Here is a simplified version of the API controller I created.
public class SampleController : ApiController
{
[System.Web.Http.HttpGet]
public string Test(string url)
{
try
{
using (WebClient webClient = new WebClientEx())
{
return webClient.DownloadString(url);
}
}
catch (Exception ex)
{
return string.Empty;
}
}
Given a perfectly valid url this will throw a WebException that says "The remote name could not be resolved".
If I execute the same method within LinqPad, using the same url, it works. I've tried WebClient and WebRequest with the same results.
To be clear, this isn't a routing issue as I am able to hit and step through the code either way and the url involved is not part of this application.
I figured it out. I was initially thrown off because it appeared to work in a regular Controller but not in an ApiController. After I failed to reproduce my earlier "success", I finally figured out that I needed to use the system proxy.
webClient.Proxy = WebRequest.GetSystemWebProxy();
Related
I am attempting to use an asp web api to populate an html table using angular. everything works great if I debug in firefox (I'm assuming because my web service is being returned in json) however in ie and chrome it does not load (the web service returns xml in these browsers). In the webapiconfig I attempted to always make the service return json by adding.
Dim appXmlType = config.Formatters.XmlFormatter.SupportedMediaTypes.FirstOrDefault(Function(t) t.MediaType = "application/xml")
config.Formatters.XmlFormatter.SupportedMediaTypes.Remove(appXmlType)
this appears to work when I navigate to the api in all browsers it is returning json however the $http get is still now working in chrome and ie.
in ie I get the following error
Unhandled exception at line 21, column 406 in http://localhost:53175/Scripts/angular.min.js
0x800a139e - JavaScript runtime error: [$injector:nomod] http://errors.angularjs.org/1.3.13/$injector/nomod?p0=api%2Fproducts
here is my get
angular.module("api/products").constant("dataUrl", "sportstore.json").controller("sportsStoreCtrl", function ($scope, $resource, dataUrl) {
$scope.data = {};
var resultPromise = $resource(dataUrl);
resultPromise.success(function (data) {
$scope.data.products = data;
})
});
any thoughts?
additional info
here is my api controller
<pre>
Imports System.Net
Imports System.Web.Http
Imports apitoform.productRepository
Namespace Controllers
Public Class productController
Inherits ApiController
Private repo As productRepository = productRepository.Current
Public Function GetAllProducts() As IEnumerable(Of product)
Return repo.GetAll()
End Function
End Class
End Namespace
</pre>
and here is the j_son that is being returned ( I am working through the pro Angular book if it looks familiar)
Sorry this is c# code, but it should illustrate the basic idea for returning Json only from web api. It's actual code from one of my projects.
[Route("api/users/getbyemail/")]
public HttpResponseMessage GetByEmail(string email)
{
try
{
var result = _userService.GetByEmail(email);
HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.OK, "value");
response.Content = new ObjectContent(typeof(IEnumerable<UserViewModel>), result ?? new List<UserViewModel>(), new JsonMediaTypeFormatter());
response.Headers.Add("Access-Control-Allow-Origin", "*");
return response;
}
catch (Exception ex)
{
HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.InternalServerError, ex.Message);
response.Headers.Add("Access-Control-Allow-Origin", "*");
return response;
}
}
So you are returning HttpResponseMessage with Json content.
I'm also doing similar in a scenario where I just need to return the data from one of the MVC controllers and that is even easier:
public ActionResult Get(string guid)
{
var profileVm = _profileService.Get(guid);
if (profileVm != null)
{
return Json(profileVm, JsonRequestBehavior.AllowGet);
}
return new HttpNotFoundResult();
}
angular.module with 1 parameter returns the module with that name - you need to define your module with a list of dependent modules (or empty array if none) like the following:
angular.module("api/products", [])...
The error referenced gives an error with details on the problem (angular's very good about their error messages): https://docs.angularjs.org/error/$injector/nomod?p0=api%2Fproducts
I create a custom BasicAuthenticationMiddleware that use a BasicAuthenticationHandler to Authenticate requests from client to WebAPI.
The BasicAuthenticationHandler derives from the AuthenticationHandler< TOptions > base class.
Everything works fine and I implemented the
AuthenticateCoreAsync
where the logic to authenticate happens
ApplyChallengeResponseAsync
where the logic, in case of not authenticated requests, sends the WWW-Authenticate header to the client.
