From a form "A" I want to open a specific form "B" when I click on a Many2One field.
I placed into the context of this field the usual
'form_view_ref': 'model.form_id'
but this works only when "A" is in edit mode. If it is in view mode it opens instead the "C" form. I noticed that JSON request just "lose" the context i set and send the standard empty one (with just timezone/uid etc.)
I never realized this before. Is it some kind of bug?
#Alessandro Ruffolo,
context is variable between server client, and context has common attributes like uid, active_d, active_ids, active_model, User timezone, user lang. When calling an ORM method, you will probably already have a context - for example the framework will provide you with one as a parameter of almost every method.
If you do have a context, it is very important that you always pass it through to every single method you call. But when you don't pass context somewhere on any method in python or js client side server will generate new context, and their are so many place with old in core code that context is broken by not passing.
When you don't pass context, it breaks context and prepare new context.
With New v8 API context is more consistent as that’s not required.
Bests
Related
I want to perform an action based to the result of an asynchronous NGXS action.
In a Angular frontend app I'm using NGXS for state management. Some of the actions involve talking to a backend via REST calls. Those actions are implemented as asynchronous actions, with the reducer functions in my state classes returning an Observable.
What I'm looking for is a way to get hands on the result of the backend call, to be able to perform some action.
One use case I'm trying to implement is navigation to just created objects: Business objects are created in the frontend (Angular) app with a couple of domain properties. They get persisted in the backend, and as a result an ID for this object is created and returned to the frontend, and incorporated into the NGXS store. As a direct response to this, I'd like to navigate to a detail view for the new object. To do so, I need
(a) the information that the call has been returned successful, and
(b) the answer from the backend (the ID in this case).
Another slightly more complicated use case is the assignment of a number of tags to an business object. The tags are entities by themselfes, and have an ID each. In the UI, the user can either pick existing or add new tags. Either way, multiple tags can be added in a single step in the UI, which means I have to
call the backend for each new tag to create the ID
after all missing tags are created, update the business object with the list of tag IDs
In general, there are use cases in the frontend that depend on the result of a backend call, and there is no clean way to find this result in the store (although it's in there)
I know I can subscribe to the Observable returned from the store's dispatch method (as shown in asynchronous actions).
I also know about action handlers. In both cases I can attach code to the event of an action finished, but neither option enables me to get the result of the backend call. In the fist case, the Observable carries the whole store, while in the latter case I get the original Action, which is unfortunately missing the essential information (the ID).
The part you're missing here are selectors. Dispatching actions is not supposed to give you back a result. The only purpose of the Observable returned by store.dispatch() is to tell you when the action's handlers are done.
To get to the data returned by your calls to the backend, you have to patch the state inside your action handler. And then, outside of your state, you can access the data using store.select() or store.selectSnapshot() depending on what you need. Your state class should look somewhat like this (untested):
#State()
export class SampleState {
#Selector(SampleState)
sampleSelector(state) {
return state.sampleObject;
}
#Action(SampleAction)
sampleAction(ctx: StateContext<any>, action: sampleAction) {
return sampleBackendCall(/* ... */).pipe(
tap((result) => {
ctx.patchState({ sampleObject: result });
})
);
}
}
Now you can access this result where ever you need using the Store. For the use case of navigating to an element after its creation, you can combine a subscription to store.dispatch() with a store.selectSnapshot() like this:
store.dispatch(new SampleAction()).subscribe(() => {
navigateTo(store.selectSnapshot(SampleState.sampleSelector));
});
Note that in this easy case a selectSnapshot is perfectly fine, as we only want to get the value we just finished writing into the state. In most cases though, you will want to use store.select() or the #Select() decorator because they return Observables which enable you to also correctly display changes in your state.
That said, I'd like to add that if saving data inside the state is not necessary for you at all, then probably NGXS is the wrong library for you in the first place and you could as well just use an ordinary angular service directly returning the result of the backend call, like suggested in the comments.
I am working on a TYPO3-backend-module. The main "overview"-Action allows to upload a file via ajax upload, which gets processed in one of my controllers.
