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Call Web API from MVC Controller Hanging Up

I've tried many different approaches for the past couple of hours, but my method call is hanging up the thread.
Here is my Web API code, which works fine when making AJAX call from the MVC client, but I'm trying to test calling from the server:
// GET api/values
[HttpGet]
public IEnumerable<string> Get()
{
return new string[] { "value1", "value2" };
}
Below is my MVC controller code and model code:
public async Task<ActionResult> TestApi()
{
try
{
var result = await VoipModels.GetValues();
return MVCUtils.JsonContent(result);
}
catch (Exception ex)
{
return MVCUtils.HandleError(ex);
}
}
...
public static async Task<string[]> GetValues()
{
string[] result = null;
using (var client = new HttpClient())
{
client.BaseAddress = new Uri("http://localhost:44305/api/");
//THIS IS THE LINE THAT HANGS UP - I'VE TRIED MANY VARIATIONS
var response = await client.GetAsync("values", HttpCompletionOption.ResponseHeadersRead).ConfigureAwait(false);
if (response.IsSuccessStatusCode)
{
result = await response.Content.ReadAsAsync<string[]>();
}
else
{
throw new Exception(response.ReasonPhrase);
}
}
return result;
}
I've used this format successfully when calling a separate, 3rd party API. I've run out of examples to try from my couple of hours of Googling.
What am I doing wrong here?

Check your port number. Based on your code, you have "hard coded" the port "http://localhost:44305/api/" which may likely be incorrect, you should convert that to grab it from the host
configuration instead.
Check your local machine's firewall. Make sure that your local machine's firewall is allowing connections to the port assigned.
Check your protocol. Ensure that you are using http or https appropriately in your request URL.
As a special note, there are very rare cases / exception cases that you would want to have a web API server call itself. Doing so, is rather inefficient design as it will consume resources for no gain (such a generating request and response).

Validate multiple endpoints using HTML status codes before failing when consuming a asmx web service C#

I am currently using a web service, which offers 2 endpoints, as backups for fall over. I need to test all 2 endpoints before my code completely fails and then will need to log the exception. My thoughts were to be to return the status code of the HTML response using this:
Function1:
public string ValidateHttpRequest(string endpointUrl)
{
try
{
var url = endpointUrl;
HttpClient httpClient = new HttpClient();
var reponse = httpClient.GetAsync(endpointUrl);
return reponse.Result.StatusCode.ToString();
}
catch (Exception ex)
{
Log.Log("exception thrown in ValidateHttpRequest()! " + ex.ToString());
Log.Log(ex);
return null;
}
}
This is called from another function, say function2().
Function 2:
private bool function2()
{
//Specify the binding to be used for the client.
BasicHttpsBinding binding = new BasicHttpsBinding();
var epA = "https://www1.endpoint1.com/endpointService.asmx";
var epB = "https://www2.endpoint1.com/endpointService.asmx";
if (ValidateHttpRequest(epA)== "OK")
{
EndpointAddress address = new EndpointAddress("https://www1.enpoint1.com/endpointService.asmx");
_Client = new WebService.SoapClient(binding, address);
return true;
}
else if ((ValidateHttpRequest(epB))== "OK")
{
EndpointAddress address2 = new EndpointAddress(("https://www2.enpoint2.com/endpointService.asmx"));
else
{
// Now Log error here completely, and only fail here if both above checks return anything apart from 200 status code
LogException(“Only log exception if all endpoints fail”);
return false;
}
}
This is all well and good, however I need this to not fail on the first call, as I will need to check if the other endpoint is valid/active. The issue is that if the response is null, the exception is handled and I will not check the rest of my endpoints, how can I correctly ensure my code is safe with i.e. exceptions are handled correctly, but continuing my code to check all endpoints before completely failing and halting execution. it should fail if i receive any other response apart from 200 OK I have researched about how to check the HTTP response and all that I can come up with is this but it doesn’t completely suit my needs .If anyone could point me in the right direction or help with a solution I would be very grateful.
Thanks in advance

