I am facing this Problem Since last day .Here it is and need help of you .
I am working on a web application, and Sending and retrieving data from Server through an RPC .
My problem is that If I clicked on any action , i am sending an request and if I Clicked on any other links which are navigate the page to other view, without retrieving data of first RPC i am getting the Exception because of that navigation .
I need to avoid it by knowing the navigation .
here i written the code .Lets check once :
#Override
public void onFailure(Throwable exception) {
if (exception instanceof StatusCodeException) {
if (((StatusCodeException) exception).getStatusCode() == 403) {
MyExcclass.showMessage("session expired");
logout();
} else {
MyExcclass.showInformation("unable to perform the action");
}
}
exception.printStackTrace();
}
I am getting the unable to perform action .
If the page is unloaded when the RPC response comes back, you should see a StatusCodeException with getStatusCode() of 0.
If you want, you can preemptively cancel the requests within a Window.addCloseHandler. This means you'd have to provide your own RpcRequestBuilder for each remote service to keep the Request instances around (in a Set) until they're completed (you'd wrap the RequestCallback to remove the associated Request from the Set in onSuccess or onFailure); and in your CloseHandler you'd iterate on the Set to cancel() all pending Request. Overall, it's easier to handle the getStatusCode() == 0 case in your AsyncCallback.onFailure methods.
Related
I am trying to implement session timeout with help of a GWT Timer which will make a RPC call to server to check whether the session is valid or expired by using lastaccessedtime. but every time i make a RPC call it updates the lastaccessedtime (understandable as i am making a RPC call), any way i can prevent my Timer RPC call from updating the lastaccessedtime?
wrote some server side logic to get the lastaccessedtime and try to find out session is valid or not
com.google.gwt.user.client.Timer elapsedTimer;
public void onModuleLoad() {
elapsedTimer = new Timer () {
public void run() {
validateSession();
}};
//giving time delay of 1sec to call the batches
elapsedTimer.scheduleRepeating(60000);
}
public void validateSession(){
//Problem code every time i make this call it updates the last accessed time
viewService.validateSessionGWT(new AsyncCallback<ModuleData>() {
#Override
public void onFailure(Throwable e) {
//do something
}
#Override
public void onSuccess(ModuleData data) {
if(data.getSessionExpired()){
//redirect to login page
}
}
});
}
any idea how to overcome this problem or any other idea to implement Session management in GWT
NOTE: already gone through this which is similar to my approach
https://itsecrets.wordpress.com/2011/07/20/session-timeouts-with-gwt-rpc-calls/
Your GWT servlets extend the RemoteServiceServlet. So you can override processPost and add a custom last call timestamp in you http session. Every request updates this field.
I suggest to implement an abstract servlet that is extended by all your gwt servlets. Additionally you should not only set the custom last access field, but check it just before and only call the super method if everything is fine.
Then your timer and the servlet request you already have should only check this Session field.
Perhaps not the best solution but this should work.
As the title suggests I'm trying to get a list of files from an FTP directory to send as a response of a GET request.
I have current rest route implementation:
rest().get("/files")
.produces(MediaType.APPLICATION_JSON_VALUE)
.route()
.routeId("restRouteId")
.to("direct:getAllFiles");
On the other side of the direct route I have the following routes:
from("direct:getAllFiles")
.routeId("filesDirectId")
.to("controlbus:route" +
"?action=start" +
"&routeId=ftpRoute");
from([ftpurl])
.noAutoStartup()
.routeId("ftpRoute")
.aggregate(constant(true), new FileAggregationStrategy())
.completionFromBatchConsumer()
.process(filesProcessor)
.to("controlbus:route" +
"?action=stop" +
"&routeId=" + BESTANDEN_ROUTE_ID);
The issue at hand is that with this method the request does not wait for the complete process to finish, it almost instantly returns an empty response with StatusCode 200.
I've tried multiple solutions but they all fail in either of two ways: either the request gets a response even though the route hasn't finished yet OR the route gets stuck waiting for inflight exchanges at some point and waits for the 5 minute timeout to continue.
Thanks in advance for your advice and/or help!
Note: I'm working in a Spring Boot application (2.0.5) and Apache Camel (2.22.1).
I think the problem here is that your two routes are not connected. You are using the control bus to start the second route but it doesn't return the value back to the first route - it just completes, as you've noted.
What I think you need (I've not tested it) is something like:
from("direct:getAllFiles")
.routeId("filesDirectId")
.pollEnrich( [ftpurl], new FileAggregationStrategy() )
.process( filesProcessor );
as this will synchronously consume your ftp consumer, and do the post processing and return the values to your rest route.
With the help of #Screwtape's answer i managed to get it working for my specific issue. A few adjustments were needed, here is a list of what you need:
Add the option "sendEmptyMessageWhenIdle=true" to the ftp url
In the AggregationStrategy add an if (exchange == null) clause
In the clause set a property "finished" to true
Wrap the pollEnrich with a loopDoWhile that checks the finished property
In its entirety it looks something like:
from("direct:ftp")
.routeId("ftpRoute")
.loopDoWhile(!finished)
.pollEnrich("ftpurl...&sendEmptyMessageWhenIdle=true", new FileAggregationStrategy())
.choice()
.when(finished)
.process(filesProcessor)
.end()
.end();
In the AggregationStrategy the aggregate method looks something like:
#Override
public Exchange aggregate(Exchange currentExchange, Exchange newExchange) {
if (currentExchange == null)
return init(newExchange);
else {
if (newExchange == null) {
currentExchange.setProperty("finished", true);
return currentExchange;
}
return update(currentExchange, newExchange);
}
}
What is best way to attempt multiple time same RPC call while failing RPC call?
just example: Here one case like if RPC get failed due to network connection, it will catch in onFailure(Throwable caught).
