---------- Forwarded message ----------
From: Sanjay Choudhary <[EMAIL PROTECTED]>
Date: Fri, 5 Nov 2004 10:49:25 -0800
Subject: Using Forward and Include using RequestProcessor
To: [EMAIL PROTECTED]
Hi All,
I have an application which contains 100+ jsp's. Use case is to
inject the Javascript conditionally into the JSP's. Condition is - If
a cookie is present in the request, inject the Javascript else leave
it alone.
I started with a simple struts example project for the proof of
concept. I thought of a Servlet Filter and I created a filter as
below
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
public class SecurePageFilter implements Filter {
private static final String SECURITY_COOKIE = "ObSSOCookie";
private static final String SECURITY_JS = "/check.js";
public void init(FilterConfig filterConfig) throws ServletException {
}
public void destroy() {
}
public void doFilter(
ServletRequest oRequest,
ServletResponse oResponse,
FilterChain oFilterChain)
throws IOException, ServletException {
oFilterChain.doFilter(oRequest, oResponse);
HttpServletRequest woRequest = (HttpServletRequest) oRequest;
Cookie[] aoCookies = woRequest.getCookies();
String strUrl = woRequest.getRequestURI();
if (strUrl != null
&& strUrl.endsWith("deleteCookie.jsp")
|| aoCookies == null)
return;
for (int i = 0; i < aoCookies.length; i++) {
Cookie oCookie = aoCookies[i];
if (oCookie.getName().equals(SECURITY_COOKIE)) {
String strValue = oCookie.getValue();
if (strValue != null && strValue.length() > 0) {
RequestDispatcher rd =
woRequest.getRequestDispatcher(SECURITY_JS);
rd.include(oRequest, oResponse);
oResponse.flushBuffer();
return;
}
}
}
return;
} // doFilter
} // SecurePageFilter
My filter is mapped to (*.jsp and *.do) in the web.xml.
This works fine if I have a URI as
http://localhost:9080/struts-example/welcome.jsp
But this doesn't work if I use the URL
http://localhost:9080/struts-example/welcome.do
To explore more I downloaded Struts 1.2 source and took a look in
RequestDispatcher class --> processForward(..) , processInclude(..),
doForward(..) and doInclude(..) methods. And off course, process(..)
method. In the process method , if request is forwarded using the
RequestDispatcher, which is normally the case in *.do types URI's,
control is returned back to the servlet without processing the
'processInclude'. I further extended the RequestDispatcher class and
implemented my own doForward method. This is more or less same as
Struts implementation but also calls includes. Code is as below :-
protected void doForward(
String uri,
HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException {
// Unwrap the multipart request, if there is one.
if (request instanceof MultipartRequestWrapper) {
request = ((MultipartRequestWrapper) request).getRequest();
}
RequestDispatcher rd = getServletContext().getRequestDispatcher(uri);
if (rd == null) {
response.sendError(
HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
getInternal().getMessage("requestDispatcher", uri));
return;
}
rd.forward(request, response);
doIncludeJS(request,response);
}
protected void doIncludeJS(
HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException {
Cookie[] aoCookies = request.getCookies();
String strUrl = request.getRequestURI();
if (strUrl != null
&& strUrl.endsWith("deleteCookie.jsp")
|| aoCookies == null)
return;
for (int i = 0; i < aoCookies.length; i++) {
Cookie oCookie = aoCookies[i];
if (oCookie.getName().equals(SECURITY_COOKIE)) {
String strValue = oCookie.getValue();
if (strValue != null && strValue.length() > 0) {
doInclude(SECURITY_JS,request, response);
break;
}
}
}
return;
}
Still to my surprise, JS file did not get injected in the response.( I
debugged the application do ensure that doInclude(..) method is
called)
[Q1] - Can we use RequestDispatcher to Forward and Include for the
same request/response? (I know we can't do Include and Forward, it
throws an error. But in case of Forward and Include no error is thrown
but nothing gets included).
[Q2] - Is there anyother way of including into request with URI like *.do?
Any help is highly appreciated.
Thanks,
Sanjay
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