I have a very large webform that is the center of my Yii web application. The form actually consists of multiple html form elements, many of which are loaded via AJAX as needed.
Because of the form's size and complexity, having multiple save or submit buttons isn't really feasible. I would rather update each field in the database as it is edited by asynchrously AJAXing the new value to the server using jeditable or jeditable-like functionality.
Has anyone done anything like this? In theory I'm thinking I could set up an AJAX endpoint and have each control pass in its name, its new value, and the CRUD operation you want to perform. Then the endpoint can route the request appropriately based on some kind of map and return the product. It just seems like someone has to have solved this problem before and I don't want to waste hours reinventing the wheel.
Your thoughts on architecture/implementation are appreciated, thanks for your time.
In similar situation I decided to use CActiveForm only for easy validation by Yii standarts (it can use Ajax validation), avoiding "required" attribute. And of course to keep logical structure of the form in a good view.
In common you're right. I manually used jQuery to generate AJAX-request (and any other actions) to the controller and process them there as you want.
So you may use CRUD in controller (analyzing parameters in requests) and in your custom jQuery (using group selectors), but you can hardly do it in CActiveForm directly (and it's good: compacting mustn't always beat the logic and structure of models).
Any composite solution with javascript in PHP will affect on flexibility of your non-trivial application.
After sleeping on it last night, I found this post:
jQuery focus/blur on form, not individual inputs
I'm using a modified version of this at the client to update each form via AJAX, instead of updating each field. Each form automatically submits its data after a two seconds of inactivity. The downside is the client might lose some data if their browser crashes, but the benefit is I can mostly use Yii's built-in controller actions and I don't have to write a lot of custom PHP. Since my forms are small, but there are many of them, it seems to be working well so far.
Thanks Alexander for your excellent input and thanks Afnan for your help :)
Related
I have a long list that I want to let the user manipulate in a browser-based web application. Using jQuery, the most straightforward way would be to render it on the server as part of the initial page load, and include a small script that registers event handlers for AJAX requests and DOM manipulation.
In the case of VueJs however, it seems to me that the most straightforward way is for the initial request to load the page layout only, then call an API to get the data for the long list. In other words, VueJs renders the initial list, not the server.
While this is workable, I am hesitant to introduce this second request unless I really have to. Is there a more straightforward way to go about this? Am I missing something about how VueJS works? I would really like to render the initial list on the server side if possible. For example, would it be workable to somehow include the initial list as 'transcluded' content?
I don't want to have to get in to VueJS' complete server side rendering, since it looks like an advanced topic (and this is a simple task). I have experimented with passing the initial list data as JSON in the <head> of the page (inside tags that register it as a javascript variable), but that seems like a hack/workaround.
In the case of VueJs however, it seems to me that the most straightforward way is for the initial request to load the page layout only, then call an API to get the data for the long list. In other words, VueJs renders the initial list, not the server.
Yes, it is most straightforward way, and considered as anti-pattern also. Just for the reason in your next sentence: "While this is workable, I am hesitant to introduce this second request"...
I think you should read following post on medium.com first. It is about Vue and Laravel framework, but the principles herein can be considered universal:
https://medium.com/js-dojo/avoid-this-common-anti-pattern-in-full-stack-vue-laravel-apps-bd9f584a724f
I have a Vue.js component which gets a big list of releases from the database, at which point we can use all the lovely reactive list-filtering functionality to drill down to what we're looking for. The problem is that there's a very noticeable lag after page load before the list appears on the page.
Obviously loading the data in via ajax may not be instantaneous, but I thought I might be able to get better results by e.g. getting the data on the server-side with Laravel, and then passing it to the component from its containing Blade template as a prop. Not much luck so far though, again, a noticeable wait for the component to receive and display the data.
Are there any simple approaches for having a Vue component ready to go as quickly as possible? I looked at the prerender-spa-plugin for webpack but I don't know if that would interact properly with the Laravel routing. Likewise server-side rerendering with node seems like it could be more trouble than it's worth.
Has anyone experienced similar issues and found anything like a great solution?
you have too spot where you could do somethings. 1 on the server. by caching queries or somethings. And the second is on client side. when you handle the received / fetched collection. If you have, lets say 10000 entry, this would take sometime to a: parse the json object, b: create necessary vue components (if you're using vue component for row), and generating corresponding dom. So if you split and handle the recieved data in sized chunk. Vue would update the dom accordingly. and Fill the dom more like a stream. Not always the best approch but working in many case.
When a screen has multiple interacting Ajax controls and you want to control the visibility of components to react to these controls (so that you only display what makes sense in any given situation), calling target.addComponent() manually on everything you want to update is getting cumbersome and isn't very maintainable.
Eventually the web of onClick and onUpdate callbacks can reach a point where adding a new component to the screen is getting much harder than it's supposed to be.
What are the commonly used strategies (or even libraries if such a thing exists) to avoid this build-up of complexity?
Update: Thank you for your answers, I found all of them very useful, but I can only accept one. Sorry.
