I'm developing a spring ratpack project, but I want to know if there is any way to bind data between handlers. I tried with registries but I can't find the way that the object only have a value in one execution. I tried to use ratpack session, but i don't want to generate a session cookie to persist that object onto my handlers. What should i do? I'm lost right now.
This is my code configuration and the way how I persist the objects:
<!-- language: java -->
//persisting with the SessionModule
ctx.get(Session.class).getData().then(d -> {
d.set("email", email);
ctx.next();
});
//Persisting with the registries
ObjectRegistryComponent objectRegistryComponent = ctx.get(ObjectRegistryComponent.class);
objectRegistryComponent.setObject(email);
ctx.next(Registry.single(objectRegistryComponent));
I found something about the requests in ratpack, you can add registries to the requests, that solve my problem as well.
Request request = ctx.getRequest();
request.add(email);
//--- into your other handlers
String email = ctx.getRequest().get(String.class);
Related
We are using MediatR to implement a "Pipeline" for our dotnet core WebAPI backend, trying to follow the CQRS principle.
I can't decide if I should try to implement a IPipelineBehavior chain, or if it is better to construct a new Request and call MediatR.Send from within my Handler method (for the request).
The scenario is essentially this:
User requests an action to be executed, i.e. Delete something
We have to check if that something is being used by someone else
We have to mark that something as deleted in the database
We have to actually delete the files from the file system.
Option 1 is what we have now: A DeleteRequest which is handled by one class, wherein the Handler checks if it is being used, marks it as deleted, and then sends a new TaskStartRequest with the parameters to Delete.
Option 2 is what I'm considering: A DeleteRequest which implements the marker interfaces IRequireCheck, IStartTask, with a pipeline which runs:
IPipelineBehavior<IRequireCheck> first to check if the something is being used,
IPipelineBehavior<DeleteRequest> to mark the something as deleted in database and
IPipelineBehavior<IStartTask> to start the Task.
I haven't fully figured out what Option 2 would look like, but this is the general idea.
I guess I'm mainly wondering if it is code smell to call MediatR.Send(TRequest2) within a Handler for a TRequest1.
If those are the options you're set on going with - I say Option 2. Sending requests from inside existing Mediatr handlers can be seen as a code smell. You're hiding side effects and breaking the Single Responsibility Principle. You're also coupling your requests together and you should try to avoid situations where you can't send one type of request before another.
However, I think there might be an alternative. If a delete request can't happen without the validation and marking beforehand you may be able to leverage a preprocessor (example here) for your TaskStartRequest. That way you can have a single request that does everything you need. This even mirrors your pipeline example by simply leveraging the existing Mediatr patterns.
Is there any need to break the tasks into multiple Handlers? Maybe I am missing the point in mediatr. Wouldn't this suffice?
public async Task<Result<IFailure,ISuccess>> Handle(DeleteRequest request)
{
var thing = await this.repo.GetById(request.Id);
if (thing.IsBeignUsed())
{
return Failure.BeignUsed();
}
var deleted = await this.repo.Delete(request.Id);
return deleted ? new Success(request.Id) : Failure.DbError();
}
How can I create object like TempData in nodejs? I thought maybe I can set flag 'IsTempData' to session and at the end of an application I would clear sessions which have this flag selected. But there is a problem: I have many asynchronous functions where I use tempdata, so application may end before I use tempdata. I hope you understand what I mean by ending application:
connect()
.use(connect.bodyParser())
.use(connect.query())
.use(connect.favicon())
.use(connect.cookieParser())
.use(connect.session({ secret: 'your secret here' }))
.use(function (req, res) {
somefunction();
// end of application, here I will clear sessions which have tempdata flag selected
}).listen(1234);
I came across your post looking for the same behavior. Since I couldn't find anything, I decided to implement something of my own, which will hopefully help you as well: NodeJS TempData Provider
Keep in mind, this was put together rather quickly, so if you have any issues, I'd appreciate your feedback.
I am using RemoteObjects to call ZendAMF PHP from Flex/Flash Builder 4.6. I want to stop or abort a method call before it sends the request to the server based on an event or similar.
I have a class where I create and store all the RemoteObjects - for example:
activityLogService = new RemoteObject("zend");
activityLogService.endpoint=endpointServer;
activityLogService.addEventListener(FaultEvent.FAULT,faultHandler);
Then later I can simply call this object:
remotingService.activityLogService .getRecords();
I am trying to find a way in my remotingService object to stop the request - and not send anything to the server - for example if some variables are not set properly.
I noticed there is an invoke event:
activityLogService.addEventListener(InvokeEvent.INVOKE,invokeHandler);
However, I can not tell if that's going to stop things at the proper point, or if it's even possible to actually STOP the request - if so, how?
