Saturday, 21 July 2012

Error Codes - Some of the frequently issues




1. 403 - Cannot Serve URLs with character in them


The HTMLServlet and the FileFinderServlet servlets in the request handling servlet pipeline check for the characters '..' and 'null'. If these appear in the URL the "Cannot serve URLs" error message is shown.


These characters are hard coded in the source and cannot be parametrized.


Source Code Snippet: - FileFinderPipelineServlet


 if(pPathInfo.indexOf("..") != -1)
                {
                    sendError(pResponse, 403, "Cannot serve URLs with ..'s in them");
                    return false;
                }
                if(pPathInfo.indexOf('\0') != -1)
                {
                    sendError(pResponse, 403, "Cannot serve URLs with nulls in them");
                    return false;
                }


2. 404 Error Pages Rendered From web.xml Definition Not Multisite Aware 


A 404 error-page was added to the application's web.xml  file
<error-page> 
    <error-code>404</error-code> 
    <location>/error.jsp</location>
</error-page>


However, the request does not appear to be processed by the pipleline, as none of the site formatting or branding for Multisite is being displayed with the 404 error.jsp


The 404 exceptions are handled via the Application Server (ie WebLogic, JBoss, WebShpere). If the web.xml file does not include instructions for how the Applications Servers, Dispatcher should handle ERRORs, the Application Server will not forward the Request to the PageFilter servlet -> DynamoHandler -> SiteContextPipelineServlet , and on down the pipeline. Hence, none of the Formatting/Branding handled by Multisite and the SiteContextPipelineServlet are triggered.


We need to abide to the pattern followed in CRS web.xml when we define the error pages for error codes:


1. Define the filters
<filter>
    <filter-name>PageFilter</filter-name>
    <filter-class>atg.filter.dspjsp.PageFilter</filter-class>
 </filter>
 <filter>
    <filter-name>ErrorFilter</filter-name>
    <filter-class>atg.servlet.ErrorFilter</filter-class>
  </filter>


2. Define the filter mappings
 <filter-mapping>
    <filter-name>ErrorFilter</filter-name>
    <url-pattern>/*</url-pattern>
    <dispatcher>ERROR</dispatcher>
  </filter-mapping>
  <filter-mapping>
    <filter-name>PageFilter</filter-name>
    <url-pattern>/*</url-pattern>
    <dispatcher>REQUEST</dispatcher>
    <dispatcher>ERROR</dispatcher>
    <dispatcher>FORWARD</dispatcher>
  </filter-mapping>


3. Include all the error page elements
 <error-page>
    <error-code>404</error-code>
    <location>/global/pageNotFound.jsp</location>
  </error-page>
  <error-page>
    <error-code>500</error-code>
    <location>/global/serverError.jsp</location>
  </error-page>

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