I want to know what is exactly the behaviour of wlCommonInit() function.
I have moved my initialization code into this function, but then it seems to be not called in the case of connection to the server failure.
is wlCommonInit() called when the Worklight server is not reachable ?
If I want to use direct update, I want to call WL.Client.updateUserInfo() on my initialization, and I want the app to be working also in offline mode, does this mean I must implement onConnectionFailure in wlInitOptions ?
If I implement onConnectionFailure in wlInitOptions, can I display the default popup that inform about the connection failure, and provide details ?
It really depends on the logic you wrote in your "initialization code" IMO. The question is somewhat cryptic...
The wlCommonInit function is called once the Worklight framework has completed initialization. If you set connectOnStartup to true, only if connection to the server is successful, it will then be called.
Direct Update is not related to any specific API you implement in your application. If you change any web resource in your project (HTML, CSS, JavaScript, images, ...), this will trigger a Direct Update in the application.
A Direct Update is checked in 2 scenarios:
on application launch, and
on return to the foreground (if the app was in the background)
The Direct Update check is performed only if and when the application connects to the Worklight Server. If you did not previously set your application by either using connectOnStartup:true or used WL.Client.connect or invoked an adapter procedure (all three send a request to the server), the Direct Update check will not be done.
If you choose to override the default dialog provided by Worklight by using onConnectionFailure, the Details button (which I assume if what you wanted) - is not available. By overriding, you select to fully customize it.
Related
when I use the cloudify(2.7) to deploy an application(e.g. an application app includes two services A and B ),I try to use the Admin.addEventListener() to add some eventListener,but it does't work !
I try to add the ProcessingUnitStatusChangedEventListener ,when I debug the code,the value of (ProcessingUnitStatusChangedEvent)event.getNewStatus() changes from SCHEDULED to INTACT,then SCHEDULED,then INTACT again,
I also try to add the ProcessingUnitInstanceLifecycleEventListener,when I debug the code,the status is intact,but the service is not available!
Is there any other listener or method to know the application(not the services) is available,or I use the listener in the wrong way?
First, the Admin API is internal - use it at your own risk. And you should not be using it the way you are - Cloudify adds a lot of logic on top of the internal Admin API.
Second, it is not exactly clear where you are executing your code from.
You can always use the rest client to get an accurate state of the application. Look at https://github.com/CloudifySource/cloudify/blob/master/rest-client/src/main/java/org/cloudifysource/restclient/RestClient.java#L388
In addition, if you are running this code in a service lifecycle event handler, the easiest way to implement this is to have your 'top' level service, the one that should be available last, write an application entry to the shared attributes store in its 'postStart' event. Everyone else can just periodically poll on this entry. The polling itself is very fast, all in-memory operations.
If you do not have a top-level service, or your logic is more complicated then that, you would need to use the Service Context API to scan each service and its instances to see if they are up. An explanation on getting service instance state is available here:
cloudify service dependsOn other service
Overview:
I am trying to create a PoC application that mimics WebIntents-like feature.
So, in my Qt application, I create two QWebviews launching two different webApps. Now let's call them apps A and B.
Scenario:
Main Application creates two QWebViews each launching an App i.e. AppA, AppB.
App A is programmed to fetch some data via AJAX, automatically.
App B also needs part of that data. AppB simply displays a button (HTML) called .
Note: Since, AppA already has that info, I would like the AppB to invoke a JavaScript API which was injected into it's(appB) DOM by means of addToJavaScriptWindowObject() method call when the QWebView was launched.
App-A completed the Ajax Call and indicates the completion in its WebView.
User clicks the button in AppB,
App B invokes that JavaScript API i.e. fetcData({source: "AppA");
Now the control is in the QT-world:
Question: the Control is in the context of AppB, How should I communicate with the WebView in AppA -- i.e. AppB asks AppA: hey AppA, please give me that data that you have fetched?
Can Signals and Slots help me here? Or should I use some other form of IPC.
I read this page: http://qt-project.org/doc/qt-4.8/qtwebkit-bridge.html, but I still didn't get a hint for a solution for my problem.
Another related question: Are QWebViews created in their own threads ?
Can't you just emit some sort of signal from AppB that basically says, "Hey, I finished fetching my data if anyone wants it" or am I missing something? It would happen at the end of AppB::fetchData().
All you have to do after that is connect any interested objects to that signal.
For manually testing an HTTP client in my application, I'd like to use a tool which starts an HTTP server my application can connect to and that lets me respond to request from my application manually. I'm basically looking for a tool with a GUI that lists all incoming requests and allows me to select a status code and type a response message. I've already tested the functionality with unit tests but I also want to verify it manually with no mocking etc.
Sounds simple but I didn't find such a tool. I've found some that can be scripted but no interactive one. Do you know one?
