Java tutorial
/* * Copyright (C) 2015, Matthias Sohn <matthias.sohn@sap.com> * and other copyright owners as documented in the project's IP log. * * This program and the accompanying materials are made available * under the terms of the Eclipse Distribution License v1.0 which * accompanies this distribution, is reproduced below, and is * available at http://www.eclipse.org/org/documents/edl-v10.php * * All rights reserved. * * Redistribution and use in source and binary forms, with or * without modification, are permitted provided that the following * conditions are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following * disclaimer in the documentation and/or other materials provided * with the distribution. * * - Neither the name of the Eclipse Foundation, Inc. nor the * names of its contributors may be used to endorse or promote * products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package org.eclipse.jgit.lfs.server.fs; import java.io.IOException; import java.io.PrintWriter; import java.text.MessageFormat; import javax.servlet.AsyncContext; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.http.HttpStatus; import org.eclipse.jgit.lfs.errors.InvalidLongObjectIdException; import org.eclipse.jgit.lfs.lib.AnyLongObjectId; import org.eclipse.jgit.lfs.lib.Constants; import org.eclipse.jgit.lfs.lib.LongObjectId; import org.eclipse.jgit.lfs.server.internal.LfsServerText; import com.google.gson.FieldNamingPolicy; import com.google.gson.Gson; import com.google.gson.GsonBuilder; /** * Servlet supporting upload and download of large objects as defined by the * GitHub Large File Storage extension API extending git to allow separate * storage of large files * (https://github.com/github/git-lfs/tree/master/docs/api). * * @since 4.3 */ @WebServlet(asyncSupported = true) public class FileLfsServlet extends HttpServlet { private static final long serialVersionUID = 1L; private final FileLfsRepository repository; private final long timeout; private static Gson gson = createGson(); /** * @param repository * the repository storing the large objects * @param timeout * timeout for object upload / download in milliseconds */ public FileLfsServlet(FileLfsRepository repository, long timeout) { this.repository = repository; this.timeout = timeout; } /** * Handles object downloads * * @param req * servlet request * @param rsp * servlet response * @throws ServletException * if a servlet-specific error occurs * @throws IOException * if an I/O error occurs */ @Override protected void doGet(HttpServletRequest req, HttpServletResponse rsp) throws ServletException, IOException { AnyLongObjectId obj = getObjectToTransfer(req, rsp); if (obj != null) { if (repository.getSize(obj) == -1) { sendError(rsp, HttpStatus.SC_NOT_FOUND, MessageFormat.format(LfsServerText.get().objectNotFound, obj.getName())); return; } AsyncContext context = req.startAsync(); context.setTimeout(timeout); rsp.getOutputStream().setWriteListener(new ObjectDownloadListener(repository, context, rsp, obj)); } } /** * Retrieve object id from request * * @param req * servlet request * @param rsp * servlet response * @return object id, or <code>null</code> if the object id could not be * retrieved * @throws IOException * if an I/O error occurs * @since 4.6 */ protected AnyLongObjectId getObjectToTransfer(HttpServletRequest req, HttpServletResponse rsp) throws IOException { String info = req.getPathInfo(); int length = 1 + Constants.LONG_OBJECT_ID_STRING_LENGTH; if (info.length() != length) { sendError(rsp, HttpStatus.SC_UNPROCESSABLE_ENTITY, MessageFormat.format(LfsServerText.get().invalidPathInfo, info)); return null; } try { return LongObjectId.fromString(info.substring(1, length)); } catch (InvalidLongObjectIdException e) { sendError(rsp, HttpStatus.SC_UNPROCESSABLE_ENTITY, e.getMessage()); return null; } } /** * Handle object uploads * * @param req * servlet request * @param rsp * servlet response * @throws ServletException * if a servlet-specific error occurs * @throws IOException * if an I/O error occurs */ @Override protected void doPut(HttpServletRequest req, HttpServletResponse rsp) throws ServletException, IOException { AnyLongObjectId id = getObjectToTransfer(req, rsp); if (id != null) { AsyncContext context = req.startAsync(); context.setTimeout(timeout); req.getInputStream().setReadListener(new ObjectUploadListener(repository, context, req, rsp, id)); } } static class Error { String message; Error(String m) { this.message = m; } } /** * Send an error response. * * @param rsp * the servlet response * @param status * HTTP status code * @param message * error message * @throws IOException * on failure to send the response * @since 4.6 */ protected static void sendError(HttpServletResponse rsp, int status, String message) throws IOException { rsp.setStatus(status); PrintWriter writer = rsp.getWriter(); gson.toJson(new Error(message), writer); writer.flush(); writer.close(); rsp.flushBuffer(); } private static Gson createGson() { GsonBuilder gb = new GsonBuilder().setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES) .setPrettyPrinting().disableHtmlEscaping(); return gb.create(); } }