What I would like to achieve now is to set a Custom Body in the Response (IOwinResponse, inside the ApplyChallengeResponseAsync, with a custom object like:
{
Code="999",
Description="My failing reason"
AdditionalInfo = "My additional infos"
}
instead of the standard message that is like
{
message="Authorization has been denied for this request."
}
Did you have any suggestion on this?
thanks
The standard message you see, which is "Authorization has been denied for this request." is created by the Authorize filter. The HandleUnauthorizedRequest method sets this message in the response.
protected virtual void HandleUnauthorizedRequest(HttpActionContext actionContext)
{
if (actionContext == null)
{
throw Error.ArgumentNull("actionContext");
}
actionContext.Response = actionContext.ControllerContext.Request
.CreateErrorResponse(
HttpStatusCode.Unauthorized,
SRResources.RequestNotAuthorized);
}
SRResources.RequestNotAuthorized is what you see as the standard message.
Now, ApplyChallengeResponseAsync is called from the OnSendingHeaders callback in Katana autentication micro framework. This callback is invoked when a component writes into the response stream. In our case, when the response message created by the filter (what you see above) gets serialized, that is when the callback is invoked and ApplyChallengeResponseAsync runs. By that time, it is already too late for you to change the response. The best bet will be to override the virtual method of the Authorize filter above like this.
public class MyAuthorizeAttribute : AuthorizeAttribute
{
protected override void HandleUnauthorizedRequest(HttpActionContext actionContext)
{
var response = actionContext.Request.CreateResponse<MyError>
(new MyError() { Description = "My failing reason" });
response.StatusCode = HttpStatusCode.Unauthorized;
actionContext.Response = response;
}
}
public class MyError
{
public string Description { get; set; }
}
Instead of using [Authorize] on the controller or action method, use [MyAuthorize].
I am working on an asp.net MVC 3.0 Application. I am using using my own CustomRoleProvider
and CustomErrorHandler by overriding default attributes.
Every thing is working fine. But ,the problem is with the exception handling.
While testing the application , tester has given invalid DB connection to test.
The result is , Custom Error Handler is not rendering Error View , instead it is routing the original path
For ex:
I am running my application as
Home/Index
It is first hitting Custom Role Provider to fetch the roles for the application
Since , the Db Connection is not correct , it is raising exception that "Not able to Connect"
Now , Instead of routing to Error View along with this error message. It is routing to Home Controller and Index action.
**The code for my Custom Error Handler is as Follows**
public class CustomHandleErrorAttribute : HandleErrorAttribute // Error handler
{
public override void OnException(ExceptionContext filterContext)
{
if (filterContext.ExceptionHandled || !filterContext.HttpContext.IsCustomErrorEnabled)
{
return;
}
if (new HttpException(null, filterContext.Exception).GetHttpCode() != 500)
{
return;
}
if (!ExceptionType.IsInstanceOfType(filterContext.Exception))
{
return;
}
// if the request is AJAX return JSON else view.
if (filterContext.HttpContext.Request.Headers["X-Requested-With"] == "XMLHttpRequest")
{
filterContext.Result = AjaxError(filterContext.Exception.Message, filterContext);
}
else
{
filterContext.ExceptionHandled = true;
var controllerName = (string)filterContext.RouteData.Values["controller"];
var actionName = (string)filterContext.RouteData.Values["action"];
var model = new HandleErrorInfo(filterContext.Exception, controllerName, actionName);
filterContext.Result = new ViewResult
{
ViewName = View,
MasterName = Master,
ViewData = new ViewDataDictionary<HandleErrorInfo>(model),
TempData = filterContext.Controller.TempData
};
}
}
protected JsonResult AjaxError(string message, ExceptionContext filterContext)
{
if (String.IsNullOrEmpty(message))
message = "Something went wrong while processing your request. Please refresh the page and try again.";
filterContext.HttpContext.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
filterContext.HttpContext.Response.TrySkipIisCustomErrors = true;
return new JsonResult { Data = new { ErrorMessage = message }, ContentEncoding = System.Text.Encoding.UTF8, JsonRequestBehavior = JsonRequestBehavior.AllowGet };
}
}
In the above code , after setting up filterContext.Result . It is not rendering Error View as Expected.