Thanks!
Check out this question
Flex : Is it possible to stop a remote call?
If you're using a RemoteObject you should be able to call
getOperation() method and then cancel() on the corresponding
operation.
I'm using mx.rpc.http.HTTPService to retrieve data from a web service. On the initial call to "loadWsData", HTTPservice accurately retrieves all the data.
However, on any and all subsequent calls HTTPService does not accurately retrieve the data; rather it always retrieves the first data set. I've confirmed that the web service is providing accurate data, both from web browsers and a ruby ws client script.
My code is below; any ideas on what could be the problem?
private function loadWsData(id:int):void
{
var webService:HTTPService = new HTTPService();
webService.url = "http://xxx.xxx.xxx.xxx:8080/profile/ + id;
webService.method = "GET";
webService.addEventListener(ResultEvent.RESULT, function(event:ResultEvent):void
{
var rawData:String = String(event.result);
var user:Object = JSON.decode(rawData).user; // User object always reflects the first data set retrieved.
....
....
});
webService.send();
}
Not sure what the issue might be, but I have a few suggestions on where to look.
First, there appears to be a bug in your code; the webService.url line is missing a quote mark. That could be messing up the URL you think you are sending. Odd, though, because I don't think what you have shown would compile, so I suspect this is just a cut-and-paste error when you posted this to StackOverflow, but I would trace out that URL just to be sure.
Also, I don't see code to remove the event listener (although it could be in the code you have abbreviated with ellipsis). Is it possible that there are lingering event listeners that are firing in addition to the ones you expect? If the original event listener fires, it will fire with the original data.
Another suggestion: instead of using a closure, try pulling it out to a separate function. That shouldn't be the issue, but maybe scope is playing a role here.
You could try to POST your results.
You might also add an event listener for FAULT, and see if there are any errors being thrown by your service request.
I've been struggling with this problem for last few hours but still got no idea what's wrong. Here's the scenario:
Application built on top of the Mate framework sometimes need to exchange data with remote server over plain binary socket.
When specific packet is received I have to switch view (using ViewStack) and create custom panel (using PopUpManager class). This custom panel contains a dataGrid component which has to be populated with some XML received along with mentioned packet.
Trouble is that when I try to assign XML to DataGrid's dataProvider I constantly get "Cannot access a property or method of a null object reference" error. The only thing I can think of is some kind of race when processing events and creating components.
Here are the most interesting pieces of code:
<!-- LoginEvent.LOGIN_OK _____________________________________________________________________ -->
<EventHandlers type="{LoginEvent.LOGIN_OK}">
<MethodInvoker generator="{UserManager}" method="storeCurrentUser" arguments="{event.fullName}"/>
<EventAnnouncer generator="{NavigationEvent}" type="{NavigationEvent.MAIN}"/>
<MethodInvoker generator="{CustomSocket}" method="listBoards"/>
In the above code I react when the LOGIN_OK packet is received.
Store user's data, change the view and ask the Socket class wrapper to send request (the reponse for that request is our verySpecificPacket)
Here's detailed info about how I change the view and create custom pop up. In MainUI.mxml:
<mate:Listener type="{NavigationEvent.MAIN}" method="handleNavigationEvent" />
private function launchBoardListWindow():void {
Logger.info("launchBoardListWindow()");
var win:BoardList = PopUpManager.createPopUp(this, BoardList, true) as BoardList;
PopUpManager.centerPopUp(win);
}
private function handleNavigationEvent(event:NavigationEvent):void {
viewStack.selectedIndex = MAIN;
launchBoardListWindow();
}
The third position in EventMap isn't important, it just ask socket wrapper to send some kind of packet. The server is supposed to respond with verySpecialPacket along with XML payload. And here we are at the part where the error is. In mxml describing my custom panel I set up a listener for an event which is being dispatched after my verySpecialPacket is received.
public function handleListBoardsEvent(e:ListBoardsEvent):void {
Logger.info("handleListBoardsEvent");
xmlData = e.xml;
boardList.dataProvider = xmlData.children(); // Here's the error!!!
}
I really don't get it, since the xmlData is OK, and custom panel with all child components were created. Thanks for reading!
You're likely on the right track in respect of a race condition.
Suggestion:
Put a try { ... } catch (e:Error) { trace("error"); } block around the code in your handleListBoardsEvent() method.
Then, put a breakpoint on the trace() and, when it hits, take a good look around at the various objects involved.
My guess is that you're attempting to access the boardList object before it is created - i.e. it's null.
The other possibility is that boardList.dataProvider is a setter and there's code in the setter that's barfing. (Although, if that were the case, I'm sure you would have noticed the stacktrace inFlexBuilder)