+
−/*
+
− * SPDX-License-Identifier: MPL-2.0
+
− *
+
− * This Source Code Form is subject to the terms of the Mozilla Public
+
− * License, v. 2.0.  If a copy of the MPL was not distributed with this
+
− * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
− *
+
− * Copyright 2024, 2025 MonetDB Foundation;
+
− * Copyright August 2008 - 2023 MonetDB B.V.;
+
− * Copyright 1997 - July 2008 CWI.
+
− */
+
−
+
−package org.monetdb.util;
+
−
+
−import org.monetdb.jdbc.MonetConnection;
+
−
+
−import java.io.BufferedReader;
+
−import java.io.BufferedWriter;
+
−import java.io.IOException;
+
−import java.io.InputStream;
+
−import java.io.InputStreamReader;
+
−import java.io.OutputStream;
+
−import java.io.OutputStreamWriter;
+
−import java.nio.charset.Charset;
+
−import java.nio.charset.StandardCharsets;
+
−import java.nio.file.FileSystems;
+
−import java.nio.file.Files;
+
−import java.nio.file.Path;
+
−import java.nio.file.StandardOpenOption;
+
−import java.util.zip.GZIPInputStream;
+
−import java.util.zip.GZIPOutputStream;
+
−
+
−/**
+
− * Default implementation of UploadHandler and DownloadHandler interfaces
+
− * for reading from and writing to files on the local file system.
+
− * It enables support for:
+
− *   COPY .. INTO table FROM 'file-name' ON CLIENT ...
+
− * and
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− *   COPY SELECT_query INTO 'file-name' ON CLIENT ...
+
− * handling.
+
− *
+
− * Currently only file compression format .gz is supported. This is intentionally
+
− * as other compression formats would introduce dependencies on external
+
− * libraries which complicates usage of JDBC driver or JdbcClient application.
+
− * Developers can of course build their own MyFileTransferHandler class
+
− * and use it instead of this default implementation.
+
− *
+
− * A FileTransferHandler object needs to be registered via
+
− * {@link MonetConnection#setUploadHandler(MonetConnection.UploadHandler)} and/or
+
− * {@link MonetConnection#setDownloadHandler(MonetConnection.DownloadHandler)}.
+
− *
+
− * @author Joeri van Ruth
+
− * @author Martin van Dinther
+
− * @version 1.1
+
− */
+
−public class FileTransferHandler implements MonetConnection.UploadHandler, MonetConnection.DownloadHandler {
+
−	private final Path root;
+
−	private final Charset encoding;
+
−
+
−	/**
+
−	 * Create a new FileTransferHandler which serves the given directory.
+
−	 *
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−	 * @param dir directory Path to read and write files from
+
−	 * @param encoding the specified characterSet encoding is used for all data files in the directory
+
−	 *                 when null the Charset.defaultCharset() is used.
+
−	 */
+
−	public FileTransferHandler(final Path dir, final Charset encoding) {
+
−		this.root = dir.toAbsolutePath().normalize();
+
−		this.encoding = encoding != null ? encoding: Charset.defaultCharset();
+
−	}
+
−
+
−	/**
+
−	 * Create a new FileTransferHandler which serves the given directory.
+
−	 *
+
−	 * @param dir directory String to read and write files from
+
−	 * @param encoding the specified characterSet encoding is used for all data files in the directory
+
−	 *                 when null the Charset.defaultCharset() is used.
+
−	 */
+
−	public FileTransferHandler(final String dir, final Charset encoding) {
+
−		this(FileSystems.getDefault().getPath(dir), encoding);
+
−	}
+
−
+
−	/**
+
−	 * Read the data from the specified file (in the root directory) and upload it to the server.
+
−	 */
+
−	public void handleUpload(final MonetConnection.Upload handle, final String name, final boolean textMode, final long linesToSkip) throws IOException {
+
−		if (name == null || name.isEmpty()) {
+
−			handle.sendError("Missing file name");
+
−			return;
+
−		}
+
−		final Path path = root.resolve(name).normalize();
+
−		if (!path.startsWith(root)) {
+
−			handle.sendError("File is not in upload directory: " + root.toString());
+
−			return;
+
−		}
+
−		if (!Files.isReadable(path)) {
+
−			handle.sendError("Cannot read file " + path.toString());
+
−			return;
+
−		}
+
−
+
−		// In this implementation we ONLY support gzip compression format and none of the other compression formats.
+
−		if (name.endsWith(".bz2") || name.endsWith(".lz4") || name.endsWith(".xz") || name.endsWith(".zip")) {
+
−			final String extension = name.substring(name.lastIndexOf('.'));
+
−			handle.sendError("Specified file compression format " + extension + " is not supported. Only .gz is supported.");
+
−			return;
+
−		}
+
−
+
−		InputStream byteStream = Files.newInputStream(path);
+
−		if (name.endsWith(".gz")) {
+
−			byteStream = new GZIPInputStream(byteStream, 128 * 1024);
+
−		}
+
−
+
−		if (!textMode || (linesToSkip == 0 && utf8Encoded())) {
+
−			// when !textMode we must upload as a byte stream
+
−			// when utf8Encoded and linesToSkip is 0 it is more efficient to upload as a byte stream
+
−			handle.uploadFrom(byteStream);
+
−			byteStream.close();
+
−		} else {
+
−			// cannot upload as a byte stream, must deal with encoding and/or linesToSkip
+
−			final BufferedReader reader = new BufferedReader(new InputStreamReader(byteStream, encoding));
+
−			handle.uploadFrom(reader, linesToSkip);
+
−			reader.close();
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Download the data from the server and write it to a new created file in the root directory.
+
−	 * When a file with the same name already exists the download request will send an error and NOT overwrite the existing file.
+
−	 */
+
−	public void handleDownload(final MonetConnection.Download handle, final String name, final boolean textMode) throws IOException {
+
−		if (name == null || name.isEmpty()) {
+
−			handle.sendError("Missing file name");
+
−			return;
+
−		}
+
−		final Path path = root.resolve(name).normalize();
+
−		if (!path.startsWith(root)) {
+
−			handle.sendError("File is not in download directory: " + root.toString());
+
−			return;
+
−		}
+
−		if (Files.exists(path)) {
+
−			handle.sendError("File already exists: " + path.toString());
+
−			return;
+
−		}
+
−
+
−		// In this implementation we ONLY support gzip compression format and none of the other compression formats.
+
−		if (name.endsWith(".bz2") || name.endsWith(".lz4") || name.endsWith(".xz") || name.endsWith(".zip")) {
+
−			final String extension = name.substring(name.lastIndexOf('.'));
+
−			handle.sendError("Requested file compression format " + extension + " is not supported. Use .gz instead.");
+
−			return;
+
−		}
+
−
+
−		OutputStream byteStream = Files.newOutputStream(path, StandardOpenOption.CREATE_NEW);
+
−		if (name.endsWith(".gz")) {
+
−			byteStream = new GZIPOutputStream(byteStream, 128 * 1024);
+
−		}
+
−
+
−		if (!textMode || utf8Encoded()) {
+
−			// when !textMode we must download as a byte stream
+
−			// when utf8Encoded it is more efficient to download as a byte stream
+
−			handle.downloadTo(byteStream);
+
−			byteStream.close();
+
−		} else {
+
−			// cannot download as a byte stream, must deal with encoding
+
−			final BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(byteStream, encoding));
+
−			handle.downloadTo(writer);
+
−			writer.close();
+
−		}
+
−	}
+
−
+
−	public boolean utf8Encoded() {
+
−		return encoding.equals(StandardCharsets.UTF_8);
+
−	}
+
−}