11/16/2002 9:19:51 PM, David Graham <[EMAIL PROTECTED]> 
wrote:
>I was trying to fix 
http://nagoya.apache.org/bugzilla/show_bug.cgi?id=11021 
>but got rather confused along the way.  The problem seems to be 
that 
>RequestUtils.forwardURL() always prepends the context path even 
for absolute 
>urls.  The version comments seem to go back and forth on how to 
behave with 
>a leading / in the url.  Sometimes no leading / means don't 
prepend the 
>context, then that decision was reversed.
>
>Maybe I'm not the right person to fix this but we need to decide 
how to 
>determine if the user has entered an absolute url like 
>http://www.google.com.



OK, let's start with the 1.0 behavior. 

There are two ways to indicate a path, an ActionMapping.forward 
and an ActionForward. 

In the case of an ActionMapping.forward, we did this 

* Get String (path) stored as the ActionMapping forward property. 
* Give it to the RequestDispatcher.

which boils down to 

String forward = ActionMapping.getForward();
// ... error checking
RequestDispatcher rd =
  getServletContext().getRequestDispatcher(forward);
// ... error checking
rd.forward(request, response);

rd.forward allows you to forwards a request from a servlet to 
another resource (servlet, JSP file, or HTML file) on the server. 
Since we obtained it via getRequestDispatcher(), the 
ServletRequest object has its path elements and parameters 
adjusted to match the path of the target resource. So, all the 
references here will *always* be context relative without our 
having to munge the path in any way.

Also, this method does *not* support absolute URL with a schema 
attached. It's meant to forward to another resource on the same 
server, and since we were using getServletContext, to a resource 
in the same application. 

In the case of an ActionForward, in 1.0 we handle it like this:

* Retrieve the ActionForward bean
* get the path property
* if the ActionForward.redirect property is true and the path 
starts with a slash, then we insert the context path before 
redirecting. If the path does not start with a slash (e.g, it has 
a schema), we leave it alone.
* if ActionForward.redirect is false (the default), we handle it 
like the ActionMapping.forward 
(getServletContext.getRequestDispatcher). 

        if (forward != null) {
            String path = forward.getPath();
            if (forward.getRedirect()) {
                if (path.startsWith("/"))
                    path = request.getContextPath() + path;
                response.sendRedirect(response.encodeRedirectURL
(path));
            } else {
                RequestDispatcher rd =
                    getServletContext().getRequestDispatcher(path);
                if (rd == null) {
                    response.sendError
(HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
                                       internal.getMessage
("requestDispatcher",
                                                           path));
                    return;
                }
                rd.forward(request, response);
            }

So, to get to another server, we had to set redirect=true and use 
an ActionForward. 

A third way to indicate a path was via the standard ForwardAction. 
In 1.0, the behavior of the ForwardAction and IncludeAction 
mimicks the ActionMapping.forward and ActionMapping.include with 
any apparent value add. I don't remember why we did this. My guess 
is that we did the Actions first and then extended the 
ActionMappings, leaving the Actions behind for backward 
compatability. 

So, in 1.0, the only place we needed to munge a path was when 

* We used an ActionForward (rather than ActionMapping.forward)
* Redirect was true
* The path started with a slash 

We only munge it here because we are going through the 
response.sendRedirect. Response.sendDirect doesn't know anything 
about the ServletContext, and so we provide this bit ourselves. In 
all other cases, RequestDispatcher does all the dirty work fr us. 

In 1.1, we munge paths more often, since we need to inject the 
module component. There are also times when we should not inject 
the module component, so we added the contextRelative property to 
the ActionForward.

When contextRelative is false (the default), we are implying that 
the path is instead module relative. 

In the case of a 1.1 ActionMapping.forward, we do this 

* Get String (path) stored as the ActionMapping forward property. 
* Inject the module prefix (which may be blank).
* Give it to the RequestDispatcher.

So, conceptually, this appears to be same behavior as 1.0. I can 
only ActionMapping.forward (or include) to another resource in the 
current application (or application module). 

In the case of an 1.1 ActionForward, we would want to

* if contextRelative is false, insert the module prefix 

and then

* if redirect is true and the path starts with a slash, insert the 
context path. 

Right now in RequestUtils.forwardURL, we're forcing a leading 
slash if context-relative is true. 

        // Handle a ForwardConfig marked as context relative
        StringBuffer sb = new StringBuffer();
        if (forward.getContextRelative()) {
            if (!path.startsWith("/")) {
                sb.append("/");
            }
            sb.append(path);
            return (sb.toString());
        }

Then in RequestProcess.processForwardConfig, we're prepending the 
context on any redirect. 

        if (forward.getRedirect()) {
            response.sendRedirect
                (response.encodeRedirectURL(request.getContextPath
() + uri));

I believe we that forwardURL is being "too helpful" and should 
just return the original path when context-relative is true. 

        // Handle a ForwardConfig marked as context relative
        if (forward.getContextRelative()) {
            return path;
        }

To take up the slack, processForwardConfig then needs to be a bit 
more helpful, and expressly cover the alternatives. Something 
like, 

        String uri = RequestUtils.forwardURL(request, forward);
        if (forward.getRedirect()) {

// -        response.sendRedirect
// -            (response.encodeRedirectURL(request.getContextPath
() + uri));

                String path = null;
                if (uri.startsWith("/")) path = 
request.getContextPath() + uri; 
                else path = uri;
                response.sendRedirect(response.encodeRedirectURL
(path));

        } else {
            doForward(uri, request, response);
        }

I don't have time to test the patch right now, but will take 
responsibilty for trying this by the middle of week (if no one has 
any input). 

To make it easier to hook up with another server, like 
http://google.com, I suggest we add a RedirectAction, which would 
work the same as ForwardAction, but also set redirect=true.

So, to link to another server (like http://google.com/), you would 
use the RedirectAction (or equivalent). 

//...

type="org.apache.struts.actions.RedirectAction"
parameter="http://google.com";

//...

To include or forward to another servlet, you use the 
IncludeAction or ForwardAction

type="org.apache.struts.actions.ForwardAction"
parameter="/myOtherServlet.whatever"

To forward *within* the same application/module (say to front a 
JSP), you use the ActionMapping.forward property. 

<action path="/whatever" forward="/pages/whatever.jsp" />

[where whatever.jsp is stored at $MODULE/pages]

I will also take responsibility for clarifying that throughout the 
documentation this week. 

When this shows up in the archive, I'll also add a link to 
Bugzilla ticket, so there is a running record.

-Ted.




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