The corresponding controller-action instantiates a StandaloneView, renders it and writes the rendered content to the response body.
My problem is, that I have no controllerContext set in the generated content, therefore a form, which should trigger a different extbase action, in that rendered content does not work, because the modulename is not set.
Can anybody tell me how I could possibly get/pass the controllerContext, to make it available in the controller action, which is called via ajax ?
Best regards and thanks in advance, Oliver !
The main problem here is that BE modules don't exactly use a standard View implementation - in the default implementation, they wrap around a StandaloneView which by definition has no controller context.
That being said, if you can change the way the View wraps around the StandaloneView, the controller context can be copied by doing:
$view->getRenderingContext()->setControllerContext($parentView->getRenderingContext()->getControllerContext());
Alternatively you may want to copy the entire rendering context rather than just the controller context.
Advise applies to TYPO3v8 only. On 7.6 you will need to copy the Request instead.
For usages outside of MVC context you will need to manually pass the original controller context values such as controller name and module name. That means the values must be part of the link you create and must be read by the receiving code (in whichever way that code's context requires) and then manually assigned to a Request you create and pass to the sub-view. Note that this is only necessary if those MVC context values actually change - if you always call the same action next, you can get the right result by simply hardcoding the desired extension name, module name, controller name and action in the form/link in the template you render from that AJAX controller.
Spring MVC 4.1
Hi,
I have a situation where, on a single page, there are several input fields. As the users enters numbers into these fields, a bunch of calculations will occur and update various other fields on the page.
I want this whole calculation model to take place in Java on the server-side. I really want to avoid replicating this logic in Javascript on the client.
What I envision is...
User opens the page, the object that does the calculations (let's call it Calculator) is created and its initial state is set (many of its fields are pre-populated with values).
This Calculator instance is stored and available for the duration of the user's time on that page.
Whenever the user changes a value in an input field, that new value is sent to the server via ajax and plugged into our Calculator object. The Calculator, re-calculates the other fields based on the new state and returns the results to the page.
The other fields on the page are updated accordingly.
The key here is that I'm not sending the state of all fields with each ajax request. I'm only sending the current value that was updated. Essentially, I'm trying to ensure that the form state and the Calculator state on the back-end are always synchronized.
I have looked into #SessionAttributes and #ModelAttribute.
The problem with #ModelAttribute, as I understand it, is that it will be re-created with each ajax request.
The problem with #SessionAttributes is that it is a session variable. What if the user has two of these windows open? And how do I ensure the object is removed from the session when they leave the page? etc...
Maybe there's no magic Spring bullet and I just have to figure out the session variable thing. But any pointers on dealing with this would be much appreciated.
Thanks!
You have a couple of options:
.1. Like you have said using the #SessionAttributes, however yes it suffers from the issue that you have mentioned, multiple instances of the same session will see the same variable.
.2. Store state somewhere else and re-hydrate the state using #ModelAttribute annotated method. I would personally prefer this approach, essentially when you create the form, create it with a identifier for the current state:
#RequestMapping(params = "form")
public String createForm(Model uiModel) {
uiModel.addAttribute("calculationId", UUID.randomUUID().toString());
return "calculationpage/create";
}
Then for subsequent ajax requests, ensure your previous calculationId is sent across:
#ModelAttribute("calculationState")
public CalculationState rehydrateState(String calculationId) {
//retrieve current state of calculation from some persistent store..
}
#RequestMapping("/calculate")
public String handleCalculation(#ModelAttribute("calculationState") CalculationState c) {
//you will get a calculationstate with the delta's at this point..
}
.3. Another potential approach may be to use session but disambiguate different instances within the session with a custom id:
public String handleCalculation(HttpSession session, #RequestParam("calcId") String calcId) {
CalculationState calcState = (CalculationState) session.getAttribute("calculation" + calcId);
}
You need any sort of persistent store outside session to store and retrieve the state of your calculator model. Like Biju said, I will go for solutions like No 2.
The specific case I've got in mind is as follows: an AjaxFormComponentUpdatingBehavior("onchange") is added to a TextField in a form. The behavior verifies the text for certain conditions (either the model object or the form component model, doesn't matter), based on which it might display a message (or hide it, if it has already been shown).
