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Posted to user@beehive.apache.org by "DeHamer, Brian" <br...@hp.com> on 2005/06/07 15:21:24 UTC
Problem with "request_uri" attribute
Never received a respone to my initial question -- reposting:
I have a custom tag that, among other things, needs to read the value of
the "javax.servlet.forward.request_uri" request attribute. Under plain
ol' Struts I found that this attribute would always contain the URI of
the original request from the client, even after multiple forwards (as
per servlet spec SRV.8.4.2).
Now that I'm trying to use my tag in conjunction with Beehive JPF
(1.0m1) I'm finding that this attribute no longer contains the URI for
the original request, but instead contains the URI for the forwarded
request. I tried to find the most simple use case that reproduces the
problem so I started with a fresh instance of the netui-blank webapp and
simply added the following line to the provided index.jsp page:
<%= request.getAttribute("javax.servlet.forward.request_uri") %>
When invoking /begin.do from my browser I get forwarded to index.jsp and
I expect that the page output will display "/netui-blank/begin.do", but
instead what I see is "/netui-blank/index.jsp".
Just as a quick sanity check, I created another JSP called forward.jsp
that contains only the following:
<%
javax.servlet.RequestDispatcher rd =
request.getRequestDispatcher("/index.jsp");
rd.forward(request, response);
%>
When I access forward.jsp directly (no JPF code involved) I still get
forwarded to index.jsp, but this time I see the output I would expect:
"/netui-blank/forward.jsp".
It would appear that this attribute isn't being set properly as a result
of being processed by the PageFlowActionServlet. Any ideas? Thanks.
Brian DeHamer
Re: Problem with "request_uri" attribute
Posted by Carlin Rogers <cr...@bea.com>.
Hi Brian,
I'll take a look at this and see if there's an issue with
the page flow servlet filter or something else, then let
you know what I find. Sorry for the slow response.
Kind regards,
Carlin
DeHamer, Brian wrote:
> Never received a respone to my initial question -- reposting:
>
> I have a custom tag that, among other things, needs to read the value of
> the "javax.servlet.forward.request_uri" request attribute. Under plain
> ol' Struts I found that this attribute would always contain the URI of
> the original request from the client, even after multiple forwards (as
> per servlet spec SRV.8.4.2).
>
> Now that I'm trying to use my tag in conjunction with Beehive JPF
> (1.0m1) I'm finding that this attribute no longer contains the URI for
> the original request, but instead contains the URI for the forwarded
> request. I tried to find the most simple use case that reproduces the
> problem so I started with a fresh instance of the netui-blank webapp and
> simply added the following line to the provided index.jsp page:
>
> <%= request.getAttribute("javax.servlet.forward.request_uri") %>
>
> When invoking /begin.do from my browser I get forwarded to index.jsp and
> I expect that the page output will display "/netui-blank/begin.do", but
> instead what I see is "/netui-blank/index.jsp".
>
> Just as a quick sanity check, I created another JSP called forward.jsp
> that contains only the following:
>
> <%
> javax.servlet.RequestDispatcher rd =
> request.getRequestDispatcher("/index.jsp");
> rd.forward(request, response);
> %>
>
> When I access forward.jsp directly (no JPF code involved) I still get
> forwarded to index.jsp, but this time I see the output I would expect:
> "/netui-blank/forward.jsp".
>
> It would appear that this attribute isn't being set properly as a result
> of being processed by the PageFlowActionServlet. Any ideas? Thanks.
>
> Brian DeHamer
>
Re: Problem with "request_uri" attribute
Posted by Carlin Rogers <cr...@bea.com>.
Just wanted to follow up and let folks know that I've
logged a Tomcat bug. Please see...
http://issues.apache.org/bugzilla/show_bug.cgi?id=35270
if you're interested.
Thanks,
Carlin
Carlin Rogers wrote:
> Hey Brian,
>
> Thanks for the detail and the simple reproduction
> information. This really helps out when digging
> into the code.
>
> It appears that this has something to do with how the
> container manages the request in the RequestDispatcher,
> and may be a problem specific to Tomcat.