This can probably be written relatively easily by creating the Swing GUI dialog popup inside the servlet servicing methods. Have never seen Tomcat running this way but probably it would. Only, mind the server time out. It may be not long enough for you to make an input and require to be configured, also on the client side. Also, parallel calls will make multiple popups that may be difficult to respond but probably this is a single client app.
As a simplest solution, server GUI can be simply disposed after call and newly created as the next call arrives. This will make eveything indepenent on how servlet container is managing the servlets (does it stays, is it destroyed, maybe class is unloaded, who knows). Advanced solution could include the "server servlet" that would interact through its own JSP page but then it may be complex to update it when the new call arrives (unless maybe refresh periodically).
How do you capture errors that happen on client side when building RIA apps using Flex and Silverlight? What are the common practices? I have seen some asynch js calls to a web service implemented but would like to know how the community is dealing with it.
First, I use client side logging all of the times.
the way I handle it depends on the entire application.
if I use an AMF gateway then there's a call for an application error, with every error that occurs the server is notified, in the server side a bug is open in BugZilla (this is what we use, you can use any other hook you want).
If I use a web-service based application then there's a web-service call for a client error.
one would say you shouldn't sample the server with every error, I disagree with this comment because an error in the client side is rare, it goes thorough QA before being released to the client so I want to know immediately on every error the client is experiencing.
In Silverlight I like to use a WebClient to log back to a web service somewhere -- you can do this directly in the Silverlight application without calling out to JavaScript.
To catch exceptions that are fired when your code isn't on the stack, you can use the Application.UnhandledException event.
I've used the same approach as Avi Tzurel - you need to know on the server side when an error appeared in the Flex client. If you want to collect more data (all the log messages, warnings) I would use an internal buffer and I will flush it asynchronously.
Anyway, you need to take into consideration if your customers are ok with this approach..maybe you need their agreement before sending the error message to the server.
I basically percolate all errors to the top, and capture them in the unhandled exception. I display a friendly message to the user. However, throughout my application I implement an ILogger interface. This interface can be initialized with various levels and handles any messaging. You can set it up so the user can add an init param to determine whether or not to transmit the errors to a service, and I typically have the logger write the messages with Debug.WriteLine if the debugger is attached to make it very easy to trace issues in debug mode.
In Silverlight you may want to consider the Logging and Exception Handling Application Blocks from the Silverlight Integration Pack for Enterprise Library.
Other than using a web service, is there anyway to call a method in a web app from a windows application? Both run on the same machine.
I basically want to schedule a job to run a windows app which updates some file (for a bayesian spam filter), then I want to notify the web app to reload that file.
I know this can be done in other ways but I'm curious to know whether it's possible anyway.
You can make your windows app connect to the web app and do a GET in a page that responds by reloading your file, I don't think it is strictly necessary to use a web service. This way you can also make it happen from a web browser.
A Web Service is the "right" way if you want them to communicate directly. However, I've found it easier in some situations to coordinate via database records. For example, my web app has bulk email capability. To make it work, the web app just leaves a database record behind specifying the email to be sent. The WinApp scans periodically for these records and, when it finds one with an "unprocessed" status, it takes the appropriate action. This works like a charm for me in a very high volume environment.
You cannot quite do this in the other direction only because web apps don't generally sit around in a timing loop (there are ways around this but they aren't worth the effort). Thus, you'll require some type of initiating action to let the web app know when to reload the file. To do this, you could use the following code to do a GET on a page:
WebRequest wrContent = WebRequest.Create("http://www.yourUrl.com/yourpage.aspx");
Stream objStream = wrContent.GetResponse().GetResponseStream();
// I don't think you'll need the stream Reader but I include it for completeness
StreamReader objStreamReader = new StreamReader(objStream);
You'll then reload the file in the PageLoad method whenever this page is opened.
How is the web application loading the file? If you were using a dependency on the Cache object, then simply updating the file will invalidate the Cache entry, causing your code to reload that entry when it is found to be null (or based on the "invalidated" event).
Otherwise, I don't know how you would notify the application to update the file.
An ASP.NET application only exists as an instance to serve a request. This is why web services are an easy way to handle this - the application has been instantiated to serve the service request. If you could be sure the instance existed and got a handle to it, you could use remoting. But without having a concrete handle to an instance of the application, you can't invoke the method directly.
There's plenty of other ways to communicate. You could use a database or some other kind of list which both applications poll and update periodically. There are plenty of asynchronous MQ solutions out there.
So you'll create a page in your webapp specifically for this purpose. Use a Get request and pass in a url parameter. Then in the page_load event check for this paremter. if it exists then do your processing. By passing in the parameter you'll prevent accidental page loads that will cause the file to be uploaded and processed when you don't want it to be.
From the windows app make the url Get request by using the .Net HttpWebRequest. Example here: http://www.codeproject.com/KB/webservices/HttpWebRequest_Response.aspx