| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.hadoop.yarn.webapp; |
| |
| import static com.google.common.base.Preconditions.checkNotNull; |
| import static com.google.common.base.Preconditions.checkState; |
| import static org.apache.hadoop.yarn.util.StringHelper.djoin; |
| import static org.apache.hadoop.yarn.util.StringHelper.join; |
| import static org.apache.hadoop.yarn.util.StringHelper.pjoin; |
| |
| import java.lang.reflect.Method; |
| import java.util.EnumSet; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.TreeMap; |
| import java.util.regex.Pattern; |
| |
| import org.apache.commons.lang.StringUtils; |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import com.google.common.base.CharMatcher; |
| import com.google.common.collect.ImmutableList; |
| import com.google.common.collect.Maps; |
| |
| /** |
| * Manages path info to controller#action routing. |
| */ |
| @InterfaceAudience.LimitedPrivate({"YARN", "MapReduce"}) |
| class Router { |
| static final Logger LOG = LoggerFactory.getLogger(Router.class); |
| static final ImmutableList<String> EMPTY_LIST = ImmutableList.of(); |
| static final CharMatcher SLASH = CharMatcher.is('/'); |
| static final Pattern controllerRe = |
| Pattern.compile("^/[A-Za-z_]\\w*(?:/.*)?"); |
| |
| static class Dest { |
| final String prefix; |
| final ImmutableList<String> pathParams; |
| final Method action; |
| final Class<? extends Controller> controllerClass; |
| Class<? extends View> defaultViewClass; |
| final EnumSet<WebApp.HTTP> methods; |
| |
| Dest(String path, Method method, Class<? extends Controller> cls, |
| List<String> pathParams, WebApp.HTTP httpMethod) { |
| prefix = checkNotNull(path); |
| action = checkNotNull(method); |
| controllerClass = checkNotNull(cls); |
| this.pathParams = pathParams != null ? ImmutableList.copyOf(pathParams) |
| : EMPTY_LIST; |
| methods = EnumSet.of(httpMethod); |
| } |
| } |
| |
| Class<?> hostClass; // starting point to look for default classes |
| |
| final TreeMap<String, Dest> routes = Maps.newTreeMap(); // path->dest |
| |
| synchronized Dest add(WebApp.HTTP httpMethod, String path, |
| Class<? extends Controller> cls, |
| String action, List<String> names){ |
| return addWithOptionalDefaultView( |
| httpMethod, path, cls, action, names, true); |
| } |
| |
| synchronized Dest addWithoutDefaultView(WebApp.HTTP httpMethod, |
| String path, Class<? extends Controller> cls, String action, |
| List<String> names){ |
| return addWithOptionalDefaultView(httpMethod, path, cls, action, |
| names, false); |
| } |
| /** |
| * Add a route to the router. |
| * e.g., add(GET, "/foo/show", FooController.class, "show", [name...]); |
| * The name list is from /foo/show/:name/... |
| */ |
| synchronized Dest addWithOptionalDefaultView(WebApp.HTTP httpMethod, |
| String path, Class<? extends Controller> cls, |
| String action, List<String> names, boolean defaultViewNeeded) { |
| LOG.debug("adding {}({})->{}#{}", new Object[]{path, names, cls, action}); |
| Dest dest = addController(httpMethod, path, cls, action, names); |
| if (defaultViewNeeded) { |
| addDefaultView(dest); |
| } |
| return dest; |
| } |
| |
| private Dest addController(WebApp.HTTP httpMethod, String path, |
| Class<? extends Controller> cls, |
| String action, List<String> names) { |
| try { |
| // Look for the method in all public methods declared in the class |
| // or inherited by the class. |
| // Note: this does not distinguish methods with the same signature |
| // but different return types. |
| // TODO: We may want to deal with methods that take parameters in the future |
| Method method = cls.getMethod(action); |
| Dest dest = routes.get(path); |
| if (dest == null) { |
| method.setAccessible(true); // avoid any runtime checks |
| dest = new Dest(path, method, cls, names, httpMethod); |
| routes.put(path, dest); |
| return dest; |
| } |
| dest.methods.add(httpMethod); |
| return dest; |
| } catch (NoSuchMethodException nsme) { |
| throw new WebAppException(action + "() not found in " + cls); |
| } catch (SecurityException se) { |
| throw new WebAppException("Security exception thrown for " + action + |
| "() in " + cls); |
| } |
| } |
| |
| private void addDefaultView(Dest dest) { |
| String controllerName = dest.controllerClass.getSimpleName(); |
| if (controllerName.endsWith("Controller")) { |
| controllerName = controllerName.substring(0, |
| controllerName.length() - 10); |
| } |
| dest.defaultViewClass = find(View.class, |
| dest.controllerClass.getPackage().getName(), |
| join(controllerName + "View")); |
| } |
| |
| void setHostClass(Class<?> cls) { |
| hostClass = cls; |
| } |
| |
| /** |
| * Resolve a path to a destination. |
| */ |
| synchronized Dest resolve(String httpMethod, String path) { |
| WebApp.HTTP method = WebApp.HTTP.valueOf(httpMethod); // can throw |
| Dest dest = lookupRoute(method, path); |
| if (dest == null) { |
| return resolveDefault(method, path); |
| } |
| return dest; |
| } |
| |
| private Dest lookupRoute(WebApp.HTTP method, String path) { |