>
> I noticed different behavior between Tomcat and Weblogic.
> With a NetUI deployment on WebLogic, your test below works
> correctly. The page displays /netui-blank/begin.do for the
> "javax.servlet.forward.request_uri" request attribute.
> And going directly to the Controller, the page displays
> /netui-blank/Controller.jpf for this attribute, as
> expected.
>
> Stepping through the Tomcat source in the debugger, it
> appears that the request's requestURI field gets stomped
> on in the forward method of the RequestDispatcher
> (ApplicationDispatcher). I'm not sure Tomcat is handling
> a ServletRequestWrapper correctly.
>
> I think the servlet spec says that users may wrap the
> request/response objects with their own implementation.
> This is what we do in NetUI Page Flow.
>
> Tomcat's ApplicationDispatcher gets the request from
> the outer request (the ServletRequestWrapper), trying to
> keep track of the previous wrapper and current wrapper
> (or request) as it loops through to get the real request.
> With a single wrapper, the value of "previous" is the
> same as the original outer request. Then Tomcat calls...
>
> ((ServletRequestWrapper) previous).setRequest(wrapper);
>
> which is the same as calling setRequest(wrapper) on the
> incoming request. Tomcat does not get and save the value
> of the original request URI. It calls setRequestURI(path)
> on the wrapper, effectively changing the request URI of the
> original incoming request to the path of the forward.
>
> Then Tomcat sets the javax.servlet.forward.request_uri
> attribute by calling getRequestURI() from the original
> request... but that just got modified. Implying the
> javax.servlet.forward.request_uri attribute is going to
> get the value of the path for the forward.
>
> You can test this on Tomcat by making a simple change to
> your test JSP that does the forward, forward.jsp. Use
> a HttpServletRequestWrapper in the JSP for the forward.
> So, forward.jsp would now contain...
>
> <%
> HttpServletRequestWrapper wrapper = new
> HttpServletRequestWrapper(request);
> javax.servlet.RequestDispatcher rd =
> wrapper.getRequestDispatcher("/index.jsp");
> rd.forward(wrapper, response);
> %>
>
> ...and "/netui-blank/index.jsp", the forward path
> used by the RequestDispatcher, is displayed.
>
> Bummer. I guess the next step is to see if this is an
> known issue or not in Tomcat or if this is expected
> behavior.
>
> Sorry the news isn't better. Hope it helps.
> Carlin
>
> DeHamer, Brian wrote:
>
>> Never received a respone to my initial question -- reposting:
>>
>> I have a custom tag that, among other things, needs to read the value of
>> the "javax.servlet.forward.request_uri" request attribute. Under plain
>> ol' Struts I found that this attribute would always contain the URI of
>> the original request from the client, even after multiple forwards (as
>> per servlet spec SRV.8.4.2).
>> Now that I'm trying to use my tag in conjunction with Beehive JPF
>> (1.0m1) I'm finding that this attribute no longer contains the URI for
>> the original request, but instead contains the URI for the forwarded
>> request. I tried to find the most simple use case that reproduces the
>> problem so I started with a fresh instance of the netui-blank webapp and
>> simply added the following line to the provided index.jsp page:
>>
>> <%= request.getAttribute("javax.servlet.forward.request_uri") %>
>>
>> When invoking /begin.do from my browser I get forwarded to index.jsp and
>> I expect that the page output will display "/netui-blank/begin.do", but
>> instead what I see is "/netui-blank/index.jsp".
>>
>> Just as a quick sanity check, I created another JSP called forward.jsp
>> that contains only the following:
>>
>> <%
>> javax.servlet.RequestDispatcher rd =
>> request.getRequestDispatcher("/index.jsp");
>> rd.forward(request, response);
>> %>
>>
>> When I access forward.jsp directly (no JPF code involved) I still get
>> forwarded to index.jsp, but this time I see the output I would expect:
>> "/netui-blank/forward.jsp".
>>
>> It would appear that this attribute isn't being set properly as a result
>> of being processed by the PageFlowActionServlet. Any ideas? Thanks.
