caught during executaion.

*/ boolean wasSuccessful() throws IOException, BuildException { if (ioexception != null) { throw ioexception; } if (exception != null) { throw exception; } return success; } /** * Closes streams, interrupts the download, may delete the * output file. */ void closeStreams() { interrupt(); FileUtils.close(os); FileUtils.close(is); if (!success && dest.exists()) { dest.delete(); } } } }




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