Java tutorial
// Copyright (C) 2008 The Android Open Source Project // // 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.gerrit.httpd.raw; import com.google.common.collect.Lists; import com.google.common.hash.Hasher; import com.google.common.hash.Hashing; import com.google.common.primitives.Bytes; import com.google.gerrit.common.Version; import com.google.gerrit.common.data.GerritConfig; import com.google.gerrit.common.data.HostPageData; import com.google.gerrit.extensions.registration.DynamicSet; import com.google.gerrit.extensions.webui.WebUiPlugin; import com.google.gerrit.httpd.HtmlDomUtil; import com.google.gerrit.httpd.WebSession; import com.google.gerrit.server.CurrentUser; import com.google.gerrit.server.IdentifiedUser; import com.google.gerrit.server.config.GerritServerConfig; import com.google.gerrit.server.config.SitePaths; import com.google.gwtexpui.linker.server.Permutation; import com.google.gwtexpui.linker.server.PermutationSelector; import com.google.gwtexpui.server.CacheHeaders; import com.google.gwtjsonrpc.server.JsonServlet; import com.google.gwtjsonrpc.server.RPCServletUtils; import com.google.inject.Inject; import com.google.inject.Provider; import com.google.inject.Singleton; import org.eclipse.jgit.lib.Config; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.w3c.dom.Document; import org.w3c.dom.Element; import java.io.File; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.StringWriter; import java.util.HashMap; import java.util.List; import java.util.Map; import javax.servlet.ServletContext; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** Sends the Gerrit host page to clients. */ @SuppressWarnings("serial") @Singleton public class HostPageServlet extends HttpServlet { private static final Logger log = LoggerFactory.getLogger(HostPageServlet.class); private static final boolean IS_DEV = Boolean.getBoolean("Gerrit.GwtDevMode"); private static final String HPD_ID = "gerrit_hostpagedata"; private final Provider<CurrentUser> currentUser; private final Provider<WebSession> session; private final GerritConfig config; private final DynamicSet<WebUiPlugin> plugins; private final HostPageData.Theme signedOutTheme; private final HostPageData.Theme signedInTheme; private final SitePaths site; private final Document template; private final String noCacheName; private final PermutationSelector selector; private final boolean refreshHeaderFooter; private volatile Page page; @Inject HostPageServlet(final Provider<CurrentUser> cu, final Provider<WebSession> w, final SitePaths sp, final ThemeFactory themeFactory, final GerritConfig gc, final ServletContext servletContext, final DynamicSet<WebUiPlugin> webUiPlugins, @GerritServerConfig final Config cfg) throws IOException, ServletException { currentUser = cu; session = w; config = gc; plugins = webUiPlugins; signedOutTheme = themeFactory.getSignedOutTheme(); signedInTheme = themeFactory.getSignedInTheme(); site = sp; refreshHeaderFooter = cfg.getBoolean("site", "refreshHeaderFooter", true); boolean checkUserAgent = cfg.getBoolean("site", "checkUserAgent", true); final String pageName = "HostPage.html"; template = HtmlDomUtil.parseFile(getClass(), pageName); if (template == null) { throw new FileNotFoundException("No " + pageName + " in webapp"); } if (HtmlDomUtil.find(template, "gerrit_module") == null) { throw new ServletException("No gerrit_module in " + pageName); } if (HtmlDomUtil.find(template, HPD_ID) == null) { throw new ServletException("No " + HPD_ID + " in " + pageName); } String src = "gerrit_ui/gerrit_ui.nocache.js"; if (!IS_DEV) { Element devmode = HtmlDomUtil.find(template, "gwtdevmode"); if (devmode != null) { devmode.getParentNode().removeChild(devmode); } InputStream in = servletContext.getResourceAsStream("/" + src); if (in != null) { Hasher md = Hashing.md5().newHasher(); try { try { final byte[] buf = new byte[1024]; int n; while ((n = in.read(buf)) > 0) { md.putBytes(buf, 0, n); } } finally { in.close(); } } catch (IOException e) { throw new IOException("Failed reading " + src, e); } src += "?content=" + md.hash().toString(); } else { log.debug("No " + src + " in webapp root; keeping noncache.js URL"); } } noCacheName = src; selector = new PermutationSelector("gerrit_ui"); if (checkUserAgent && !IS_DEV) { selector.init(servletContext); } page = new Page(); } private void json(final Object data, final StringWriter w) { JsonServlet.defaultGsonBuilder().create().toJson(data, w); } private Page get() { Page p = page; if (refreshHeaderFooter && p.isStale()) { final Page newPage; try { newPage = new Page(); } catch (IOException e) { log.error("Cannot refresh site header/footer", e); return p; } p = newPage; page = p; } return p; } @Override protected void doGet(final HttpServletRequest req, final HttpServletResponse rsp) throws IOException { final Page.Content page = select(req); final StringWriter w = new StringWriter(); final CurrentUser user = currentUser.get(); if (user instanceof IdentifiedUser) { w.write(HPD_ID + ".account="); json(((IdentifiedUser) user).getAccount(), w); w.write(";"); w.write(HPD_ID + ".xGerritAuth="); json(session.get().getXGerritAuth(), w); w.write(";"); w.write(HPD_ID + ".accountDiffPref="); json(((IdentifiedUser) user).getAccountDiffPreference(), w); w.write(";"); w.write(HPD_ID + ".theme="); json(signedInTheme, w); w.write(";"); } else { w.write(HPD_ID + ".theme="); json(signedOutTheme, w); w.write(";"); } plugins(w); final byte[] hpd = w.toString().getBytes("UTF-8"); final byte[] raw = Bytes.concat(page.part1, hpd, page.part2); final byte[] tosend; if (RPCServletUtils.acceptsGzipEncoding(req)) { rsp.setHeader("Content-Encoding", "gzip"); tosend = HtmlDomUtil.compress(raw); } else { tosend = raw; } CacheHeaders.setNotCacheable(rsp); rsp.setContentType("text/html"); rsp.setCharacterEncoding(HtmlDomUtil.ENC); rsp.setContentLength(tosend.length); final OutputStream out = rsp.getOutputStream(); try { out.write(tosend); } finally { out.close(); } } private void plugins(StringWriter w) { List<String> urls = Lists.newArrayList(); for (WebUiPlugin u : plugins) { urls.add(String.format("plugins/%s/%s", u.getPluginName(), u.getJavaScriptResourcePath())); } if (!urls.isEmpty()) { w.write(HPD_ID + ".plugins="); json(urls, w); w.write(";"); } } private Page.Content select(HttpServletRequest req) { Page pg = get(); if ("1".equals(req.getParameter("dbg"))) { return pg.debug; } else if ("0".equals(req.getParameter("s"))) { // If s=0 is used in the URL, the user has explicitly asked us // to not perform selection on the server side, perhaps due to // it incorrectly guessing their user agent. return pg.get(null); } return pg.get(selector.select(req)); } private static class FileInfo { private final File path; private final long time; FileInfo(final File p) { path = p; time = path.lastModified(); } boolean isStale() { return time != path.lastModified(); } } private class Page { private final FileInfo css; private final FileInfo header; private final FileInfo footer; private final Map<Permutation, Content> permutations; private final Content debug; Page() throws IOException { Document hostDoc = HtmlDomUtil.clone(template); css = injectCssFile(hostDoc, "gerrit_sitecss", site.site_css); header = injectXmlFile(hostDoc, "gerrit_header", site.site_header); footer = injectXmlFile(hostDoc, "gerrit_footer", site.site_footer); final HostPageData pageData = new HostPageData(); pageData.version = Version.getVersion(); pageData.config = config; final StringWriter w = new StringWriter(); w.write("var " + HPD_ID + "="); json(pageData, w); w.write(";"); final Element data = HtmlDomUtil.find(hostDoc, HPD_ID); asScript(data); data.appendChild(hostDoc.createTextNode(w.toString())); data.appendChild(hostDoc.createComment(HPD_ID)); permutations = new HashMap<Permutation, Content>(); for (Permutation p : selector.getPermutations()) { final Document d = HtmlDomUtil.clone(hostDoc); Element nocache = HtmlDomUtil.find(d, "gerrit_module"); nocache.getParentNode().removeChild(nocache); p.inject(d); permutations.put(p, new Content(d)); } Element nocache = HtmlDomUtil.find(hostDoc, "gerrit_module"); asScript(nocache); nocache.removeAttribute("id"); nocache.setAttribute("src", noCacheName); permutations.put(null, new Content(hostDoc)); nocache.setAttribute("src", "gerrit_ui/gerrit_dbg.nocache.js"); debug = new Content(hostDoc); } Content get(Permutation p) { Content c = permutations.get(p); if (c == null) { c = permutations.get(null); } return c; } boolean isStale() { return css.isStale() || header.isStale() || footer.isStale(); } private void asScript(final Element scriptNode) { scriptNode.setAttribute("type", "text/javascript"); scriptNode.setAttribute("language", "javascript"); } class Content { final byte[] part1; final byte[] part2; Content(Document hostDoc) throws IOException { final String raw = HtmlDomUtil.toString(hostDoc); final int p = raw.indexOf("<!--" + HPD_ID); if (p < 0) { throw new IOException("No tag in transformed host page HTML"); } part1 = raw.substring(0, p).getBytes("UTF-8"); part2 = raw.substring(raw.indexOf('>', p) + 1).getBytes("UTF-8"); } } private FileInfo injectCssFile(final Document hostDoc, final String id, final File src) throws IOException { final FileInfo info = new FileInfo(src); final Element banner = HtmlDomUtil.find(hostDoc, id); if (banner == null) { return info; } while (banner.getFirstChild() != null) { banner.removeChild(banner.getFirstChild()); } String css = HtmlDomUtil.readFile(src.getParentFile(), src.getName()); if (css == null) { return info; } banner.appendChild(hostDoc.createCDATASection("\n" + css + "\n")); return info; } private FileInfo injectXmlFile(final Document hostDoc, final String id, final File src) throws IOException { final FileInfo info = new FileInfo(src); final Element banner = HtmlDomUtil.find(hostDoc, id); if (banner == null) { return info; } while (banner.getFirstChild() != null) { banner.removeChild(banner.getFirstChild()); } Document html = HtmlDomUtil.parseFile(src); if (html == null) { return info; } final Element content = html.getDocumentElement(); banner.appendChild(hostDoc.importNode(content, true)); return info; } } }