org.mule.maven.client.internal.util.FileUtils Maven / Gradle / Ivy

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/*
 * Copyright (c) MuleSoft, Inc.  All rights reserved.  http://www.mulesoft.com
 * The software in this package is published under the terms of the CPAL v1.0
 * license, a copy of which has been included with this distribution in the
 * LICENSE.txt file.
 */
package org.mule.maven.client.internal.util;

import static java.util.Optional.empty;
import static java.util.Optional.of;
import static org.apache.commons.io.IOUtils.toByteArray;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.JarURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.Optional;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

public class FileUtils {


  /**
   * Loads the content of a file within a jar into a byte array.
   *
   * @param jarFile the jar file
   * @return the content of the file as byte array or empty if the file does not exists within the jar file.
   * @throws IOException if there was a problem reading from the jar file.
   */
  public static Optional loadFileContentFrom(URL jarFile) throws IOException {
    /* A specific implementation of JarURLConnection is required to read jar content because not all implementations
     * support ways to disable connection caching. Disabling connection caching is necessary to avoid file descriptor leaks.
     * See MULE-13139.
     */
    JarURLConnection jarConnection =
        new sun.net.www.protocol.jar.JarURLConnection(jarFile, new sun.net.www.protocol.jar.Handler());
    jarConnection.setUseCaches(false);

    try (InputStream stream = jarConnection.getInputStream()) {
      return of(toByteArray(stream));
    } catch (FileNotFoundException e) {
      return empty();
    }
  }

  /**
   * Creates an URL to a path within a jar file.
   *
   * @param jarFile the jar file
   * @param filePath the path within the jar file
   * @return an URL to the {@code filePath} within the {@code jarFile}
   * @throws MalformedURLException if the provided {@code filePath} is malformed
   */
  public static URL getUrlWithinJar(File jarFile, String filePath) throws MalformedURLException {
    return new URL("jar:" + jarFile.toURI().toString() + "!/" + filePath);
  }

  /**
   * Gets all the URL of files within a directory
   *
   * @param file the jar file
   * @param directory the directory within the jar file
   * @return a collection of URLs to files within the directory {@code directory}. Empty collection if the directory does not
   *         exists or is empty.
   * @throws IOException
   */
  public static List getUrlsWithinJar(File file, String directory) throws IOException {
    List urls = new ArrayList<>();
    try (JarFile jarFile = new JarFile(file)) {
      Enumeration entries = jarFile.entries();
      while (entries.hasMoreElements()) {
        JarEntry jarEntry = entries.nextElement();
        if (!jarEntry.isDirectory() && jarEntry.getName().startsWith(directory + "/")) {
          urls.add(getUrlWithinJar(file, jarEntry.getName()));
        }
      }
    }
    return urls;
  }

}