Java tutorial
/** * 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.gateway.websockets; import java.io.File; import java.net.MalformedURLException; import java.net.URI; import java.net.URL; import java.util.Set; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import org.apache.commons.lang3.StringUtils; import org.apache.hadoop.gateway.config.GatewayConfig; import org.apache.hadoop.gateway.i18n.messages.MessagesFactory; import org.apache.hadoop.gateway.service.definition.ServiceDefinition; import org.apache.hadoop.gateway.services.GatewayServices; import org.apache.hadoop.gateway.services.registry.ServiceDefEntry; import org.apache.hadoop.gateway.services.registry.ServiceDefinitionRegistry; import org.apache.hadoop.gateway.services.registry.ServiceRegistry; import org.apache.hadoop.gateway.util.ServiceDefinitionsLoader; import org.eclipse.jetty.websocket.server.WebSocketHandler; import org.eclipse.jetty.websocket.servlet.ServletUpgradeRequest; import org.eclipse.jetty.websocket.servlet.ServletUpgradeResponse; import org.eclipse.jetty.websocket.servlet.WebSocketCreator; import org.eclipse.jetty.websocket.servlet.WebSocketServletFactory; /** * Websocket handler that will handle websocket connection request. This class * is responsible for creating a proxy socket for inbound and outbound * connections. This is also where the http to websocket handoff happens. * * @since 0.10 */ public class GatewayWebsocketHandler extends WebSocketHandler implements WebSocketCreator { private static final WebsocketLogMessages LOG = MessagesFactory.get(WebsocketLogMessages.class); public static final String WEBSOCKET_PROTOCOL_STRING = "ws://"; static final String REGEX_SPLIT_CLUSTER_NAME = "^((?:[^/]*/){1}[^/]*)"; static final String REGEX_SPLIT_CONTEXT = "^((?:[^/]*/){2}[^/]*)"; private static final int POOL_SIZE = 10; /** * Manage the threads that are spawned * @since 0.13 */ private final ExecutorService pool; final GatewayConfig config; final GatewayServices services; /** * Create an instance * * @param config * @param services */ public GatewayWebsocketHandler(final GatewayConfig config, final GatewayServices services) { super(); this.config = config; this.services = services; pool = Executors.newFixedThreadPool(POOL_SIZE); } /* * (non-Javadoc) * * @see * org.eclipse.jetty.websocket.server.WebSocketHandler#configure(org.eclipse. * jetty.websocket.servlet.WebSocketServletFactory) */ @Override public void configure(final WebSocketServletFactory factory) { factory.setCreator(this); factory.getPolicy().setMaxTextMessageSize(config.getWebsocketMaxTextMessageSize()); factory.getPolicy().setMaxBinaryMessageSize(config.getWebsocketMaxBinaryMessageSize()); factory.getPolicy().setMaxBinaryMessageBufferSize(config.getWebsocketMaxBinaryMessageBufferSize()); factory.getPolicy().setMaxTextMessageBufferSize(config.getWebsocketMaxTextMessageBufferSize()); factory.getPolicy().setInputBufferSize(config.getWebsocketInputBufferSize()); factory.getPolicy().setAsyncWriteTimeout(config.getWebsocketAsyncWriteTimeout()); factory.getPolicy().setIdleTimeout(config.getWebsocketIdleTimeout()); } /* * (non-Javadoc) * * @see * org.eclipse.jetty.websocket.servlet.WebSocketCreator#createWebSocket(org. * eclipse.jetty.websocket.servlet.ServletUpgradeRequest, * org.eclipse.jetty.websocket.servlet.ServletUpgradeResponse) */ @Override public Object createWebSocket(ServletUpgradeRequest req, ServletUpgradeResponse resp) { try { final URI requestURI = req.getRequestURI(); final String path = requestURI.getPath(); /* URL used to connect to websocket backend */ final String backendURL = getMatchedBackendURL(path); /* Upgrade happens here */ return new ProxyWebSocketAdapter(URI.create(backendURL), pool); } catch (final Exception e) { LOG.failedCreatingWebSocket(e); throw e; } } /** * This method looks at the context path and returns the backend websocket * url. If websocket url is found it is used as is, or we default to * ws://{host}:{port} which might or might not be right. * * @param The context path * @return Websocket backend url */ private synchronized String getMatchedBackendURL(final String path) { final ServiceRegistry serviceRegistryService = services .getService(GatewayServices.SERVICE_REGISTRY_SERVICE); final ServiceDefinitionRegistry serviceDefinitionService = services .getService(GatewayServices.SERVICE_DEFINITION_REGISTRY); /* Filter out the /cluster/topology to get the context we want */ String[] pathInfo = path.split(REGEX_SPLIT_CONTEXT); final ServiceDefEntry entry = serviceDefinitionService.getMatchingService(pathInfo[1]); if (entry == null) { throw new RuntimeException(String.format("Cannot find service for the given path: %s", path)); } final File servicesDir = new File(config.getGatewayServicesDir()); final Set<ServiceDefinition> serviceDefs = ServiceDefinitionsLoader.getServiceDefinitions(servicesDir); /* URL used to connect to websocket backend */ String backendURL = urlFromServiceDefinition(serviceDefs, serviceRegistryService, entry, path); try { /* if we do not find websocket URL we default to HTTP */ if (!StringUtils.contains(backendURL, WEBSOCKET_PROTOCOL_STRING)) { URL serviceUrl = new URL(backendURL); final StringBuffer backend = new StringBuffer(); /* Use http host:port if ws url not configured */ final String protocol = (serviceUrl.getProtocol() == "ws" || serviceUrl.getProtocol() == "wss") ? serviceUrl.getProtocol() : "ws"; backend.append(protocol).append("://"); backend.append(serviceUrl.getHost()).append(":"); backend.append(serviceUrl.getPort()).append("/"); ; backend.append(serviceUrl.getPath()); backendURL = backend.toString(); } } catch (MalformedURLException e) { LOG.badUrlError(e); throw new RuntimeException(e.toString()); } return backendURL; } private static String urlFromServiceDefinition(final Set<ServiceDefinition> serviceDefs, final ServiceRegistry serviceRegistry, final ServiceDefEntry entry, final String path) { final String[] contexts = path.split("/"); final String serviceURL = serviceRegistry.lookupServiceURL(contexts[2], entry.getName().toUpperCase()); /* * we have a match, if ws:// is present it is returend else http:// is * returned */ return serviceURL; } }