/*
* 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.
*/
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;
import java.util.Locale;
import java.util.ResourceBundle;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.tomcat.util.json.JSONFilter;
import util.CookieFilter;
import util.HTMLFilter;
/**
* Example servlet showing request headers
*/
public class RequestHeaderExample
extends HttpServlet
{
private static final long serialVersionUID = 1L
;
@
Override
public void doGet
(HttpServletRequest request, HttpServletResponse response
) throws IOException, ServletException
{
if (prefersJSON
(request.
getHeader("Accept"))) {
renderJSON
(request, response
);
} else {
renderHTML
(request, response
);
}
}
/**
* Returns true if the client appears to prefer a JSON response, false otherwise. Note that this method is not very
* pedantic and uses only a very lazy algorithm for checking whether JSON is "preferred".
*
* @param acceptHeader The value of the HTTP "Accept" header from the client.
*
* @return true if the client appears to prefer a JSON response, false otherwise.
*/
protected boolean prefersJSON
(String acceptHeader
) {
if (null == acceptHeader
) {
return false;
}
// mime/type, mime/type;q=n, ...
// Don't bother with the q-factor.
// This is not expected to be 100% accurate or spec-compliant
String[] accepts = acceptHeader.
split(",");
for (String accept : accepts
) {
if (accept.
contains("application/json")) {
return true;
}
// text/html, application/html, etc.
if (accept.
contains("html")) {
return false;
}
}
return false;
}
protected void renderHTML
(HttpServletRequest request, HttpServletResponse response
) throws IOException {
ResourceBundle rb =
ResourceBundle.
getBundle("LocalStrings", request.
getLocale());
response.
setContentType("text/html");
response.
setCharacterEncoding("UTF-8");
PrintWriter out = response.
getWriter();
out.
println("<!DOCTYPE html><html>");
out.
println("<head>");
out.
println("<meta charset=\"UTF-8\" />");
String title = rb.
getString("requestheader.title");
out.
println("<title>" + title +
"</title>");
out.
println("</head>");
out.
println("<body bgcolor=\"white\">");
out.
println("<a href=\"../reqheaders.html\">");
out.
println(
"<img src=\"../images/code.gif\" height=24 " +
"width=24 align=right border=0 alt=\"view code\"></a>");
out.
println("<a href=\"../index.html\">");
out.
println(
"<img src=\"../images/return.gif\" height=24 " +
"width=24 align=right border=0 alt=\"return\"></a>");
out.
println("<h3>" + title +
"</h3>");
out.
println("<table border=0>");
Enumeration<String> e = request.
getHeaderNames();
while (e.
hasMoreElements()) {
String headerName = e.
nextElement();
String headerValue = request.
getHeader(headerName
);
out.
println("<tr><td bgcolor=\"#CCCCCC\">");
out.
println(HTMLFilter.
filter(headerName
));
out.
println("</td><td>");
if (headerName.
toLowerCase(Locale.
ENGLISH).
contains("cookie")) {
HttpSession session = request.
getSession(false);
String sessionId =
null;
if (session
!=
null) {
sessionId = session.
getId();
}
out.
println(HTMLFilter.
filter(CookieFilter.
filter(headerValue, sessionId
)));
} else {
out.
println(HTMLFilter.
filter(headerValue
));
}
out.
println("</td></tr>");
}
out.
println("</table>");
}
protected void renderJSON
(HttpServletRequest request, HttpServletResponse response
) throws IOException {
response.
setContentType("application/json");
response.
setCharacterEncoding("UTF-8");
PrintWriter out = response.
getWriter();
out.
append('[');
Enumeration<String> e = request.
getHeaderNames();
while (e.
hasMoreElements()) {
String headerName = e.
nextElement();
String headerValue = request.
getHeader(headerName
);
out.
append("{\"").
append(JSONFilter.
escape(headerName
)).
append("\":\"");
if (headerName.
toLowerCase(Locale.
ENGLISH).
contains("cookie")) {
HttpSession session = request.
getSession(false);
String sessionId =
null;
if (session
!=
null) {
sessionId = session.
getId();
}
out.
append(JSONFilter.
escape(CookieFilter.
filter(headerValue, sessionId
)));
} else {
out.
append(JSONFilter.
escape(headerValue
));
}
out.
append("\"}");
if (e.
hasMoreElements()) {
out.
append(',');
}
}
out.
print("]");
}
@
Override
public void doPost
(HttpServletRequest request, HttpServletResponse response
) throws IOException, ServletException
{
doGet
(request, response
);
}
}