In Wicket 1.5 there is an event bus. Each component has onEvent(Object payload) method. With component.send() you can broadcast events and each component can check the payload (e.g. UserJoinedEvent object) and decide whether it wants to participate in the current Ajax response. See http://www.wicket-library.com/wicket-examples/events/ for a simple demo.
You could add structural components such as WebMarkupContainers, when you add this to the AjaxTarget everything contained in it will also get updated. This allows you to update groups of components in a single line.
When I'm creating components for a page I tend to add them to component arrays:
Component[] pageComponents = {
new TextField<String>("Field1"),
new TextField<String>("Field2"),
new TextField<String>("Field3")
}
As of Wicket 1.5 the add functions take array parameters [1]. Therefore elements can be added to the page or target like this:
add(pageComponents);
target.add(pageComponents);
Components can then be grouped based on which you want to refresh together.
[1] http://www.jarvana.com/jarvana/view/org/apache/wicket/wicket/1.5-M3/wicket-1.5-M3-javadoc.jar!/org/apache/wicket/ajax/AjaxRequestTarget.html
Well, of how many components do we speak here? Ten? Twenty? Hundreds?
For up to twenty or about this you can have a state controller which controls which components should be shown. This controller sets the visible field of a components model and you do always add all components to your requests which are handled by the controller. The components ajax events you simply redirect to the controller handle method.
For really large numbers of components which have a too heavy payload for a good performance you could use javascript libraries like jQuery to do the show and hide things by the client.
I currently use some sort of modified Observer-Pattern to simulate an event-bus in Wicket 1.4.
My Pages act as an observable observer since my components don't know each other and are reused in different combinations across multiple pages. Whenever one component receives an Ajax-event that could affect other components as well, it calls a method on it's page with an event-object and the ajax-target. The page calls a similar method on all components which have registered themselves for this kind of event and each component can decide, on the base of the supplied event-object if and how it has to react and can attach itself to the target.
The same can be archived by using the wicket visitor. I don't know which one is better, but I think that's mainly a matter of taste.
Background
I'm working on a web application utilizing AJAX to fetch content/data and what have you - nothing out of the ordinary.
On the server-side certain events can happen that the client-side JavaScript framework needs to be notified about and vice versa. These events are not always related to the users immediate actions. It is not an option to wait for the next page refresh to include them in the document or to stick them in some hidden fields because the user might never submit a form.
Right now it is design in such a way that events to and from the server are riding a long with the users requests. For instance if the user clicks a 'view details' link this would fire a request to the server to fetch some HTML or JSON with details about the clicked item. Along with this request or rather the response, a server-side (invoked) event will return with the content.
Question/issue 1:
I'm unsure how to control the queue of events going to the server. They can ride along with user invoked events, but what if these does not occur, the events will get lost. I imagine having a timer setup up to send these events to the server in the case the user does not perform some action. What do you think?
Question/issue 2:
With regards to the responds, some being requested as HTML some as JSON it is a bit tricky as I would have to somehow wrap al this data for allow for both formalized (and unrelated) events and perhaps HTML content, depending on the request, to return to the client. Any suggestions? anything I should be away about, for instance returning HTML content wrapped in a JSON bundle?
Update:
Do you know of any framework that uses an approach like this, that I can look at for inspiration (that is a framework that wraps events/requests in a package along with data)?
I am tackling a similar problem to yours at the moment. On your first question, I was thinking of implementing some sort of timer on the client side that makes an asycnhronous call for the content on expiry.
On your second question, I normaly just return JSON representing the data I need, and then present it by manipulating the Document model. I prefer to keep things consistent.
As for best practices, I cant say for sure that what I am doing is or complies to any best practice, but it works for our present requirement.
You might want to also consider the performance impact of having multiple clients making asynchrounous calls to your web server at regular intervals.
I think about AJAX in this way:
Model: The server-side where the data is stored and exposed through webservices. In a way this is a model-view-controller within the larger model-view-controller (model = data, view = XML or some other parsable data structure, controller = server-side code that manipulates the data).
View: XHTML/DOM
Controller: Javascript/JQuery
Is this a reasonable way to think about AJAX programming?
You too, huh?
Yes. I think this is a very good way to structure edit operations.
However... You probably want to keep to traditional HTML "view" pages for many documents or objects within an application so that you can support search engines if need be, and so that deep links into pages in your application come up with something meaningful.
This way, using both approaches, you have a hybrid, rather than the "un-webby rectangle" problem where you can never bookmark anything, send links to your friends, or have search engines generate [good] links.
8/10: I guess this also means that you should think of the "server" side of your application as a "REST" service, ideally. Also, be sure not to fall into the trap of thinking the client code is in any way, whatsoever, secure (or even "obscure", for that matter). Make sure the supporting "service calls" back to your web server have a good security infrastructure.
I've been finding it more useful to design ajax code around an event based paradigm. MVC is not mutually exclusive to event based organization but the focus for me has been more and more on the event handling side of things and less on the traditional model view controller way of looking at things.
It's more of a MWE (Model, Widget, Event) organization with the event code taking the place or wrapping the Controller code.