I have Restful controller that renders a view with data from database and I want to load this view with its data in another view via ajax. There is a problem "undefined variable". Is there any solution?
When you pass variables to your view they are only available on the server side while the view renders and then they are discarded. What this means is that the variables are only available to the php of your application and then they are gone by the time the view has been rendered and sent to the visitors web browser.
If you try to use the variables with JavaScript then you are running the JavaScript on the client side (as opposed to the server side). The variables that you pass to your view do not exist on the client side where your JavaScript runs.
From what it sounds like. You are defining a variable in your controller via laravel. Then you are passing the variable from the controller to the view. The view is then rendered as html and sent to the visitor's computer (the client) which the html is then loaded and that is when the JavaScript starts to load.
That's the problem, now possible solutions.
First you could send the variable (assuming it is simple data and not like an object) to the browser through laravel flash variables which are actually stored on one time cookies on the client side. Then you use JavaScript to access the cookie and get the data then storing it to a js variable and using it in your script.
Second you create an Api to respond to your http requests and then send an Ajax request from your JavaScript to the api to get the data. Then you would store it in JavaScript and use it. This allows complex data like objects because you would use the JSON format to send information to respond to the Ajax call. While cookies are restricted to (5kb I think) there is really no theoretical limit to JSON data.
I hope that helps and I hope I'm understanding your problem.
Would need to see your javascript before anything, but usually for me this means a misspelled element id or misspelled a reference file
Related
I know that the webpage that is opened by the user is part of the view. This one is easy, but what about js code calling the server to retrieve data via ajax? Is this part of the controller or still the view?
Can the view request data like this?
Thank you very much for any help.
Javascript, including Ajax, is a client-side technology. Therefore, in the context of MVC, any js script must be part of a template file.
Note that a template file is not the view (the V in MVC), but a part of it. The view should incorporate both server-side components (classes, interfaces, etc) and client-side components (html, js, css, images, etc). For example, an instance of a view class could read some data from the domain model and then load and render a certain template file, injecting the fetched data into it (formatted), in order to be printed on the screen.
So, an ajax object should be defined in a template file. Its request to the server is handled either by the controller, or by the server-side components of the view, depending on the MVC approach that you are choosing to implement. Though, the server response should always be created by the server-side components of the view.
I am a complete newbie to AngularJS. I want to check the feasibility of using it in my new Project which is a web application. I already have a few pages created in project using Struts2 Spring and hibernate. To convert these following are points I understand:
Convert server side API to REST style which returns JSON data
Question: Can I use dynamic HTML to load using AngularJS. I guess yes. not sure how?
Currently I use velocity Templates on server side to populate data in HTML templates and send it as response in AJAX? What would change if i try to use AngularJS?
I have a landing page which is used to show some images and data associated with it which is stored in DB. How can I show it using AngularJS?
Question: Shall I load the HTML template which contains only one div tag when I hit website URL(mysite.com) and then fire AJAX requests to load the dynamic HTML?
If I use AndularJS does it invalidate use of Struts2 altogether if I choose to implement my Data API as REST with JSON? I guess not as I will still need to load dynamic HTML views which will be generated on Server correct?
How to maintain HTTP session state on server side if I use REST data API with AngularJS on client?
I know I can search and read about answers to above questions on net somewhere. I just need them at one place so that I can carry discussion and other questions that arise from it.
I may answer some of your questions:
1) Convert server side API to REST style which returns JSON data
Yes
Question : Can I use dynamic HTML to load using AngularJS. I guess
yes. not sure how?
Currently I use velocity Templates on server side to populate data in HTML templates and send it as response in AJAX? What would change
if i try to use AngularJS?
If I understood you right, you want to generate templates on server-side. In this case - you just don't need AngularJs - your views are prepopulated on server and browser recieves static content (from client-side point of view). If you want to use AngularJs, then your templates will become static content (from server-side point of view) and they will be populated by angular via REST services.
2) I have a landing page which is used to show some images and data
associated with it which is stored in DB. How can I show it using
AngularJS?
Question : Shall I load the HTML template which contains
only one div tag when I hit website URL(mysite.com) and then fire AJAX
requests to load the dynamic HTML?
Not exactly. One div would be enough for jQuery-based approuch (you would use something like $.ajax and then appended data in imperative way). In case of Angular you will need to return template. It may look like this:
<ul ng-controller="MyCtrl">
<li ng-repeat="item in data">
<img ng-src="item.image.src">
<span>{{item.data.someTextProperty}}</span>
</li>
</ul>
And some AngularJs controller that will fire request to REST service (via your AngularJs service, probably) and autmatically fill template with results
function MyCtrl($scope, $http) {
$http.get('/rest/data').success(function(result) {
$scope.data = result;
});
}
3) If I use AndularJS does it invalidate use of Struts2 altogether if
I choose to implement my Data API as REST with JSON? I guess not as I
will still need to load dynamic HTML views which will be generated on
Server correct?
