Java tutorial
/* * Copyright (C) 2009-2010, Google Inc. * 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.http.server; import static java.nio.charset.StandardCharsets.UTF_8; import static org.eclipse.jgit.util.HttpSupport.ENCODING_GZIP; import static org.eclipse.jgit.util.HttpSupport.ENCODING_X_GZIP; import static org.eclipse.jgit.util.HttpSupport.HDR_ACCEPT_ENCODING; import static org.eclipse.jgit.util.HttpSupport.HDR_CONTENT_ENCODING; import static org.eclipse.jgit.util.HttpSupport.HDR_ETAG; import static org.eclipse.jgit.util.HttpSupport.TEXT_PLAIN; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.security.MessageDigest; import java.text.MessageFormat; import java.util.zip.GZIPInputStream; import java.util.zip.GZIPOutputStream; import javax.servlet.ServletRequest; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.eclipse.jgit.lib.Constants; import org.eclipse.jgit.lib.ObjectId; import org.eclipse.jgit.lib.Repository; /** * Common utility functions for servlets. */ public final class ServletUtils { /** Request attribute which stores the {@link Repository} instance. */ public static final String ATTRIBUTE_REPOSITORY = "org.eclipse.jgit.Repository"; /** Request attribute storing either UploadPack or ReceivePack. */ public static final String ATTRIBUTE_HANDLER = "org.eclipse.jgit.transport.UploadPackOrReceivePack"; /** * Get the selected repository from the request. * * @param req * the current request. * @return the repository; never null. * @throws IllegalStateException * the repository was not set by the filter, the servlet is * being invoked incorrectly and the programmer should ensure * the filter runs before the servlet. * @see #ATTRIBUTE_REPOSITORY */ public static Repository getRepository(ServletRequest req) { Repository db = (Repository) req.getAttribute(ATTRIBUTE_REPOSITORY); if (db == null) throw new IllegalStateException(HttpServerText.get().expectedRepositoryAttribute); return db; } /** * Open the request input stream, automatically inflating if necessary. * <p> * This method automatically inflates the input stream if the request * {@code Content-Encoding} header was set to {@code gzip} or the legacy * {@code x-gzip}. * * @param req * the incoming request whose input stream needs to be opened. * @return an input stream to read the raw, uncompressed request body. * @throws IOException * if an input or output exception occurred. */ public static InputStream getInputStream(HttpServletRequest req) throws IOException { InputStream in = req.getInputStream(); final String enc = req.getHeader(HDR_CONTENT_ENCODING); if (ENCODING_GZIP.equals(enc) || ENCODING_X_GZIP.equals(enc)) in = new GZIPInputStream(in); else if (enc != null) throw new IOException(MessageFormat.format(HttpServerText.get().encodingNotSupportedByThisLibrary, HDR_CONTENT_ENCODING, enc)); return in; } /** * Consume the entire request body, if one was supplied. * * @param req * the request whose body must be consumed. */ public static void consumeRequestBody(HttpServletRequest req) { if (0 < req.getContentLength() || isChunked(req)) { try { consumeRequestBody(req.getInputStream()); } catch (IOException e) { // Ignore any errors obtaining the input stream. } } } static boolean isChunked(HttpServletRequest req) { return "chunked".equals(req.getHeader("Transfer-Encoding")); } /** * Consume the rest of the input stream and discard it. * * @param in * the stream to discard, closed if not null. */ public static void consumeRequestBody(InputStream in) { if (in == null) return; try { while (0 < in.skip(2048) || 0 <= in.read()) { // Discard until EOF. } } catch (IOException err) { // Discard IOException during read or skip. } finally { try { in.close(); } catch (IOException err) { // Discard IOException during close of input stream. } } } /** * Send a plain text response to a {@code GET} or {@code HEAD} HTTP request. * <p> * The text response is encoded in the Git character encoding, UTF-8. * <p> * If the user agent supports a compressed transfer encoding and the content * is large enough, the content may be compressed before sending. * <p> * The {@code ETag} and {@code Content-Length} headers are automatically set * by this method. {@code Content-Encoding} is conditionally set if the user * agent supports a compressed transfer. Callers are responsible for setting * any cache control headers. * * @param content * to return to the user agent as this entity's body. * @param req * the incoming request. * @param rsp * the outgoing response. * @throws IOException * the servlet API rejected sending the body. */ public static void sendPlainText(final String content, final HttpServletRequest req, final HttpServletResponse rsp) throws IOException { final byte[] raw = content.getBytes(UTF_8); rsp.setContentType(TEXT_PLAIN); rsp.setCharacterEncoding(UTF_8.name()); send(raw, req, rsp); } /** * Send a response to a {@code GET} or {@code HEAD} HTTP request. * <p> * If the user agent supports a compressed transfer encoding and the content * is large enough, the content may be compressed before sending. * <p> * The {@code ETag} and {@code Content-Length} headers are automatically set * by this method. {@code Content-Encoding} is conditionally set if the user * agent supports a compressed transfer. Callers are responsible for setting * {@code Content-Type} and any cache control headers. * * @param content * to return to the user agent as this entity's body. * @param req * the incoming request. * @param rsp * the outgoing response. * @throws IOException * the servlet API rejected sending the body. */ public static void send(byte[] content, final HttpServletRequest req, final HttpServletResponse rsp) throws IOException { content = sendInit(content, req, rsp); try (OutputStream out = rsp.getOutputStream()) { out.write(content); out.flush(); } } private static byte[] sendInit(byte[] content, final HttpServletRequest req, final HttpServletResponse rsp) throws IOException { rsp.setHeader(HDR_ETAG, etag(content)); if (256 < content.length && acceptsGzipEncoding(req)) { content = compress(content); rsp.setHeader(HDR_CONTENT_ENCODING, ENCODING_GZIP); } rsp.setContentLength(content.length); return content; } static boolean acceptsGzipEncoding(HttpServletRequest req) { return acceptsGzipEncoding(req.getHeader(HDR_ACCEPT_ENCODING)); } static boolean acceptsGzipEncoding(String accepts) { if (accepts == null) return false; int b = 0; while (b < accepts.length()) { int comma = accepts.indexOf(',', b); int e = 0 <= comma ? comma : accepts.length(); String term = accepts.substring(b, e).trim(); if (term.equals(ENCODING_GZIP)) return true; b = e + 1; } return false; } private static byte[] compress(byte[] raw) throws IOException { final int maxLen = raw.length + 32; final ByteArrayOutputStream out = new ByteArrayOutputStream(maxLen); final GZIPOutputStream gz = new GZIPOutputStream(out); gz.write(raw); gz.finish(); gz.flush(); return out.toByteArray(); } private static String etag(byte[] content) { final MessageDigest md = Constants.newMessageDigest(); md.update(content); return ObjectId.fromRaw(md.digest()).getName(); } static String identify(Repository git) { String identifier = git.getIdentifier(); if (identifier == null) { return "unknown"; } return identifier; } private ServletUtils() { // static utility class only } }