How do I use ajax with mvc4 without a service? - javascript

I'm pretty new to MVC and I'm just thinking ahead to my next project. I haven't been able to find any examples of how to do this, so I apologize if it seems like a question that may have already been answered somewhere else.
I'm going to want to create asynchronous cascading dropdown menus. So menu B will update as the values in menu A change, and menu C will update as either A or B update. What is the normal pattern for this?
Normally, as list events fire, I would use ajax to call a service that would process my input data and return json which I would use to update my lists. In this case, there is no service, only the controller feeding the view. We could create a service, but we prefer not to if at all possible. So I'm wondering if there is a technique in MVC4 that can feed me back what I need to update the view without re-rendering the page.
If someone could refer me to an example or at least explain what I might be looking for, that would be a great help. TIA

You can implement the Ajax callback URL as a controller action (in fact, that is how I typically do it).
There is no need for a separate service.
public class CallbackController : Controller
{
public ActionResult MenuOptions()
{
// return e.g. JSON
}
}
The Ajax URL would be
http://myserver.com/Callback/MenuOptions

There are a lot of answers around the web for this type of functionality. Here is one, and here is another similar example. What you should really do is read up on MVC actions / controllers and do some spiking / messing around.
Building the example starter app will help you get a grasp on the differences between classic ASP.NET and MVC.

Related

How to add live javascript interaction with an object from the database?

I'm working on a restaurant ordering website. The idea is there's a menu and there's a "My order" bar on the right. The meals from the menu are database objects. I want to be able to click the "add" button on the object and it should appear in the "my order" bar immediately without refreshing the page. I have no idea how to implement it so fat. Could you guys offer me any ideas? Desirable technologies are Rails and JavaScript. Thanks.
You want to use AJAX to asynchronously call the database and handle the response. You can do this a number of ways. Popular ways in Rails include JQuery and/or Rails's UJS. Modern options include Turbolinks 3. They all operate on the same principles.
Any way you do it, you'll make a call to a controller (your "endpoint") to retrieve data from the db and return a response, probably a JSON object or maybe even an html partial. You'll handle that response in your front end code.
Here's a fairly old but good tutorial on the basics. http://railscasts.com/episodes/136-jquery-ajax-revised

