I want to submit a form using AJAX to a MVC 3 Controller.
The form and the controller are on two different domains, which is why i want to use CORS.
I have read that the following code should do the trick in ASP.NET:
Response.AppendHeader("Access-Control-Allow-Origin", "*");
from http://enable-cors.org/#how-asp.net
Should this code go directly in the controller that takes the form data?
As far as i know, there has to be some exchange of data between the client posting data and the server, to determine wether CORS is enabled/supported or not, so i figure that the one line of code has to go somewhere else?
Thanks
This could go in the controller. Actually I would probably externalize it in a custom action filter to avoid repeating it in every controller action that needs to be invoked from a cross domain AJAX call. There are no additional steps necessary. Just make sure that your browser supports CORS because if it doesn't adding this line will have strictly no effect whatsoever.
Related
I have an asp.net application that I'm attempting convert the front end to Angular. Getting header information is important to the view. I'm used to getting the header information like so in C#:
httpContext.Request.Headers["USERID"]
How can I do the same thing in an angular controller?
In asp.net each request runs in its own independent context and hence the header access as you have shown in your code make sense.
This does not hold good for angular or in fact any client side framework. You can always get the headers for any request or response made using angular $http but the question is which request? During the lifetime of the app you would make many such requests.
Let's say you want to get the current userid, you can create a service that returns the logged in user. There are two ways to implement such a sevice
create a method on server to return this data. Invoke this method from service and cache results
on the client side assuming there is a login request made through angular, implement a success callback method which can update the service with the logged user id.
You can look at $http documentation here to understand how to access headers.
I've been following a series of videos on how to create a web API using MVC 4. The sixth video describes the authorization process, but it is both too complex for what I want, and it somehow redirects to a form (which makes no sense to me, but then I'm new to this stuff).
I've used API's from other sites, and they usually use one of 2 methods:
a token in the url (http://myurl/api/service/?token=[bunch of characters here]
a username or password (or token) in the header
I'm leaning towards the second method, as it means I wouldn't have to add a parameter to each of my methods.
If I use this approach, do I need to add code to the beginning of each method to check the headers (request.headers?) for username/password (then find them in our database and see if they have permission to access this method)...Or is there a simpler way of doing this?
You can mark your Controller class with attribute which is derived from AthorizationFilterAttribute.
http://msdn.microsoft.com/en-us/library/system.web.http.filters.authorizationfilterattribute(v=vs.108).aspx
In this case you will not need to write authorization checks in every method, but only in one place.
This approach is well described under the following link:
http://www.tugberkugurlu.com/archive/api-key-authorization-through-query-string-in-asp-net-web-api-authorizationfilterattribute
I have a web cam that can send an image via HTTP PUT to a web server. I'd like to process this in ASP.NET MVC, but it doesn't natively support PUT. Is there any way to trick it into treating the request as a POST? I'm looking to get the Request.Form and Request.Files properties populated.
ASP.NET MVC supports PUT requests by putting the HttpPut attribute on the action.
(In earlier versions you might need to use the AcceptVerbs attribute...)
Are you sure it doesn't support HTTP Put? I see that it is listed within the HttpVerbs Enumeration: http://msdn.microsoft.com/en-us/library/system.web.mvc.httpverbs.aspx
All you should have to do is ensure that you have decorated your action appropriately.
This does not appear to be possible. I've just used the Request.InputStream to read in a bitmap directly.
I have some functionality in the code behind, which after executing needs to forward the request to another page. I want to pass along data like you would by setting a request attribute in Java (i.e. - I don't want it in the query string of the redirected response). Is this possible with ASP.NET (c#)?
You can use Server.Transfer if you want to forward the request and keep all of the Request variables, or you can use Session.
Are you using ASP.NET Webforms or MVC? The following will redirect your request to a new page. You'll have to test and see if it forwards post data (I'm not sure). Now that you mention it, I don't think ASP.NET has a built in "forward:" request like java does. I think it just has "redirect" for security reasons. (Someone correct me if I'm wrong).
In Webforms:
try Response.Redirect("mynewpage").
In MVC:
at the completion of your action method return Redirect("mynewpage")
I don't know your use case, but it is generally not good practice to pass post data to a different page/request. Typically the posted action will take care of persistence, and then a GET request will be issued to the redirect page. If the redirected view needs access to the posted data, it should go to the persistence mechanism (DB) to retrieve it. This method is more secure, and generally better practice. This is a very general guideline, so use it as your needs allow.
HTH
Yes - See the reflection code at:
HttpModule to add headers to request
However - the question is - do you really want to use request headers? probably not. its a hack to use them. If you simply want to pass information, use the Context.Items dictionary to transfer your items between requests with Server.Transfer.
Depending on what you are doing and where your events are, you can also make use of Cross Page Postback.
See http://msdn.microsoft.com/en-us/library/ms178139.aspx
Otherwise, I'd go with vcsjones answer of Server.Transfer
I've been using user controls extensively but never use a HttpHandler and was wondering if I am doing something suboptimal or wrong
Unfortunately your question is a little like "Should I use a sandwich or a cement mixer". HttpHandlers and User controls are completely different things.
HttpHandlers are used to process HTTP requests. For example, if you wanted to dynamically create an RSS feed, you could write an HTTP handler that handles all requests for ".rss" files, creates the output and sends it back to the user.
User controls are used within ASPX pages to encapsulate units of functionality that you want to re-use accross many pages.
Chances are, if you're using user controls successfully, you don't want to use HttpHandlers!
Basically a user control is a piece of server logic and UI. An HTTP Handler is only a piece of logic that is executed when a resource on your server is requested. For example you may decide to handle requests for images sent to your server through your own handler and serve images from a database instead of the file system. However, in this case there's no interface that the user sees and when he visits a URL on your server he would get the response you constructed in your own handler. Handlers are usually done for specific extensions and HTTP request types (POST, GET). Here's some more info on MSDN: http://msdn.microsoft.com/en-us/library/ms227675(VS.80).aspx
Expect a better answer (probably before I finish typing this) but as a quick summary.
A user control is something that can be added to a page.
A HttpHandler can be used instead of a page.
Just to clarify the question. I was reading the Hanselman post
http://www.hanselman.com/blog/CompositingTwoImagesIntoOneFromTheASPNETServerSide.aspx
and thinking that I would never solved the problem with a HttpHandler, maybe with a simple page returning a binary content.
This led me to think that I should add HttpHandler to my developer tool belt.
Even an Asp.Net page is an HttpHandler.
public class Page : TemplateControl, IHttpHandler
A user control actually resides within the asp.net aspx page.