>>
>> Brian DeHamer
>>
>
>
Re: Problem with "request_uri" attribute
Posted by Carlin Rogers <cr...@bea.com>.
Hey Brian,
Thanks for the detail and the simple reproduction
information. This really helps out when digging
into the code.
It appears that this has something to do with how the
container manages the request in the RequestDispatcher,
and may be a problem specific to Tomcat.
I noticed different behavior between Tomcat and Weblogic.
With a NetUI deployment on WebLogic, your test below works
correctly. The page displays /netui-blank/begin.do for the
"javax.servlet.forward.request_uri" request attribute.
And going directly to the Controller, the page displays
/netui-blank/Controller.jpf for this attribute, as
expected.
Stepping through the Tomcat source in the debugger, it
appears that the request's requestURI field gets stomped
on in the forward method of the RequestDispatcher
(ApplicationDispatcher). I'm not sure Tomcat is handling
a ServletRequestWrapper correctly.
I think the servlet spec says that users may wrap the
request/response objects with their own implementation.
This is what we do in NetUI Page Flow.
Tomcat's ApplicationDispatcher gets the request from
the outer request (the ServletRequestWrapper), trying to
keep track of the previous wrapper and current wrapper
(or request) as it loops through to get the real request.
With a single wrapper, the value of "previous" is the
same as the original outer request. Then Tomcat calls...
((ServletRequestWrapper) previous).setRequest(wrapper);
which is the same as calling setRequest(wrapper) on the
incoming request. Tomcat does not get and save the value
of the original request URI. It calls setRequestURI(path)
on the wrapper, effectively changing the request URI of the
original incoming request to the path of the forward.
Then Tomcat sets the javax.servlet.forward.request_uri
attribute by calling getRequestURI() from the original
request... but that just got modified. Implying the
javax.servlet.forward.request_uri attribute is going to
get the value of the path for the forward.
You can test this on Tomcat by making a simple change to
your test JSP that does the forward, forward.jsp. Use
a HttpServletRequestWrapper in the JSP for the forward.
So, forward.jsp would now contain...
<%
HttpServletRequestWrapper wrapper = new
HttpServletRequestWrapper(request);
javax.servlet.RequestDispatcher rd =
wrapper.getRequestDispatcher("/index.jsp");
rd.forward(wrapper, response);
%>
...and "/netui-blank/index.jsp", the forward path
used by the RequestDispatcher, is displayed.
Bummer. I guess the next step is to see if this is an
known issue or not in Tomcat or if this is expected
behavior.
Sorry the news isn't better. Hope it helps.
Carlin
DeHamer, Brian wrote:
> Never received a respone to my initial question -- reposting:
>
> I have a custom tag that, among other things, needs to read the value of
> the "javax.servlet.forward.request_uri" request attribute. Under plain
> ol' Struts I found that this attribute would always contain the URI of
> the original request from the client, even after multiple forwards (as
> per servlet spec SRV.8.4.2).
>
> Now that I'm trying to use my tag in conjunction with Beehive JPF
> (1.0m1) I'm finding that this attribute no longer contains the URI for
> the original request, but instead contains the URI for the forwarded
> request. I tried to find the most simple use case that reproduces the
> problem so I started with a fresh instance of the netui-blank webapp and
> simply added the following line to the provided index.jsp page:
>
> <%= request.getAttribute("javax.servlet.forward.request_uri") %>
>
> When invoking /begin.do from my browser I get forwarded to index.jsp and
> I expect that the page output will display "/netui-blank/begin.do", but
> instead what I see is "/netui-blank/index.jsp".
>
> Just as a quick sanity check, I created another JSP called forward.jsp
> that contains only the following:
>
> <%
> javax.servlet.RequestDispatcher rd =
> request.getRequestDispatcher("/index.jsp");
> rd.forward(request, response);
> %>
>
> When I access forward.jsp directly (no JPF code involved) I still get
> forwarded to index.jsp, but this time I see the output I would expect:
> "/netui-blank/forward.jsp".
>
> It would appear that this attribute isn't being set properly as a result
> of being processed by the PageFlowActionServlet. Any ideas? Thanks.
>
> Brian DeHamer
>