Returning an HttpResponseMessage contents from a pass through API in ASP.NET Core [duplicate]

I'm developing an ASP.Net Core web application where I need to create a kind of "authentication proxy" to another (external) web service.
What I mean by authentication proxy is that I will receive requests through a specific path of my web app and will have to check the headers of those requests for an authentication token that I'll have issued earlier, and then redirect all the requests with the same request string / content to an external web API which my app will authenticate with through HTTP Basic auth.
Here's the whole process in pseudo-code
Client requests a token by making a POST to a unique URL that I sent him earlier
My app sends him a unique token in response to this POST
Client makes a GET request to a specific URL of my app, say /extapi and adds the auth-token in the HTTP header
My app gets the request, checks that the auth-token is present and valid
My app does the same request to the external web API and authenticates the request using BASIC authentication
My app receives the result from the request and sends it back to the client
Here's what I have for now. It seems to be working fine, but I'm wondering if it's really the way this should be done or if there isn't a more elegant or better solution to this? Could that solution create issues in the long run for scaling the application?
[HttpGet]
public async Task GetStatement()
{
//TODO check for token presence and reject if issue
var queryString = Request.QueryString;
var response = await _httpClient.GetAsync(queryString.Value);
var content = await response.Content.ReadAsStringAsync();
Response.StatusCode = (int)response.StatusCode;
Response.ContentType = response.Content.Headers.ContentType.ToString();
Response.ContentLength = response.Content.Headers.ContentLength;
await Response.WriteAsync(content);
}
[HttpPost]
public async Task PostStatement()
{
using (var streamContent = new StreamContent(Request.Body))
{
//TODO check for token presence and reject if issue
var response = await _httpClient.PostAsync(string.Empty, streamContent);
var content = await response.Content.ReadAsStringAsync();
Response.StatusCode = (int)response.StatusCode;
Response.ContentType = response.Content.Headers.ContentType?.ToString();
Response.ContentLength = response.Content.Headers.ContentLength;
await Response.WriteAsync(content);
}
}
_httpClient being a HttpClient class instantiated somewhere else and being a singleton and with a BaseAddressof http://someexternalapp.com/api/
Also, is there a simpler approach for the token creation / token check than doing it manually?

If anyone is interested, I took the Microsoft.AspNetCore.Proxy code and made it a little better with middleware.
Check it out here: https://github.com/twitchax/AspNetCore.Proxy. NuGet here: https://www.nuget.org/packages/AspNetCore.Proxy/. Microsoft archived the other one mentioned in this post, and I plan on responding to any issues on this project.
Basically, it makes reverse proxying another web server a lot easier by allowing you to use attributes on methods that take a route with args and compute the proxied address.
[ProxyRoute("api/searchgoogle/{query}")]
public static Task<string> SearchGoogleProxy(string query)
{
// Get the proxied address.
return Task.FromResult($"https://www.google.com/search?q={query}");
}

I ended up implementing a proxy middleware inspired by a project in Asp.Net's GitHub.
It basically implements a middleware that reads the request received, creates a copy from it and sends it back to a configured service, reads the response from the service and sends it back to the caller.