Now here it should recall same RPC again for check network connection. The maximum attempt should be 3 times only then show message to user like "Network is not established"
How can I achieve it?
Some couple of thoughts like call same rpc call in onFailure but here request become different.but I want same request have a three request and it is not good approach and I don't know if any good solution for it.
Thanks In Advance.
Use a counter in your AsynCallBack implementation. I recommend as well to use a timer before requesting the server again.
This code should work:
final GreetingServiceAsync greetingService = GWT.create(GreetingService.class);
final String textToServer = "foo";
greetingService.greetServer(textToServer, new AsyncCallback<String>() {
int tries = 0;
public void onSuccess(String result) {
// Do something
}
public void onFailure(Throwable caught) {
if (tries ++ < 3) {
// Optional Enclose the new call in a timer to wait sometime before requesting the server again
new Timer() {
public void run() {
greetingService.greetServer(textToServer, this);
}
}.schedule(4000);
}
}
});
#Jens given this answer from Google Groups.
You could transparently handle this for all your requests of a given GWT-RPC interface by using a custom RpcRequestBuilder. This custom RpcRequestBuilder would make 3 request attempts and if all 3 fail, calls the onFailure() method.
MyRemoteServiceAsync service = GWT.create(MyRemoteService.class);
((ServiceDefTarget) service).setRpcRequestBuilder(new RetryThreeTimesRequestBuilder());
The custom RequestBuilder could also fire a "NetworkFailureEvent" on the eventBus if multiple application components may be interested in that information. For example you could overlay the whole app with a dark screen and periodically try sending Ping requests to your server until network comes back online. There is also the onLine HTML 5 property you can check, but its not 100% reliable (https://developer.mozilla.org/en-US/docs/Web/API/window.navigator.onLine)
I have a project that does 2 RPC calls and then saves the data that the user provided in tha datastore. The first RPC call works ok, but from the second I always recieve the onFailure() message. How can I determine why the onFailure() is triggered? I tried caught.getCause() but it doesn't return anything.
feedbackService.saveFeedback(email,studentName,usedTemplates,
new AsyncCallback<String>() {
public void onFailure(Throwable caught) {
// Show the RPC error message to the user
caught.getCause();
Window.alert("Failure!");
}
public void onSuccess(String result) {
Window.alert("Saved!");
}
});
Throwable instance is instance of an Exception. You can check if it is a custom Exception like this:
if (caught instanceOf CustomException){
or if you want to show the message of exception you can use the getMessage():
Window.alert("Failure: " + caught.getMessage());
GWT-rpc is not not easy to ebug if an error occurs.
The easiest part is th check if the Exception is part of StatusCodeException.
A Statuscode of 404 means, you are pointing to a wrong endpoint
0 means, that
The searver is unreachable
You don't have permissions to check, if the server is available (X-domain-request)
You can use the Chrome-Web-Inspector to bedug GWT-RPC
You should be able to see all calls from the browser to you backend.
The most common failures are because of serialization of object. You have to ensure, that all dtransferred object implement java.io.Serializable
Most of the time it will just be a server side exception being raised which fires the onFailure() method.
Try putting breakpoints on your server side. That should help you pinpoint what's going wrong.
I have a GWT application and I want to run some code when the user leaves the application to force a logout and remove any data etc.
To do this I am using a CloseHandler and registering it using Window.addCloseHandler.
I have noticed that when the refresh button is clicked the onClose method is run but I have been unable to differentiate this event from a close where the user has closed the browser. If it is a refresh I do not want to do the logout etc, I only want to do this when the user closes the browser/tab or navigates away from the site.
Does anybody know how I can do this?
There is no way to differentiate the 'close' from 'refresh'. But, you can set a cookie that holds the last CloseHandler call time and check, when loading the module, if this time is old enough to clean the information before showing the page.
You can do that with the folowing utility class (BrowserCloseDetector). Here is an example using it on the onModuleLoad.
The test lines:
#Override
public void onModuleLoad() {
if (BrowserCloseDetector.get().wasClosed()) {
GWT.log("Browser was closed.");
}
else {
GWT.log("Refreshing or returning from another page.");
}
}
The utility class:
import com.google.gwt.user.client.Cookies;
import com.google.gwt.user.client.Window;
public class BrowserCloseDetector {
private static final String COOKIE = "detector";
private static BrowserCloseDetector instance;
private BrowserCloseDetector() {
Window.addWindowClosingHandler(new Window.ClosingHandler() {
public void onWindowClosing(Window.ClosingEvent closingEvent) {
Cookies.setCookie(COOKIE, "");
}
});
}
public static BrowserCloseDetector get() {
return (instance == null) ? instance = new BrowserCloseDetector() : instance;
}
public boolean wasClosed() {
return Cookies.getCookie(COOKIE) == null;
}
}
Have you tried
<BODY onUnload = "scriptname">
in your gwt hosting/launching html file?
I am thinking that if you defined a map "hash" (i.e. a javascript pseudo hash) in the hosting file and then accessed the "hash" in GWT through Dictionary class, you could update values in that hash as the user progresses through the gwt app. Which means, your programming style would require you to log milestones on the user's progress onto this map.
When the user closes the browser page, the onunload script of the launching html page would be triggered. That script would access the map to figure out what needs to be updated to the server, or what other url to launch.
I am intereted too if someone got a solution (GWT/java side only).
Maybe we can do it with HistoryListerner ?
1-set a flag for your current viewing page.
2-when ClosingHandler event, launch a "timeout" on server-side (for example 10s)
3-if during this time your got a massage from HistoryListerner with the same last flag so it was just a refresh.
of disconnect if timer is over...
Is not a good solution but I think it is easy to do... If someone have a better one...