Angular JS and Symfony2

I am currently working on a project using Symfony2 and seeking some advice on that.
I am thinking of a hybrid application in two(2) different ways a) Login Page shall use traditional form with CRF Token and let symfonty2 handle it. b) All Inner pages ( which potentially are modules ) I want them to be non AJAX, but the other activities inside that shall behave like a Single Page.
For example I have an employee module. When user clicks on that it is entirely loaded from Server ( all the templates and forms etc ) now each activity under employee module like add/update delete/view etc shall be loaded through AJAX and response to be returned in JSON i.e AngularJS.
I am currently thinking of using FOSUserBundle to return html on initial request and then based on request type Accept: application/json it will return the JSON ( remember the add/updat delete/view part? ).
My question is it a better idea to use Angular Partials (html) files or Symfony2 Twig? or would it be better to use Angular JS, but let those partials be rendered by Symfony2 twig? ( I am thinking of Forms here, would want to validate that both from client and server side )
Has any one been through similar problem, if yes then what approach was used to develop HYBRID application using AngularJS and Symfony2 or any other framework? any relevant ideas are appreciated.
I was in the same situation you are. AngularJS+Symfony2 project, REST API, login using FOSUserBundle, etc.
... And every way has pros and cons, so there is no right way, i'm just gonna say exactly what i did.
I choose AngularJS native templates, no CSRF validation, a base template built using Twig, server-side validation, use of the FOSJSRoutingBundle, and some helpers (BuiltResponse and BaseController).
Why native templates?
With the use of verbatim, we solve the variable problems, but we gonna have a more complex logic in our templates.
We also will have a less scalable application. All our forms templates are doing a request in the Symfony application, and one of the best pros of the AngularJS is load our controllers, templates, etc from a storage service, like S3, or CDN, like Cloudfront. As there is no server-side processing, our templates would load so much faster. Even with caching, Twig is slower, obviously.
And both, Twig and AngularJS templates, are really complex to manage, in my own experience. I started making them together, but was painful to manage.
What i did?
I created static templates in front-end, with the same field names, it's not really good. We need to update the templates every time we update the forms, manually. But was the best way i found. As the field names are equal, we won't have problems to ajust the model names in the Angular controllers.
And if you are creating the software as a service, you will need to do it anyway. Will you not load the form templates from the application in a mobile app, right?
Why no CSRF validation?
We don't use CSRF validation in a REST API, obviously. But, if you wanna do it, you need to make a request every time you load a form, to get the CSRF token. It's really, really bad. So, we create a CRUD, and also we need to create a "csrf-CRUD", 4 routes more. That doesn't make any sense.
What i did?
I disabled the CSRF in the forms.
Base template?!
Yep. A base template is just to load any route in our application. Here is what i'm doing:
This will help us to avoid errors when users are going directly to some Application URL if you are using html5 angularjs urls. Simple like that.
Server-side validation, why?
If we do a validation in the Angular, we need to do the same in the server-side, so we have 2 validation codes to maintain. That is painful. Every change we do in the form, we need to change the validation in the front, validation in the back and also the Angular static form. Really, really painful.
What i did?
I basically did a server-side validation using the Symfony constraints. For every request, the application validates the form and check if any error was found, if yes, it gets the first one and send it as a response.
In the AngularJS, the application checks if there is any error inside of the errors key. So, we have a proccess used in all application to do any form request. It's like that:
And the routes?
There is another problem: the routes. Put the url directly is not a reliable way. If we change anything in the url, that route is gone and the users won't like that.
To fix that, we can use the FOSJsRoutingBundle. With that library, we can put the route name directly in the Angular controller, and it will fill with the exact url of the route. It's completely integrated with the Symfony, so parameters will work very well.
Instead using the url directly, we can do it:
Routing.generate('panel_products_show', {id: $routeParams.product_id});
And voilá! We get the route url.
That will solve the biggest part of the problems you have. But there are more.
Problem 1 - Form inputs
The forms from Symfony generally have a prefix, like "publish_product", so every field has a name like [publish_product]name. Ah, how that was a problem for me.
In the Angular, publish_product is not considered a array. You need to put the single quote to do this, like ['publish_product']name. And it's really bad, we need to change every key to use this format. In AngularJS, i was doing like that:
{{ formData('[publish_product]name') }}
Absolutely stupid.
The best solution was simply remove the form prefix in the Symfony, using the createNamedBuilder method instead just createBuilder. I let the first parameter null, and yeah, we don't need to use the prefix anymore. Now, we use:
{{ formData.name }}
So much better.
Problem 2 - Routes hard do maintain
Every request can return anything, i need to repeat much code. That is really hard to maintain, so i just create some application rules, built responses, a BaseController, etc.
createNamedBuilder
createNamedBuilder is a big method. We need to do this, for every form we have:
It's simple to solve. I just created a BaseController and i'm extending every controller from it. I created a simple method that does it.
For every route, we do not need to repeat 3 lines, much better.
Responses
When my application started growing, i had a serious problem: all my responses are different. That was really hard to maintain. For every request i was doing, sometimes i was using "response", sometimes "data", the error messages were lost in the response, etc.
So, i decided to create a buildResponse, that i just need to set some parameters and i get the same result for every route, even GET routes.
response key shows me the status and the message. It can be error or success, and the message os a optional field, that can come blank. For example, a success status with the message "You created the product".
data key shows me any information i need. For example, the user added the product, and now he needs the link to see it. In the data, i put the url of the post, and i easily can get it from the AngularJS controller.
notifications is a specific key for my business logic. Every action can return a notification to the user.
It doesn't matter what keys you have. The most important thing is have a standardized response, because when your application grows, it will be really helpful.
That is a route from my controller:
Completely standardized. The Scrutinizer code quality tool says all my routes are duplicated. :D
Have a BaseController and a builtResponse will help you so much. When i started refactoring my code, each route lost about 4-10 lines.
Details: getFormError return the first error of the form. Here is my method:
public function getFormError(FormInterface $form)
{
if ($form->getErrors()->current()) {
return $form->getErrors()->current()->getMessage();
}
return 'errors.unknown';
}
... And the parameters from the buildResponse are:
1. Status. I get it from a constant in the BaseController. It can be changed, so i believe is important do not use a string value in each route.
2. The translation message. (I use a preg_match to check if it has a translation format, because getFormError already translates the error).
3. The data (array) parameter.
4. The notifications (array) parameter.
Other problem i'm gonna have
The project just have one supported language until now. When i start to work in a multilingual version, i'm gonna have another big problem: maintain 2 versions of the translations: the back-end messages and validations and the text from the front-end. That probably will be a big problem. When i get the best approach, i'll update this answer.
I took some months to get the this approach. So many code refactorings and probaly much more in the future. So i hope it help someone to do not need to do the same.
1. If i get a better way to do this, i'll update this answer.
2. I'm not good at writing english, so this answer probably will have many grammatical errors. Sorry, i'm fixing what i'm seeing.