This post talks about writing a simple HTTP proxy logic in C# or ASP.NET Core. And allowing your project to proxy the request to any other URL. It is not about deploying a proxy server for your ASP.NET Core project.
Add the following code anywhere of your project.
public static HttpRequestMessage CreateProxyHttpRequest(this HttpContext context, Uri uri)
{
var request = context.Request;
var requestMessage = new HttpRequestMessage();
var requestMethod = request.Method;
if (!HttpMethods.IsGet(requestMethod) &&
!HttpMethods.IsHead(requestMethod) &&
!HttpMethods.IsDelete(requestMethod) &&
!HttpMethods.IsTrace(requestMethod))
{
var streamContent = new StreamContent(request.Body);
requestMessage.Content = streamContent;
}
// Copy the request headers
foreach (var header in request.Headers)
{
if (!requestMessage.Headers.TryAddWithoutValidation(header.Key, header.Value.ToArray()) && requestMessage.Content != null)
{
requestMessage.Content?.Headers.TryAddWithoutValidation(header.Key, header.Value.ToArray());
}
}
requestMessage.Headers.Host = uri.Authority;
requestMessage.RequestUri = uri;
requestMessage.Method = new HttpMethod(request.Method);
return requestMessage;
}
This method covert user sends HttpContext.Request to a reusable HttpRequestMessage. So you can send this message to the target server.
After your target server response, you need to copy the responded HttpResponseMessage to the HttpContext.Response so the user's browser just gets it.
public static async Task CopyProxyHttpResponse(this HttpContext context, HttpResponseMessage responseMessage)
{
if (responseMessage == null)
{
throw new ArgumentNullException(nameof(responseMessage));
}
var response = context.Response;
response.StatusCode = (int)responseMessage.StatusCode;
foreach (var header in responseMessage.Headers)
{
response.Headers[header.Key] = header.Value.ToArray();
}
foreach (var header in responseMessage.Content.Headers)
{
response.Headers[header.Key] = header.Value.ToArray();
}
// SendAsync removes chunking from the response. This removes the header so it doesn't expect a chunked response.
response.Headers.Remove("transfer-encoding");
using (var responseStream = await responseMessage.Content.ReadAsStreamAsync())
{
await responseStream.CopyToAsync(response.Body, _streamCopyBufferSize, context.RequestAborted);
}
}
And now the preparation is complete. Back to our controller:
private readonly HttpClient _client;
public YourController()
{
_client = new HttpClient(new HttpClientHandler()
{
AllowAutoRedirect = false
});
}
public async Task<IActionResult> Rewrite()
{
var request = HttpContext.CreateProxyHttpRequest(new Uri("https://www.google.com"));
var response = await _client.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, HttpContext.RequestAborted);
await HttpContext.CopyProxyHttpResponse(response);
return new EmptyResult();
}
And try to access it. It will be proxied to google.com

A nice reverse proxy middleware implementation can also be found here: https://auth0.com/blog/building-a-reverse-proxy-in-dot-net-core/
Note that I replaced this line here
requestMessage.Content?.Headers.TryAddWithoutValidation(header.Key, header.Value.ToArray());
with
requestMessage.Headers.TryAddWithoutValidation(header.Key, header.Value.ToString());
Original headers (e.g. like an authorization header with a bearer token) would not be added without my modification in my case.

I had luck using twitchax's AspNetCore.Proxy NuGet package, but could not get it to work using the ProxyRoute method shown in twitchax's answer. (Could have easily been a mistake on my end.)
Instead I defined the mapping in Statup.cs Configure() method similar to the code below.
app.UseProxy("api/someexternalapp-proxy/{arg1}", async (args) =>
{
string url = "https://someexternalapp.com/" + args["arg1"];
return await Task.FromResult<string>(url);
});

Piggy-backing on James Lawruk's answer https://stackoverflow.com/a/54149906/6596451 to get the twitchax Proxy attribute to work, I was also getting a 404 error until I specified the full route in the ProxyRoute attribute. I had my static route in a separate controller and the relative path from Controller's route was not working.
This worked:
public class ProxyController : Controller
{
[ProxyRoute("api/Proxy/{name}")]
public static Task<string> Get(string name)
{
return Task.FromResult($"http://www.google.com/");
}
}
This does not:
[Route("api/[controller]")]
public class ProxyController : Controller
{
[ProxyRoute("{name}")]
public static Task<string> Get(string name)
{
return Task.FromResult($"http://www.google.com/");
}
}
Hope this helps someone!

