What is the best way to load ASP.Net usercontrols via JSON? - json

What is the best way to emit an asp.net usercontrol back to the browser based on a JSON request?
So far I have a web service which creates the user control and sends it back to the browser. However when I post back the whole page, I get an error about "the state information is invalid for this page and might be corrupted."
Considering I'm new to Json, I'm going to guess I'm doing it wrong. What's the best way?
Should I just turn off view state validation?

Answer: turn off view state validation.

Related

How to prevent Ajax JSON call directly from browser in ASP.net Core

On my website I use an ajax called GetAllPatient(). It will return a JSON list. Now anybody can access it in browser. if anybody hits in a browser as www.domain-name.com/controller-name.GetAllPatient() he looks my all patient.
How do I prevent directly access my data from the browser as JSON?

Turned Based Game with Servlet

I want to make a turn based game (Something like Checkers) with the help of Servlets and jsp pages.I created a page that has a newGame button that redircet to the gamePage(It redirect the first into a Black.jsp and the other request will be redirected to Red.jsp).
My problem is ,how could I refresh the other jsp automaticaly if one of them changed.
Note:After the change in one of the jsp it redirect the request to servlet and servlet update the changed jsp graphics.but the other jsp stay inactive.I want to make it active.
Thank You
It sounds like what you need is Comet. Here's an overview of how it works.
http://www.ibm.com/developerworks/web/library/wa-cometjava/
Basically, the "other" user's browser will send a request to a servlet to get an update, but that request won't receive receive its response until the current player makes a move. This gets around the problem posed by the fact that, with traditional HTTP, the browser always has to be the one sending the request to the server, it can't be the other way around.
There are some variations on the technique. Now that you know the name, I'm sure you'll be able to find lots of useful information about it.
There's another technology called WebSocket which can also serve this purpose, but it requires additional capability built into the browser and, as of now, probably not all of your users will be using compatible browsers.

Overridding GWT RequestTransport

I want to create a GWT client application that retrieves data using RequestFactory. However, I want this client application to hit a JSON webservice backend.
If this is possible at all, it should have something to do with overriding DefaultRequestTransport and setting a new request URL for the data. However, from this point on, the weeds get pretty thick, and the docs are rather thin.
Anyone have any idea if this is possible?
Overriding RequestFactory to work with JSON will be very hard, if at all possible.
Why not use the GWT default support for JSON?

Testing PUT methods on a RESTful web service

I have a simple RESTful web service and I wish to test the PUT method on a certain resource. I would like to do it in the most simple way using as few additional tools as possible.
For instance, testing the GET method of a resource is the peak of simplicity - just going to the resource URL in the browser. I understand that it is impossible to reach the same level of simplicity when testing a PUT method.
The following two assumptions should ease the task:
The request body is a json string prepared beforehand. Meaning, whatever is the solution to my problem it does not have to compose a json string from the user input - the user input is the final json string.
The REST engine I use (OpenRasta) understands certain URL decorators, which tell it what is the desired HTTP method. Hence I can issue a POST request, which would be treated as a PUT request inside the REST engine. This means, regular html form can be used to test the PUT action.
However, I wish the user to be able to enter the URL of the resource to be PUT to, which makes the task more complicated, but eases the testing.
Thanks to all the good samaritans out there in advance.
P.S.
I have neither PHP nor PERL installed, but I do have python. However, staying within the realm of javascript seems to be the simplest approach, if possible. My OS is Windows, if that matters.
I'd suggest using the Poster add-on for Firefox. You can find it over here.
As well as providing a means to inspect HTTP requests coming from desktop and web applications, Fiddler allows you to create arbitrary HTTP requests (as well as resend ones that were previously sent by an application).
It is browser-agnostic.
I use the RESTClient firefox plugin (you can not use an URL for the message body but at least you can save your request) but also would recommend curl on the command line.
Maybe you should also have a look at this SO question.