ajax update site from form submit

As mentioned in this question How can I check for live updates without using setInterval/timeout?
I am aware of websockets, but im interested in maybe a more simplistic solution, could I effectively just let php update a key value pair file and have all pages update accordingly only if a value has changed?
eg. a bidding site where instead of polling for 100 or more items I only update the whole application when someone has essentially placed a bid , making it a one way flow
place bid->process form->update database->refresh all instances of said bid currently open in other windows - hence the file that will store the info and maybe two way binding setup via angular template , or will caching be a issue?
how else do I update the views but all based on the action of someone placing a bid(submitting a form)?
Any ideas as to this approach?
You should use websockets...
if you are new to socket.IO you can use some backend as a service like firebase, this should be really easy to implement.

How to make a SPA testable outside of the browser?

I have a SPA that pulls configuration data down from a server and generates a form that a user can proceed to fill out.
I want to be able to make this SPA testable outside of the browser, which would imply that the views and their implementations are not being tested.
Currently, the structure of a form is like so:
form
page 1
firstName
lastName
page 2
email
There is a form model which holds the data of the form and its configuration, and then there is a controller and a view. The controller attaches data from the model directly into the view, and also manipulates the view based on events. The view also has logic for creating and controlling certain aspects, such as inline scrollers (iScroll).
As you can probably see, this makes it impossible to test the code without the browser because the code is so tightly coupled to the view.
I think the way to fix the problem would be to have a controller, a controller model, a view, and then a concrete class that joins them together while providing the form configuration to the controller. But this raises some issues, specifically, that I would then need a factory for creating a controller for the form, pages, and fields, and then something that creates the concrete binder between the view and the controller, and then something that joins them all together in the correct way.
I feel like there has to be a better way to do this.
Any guidance would be greatly appreciated.
I think what you need is AngularJS. There is a template you can clone with git. It has testable capability right out of the box. I don't think there is a need to reinvent the wheel since there is already a well known framework that has this.

Best practice for node - mongo - angular

I have an app I am designing using node/mongo/angular, what I am not getting is how is the best way to get my data from mongo into my pages? I can use node, and thru my routes send back data from mongo with my template(hogan in this case), and bind using mustachejs. That works fine for most things. I have one screen that has a decent amount of drop down lists, to bind them for an edit scenario now seems a challenge. I would like to get them bound to an angular model and go about it that way. Is it better to get the data thru the route in node, then use something like ng-init and get it into angular? Or would I be better off not getting the data thru the route in node, and then using angular to perform a "get" request and bind that way?
From the documentation of ng-init, more precisely from the red warning alert at the top of the page...:
The only appropriate use of ngInit is for aliasing special properties of ngRepeat, as seen in the demo below. Besides this case, you should use controllers rather than ngInit to initialize values on a scope.
So no, do not use ng-init. While that can be a good strategy for lazy migrations from regular applications to single page applications, it's a bad idea from an architectural point of view.
Most importantly, you lose two things:
An API. The benefit of SPAs is that you have an API and that you're constantly developing and maintaining it, even before it has external users
A clean separation of concerns. Views are strictly limited to presentation, can be cached by the client and all data is transferred through JSON API endpoints.
I would say that the best way to get data from Mongo into your page, is as mnemosyn said, using an API.
Basicly, you can have your API route, f.ex '/api/data' configured and then it can be used by a angular service, (which can use ngResource to make things easier). Any controller that wishes to access this data can use the angular service to get it, do some stuff with it, and then update it using the same angular service.

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