First, what I want to achieve:
Let's say I'm doing some stuff in onClick() method of a AjaxLink. I want to give user some feedback with mid-status and continue on doing, and give another feedback.
To do this I thought of adding some component, or behaviour that would send ajax request immediately after being rendered onto page so that I could continue in onEvent() of this behaviour. How can I achieve something like this?
The solution you noted can likely lead to a solution, but a common approach for giving continuing updates is to use an AjaxSelfUpdatingTimerBehavior, as in this simple clock example.
I have found out myself. It is enough to add such implementation of AbstractDefaultAjaxBehavior:
new AbstractDefaultAjaxBehavior() {
#Override
protected void respond(AjaxRequestTarget target) {
}
#Override
public void renderHead(IHeaderResponse response) {
super.renderHead(response);
response.renderOnLoadJavascript(getCallbackScript().toString());
}
}
respond(AjaxRequestTarget target) will be invoked when component it was added to is rendered.
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.
I need to run some c# code each time any page based on _layout.cshtml is viewed. I don't want to put something in every controller.cs file, just something central like you used to have in ASP.NET's MasterPage.cs
Can't get this
Run a method in each request in MVC, C#?
or this
#Html.Action in Asp.Net Core
to run, not sure if it's because they're not CORE 2.0.0, I just get a lot of compilation errors. All I want to do is be able to run some code like this
public class myClass {
public static bool returnTrue() {
return true;
}
}
every time each page is loaded.
You can accomplish this with an action filter
public class GlobalFilter : IActionFilter{
public void OnActionExecuting(ActionExecutingContext context) {
//code here runs before the action method executes
}
public void OnActionExecuted(ActionExecutedContext context) {
//code here runs after the action method executes
}
}
Then in the Startup.cs file in the ConfigureServices method you wire up the ActionFilter like so:
services.AddScoped<GlobalFilter>(); //add it to IoC container.
services.AddMvc().AddMvcOptions(options => {
options.Filters.AddService(typeof(GlobalFilter)); //Tell MVC about it
});
Then you can place code in this ActionFilter which can run before every action method and you can place code in it to run after every action method. See code comments.
Through the context parameter you have access to the Controller, Controller Name, Action Descriptor, Action Name, Request object (Including the path) and so on, so there is lots of info available for you to determine which page you want to execute the code for. I'm not aware of a specific property that will tell you if the page is using _layout.cshtml but you could probably deduce that based on the other properties I mentioned.
Enjoy.
Filter would also work, but the correct way to go in .Net Core is Middleware. You can read more about it here.
If it's something simple as your example, you can go with the first examples on the link like:
app.Use(async (context, next) =>
{
returnTrue();
await next.Invoke();
});
Let me know if it helped!
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)
We are trying to handle a scenario that when a user in quitting a room ,we send a message using MetaBroadcaster to all room .We implemented this feature by override broadcast method of AtmosphereGwtHandler .
The feature is good when we testing in development mode, but when we test it in Jetty8 production mode, telling by log, the override method is void which never get called.
So anybody know what's wrong with it, or do we have a better solution to this feature.
here is our code snippet:
public class ChatHandler extends AtmosphereGwtHandler {
...
#Override
public void broadcast(Object message, GwtAtmosphereResource resource) {
MsgType msgtype=((ChatMessage)message).getMsgtype();
if(msgtype==MsgType.Broad){
MetaBroadcaster.getDefault().broadcastTo(((ChatMessage)message).getChanel(), message);
System.out.println("Doing to all room);
}else{
super.broadcast(message, resource);
System.out.println("Doing to myself);
}
}
}
Can't really give an answer on the info provided.
Where have you configured your handler?
web.xml or atmosphere.xml
What servlet are you using Meteor/Atmosphere?
What version of Atmosphere?
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...