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

[Afkham Azeez]

What I was thinking is making the location from where the initialization 
happened irrelevant. Whoever gets initialized first, will initialize the 
system.

Azeez

sumedha rubasinghe wrote:
>   If this is the case, how about initializing filters manually using a 
> Servlet Context Listener?
> 
> /sumedha
> 
> 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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>>   
> 
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