Twitchax's answer seems to be the best solution at the moment. In researching this, I found that Microsoft is developing a more robust solution that fits the exact problem the OP was trying to solve.
Repo: https://github.com/microsoft/reverse-proxy
Article for Preview 1 (they actually just released prev 2): https://devblogs.microsoft.com/dotnet/introducing-yarp-preview-1/
From the Article...
YARP is a project to create a reverse proxy server. It started when we noticed a pattern of questions from internal teams at Microsoft who were either building a reverse proxy for their service or had been asking about APIs and technology for building one, so we decided to get them all together to work on a common solution, which has become YARP.
YARP is a reverse proxy toolkit for building fast proxy servers in .NET using the infrastructure from ASP.NET and .NET. The key differentiator for YARP is that it is being designed to be easily customized and tweaked to match the specific needs of each deployment scenario. YARP plugs into the ASP.NET pipeline for handling incoming requests, and then has its own sub-pipeline for performing the steps to proxy the requests to backend servers. Customers can add additional modules, or replace stock modules as needed.
...
YARP works with either .NET Core 3.1 or .NET 5 preview 4 (or later). Download the preview 4 (or greater) of .NET 5 SDK from https://dotnet.microsoft.com/download/dotnet/5.0
More specifically, one of their sample apps implements authentication (as for the OP's original intent)
https://github.com/microsoft/reverse-proxy/blob/master/samples/ReverseProxy.Auth.Sample/Startup.cs

Here is a basic implementation of Proxy library for ASP.NET Core:
This does not implement the authorization but could be useful to someone looking for a simple reverse proxy with ASP.NET Core. We only use this for development stages.
using System;
using System.Globalization;
using System.Linq;
using System.Net.Http;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Primitives;
namespace Sample.Proxy
{
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddLogging(options =>
{
options.AddDebug();
options.AddConsole(console =>
{
console.IncludeScopes = true;
});
});
services.AddProxy(options =>
{
options.MessageHandler = new HttpClientHandler
{
AllowAutoRedirect = false,
UseCookies = true
};
options.PrepareRequest = (originalRequest, message) =>
{
var host = GetHeaderValue(originalRequest, "X-Forwarded-Host") ?? originalRequest.Host.Host;
var port = GetHeaderValue(originalRequest, "X-Forwarded-Port") ?? originalRequest.Host.Port.Value.ToString(CultureInfo.InvariantCulture);
var prefix = GetHeaderValue(originalRequest, "X-Forwarded-Prefix") ?? originalRequest.PathBase;
message.Headers.Add("X-Forwarded-Host", host);
if (!string.IsNullOrWhiteSpace(port)) message.Headers.Add("X-Forwarded-Port", port);
if (!string.IsNullOrWhiteSpace(prefix)) message.Headers.Add("X-Forwarded-Prefix", prefix);
return Task.FromResult(0);
};
});
}
private static string GetHeaderValue(HttpRequest request, string headerName)
{
return request.Headers.TryGetValue(headerName, out StringValues list) ? list.FirstOrDefault() : null;
}
public void Configure(IApplicationBuilder app)
{
app.UseWebSockets()
.Map("/api", api => api.RunProxy(new Uri("http://localhost:8833")))
.Map("/image", api => api.RunProxy(new Uri("http://localhost:8844")))
.Map("/admin", api => api.RunProxy(new Uri("http://localhost:8822")))
.RunProxy(new Uri("http://localhost:8811"));
}
public static void Main(string[] args)
{
var host = new WebHostBuilder()
.UseKestrel()
.UseIISIntegration()
.UseStartup<Startup>()
.Build();
host.Run();
}
}
}

