Java tutorial
// Copyright 2015 Google Inc. All Rights Reserved. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. package com.google.gitiles.doc; import static java.nio.charset.StandardCharsets.UTF_8; import static javax.servlet.http.HttpServletResponse.SC_INTERNAL_SERVER_ERROR; import static javax.servlet.http.HttpServletResponse.SC_NOT_FOUND; import static javax.servlet.http.HttpServletResponse.SC_NOT_MODIFIED; import static org.eclipse.jgit.lib.Constants.OBJ_BLOB; import static org.eclipse.jgit.lib.FileMode.TYPE_FILE; import static org.eclipse.jgit.lib.FileMode.TYPE_MASK; import static org.eclipse.jgit.lib.FileMode.TYPE_TREE; import com.google.common.base.MoreObjects; import com.google.common.base.Strings; import com.google.common.hash.Hasher; import com.google.common.hash.Hashing; import com.google.common.net.HttpHeaders; import com.google.gitiles.BaseServlet; import com.google.gitiles.FormatType; import com.google.gitiles.GitilesAccess; import com.google.gitiles.GitilesView; import com.google.gitiles.Renderer; import com.google.gitiles.ViewFilter; import org.eclipse.jgit.errors.IncorrectObjectTypeException; import org.eclipse.jgit.http.server.ServletUtils; import org.eclipse.jgit.lib.Config; import org.eclipse.jgit.lib.Constants; import org.eclipse.jgit.lib.ObjectId; import org.eclipse.jgit.lib.ObjectLoader; import org.eclipse.jgit.lib.ObjectReader; import org.eclipse.jgit.lib.Repository; import org.eclipse.jgit.revwalk.RevTree; import org.eclipse.jgit.revwalk.RevWalk; import org.eclipse.jgit.treewalk.TreeWalk; import org.eclipse.jgit.util.RawParseUtils; import org.pegdown.ast.RootNode; import java.io.IOException; import java.util.HashMap; import java.util.Map; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class DocServlet extends BaseServlet { private static final long serialVersionUID = 1L; private static final String INDEX_MD = "index.md"; private static final String NAVBAR_MD = "navbar.md"; private static final String SOY_FILE = "Doc.soy"; private static final String SOY_TEMPLATE = "gitiles.markdownDoc"; // Generation of ETag logic. Bump this only if DocServlet logic changes // significantly enough to impact cached pages. Soy template and source // files are automatically hashed as part of the ETag. private static final int ETAG_GEN = 1; public DocServlet(GitilesAccess.Factory accessFactory, Renderer renderer) { super(renderer, accessFactory); } @Override protected void doGetHtml(HttpServletRequest req, HttpServletResponse res) throws IOException { Config cfg = getAccess(req).getConfig(); if (!cfg.getBoolean("markdown", "render", true)) { res.setStatus(SC_NOT_FOUND); return; } GitilesView view = ViewFilter.getView(req); Repository repo = ServletUtils.getRepository(req); RevWalk rw = new RevWalk(repo); try { String path = view.getPathPart(); RevTree root; try { root = rw.parseTree(view.getRevision().getId()); } catch (IncorrectObjectTypeException e) { res.setStatus(SC_NOT_FOUND); return; } SourceFile srcmd = findFile(rw, root, path); if (srcmd == null) { res.setStatus(SC_NOT_FOUND); return; } SourceFile navmd = findFile(rw, root, NAVBAR_MD); String reqEtag = req.getHeader(HttpHeaders.IF_NONE_MATCH); String curEtag = etag(srcmd, navmd); if (reqEtag != null && reqEtag.equals(curEtag)) { res.setStatus(SC_NOT_MODIFIED); return; } view = view.toBuilder().setPathPart(srcmd.path).build(); int inputLimit = cfg.getInt("markdown", "inputLimit", 5 << 20); RootNode doc = GitilesMarkdown.parseFile(view, srcmd.path, srcmd.read(rw.getObjectReader(), inputLimit)); if (doc == null) { res.sendRedirect(GitilesView.show().copyFrom(view).toUrl()); return; } RootNode nav = null; if (navmd != null) { nav = GitilesMarkdown.parseFile(view, navmd.path, navmd.read(rw.getObjectReader(), inputLimit)); if (nav == null) { res.setStatus(SC_INTERNAL_SERVER_ERROR); return; } } int imageLimit = cfg.getInt("markdown", "imageLimit", 256 << 10); ImageLoader img = null; if (imageLimit > 0) { img = new ImageLoader(rw.getObjectReader(), view, root, srcmd.path, imageLimit); } res.setHeader(HttpHeaders.ETAG, curEtag); showDoc(req, res, view, cfg, img, nav, doc); } finally { rw.release(); } } private String etag(SourceFile srcmd, SourceFile navmd) { byte[] b = new byte[Constants.OBJECT_ID_LENGTH]; Hasher h = Hashing.sha1().newHasher(); h.putInt(ETAG_GEN); renderer.getTemplateHash(SOY_FILE).writeBytesTo(b, 0, b.length); h.putBytes(b); if (navmd != null) { navmd.id.copyRawTo(b, 0); h.putBytes(b); } srcmd.id.copyRawTo(b, 0); h.putBytes(b); return h.hash().toString(); } @Override protected void setCacheHeaders(HttpServletResponse res) { long now = System.currentTimeMillis(); res.setDateHeader(HttpHeaders.EXPIRES, now); res.setDateHeader(HttpHeaders.DATE, now); res.setHeader(HttpHeaders.CACHE_CONTROL, "private, max-age=0, must-revalidate"); } private void showDoc(HttpServletRequest req, HttpServletResponse res, GitilesView view, Config cfg, ImageLoader img, RootNode nav, RootNode doc) throws IOException { Map<String, Object> data = new HashMap<>(); data.putAll(Navbar.bannerSoyData(view, img, nav)); data.put("pageTitle", MoreObjects.firstNonNull(MarkdownUtil.getTitle(doc), view.getPathPart())); data.put("sourceUrl", GitilesView.show().copyFrom(view).toUrl()); data.put("logUrl", GitilesView.log().copyFrom(view).toUrl()); data.put("blameUrl", GitilesView.blame().copyFrom(view).toUrl()); data.put("navbarHtml", new MarkdownToHtml(view, cfg).toSoyHtml(nav)); data.put("bodyHtml", new MarkdownToHtml(view, cfg).setImageLoader(img).toSoyHtml(doc)); String page = renderer.render(SOY_TEMPLATE, data); byte[] raw = page.getBytes(UTF_8); res.setContentType(FormatType.HTML.getMimeType()); res.setCharacterEncoding(UTF_8.name()); setCacheHeaders(res); if (acceptsGzipEncoding(req)) { res.setHeader(HttpHeaders.CONTENT_ENCODING, "gzip"); raw = gzip(raw); } res.setContentLength(raw.length); res.setStatus(HttpServletResponse.SC_OK); res.getOutputStream().write(raw); } private static SourceFile findFile(RevWalk rw, RevTree root, String path) throws IOException { if (Strings.isNullOrEmpty(path)) { path = INDEX_MD; } ObjectReader reader = rw.getObjectReader(); TreeWalk tw = TreeWalk.forPath(reader, path, root); if (tw == null) { return null; } if ((tw.getRawMode(0) & TYPE_MASK) == TYPE_TREE) { if (findIndexFile(tw)) { path = tw.getPathString(); } else { return null; } } if ((tw.getRawMode(0) & TYPE_MASK) == TYPE_FILE) { if (!path.endsWith(".md")) { return null; } return new SourceFile(path, tw.getObjectId(0)); } return null; } private static boolean findIndexFile(TreeWalk tw) throws IOException { tw.enterSubtree(); while (tw.next()) { if ((tw.getRawMode(0) & TYPE_MASK) == TYPE_FILE && INDEX_MD.equals(tw.getNameString())) { return true; } } return false; } private static class SourceFile { final String path; final ObjectId id; SourceFile(String path, ObjectId id) { this.path = path; this.id = id; } String read(ObjectReader reader, int inputLimit) throws IOException { ObjectLoader obj = reader.open(id, OBJ_BLOB); byte[] raw = obj.getCachedBytes(inputLimit); return RawParseUtils.decode(raw); } } }