| /* |
| * 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.tinkerpop.gremlin.server.handler; |
| |
| import com.codahale.metrics.MetricRegistry; |
| import io.netty.channel.ChannelHandlerContext; |
| import io.netty.channel.ChannelInboundHandlerAdapter; |
| import io.netty.handler.codec.http.HttpHeaders; |
| import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler; |
| import io.netty.util.AttributeKey; |
| import org.apache.tinkerpop.gremlin.server.GremlinServer; |
| import org.apache.tinkerpop.gremlin.server.util.MetricManager; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * Channel handler which extracts a user agent header from a web socket handshake if present |
| * then logs the user agent and stores it as a channel attribute for future reference. |
| */ |
| public class WsUserAgentHandler extends ChannelInboundHandlerAdapter { |
| /** |
| * This constant caps the number of unique user agents which will be tracked in the metrics. Any new unique |
| * user agents will be replaced with "other" in the metrics after this cap has been reached. |
| */ |
| private static final int MAX_USER_AGENT_METRICS = 10000; |
| |
| private static final String USER_AGENT_HEADER_NAME = "User-Agent"; |
| |
| private static final Logger logger = LoggerFactory.getLogger(WsUserAgentHandler.class); |
| public static final AttributeKey<String> USER_AGENT_ATTR_KEY = AttributeKey.valueOf(USER_AGENT_HEADER_NAME); |
| |
| @Override |
| public void userEventTriggered(final ChannelHandlerContext ctx, java.lang.Object evt) { |
| if (evt instanceof WebSocketServerProtocolHandler.HandshakeComplete) { |
| final HttpHeaders requestHeaders = ((WebSocketServerProtocolHandler.HandshakeComplete) evt).requestHeaders(); |
| |
| if (requestHeaders.contains(USER_AGENT_HEADER_NAME)){ |
| final String userAgent = requestHeaders.get(USER_AGENT_HEADER_NAME); |
| |
| ctx.channel().attr(USER_AGENT_ATTR_KEY).set(userAgent); |
| logger.debug("New Connection on channel [{}] with user agent [{}]", ctx.channel().id().asShortText(), userAgent); |
| |
| String metricName = MetricRegistry.name(GremlinServer.class, "user-agent", userAgent); |
| |
| // This check is to address a concern that an attacker may try to fill the server's memory with a very |
| // large number of unique user agents. For this reason the user agent is replaced with "other" |
| // for the purpose of metrics if this cap is ever exceeded and the user agent is not already being tracked. |
| if(MetricManager.INSTANCE.getCounterSize() > MAX_USER_AGENT_METRICS && |
| !MetricManager.INSTANCE.contains(metricName)) { |
| metricName = MetricRegistry.name(GremlinServer.class, "user-agent", "other"); |
| } |
| MetricManager.INSTANCE.getCounter(metricName).inc(); |
| } else { |
| logger.debug("New Connection on channel [{}] with no user agent provided", ctx.channel().id().asShortText()); |
| } |
| } |
| ctx.fireUserEventTriggered(evt); |
| } |
| } |