The problem is, there are also validators added to the TextField. One of the possible (and likely) scenarios consists of the user typing in, first, a value that causes the message to be displayed by the AJAX request. If, then, he/she types in a value that doesn't pass validation, the message should disappear, but it does not.
Apparently, either the onUpdate() method for the AJAX behavior is not called at all, or I am failing in my attempts to insert a check for non-validated entries (I have tried to test for both null values and empty strings, to no avail; I have no idea what exactly Wicket's validators do to models when data is invalid).
I am wondering if someone who actually understands validators (or AJAX, actually) has any ideas on where the problem could be.
I can post edit and post code if someone tells me this is not a general issue tying validators and AJAX, but most likely a programming mistake. I still believe the former and thus I'll refrain from posting code sections, in order to keep the discussion on an API/theoretical frame.
Thanks.
When using an AjaxFormComponentUpdatingBehavior, if any of the IValidators fail their validation, onError() will be called instead of onUpdate(). Wicket will effectively prevent invalid user input from reaching the IModels in your components, so the component's ModelObject will not be changed at all. The invalid input will probably remain available by means of getInput()/getConvertedInput() (not sure if it will in an AJAX scenario, it sure is in a traditional form submission).
However, take into account that IFormValidators are not executed when using this mechanism. If you've got any, you might be interested in overriding getUpdateModel() so that AjaxFormComponentUpdatingBehavior will not bring maybe-invalid user input into your IModels, and set modelobjects manually when you're certain user input is valid.
Regarding your specific case, you could perform all the required logic in onError() (or rely on Models that will grab data from somewhere else), and just add the components that need refreshing to the AjaxRequestTarget. This is probably what's missing in your scenario.
I've been having a look at several MVC frameworks (like rails, merb, cakephp, codeignitier, and similars...)
All the samples I've seen are basically plain and simple CRUD pages, carrying all the infr needed in the querystring and the posted field values.
I've got a couple of apps made with some sort of framework built with classic asp.
This framework handles some CRUD stuff a little more complex than the examples I found.
Something like master-detail, filtering by example, paging, sorting and similars.
I have a controller class that it's just a finite state machine, that goes thru diferent states (like new, browse, filter, show, etc.), then performs the appropiate action depending on the event raised and finally retrieves the neede info to the calling page.
To achieve this I have several hidden inputs to keep the state of the web page (like current id, filter criterias, order criterias, previous state, previous event, well, you get the idea)
What do you think would be the finnest approach to achieve this kind of funcionality?
hidden inputs built in the view and used from the controller??? (I guess that would be the equivalent of what I'm doing right now in classi asp)
--
(added in response to tvanfosson)
basically, my question refers to the third category, the context-dependent setting (in respect to the other two categories I agree with you) the info I was storing in hidden fields to store them on the querystring, I guess that when you click on the "next page" you include everything you need to save in the querystring, right? so that piece of query string gets appended in each and every link that performns some kind of action...
I'm not sure, what are the advantages and disadvantages of using the querystring instead of hidden inputs???
I use different strategies depending on the character of the actual data. Things that are preferences, like default page size, I keep in a Preferences object (table) that is associated with the current logged in user and retrieve from there when needed.
Persistent settings associated with the current logon, like filter settings for a page, are stored in the user's session. Generally these are things that if a user sets them in the current session they should remain sticky. I think filter settings and visibility are like this. If I filter a list, navigate away from it to drill down into a particular item, then come back to the list, I want my filter settings to be reapplied -- so I make it part of the session.
Context-dependent settings -- like the current sort column or page number, are controlled using query parameters. Paging and sort controls (links) are built with the appropriate query parameters to "do the right thing" when clicked and pass any necessary query parameters to maintain or update the current context of the control. Using the query parameters allows you to use an HTTP GET, which is bookmarkable, rather than a POST. Using hidden form parameters makes it much harder for the user to save or enter a URL that takes them directly where they want to go. This is probably more useful for sorting than it is for paging, but the principle applies equally.