| String key = path; |
| do { |
| Dest dest = routes.get(key); |
| if (dest != null && methodAllowed(method, dest)) { |
| if ((Object)key == path) { // shut up warnings |
| LOG.debug("exact match for {}: {}", key, dest.action); |
| return dest; |
| } else if (isGoodMatch(dest, path)) { |
| LOG.debug("prefix match2 for {}: {}", key, dest.action); |
| return dest; |
| } |
| return resolveAction(method, dest, path); |
| } |
| Map.Entry<String, Dest> lower = routes.lowerEntry(key); |
| if (lower == null) { |
| return null; |
| } |
| dest = lower.getValue(); |
| if (prefixMatches(dest, path)) { |
| if (methodAllowed(method, dest)) { |
| if (isGoodMatch(dest, path)) { |
| LOG.debug("prefix match for {}: {}", lower.getKey(), dest.action); |
| return dest; |
| } |
| return resolveAction(method, dest, path); |
| } |
| // check other candidates |
| int slashPos = key.lastIndexOf('/'); |
| key = slashPos > 0 ? path.substring(0, slashPos) : "/"; |
| } else { |
| key = "/"; |
| } |
| } while (true); |
| } |
| |
| static boolean methodAllowed(WebApp.HTTP method, Dest dest) { |
| // Accept all methods by default, unless explicity configured otherwise. |
| return dest.methods.contains(method) || (dest.methods.size() == 1 && |
| dest.methods.contains(WebApp.HTTP.GET)); |
| } |
| |
| static boolean prefixMatches(Dest dest, String path) { |
| LOG.debug("checking prefix {}{} for path: {}", new Object[]{dest.prefix, |
| dest.pathParams, path}); |
| if (!path.startsWith(dest.prefix)) { |
| return false; |
| } |
| int prefixLen = dest.prefix.length(); |
| if (prefixLen > 1 && path.length() > prefixLen && |
| path.charAt(prefixLen) != '/') { |
| return false; |
| } |
| // prefix is / or prefix is path or prefix/... |
| return true; |
| } |
| |
| static boolean isGoodMatch(Dest dest, String path) { |
| if (SLASH.countIn(dest.prefix) > 1) { |
| return true; |
| } |
| // We want to match (/foo, :a) for /foo/bar/blah and (/, :a) for /123 |
| // but NOT / for /foo or (/, :a) for /foo or /foo/ because default route |
| // (FooController#index) for /foo and /foo/ takes precedence. |
| if (dest.prefix.length() == 1) { |
| return dest.pathParams.size() > 0 && !maybeController(path); |
| } |
| return dest.pathParams.size() > 0 || // /foo should match /foo/ |
| (path.endsWith("/") && SLASH.countIn(path) == 2); |
| } |
| |
| static boolean maybeController(String path) { |
| return controllerRe.matcher(path).matches(); |
| } |
| |
| // Assume /controller/action style path |
| private Dest resolveDefault(WebApp.HTTP method, String path) { |
| List<String> parts = WebApp.parseRoute(path); |
| String controller = parts.get(WebApp.R_CONTROLLER); |
| String action = parts.get(WebApp.R_ACTION); |
| // NameController is encouraged default |
| Class<? extends Controller> cls = find(Controller.class, |
| join(controller, "Controller")); |
| if (cls == null) { |
| cls = find(Controller.class, controller); |
| } |
| if (cls == null) { |
| throw new WebAppException(join(path, ": controller for ", controller, |
| " not found")); |
| } |
| return add(method, defaultPrefix(controller, action), cls, action, null); |
| } |
| |
| private String defaultPrefix(String controller, String action) { |
| if (controller.equals("default") && action.equals("index")) { |
| return "/"; |
| } |
| if (action.equals("index")) { |
| return join('/', controller); |
| } |
| return pjoin("", controller, action); |
| } |
| |
| private <T> Class<? extends T> find(Class<T> cls, String cname) { |
| String pkg = hostClass.getPackage().getName(); |
| return find(cls, pkg, cname); |
| } |
| |
| private <T> Class<? extends T> find(Class<T> cls, String pkg, String cname) { |
| String name = StringUtils.capitalize(cname); |
| Class<? extends T> found = load(cls, djoin(pkg, name)); |
| if (found == null) { |
| found = load(cls, djoin(pkg, "webapp", name)); |
| } |
| if (found == null) { |
| found = load(cls, join(hostClass.getName(), '$', name)); |
| } |
| return found; |
| } |
| |
| @SuppressWarnings("unchecked") |
| private <T> Class<? extends T> load(Class<T> cls, String className) { |
| LOG.debug("trying: {}", className); |
| try { |
| Class<?> found = Class.forName(className); |
| if (cls.isAssignableFrom(found)) { |
| LOG.debug("found {}", className); |
| return (Class<? extends T>) found; |
| } |
| LOG.warn("found a {} but it's not a {}", className, cls.getName()); |
| } catch (ClassNotFoundException e) { |
| // OK in this case. |
| } |
| return null; |
| } |
| |
| // Dest may contain a candidate controller |
| private Dest resolveAction(WebApp.HTTP method, Dest dest, String path) { |
| if (dest.prefix.length() == 1) { |
| return null; |
| } |
| checkState(!isGoodMatch(dest, path), dest.prefix); |
| checkState(SLASH.countIn(path) > 1, path); |
| List<String> parts = WebApp.parseRoute(path); |
| String controller = parts.get(WebApp.R_CONTROLLER); |
| String action = parts.get(WebApp.R_ACTION); |
| return add(method, pjoin("", controller, action), dest.controllerClass, |
| action, null); |
| } |
| } |