cache clear issue in gwt

[Bhumika Thaker]

Hi,

I have deployed new version of my application on production server. 

It does not allow user to login and throw below error in my console server.

09:24:20,106 INFO  [org.apache.catalina.core.ContainerBase.[jboss.web].[default-host].[/]] (http--0.0.0.0-80-33)
 loginrpc: ERROR: The serialization policy file '/v4workflow/FB64C6F0204DFD63FB92E5485E94A4E0.gwt.rpc' was not found; 
did you forget to include it in this deployment?
09:24:20,106 INFO  [org.apache.catalina.core.ContainerBase.[jboss.web].[default-host].[/]] 
(http--0.0.0.0-80-33) loginrpc: WARNING: Failed to get the SerializationPolicy 'FB64C6F0204DFD63FB92E5485E94A4E0'
 for module  a legacy, 1.3.3 compatible, serialization policy will be used.
you may experience SerializationExceptions as a result.

It's cache issue. it works fine. because after clearing cache in my browser

To solve this issue, If I add cache clear header in index.html, 

it will add cost to load js every time at client side and give performance issue.

I got so anwser from Thomas Broyer, I can't understand some portion like

servlet.getServletContext().getResourceAsStream. You can customize this by overriding doGetSerializationPolicy (as said in the JavaDoc).
The file name (resource URL) is built from the request's path and X-GWT-Permutation request 

Refer link:

http://stackoverflow.com/questions/11140372/how-gwt-rpc-loads-the-serialization-policy-files

do you know how to resolve cache clear issue in gwt?

Thanks,

Bhumika Thaker

[Jens]

If you apply the correct caching headers there is only minimal overhead on each request because the browser first checks if a new version on the server is available and only if it is available it will download the new version. Otherwise it will continue to use the already cached version.

A lot of people use https://github.com/realityforge/gwt-cache-filter to apply caching headers to their gwt apps.

-- J.

[Bhumika Thaker]

Hi,

Thanks for reply.

Let me implement it.

I have used local storage "Storage.getLocalStorageIfSupported()" to store certificate private key.

is value of local storage clear when cache clear?

Thanks,

Bhumika

[Bhumika Thaker]

Hi Jens,

I have try this  -https://github.com/realityforge/gwt-cache-filter  with sample gwt example.

I have cross check with firebug. I found that each request is all time request new file instead of load from cache.

Have you add any extra setting for same?

Thanks,

Bhumika 

[Bhumika Thaker]

I have implemented it successfully. It works fine. Below code needs to implement.

Added filter in web.xml

<filter> 
    <filter-name>gwtCacheControlFilter</filter-name>
    <filter-class>com.server.GWTCacheControlFilter</filter-class>
    <init-param>
       <param-name>private</param-name>
       <param-value>true</param-value>
   </init-param>
   <init-param>
       <param-name>expirationTime</param-name>
       <param-value>2592000</param-value>
   </init-param>
</filter>

GWTCacheControlFilter.java 

import java.io.IOException;
import java.util.Calendar;
import java.util.Date;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.log4j.Logger;

import com.samaxes.filter.util.CacheConfigParameter;
import com.samaxes.filter.util.Cacheability;
import com.samaxes.filter.util.HTTPCacheHeader;
/**
 * Code imported from cachefilter.jar
 * <br/><br/>
 */
public class GWTCacheControlFilter implements Filter {
private final static String[] STATIC_CONTENTS = { ".jpeg", ".jpg", ".gif",
".png", ".css", ".js", ".html" };
private Cacheability cacheability;
private boolean isStatic;
private long seconds;
private static final Logger LOGGER = Logger.getLogger(GWTCacheControlFilter.class);
public static final int YEAR_IN_MINUTES = 365 * 24 * 60 * 60;

public void destroy() {
}
public void init(FilterConfig filterConfig) throws ServletException {
this.cacheability = (Boolean.valueOf(filterConfig.getInitParameter(CacheConfigParameter.PRIVATE.getName())).booleanValue() ? Cacheability.PRIVATE : Cacheability.PUBLIC);
   this.isStatic = Boolean.valueOf(filterConfig.getInitParameter(CacheConfigParameter.STATIC.getName())).booleanValue();
   try{
     this.seconds = Long.valueOf(filterConfig.getInitParameter(CacheConfigParameter.EXPIRATION_TIME.getName())).longValue();
   } catch (NumberFormatException e) {
     throw new ServletException("The initialization parameter " + 
       CacheConfigParameter.EXPIRATION_TIME.getName() + " is missing for filter " + 
       filterConfig.getFilterName() + ".");
   }
}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain filterChain) throws IOException, ServletException {

HttpServletRequest httpRequest = (HttpServletRequest) request;
String requestURI = httpRequest.getRequestURI();
HttpServletResponse httpResponse = (HttpServletResponse) response;
if (requestURI.contains(".nocache.")) {
Date now = new Date();
httpResponse.setDateHeader("Date", now.getTime());
// one day old
httpResponse.setDateHeader("Expires", now.getTime() - 86400000L);
httpResponse.setHeader("Pragma", "no-cache");
httpResponse.setHeader("Cache-control",
"no-cache, no-store, max-age=0, must-revalidate");
}else if ( requestURI.contains( ".cache." ) ){
     // set expiry to back in the past (makes us a bad candidate for caching)
     final Calendar calendar = Calendar.getInstance();
     calendar.setTime( new Date() );
     calendar.add( Calendar.YEAR, 1 );
     httpResponse.setDateHeader( "Expires", calendar.getTime().getTime() );
     httpResponse.setHeader( "Cache-control", "max-age=" + YEAR_IN_MINUTES + ", public" );
     httpResponse.setHeader( "Pragma", "" );
   } else if (isStaticContentUri(requestURI)) {
StringBuilder cacheControl = new StringBuilder(this.cacheability.getValue()).append(", max-age=").append(this.seconds);
if (!this.isStatic) {
  cacheControl.append(", must-revalidate");
}
httpResponse.setHeader(HTTPCacheHeader.CACHE_CONTROL.getName(), cacheControl.toString());
httpResponse.setDateHeader(HTTPCacheHeader.EXPIRES.getName(), System.currentTimeMillis() + this.seconds * 1000L);
   if (httpResponse.containsHeader("Pragma")) {
     LOGGER.debug("found pragma header");
     httpResponse.setHeader(HTTPCacheHeader.PRAGMA.getName(), "");
   } else {
     LOGGER.debug("did not find pragma header");
   }
}
filterChain.doFilter(request, response);
}
private boolean isStaticContentUri(String uri) {
uri = uri.toLowerCase();
for (String contentType : STATIC_CONTENTS) {
if (uri.endsWith(contentType.toLowerCase()))
return true;
}
return false;
}
}

I have a query related to localstorage, like it's cache or cookie..It is part of cookie. 

Storage.getLocalStorageIfSupported() is part of cookie not cache. when I have clear cookie than it is clear.