Java tutorial
package edu.gatech.i3l.fhir.jpa.provider; /* * #%L * HAPI FHIR JPA Server * %% * Copyright (C) 2014 - 2015 University Health Network * %% * 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. * #L% */ import java.util.Enumeration; import java.util.Set; import java.util.TreeSet; import javax.servlet.http.HttpServletRequest; import org.apache.commons.lang3.StringUtils; import org.jboss.logging.MDC; public class BaseJpaProvider { public static final String REMOTE_ADDR = "req.remoteAddr"; public static final String REMOTE_UA = "req.userAgent"; private static final org.slf4j.Logger ourLog = org.slf4j.LoggerFactory.getLogger(BaseJpaProvider.class); public void startRequest(HttpServletRequest theRequest) { if (theRequest == null) { return; } Set<String> headerNames = new TreeSet<String>(); for (Enumeration<String> enums = theRequest.getHeaderNames(); enums.hasMoreElements();) { headerNames.add(enums.nextElement()); } ourLog.debug("Request headers: {}", headerNames); Enumeration<String> forwardedFors = theRequest.getHeaders("x-forwarded-for"); StringBuilder b = new StringBuilder(); for (Enumeration<String> enums = forwardedFors; enums.hasMoreElements();) { if (b.length() > 0) { b.append(" / "); } b.append(enums.nextElement()); } String forwardedFor = b.toString(); String ip = theRequest.getRemoteAddr(); if (StringUtils.isBlank(forwardedFor)) { org.slf4j.MDC.put(REMOTE_ADDR, ip); ourLog.debug("Request is from address: {}", ip); } else { org.slf4j.MDC.put(REMOTE_ADDR, forwardedFor); ourLog.debug("Request is from forwarded address: {}", forwardedFor); } String userAgent = StringUtils.defaultString(theRequest.getHeader("user-agent")); org.slf4j.MDC.put(REMOTE_UA, userAgent); } public void endRequest(HttpServletRequest theRequest) { MDC.remove(REMOTE_ADDR); MDC.remove(REMOTE_UA); } }