GetAsync azure call no result

Using VS 2017 Community. Azure.
I have Azure setup, I have a blank webapp created just for test purpose.
My actual site is an Angular2 MVC5 site, currently run locally.
The following is the code that should... Contact azure providing secret key(the site is registered in azure Active directory).
From this i get a token i then can use to contact azure api and get list of sites.
WARNING: code is all Sausage code/prototype.
Controller
public ActionResult Index()
{
try
{
MainAsync().ConfigureAwait(false);
}
catch (Exception e)
{
Console.WriteLine(e.GetBaseException().Message);
}
return View();
}
static async System.Threading.Tasks.Task MainAsync()
{
string tenantId = ConfigurationManager.AppSettings["AzureTenantId"];
string clientId = ConfigurationManager.AppSettings["AzureClientId"];
string clientSecret = ConfigurationManager.AppSettings["AzureClientSecret"];
string token = await AuthenticationHelpers.AcquireTokenBySPN(tenantId, clientId, clientSecret).ConfigureAwait(false);
using (var client = new HttpClient())
{
client.DefaultRequestHeaders.Add("Authorization", "Bearer " + token);
client.BaseAddress = new Uri("https://management.azure.com/");
await MakeARMRequests(client);
}
}
static async System.Threading.Tasks.Task MakeARMRequests(HttpClient client)
{
const string ResourceGroup = "ProtoTSresGrp1";
// Create the resource group
// List the Web Apps and their host names
using (var response = await client.GetAsync(
$"/subscriptions/{Subscription}/resourceGroups/{ResourceGroup}/providers/Microsoft.Web/sites?api-version=2015-08-01"))
{
response.EnsureSuccessStatusCode();
var json = await response.Content.ReadAsAsync<dynamic>().ConfigureAwait(false);
foreach (var app in json.value)
{
Console.WriteLine(app.name);
foreach (var hostname in app.properties.enabledHostNames)
{
Console.WriteLine(" " + hostname);
}
}
}
}
Controller class uses a static helper class that gets the token from Azure...
public static class AuthenticationHelpers
{
const string ARMResource = "https://management.core.windows.net/";
const string TokenEndpoint = "https://login.windows.net/{0}/oauth2/token";
const string SPNPayload = "resource={0}&client_id={1}&grant_type=client_credentials&client_secret={2}";
public static async Task<string> AcquireTokenBySPN(string tenantId, string clientId, string clientSecret)
{
var payload = String.Format(SPNPayload,
WebUtility.UrlEncode(ARMResource),
WebUtility.UrlEncode(clientId),
WebUtility.UrlEncode(clientSecret));
var body = await HttpPost(tenantId, payload).ConfigureAwait(false);
return body.access_token;
}
static async Task<dynamic> HttpPost(string tenantId, string payload)
{
using (var client = new HttpClient())
{
var address = String.Format(TokenEndpoint, tenantId);
var content = new StringContent(payload, Encoding.UTF8, "application/x-www-form-urlencoded");
using (var response = await client.PostAsync(address, content).ConfigureAwait(false))
{
if (!response.IsSuccessStatusCode)
{
Console.WriteLine("Status: {0}", response.StatusCode);
Console.WriteLine("Content: {0}", await response.Content.ReadAsStringAsync());
}
response.EnsureSuccessStatusCode();
return await response.Content.ReadAsAsync<dynamic>().ConfigureAwait(false);
}
}
}
}
ISSUE:
Ok so the issue I was faced with was Async Deadlocks in my code. So i looked at this stack post stack post here
I fixed the issues by putting in .ConfigureAwait(false) on most of the await declarations.
Code runs and gets all the way back to the controller with a token etc and runs through the MakeARMRequests(HttpClient client) method, however the json only returns 1 result "{[]}" when i debug and as such ignores the loops.
My question is, is my code the culprit here? or would this point to a configuration setting in azure?