Please correct/suggest me, where i am going wrong..
Updated:
public class CustomRoleProvider : RoleProvider // Custom role provider
{
public override string[] GetRolesForUser(string username)
{
// Fetching roles for user from database
}
// Some other Methods
}
This is method is generating exception , since it is trying to connect to wrong connection
Updated2:
1) I am using Custom Error Handler for the entire controller.
2) I need to catch all the exceptions including Ajax Errors
3) I have included my code for Custom Error Handler Above
4) I am also using CustomRole Provider for entire controller
5) Here, I am trying to generate exception , by giving wrong database connection
6) I am running the URL : Home/Index
7) Before going to thatr URL, it is hitting the methods in Role Provider class since i am using it as a attribute
8) Since, i have gave wrong DB Connection , It is generating exception
9) Then, it fires on exception method of Custom error handler
10) Building the Error Model for the error view
11) But, here is the problem. Instead of rendering Error View , it is going to index method of the Home Controller.
12) But, i need Error View to be rendered here, because it has failed to connect to database and getting roles . I want furthuer execution of URL Home/Index to be stopped here.
Hope this clarifies the problem..i am running in to. please feel free to ask me for furthuer details/Clarification
HandleError is designed to be able to register multiple filters (for example for different exceptions). One filter can handle only some specific exceptions or error cases and another unhandle cases can be handled by another HandleError. I suppose that currently both standard and your [CustomHandleError] filter are applied. You can set the Order property to an integer value that specifies a priority from -1 (highest priority) to any positive integer value. The greater the integer value is, the lower the priority of the filter is. You can use Order parameter for example (see here) to make your filter working before. More full description of the order you can find in the MSDN documentation.
The answer, this one and the article for example provide small examples of usage Order property of HandleError.
I have a custom ActionResult that sets HttpResponse.BufferOutput = false and then writes data to the response stream. I noticed that when the action result comes from a task-based asynchronous action method in ASP.NET MVC, writing to the response stream blocks. This happens only when Glimpse plugin is enabled in web.config. Glimpse is very useful to me, I really want to have it enabled, at least during development and testing. BufferOutput property should remain false, because the content length can be quite large and I don't want to buffer it in memory.
This is the shortest code that could reproduce this exact behaviour:
public sealed class CustomResult : ActionResult
{
public override void ExecuteResult(ControllerContext context)
{
var resp = context.HttpContext.Response;
resp.BufferOutput = false;
resp.ContentType = "text/plain";
resp.Output.Write(DateTime.UtcNow.ToString());
resp.Flush();
}
}
public sealed class DownloadController : Controller
{
// the client nevers gets the response from this action
public async Task<ActionResult> Async()
{
await Task.Yield();
return new CustomResult();
}
// this works
public ActionResult Sync()
{
return new CustomResult();
}
}
I tested this with the latest Glimpse.Mvc4 package (version 1.3.2).
Am I doing something wrong, is there a workaround to this issue or is this a Glimpse bug and I should report it?
I want to know is there any open source action result code available for asp.net mvc in which i can pass a URL and it will response out the content.
Just like there are some inbuilt Action results
FileResult
FileStreamResult
I want to build a custom Action Result in which i can pass a URL (basically an mp3 url) which will get downloaded in memory and the content will be streamed to the current executing response.
It should also support resume download if supported by server and client. Thats a must for me.
public UrlActionResult DownloadUrl(string url)
{
return new UrlActionResult("http://www.example.com/audiofile.mp3");
}
For a basic scenario you could use something like this:
public class DownloadResult : ActionResult
{
private readonly FileStreamResult _fileStreamResult;
public DownloadResult(string url, string contentType)
{
using (var myWebClient = new WebClient())
{
var myStream = myWebClient.OpenRead(url);
_fileStreamResult = new FileStreamResult(myStream, contentType);
}
}
public override void ExecuteResult(ControllerContext context)
{
_fileStreamResult.ExecuteResult(context);
}
}
However if you want to do the resume download it becomes a lot more complicated. Here is a great article with example code.
If you don't need to hide the url just use a redirect. Using a redirect with spare you server bandwidth:
public ActionResult DownloadUrl(string url)
{
return new Redirect("http://www.example.com/audiofile.mp3");
}