185 lines
6.3 KiB
Java
185 lines
6.3 KiB
Java
/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import java.io.IOException;
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import java.io.PrintWriter;
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import java.util.Enumeration;
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import java.util.Locale;
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import java.util.ResourceBundle;
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import jakarta.servlet.ServletException;
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import jakarta.servlet.http.HttpServlet;
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import jakarta.servlet.http.HttpServletRequest;
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import jakarta.servlet.http.HttpServletResponse;
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import jakarta.servlet.http.HttpSession;
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import org.apache.tomcat.util.json.JSONFilter;
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import util.CookieFilter;
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import util.HTMLFilter;
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/**
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* Example servlet showing request headers
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*
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* @author James Duncan Davidson <duncan@eng.sun.com>
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*/
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public class RequestHeaderExample extends HttpServlet {
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private static final long serialVersionUID = 1L;
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@Override
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public void doGet(HttpServletRequest request,
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HttpServletResponse response)
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throws IOException, ServletException
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{
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if (prefersJSON(request.getHeader("Accept"))) {
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renderJSON(request, response);
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} else {
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renderHTML(request, response);
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}
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}
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/**
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* Returns true if the client appears to prefer a JSON response,
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* false otherwise.
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*
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* Note that this method is not very pedantic and uses only a very lazy
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* algorithm for checking whether JSON is "preferred".
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*
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* @param acceptHeader The value of the HTTP "Accept" header from the client.
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*
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* @return true if the client appears to prefer a JSON response,
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* false otherwise.
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*/
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protected boolean prefersJSON(String acceptHeader) {
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if (null == acceptHeader) {
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return false;
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}
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// mime/type, mime/type;q=n, ...
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// Don't bother with the q-factor.
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// This is not expected to be 100% accurate or spec-compliant
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String[] accepts = acceptHeader.split(",");
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for (String accept : accepts) {
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if (accept.contains("application/json")) {
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return true;
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}
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// text/html, application/html, etc.
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if (accept.contains("html")) {
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return false;
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}
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}
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return false;
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}
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protected void renderHTML(HttpServletRequest request,
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HttpServletResponse response)
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throws IOException
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{
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ResourceBundle rb = ResourceBundle.getBundle("LocalStrings",request.getLocale());
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response.setContentType("text/html");
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response.setCharacterEncoding("UTF-8");
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PrintWriter out = response.getWriter();
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out.println("<!DOCTYPE html><html>");
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out.println("<head>");
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out.println("<meta charset=\"UTF-8\" />");
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String title = rb.getString("requestheader.title");
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out.println("<title>" + title + "</title>");
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out.println("</head>");
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out.println("<body bgcolor=\"white\">");
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// all links relative
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// XXX
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// making these absolute till we work out the
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// addition of a PathInfo issue
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out.println("<a href=\"../reqheaders.html\">");
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out.println("<img src=\"../images/code.gif\" height=24 " +
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"width=24 align=right border=0 alt=\"view code\"></a>");
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out.println("<a href=\"../index.html\">");
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out.println("<img src=\"../images/return.gif\" height=24 " +
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"width=24 align=right border=0 alt=\"return\"></a>");
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out.println("<h3>" + title + "</h3>");
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out.println("<table border=0>");
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Enumeration<String> e = request.getHeaderNames();
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while (e.hasMoreElements()) {
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String headerName = e.nextElement();
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String headerValue = request.getHeader(headerName);
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out.println("<tr><td bgcolor=\"#CCCCCC\">");
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out.println(HTMLFilter.filter(headerName));
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out.println("</td><td>");
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if (headerName.toLowerCase(Locale.ENGLISH).contains("cookie")) {
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HttpSession session = request.getSession(false);
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String sessionId = null;
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if (session != null) {
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sessionId = session.getId();
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}
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out.println(HTMLFilter.filter(CookieFilter.filter(headerValue, sessionId)));
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} else {
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out.println(HTMLFilter.filter(headerValue));
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}
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out.println("</td></tr>");
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}
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out.println("</table>");
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}
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protected void renderJSON(HttpServletRequest request, HttpServletResponse response)
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throws IOException
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{
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response.setContentType("application/json");
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response.setCharacterEncoding("UTF-8");
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PrintWriter out = response.getWriter();
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out.append('[');
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Enumeration<String> e = request.getHeaderNames();
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while (e.hasMoreElements()) {
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String headerName = e.nextElement();
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String headerValue = request.getHeader(headerName);
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out.append("{\"")
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.append(JSONFilter.escape(headerName))
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.append("\":\"")
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.append(JSONFilter.escape(headerValue))
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.append("\"}")
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;
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if(e.hasMoreElements()) {
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out.append(',');
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}
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}
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out.print("]");
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}
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@Override
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public void doPost(HttpServletRequest request,
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HttpServletResponse response)
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throws IOException, ServletException
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{
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doGet(request, response);
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}
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}
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