Not sure if this is the issue you are facing now BUT you never wait for a result from your async action in the first method Index in your code. MainAsync().ConfigureAwait(false); will immediately return and continue to the next block while the task MainAsync() will start in the background. The catch handler also does nothing because you dont wait f or a result.
Option 1 (recommended)
public async Task<ActionResult> Index()
{
try
{
await MainAsync().ConfigureAwait(false);
}
catch (Exception e)
{
Console.WriteLine(e.GetBaseException().Message);
}
return View();
}
Option 2 if you can't use async/await for some reason
public ActionResult Index()
{
try
{
MainAsync().GetAwaiter().GetResult();
}
catch (Exception e)
{
Console.WriteLine(e.GetBaseException().Message);
}
return View();
}

The Code looks OK and runs fine, Anyone who could help verify would be good, but one can assume this is OK.
The issue for this was configuration in azure, When you register an app you must set a certain number of Access controls via the subscription.
In this case I set some more specific things for the web api , for now set the app as owner and made reference to service management api.
Probably don't need half the "IAM" added in the subscription to the registered app, I simply went through adding the relevant ones and debugging each time until finally i got the results expected.

Can't get Fiddler to capture HttpClient web api calls from MVC with localhost different port

Yet another fiddler can't get it to capture post.
Similar to this SO Post I have spent two hours now reading and trying different solution yet none of them allow me to see my fiddler web api traffic.
As a side note my code is working I am just focused on getting fiddler to show me the api calls.
I will describe my setup then what I have tried.
My Web API is a separate MVC 6, EF 7 project running on port 63381
http://localhost:63381/
My ASP.NET MVC 5 web client project is running on port: 59722
http://localhost:59722/
A typical action controller in the mvc client:
//Controller CTOR
public ClientController()
{
client = new HttpClient();
client.BaseAddress = new Uri("http://localhost:63381/api/MyApi");
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
}
//Action within ClientController
public async Task<JsonResult> AddNewSubCategory()
{
HttpResponseMessage responseMessage = await client.PostAsJsonAsync(url2, content);
if (responseMessage.IsSuccessStatusCode)
{
return Json("[{Update Success}]", JsonRequestBehavior.AllowGet);
}
return Json("[{Error Updating}]", JsonRequestBehavior.AllowGet);
}
}
Added the block to 32 & 62 machine.config. Restarted visual studio did NOT restart machine or any other service. This did not work.
Added the block to the client web.config and this didn't work.
Changed localhost to machinename:port
Specifically I changed http://localhost:63381/api/MyApi to http://gpgvm-pc:63381/api/MyApi
Modified Global.asax with:
ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(delegate { return true; });
Fiddler custom rules
Reverse proxy
Set fiddler listening on a different port.
At this point I surrender. It seems to me #1 should work to capture everything but I am obviously still doing something wrong because I can get fiddler to capture one or the other but NOT the client calling off to the client???
Update:
My machine locked and after reboot I started seeing the api calls so this issue was something with my machine. So sorry to bother.

The problem is most likely that you are using localhost which are handled in a special way.
Try using machine name or your ip instead (do not use 127.0.0.1).
The documentation have information about this as well:
http://docs.telerik.com/fiddler/Observe-Traffic/Troubleshooting/NoTrafficToLocalhost

If you try to hit specific action in api then use that code in webapi config
public static void Register(HttpConfiguration config)
{
//config.Routes.MapHttpRoute(
// name: "DefaultApi",
// routeTemplate: "api/{controller}/{id}",
// defaults: new { id = RouteParameter.Optional });
config.Routes.MapHttpRoute("API Default", "api/{controller}/{action}/{id}",
new { id = RouteParameter.Optional });
}
This code where u call your api.
public ActionResult ClientController(model content)
{
try
{
HttpClient client = new HttpClient("http://localhost:63381/");
client.BaseAddress = new Uri();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
HttpResponseMessage response = client.PostAsJsonAsync("api/MyApi/url2", content).Result;
if (response.IsSuccessStatusCode)
{
return Json(new { code = 0, message = "Success" });
}
else
{
return Json(new { code = -1, message = "Failed" });
}
}
catch (Exception ex)
{
int code = -2;
return Json(new { code = code, message = "Failed" });
}
}
}