HTML interface to RESTful web service *without* javascript

Even if I offer alternatives to PUT and DELETE (c.f. "Low REST"), how can I provide user-friendly form validation for users who access my web service from the browser, while still exposing RESTful URIs? The form validation problem (described below) is my current quandry, but the broader question I want to ask is: if I go down the path of trying to provide both a RESTful public interface and a non-javascript HTML interface, is it going to make life easier or harder? Do they play together at all?
In theory, it should be merely a matter of varying the output format. A machine can query the URL "/people", and get a list of people in XML. A human user can point their browser at the same URL, and get a pretty HTML response instead. (I'm using the URL examples from the microformats wiki, which seem fairly reasonable).
Creating a new person resource is done with a POST request to the "/people" URL. To achieve this, the human user can first visit "/people/new", which returns a static HTML form for creating the resource. The form has method=POST and action="/people". That will work fine if the user's input is valid, but what if we do validation on the server side and discover an error? The friendly thing would be to return the form, populated with the data the user just entered, plus an error message so that they can fix the problem and resubmit. But we can't return that output directly from a POST to "/people" or it breaks our URL system, and if we redirect the user back to the "/people/new" form then there is no way to report the error and repopulate the form (unless we store the data to session state, which would be even less RESTful).
With javascript, things would be much easier. Just do the POST in the background, and if it fails then display the error at the top of the form. But I want the app to degrade gracefully when javascript support isn't available. At the moment, I'm led to conclude that a non-trivial web app cannot implement an HTML interface without javascript, and use a conventional RESTful URL scheme (such as that described on the microformats wiki). If I'm wrong, please tell me so!
Related questions on Stack Overflow (neither of which deal with form validation):
How to send HTML form RESTfully?
How do you implement resource "edit" forms in a RESTful way?
you could have the html form post directly to /people/new. If the validation fails, rerender the edit form with the appropriate information. If it succeeds, forward the user to the new URL. This would be consistent with the REST architecture as I understand it.
I saw you comment to Monis Iqbal, and I have to admit I don't know what you mean by "non-RESTful URLS". The only thing the REST architecture asks from a URL is that it be opaque, and that it be uniquely paired to a resource. REST doesn't care what it looks like, what's in it, how slashes or used, how many are used, or anything like that. The visible design of the URL is up to you and REST has no bearing.
Thanks for the responses. They have freed my mind a bit, and so in response to my own question I would like to propose an alternative set of RESTful URL conventions which actually embrace the two methods (GET and POST) of the non-AJAX world, instead of trying to work around them.
Edit: As commenters have pointed out, these "conventions" should not be part of the RESTful API itself. On the other hand, internal conventions are useful because they make the server-side implementation more consistent and hence easier for developers to understand and maintain. RESTful clients, however, should treat the URLs as opaque, and always obtain them as hyperlinks, never by constructing URLs themselves.
GET /people
return a list of all records
GET /people/new
return a form for adding a new record
POST /people/new
create a new record
(for an HTML client, return the form again if the input is invalid, otherwise redirect to the new resource)
GET /people/1
return the first record
GET /people/1/edit
return a form for editing the first record
POST /people/1/edit
update the first record
GET /people/1/delete
return a form for deleting the record
(may be simply a confirmation - are you sure you want to delete?)
POST /people/1/delete
delete the record
There is a pattern here: GET on a resource, e.g. "/people/1", returns the record itself. GET on resource+operation returns an HTML form, e.g. "/people/1/edit". POST on resource+operation actually executes the operation.
Perhaps this is not quite so elegant as using additional HTTP verbs (PUT and DELETE), but these URLs should work well with vanilla HTML forms. They should also be pretty self-explanatory to a human user...I'm a believer in the idea that "the URL is part of the UI" for users accessing the web server via a browser.
P.S. Let me explain how I would do the deletes. The "/people/1" view will have a link to "/people/1/delete", with an onclick javascript handler. With javascript enabled, the click is intercepted and a confirmation box presented to the user. If they confirm the delete, a POST is sent, deleting the record immediately. But if javascript is disabled, clicking the link will instead send a GET request, which returns a delete confirmation form from the server, and that form sends the POST to perform the delete. Thus, javascript improves the user experience (faster response), but without it the website degrades gracefully.
Why do you want to create a second "API" using XML?
Your HTML contains the data your user needs to see. HTML is relatively easy to parse. The class attribute can be used to add semantics as microformats do. Your HTML contains forms and links to be able to access all of the functionality of your application.
Why would you create another interface that delivers completely semantic free application/xml that will likely contain no hypermedia links so that you now have to hard code urls into your client, creating nasty coupling?
If you can get your application working using HTML in a web browser without needing to store session state, then you already have a RESTful API. Don't kill yourself trying to design a bunch of URLs that corresponds to someone's idea of a standard.
Here is a quote from Roy Fielding,
A REST API must not define fixed
resource names or hierarchies
I know this flies in the face of probably almost every example of REST that you have seen but that is because they are all wrong. I know I am starting to sound like a religious zealot, but it kills me to see people struggling to design RESTful API's when they are starting off on completely the wrong foot.
Listen to Breton when he says "REST doesn't care what [the url] looks like" and #Wahnfrieden will be along soon to tell you the same thing. That microformats page is horrible advice for someone trying to do REST. I'm not saying it is horrible advice for someone creating some other kind of HTTP API, just not a RESTful one.
Why not use AJAX to do the work on the client side and if javascript is disabled then design the html so that the conventional POST would work.