Compress directory to tar.gz with Commons Compress

Question

I\'m running into a problem using the commons compress library to create a tar.gz of a directory. I have a directory structure that is as follows.

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Answer 1

Check below for Apache commons-compress and File walker examples.

This example tar.gz a directory.

public static void createTarGzipFolder(Path source) throws IOException {

        if (!Files.isDirectory(source)) {
            throw new IOException("Please provide a directory.");
        }

        // get folder name as zip file name
        String tarFileName = source.getFileName().toString() + ".tar.gz";

        try (OutputStream fOut = Files.newOutputStream(Paths.get(tarFileName));
             BufferedOutputStream buffOut = new BufferedOutputStream(fOut);
             GzipCompressorOutputStream gzOut = new GzipCompressorOutputStream(buffOut);
             TarArchiveOutputStream tOut = new TarArchiveOutputStream(gzOut)) {

            Files.walkFileTree(source, new SimpleFileVisitor<>() {

                @Override
                public FileVisitResult visitFile(Path file,
                                            BasicFileAttributes attributes) {

                    // only copy files, no symbolic links
                    if (attributes.isSymbolicLink()) {
                        return FileVisitResult.CONTINUE;
                    }

                    // get filename
                    Path targetFile = source.relativize(file);

                    try {
                        TarArchiveEntry tarEntry = new TarArchiveEntry(
                                file.toFile(), targetFile.toString());

                        tOut.putArchiveEntry(tarEntry);

                        Files.copy(file, tOut);

                        tOut.closeArchiveEntry();

                        System.out.printf("file : %s%n", file);

                    } catch (IOException e) {
                        System.err.printf("Unable to tar.gz : %s%n%s%n", file, e);
                    }

                    return FileVisitResult.CONTINUE;
                }

                @Override
                public FileVisitResult visitFileFailed(Path file, IOException exc) {
                    System.err.printf("Unable to tar.gz : %s%n%s%n", file, exc);
                    return FileVisitResult.CONTINUE;
                }

            });

            tOut.finish();
        }

    }

This example extracts a tar.gz, and checks zip slip attack.

public static void decompressTarGzipFile(Path source, Path target)
        throws IOException {

        if (Files.notExists(source)) {
            throw new IOException("File doesn't exists!");
        }

        try (InputStream fi = Files.newInputStream(source);
             BufferedInputStream bi = new BufferedInputStream(fi);
             GzipCompressorInputStream gzi = new GzipCompressorInputStream(bi);
             TarArchiveInputStream ti = new TarArchiveInputStream(gzi)) {

            ArchiveEntry entry;
            while ((entry = ti.getNextEntry()) != null) {

                Path newPath = zipSlipProtect(entry, target);

                if (entry.isDirectory()) {
                    Files.createDirectories(newPath);
                } else {

                    // check parent folder again
                    Path parent = newPath.getParent();
                    if (parent != null) {
                        if (Files.notExists(parent)) {
                            Files.createDirectories(parent);
                        }
                    }

                    // copy TarArchiveInputStream to Path newPath
                    Files.copy(ti, newPath, StandardCopyOption.REPLACE_EXISTING);

                }
            }
        }
    }

    private static Path zipSlipProtect(ArchiveEntry entry, Path targetDir)
        throws IOException {

        Path targetDirResolved = targetDir.resolve(entry.getName());

        Path normalizePath = targetDirResolved.normalize();

        if (!normalizePath.startsWith(targetDir)) {
            throw new IOException("Bad entry: " + entry.getName());
        }

        return normalizePath;
    }

References

1. https://mkyong.com/java/how-to-create-tar-gz-in-java/
2. https://commons.apache.org/proper/commons-compress/examples.html