I think it will only invalidate use of View of MVC in Struts, since AngularJS will just replace it. Also it will make you to use something like RESTful controllers (not quite familliar with Struts, but I think there is something like this)
4) How to maintain HTTP session state on server side if I use REST
data API with AngularJS on client?
This is not short answer, but basically there is following pattern. AngualrJs provides http interceptors, that may intercept requests and responses. If response with code 401 (which is unauthorized) is intercepted, you may provide your user with a login form to restore session and after this action will be completed, retry last request. Also, here you may find another aspect of this question.
I hope my answer helped you.
Reading the Ember guide about the data store it's not clear how you pre-populate the store with your data. I see you can set up the RESTadapter with the host name, and the 'store.find' method will trigger a 'get' request if the data is not cached, but how can I initialize a DS.Store with JSON data via ajax before ever doing a find?
Ember guide model HTTP
The context for this is, a single page app that on page load gets a blob of json, which is used to model out the rest of the site. The end result gives the illusion that the site contains multiple pages.
Sounds like you want this.store.pushPayload(..)
http://emberjs.com/api/data/classes/DS.Store.html#method_pushPayload
Note that you only have access to the store inside Routes and Controllers. Consider putting this inside the activate hook of App.ApplicationRoute
http://emberjs.com/guides/routing/defining-your-routes/#toc_initial-routes
http://emberjs.com/api/classes/Ember.Route.html#method_activate
I have tried to incorporate AJAX into an application that I built.
The basic function is:
-The user clickes a button, which triggers JS code that makes an AJAX call that does a POST to a Servlet(sending account data).
-The Servlet(which has an EJB injected into it), communicates with an EJB through it's local interface.
-The EJB(on init) initializes a DAO object, injects an EntityManager into it, and uses that DAO object to communicate with a database through JPA (Hibernate as the provider).
-The local interface methods of the EJB return Data Transfer Objects, which are parsed in the Servlets doPost() method, and the DTO's are used to build an HTML table(String) that the Servlet responds to the AJAX call with.
-On the client side, I use that HTML table(responseText) to update a div on the page.
I have 2 questions:
1) Is using a data-centric approach to the AJAX call (returning an HTML table instead of JSON Strings) a common choice in enterprise level applications that make use of AJAX?
2)I've noticed that sometimes the POST is not even called. It seems to be intermittent. I tried to add the Cache Control header, but that doesn't seem to work. This concerns me especially when I think about eventually deploying the application to production, that maybe AJAX is not the way to go, but when it works, the application works smoothly.
1) Using AJAX to submit data or update the web page is very common. Page at a time applications are the old way web applications used to be done where you would need to reload the entire page just to update a little bit of information - which would be inefficient and not to mention would create a bad user experience. These days, updating just "Part of a page" is very common and is mostly done using AJAX, and if not WebSockets.
Now you question regarding updating the page using the servers response which is HTML - to update the page, or just get a JSON String, and manipulate the DOM (ie adding tables etc). I have used a combination of these. For example if needed to add a row to a table, you could get the server to generate the HTML using a tempting engine (groovy or similar). In addition you you need a response code, so you can package the HTML and Response code in a JSON, and send it back to the client. Any combination of these works depending on your use case.
JsonObject json = new JsonObject();
json.addProperty("responseCode", responseCode);
json.addProperty("html", html);
2) You can write a simple script to send multiple requests to the AJAX url to see if it is the server that is not able to handle the amount of requests. If it works, then you can narrow down the problem to be client side. Make sure you are not using blocking techniques. You can also setup a callback function to see if there is any response if any. AJAX Post is similar to a normal POST request, just make sure you have some indicator for the user notifying them that the request is in progress/complete.
Greeting to the community. This is my very first question.
I had in mind to add Livezilla live support in my MVC website, but I realised that there are some problems.
First of all, it is written in php and mysql, so is it possible to comply with MVC and sql server?
Does anybody know a similar solution (like livezilla) in my case?
PS. Excuse my poor english...
you could even look into using an iFrame to run livezilla inside of an mvc3 page if you wanted.
or, you could roll your own. if you wanted to try implementing a live response mvc3 page look into jquery and ajax asynchronous calls such as $.post and also look into the extension for controller AsyncController, and [AsyncTimeout(XXX)]. you will also have to read up on sending and receiving json objects in ajax and from a controller to the view.
Simple psuedo:
View:
setTimeOut calls a javascript function every X milliseconds
the javascript function uses json to wrap page data and pass it to the controller inside a $.post() call
Controller:
recieves page data as an model object in a post
determines if page is out of sync or not
returns relevant sync data in a json object back to the view
View:
the same javascript function receives the json object from controller
updates the page based on relevant sync data
Problem solved. I just uploaded the folder given from livezilla in the root folder of my website. Then the only need to met is to have a Mysql server to create the database for livezilla. After that php and mvc runs together with no problem.