[wsas-java-dev] Websphere, WSAS and Servlet, Filter Loading

[Afkham Azeez]

Thanks Upul. I'll look into this.

Thanks
Azeez

Upul Godage wrote:
> Hi all,
> 
> WebSphere 6.1 in Windows XP
> 
> While installing WSAS in WebSphere I found this problem. It seems WSAS
> depends on the state and of loading of Servlets and Filters and having
> them as single instances unreasonably. It seems it assumes Filters will
> be loaded first. And it tries to keep tabs on the Servlet instances that
> is loaded by registering them with their init() method in the servlet
> context.
> 
> 
> org.wso2.wsas.MainServlet (with load-on-startup = 0) calls
> initAdminUIServletFilter which initializes a AdminUIServletFilter object
> usingorg.wso2.adminui.init(Map ....). MainServlet assumes that
> AdminUIServletFilter has already initialized and registered with the
> servletContext. I think that is not a good assumption.
> 
> 
> In WebSphere it seems Filters are not initialized until they are needed.
> In other used servers it looks like Filters are initialized at the
> startup. I think spec does not say anything about Filter loading time.
> So it is not predictable. WebSphere init() them when they are needed for the
> first time. Only Servlets can be manipulated with load-on-startup or
> something.
> 
> 
> Also AdminUIServletFilter.init() (Standard method for initialzing
> Filters) is called again and again using
> UIInitializerServlet.initFilters().
> 
> 
> WSAS tries to keep a reference of AdminUIServletFilter in the
> servletContext and assumes its instance variables are initialized at
> startup. Although spec says there will be only once Servlet instance per
> "JVM", it is not wise to assume there will be only one instance and it's
> instance variables will be initialized as given.
> 
> 
> Check out these fragments.
> 
> 
> 
> org.wso2.wsas.MainServlet
> 
> 
> (AdminUIServletFilter has not initialized yet in WebSphere at
> MainServlet startup.)
> 
> 
> privatevoidinitAdminUIServletFilter(ServletConfig servletConfig)
> throwsServletException {
> 
> ConfigurationContext configCtx =serverManager.configContext;
> 
> ServletContext servletContext = servletConfig.getServletContext();
> 
> AdminUIServletFilter adminUIServletFilter =
> 
> (AdminUIServletFilter) servletContext.
> 
> getAttribute(AdminUIServletFilter.class.getName());
> 
> if(adminUIServletFilter != null) {
> 
> adminUIServletFilter.
> 
> init((Map) configCtx.getProperty(ServerConstants.GENERATED_PAGES),
> 
> Utils.isAdminConsoleEnabled(),
> 
> ServerManager.httpsPort,
> 
> ServerManager.httpPort,
> 
> configCtx.getServicePath());
> 
> }
> 
> 
> }
> 
> 
> 
> 
> privatevoidreinitializeServlets(ServletContext servletContext)
> throwsServletException {
> 
> // Reinitialize all of the servlets, for this puprpose,
> 
> // the servlets should have added themselves
> 
> // as ServletContext attributes in the previous init call
> 
> Enumeration attributeNames = servletContext.getAttributeNames();
> 
> while(attributeNames.hasMoreElements()) {
> 
> Object attrib = servletContext.getAttribute((String)
> attributeNames.nextElement());
> 
> if(attrib instanceofHttpServlet) {
> 
> ((HttpServlet) attrib).init();
> 
> } elseif(attrib instanceofAdminUIServletFilter) {
> 
> AdminUIServletFilter adminUIServletFilter = (AdminUIServletFilter)
> attrib;
> 
> Map genPages = (Map)serverManager.configContext.
> 
> getProperty(ServerConstants.GENERATED_PAGES);
> 
> adminUIServletFilter.init(genPages, Utils.isAdminConsoleEnabled(),
> 
> ServerManager.httpsPort, ServerManager.httpPort,
> 
> serverManager.configContext.getServicePath());
> 
> }
> 
> }
> 
> }
> 
> 
> When run in WebSphere uninitialized AdminUIServletFilter.doFilter()
> quits at,
> 
> 
> if(!enableConsole) {
> 
> ServletOutputStream out = response.getOutputStream();
> 
> out.write(("<b>Management Console has been disabled.</b> "+
> 
> "Enable it in the server.xml and try again.").getBytes());
> 
> ((HttpServletResponse)
> response).setStatus(HttpServletResponse.SC_FORBIDDEN);
> 
> out.flush();
> 
> out.close();
> 
> return;
> 
> }
> 
> 
> because enableConsole is always false in "fresh" AdminUIServletFilter
> object and it looks like it is a security problem from outside. I didn't
> get the given message anyway.  It gave the wrong impression that
> something is wrong with the security settings of the unknown WebSpehere
> territory.
> 
> --
> Upul
> 
> 
> 
> 
> 
> ------------------------------------------------------------------------
> 
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