I created a Web API and would like to access it in my Android XAMARIN App. It's a XAMARIN Forms App, which references a .NET Standard 2.0 library with the newest RestSharp nuget package installed.
Unfortunately I get the error:
Error: ConnectFailure (No route to host)
whenever I do the following:
public async Task<List<ETFPortfolio>> GetPortfolios()
{
var client = new RestClient("http://10.0.2.2:51262/api/");
var request = new RestRequest("portfolio", Method.GET);
request.AddHeader("Accept", "application/json");
var response = client.Execute(request); // Result with the error stated above
throw new Exception();
}
My WebAPI controller is set up like this:
[Route("api/[controller]")]
public class PortfolioController : Controller
{
// GET api/portfolio
[HttpGet]
public async Task<IActionResult> Get()
{
try
{
var handler = new MyHandler();
var portfolioList = await handler.Handle();
return Ok(portfolioList);
}
catch (Exception ex)
{
return BadRequest(ex.Message);
}
}
I found a similar question, unfortunately there were no answers yet.
Error: ConnectFailure (No route to host)
Is there anything I'm missing here or could check out to make this work?
Since you are using a real device, your API url should not be a localhost but an IP address of the computer on which you have the API running.
localhost will work only on the emulator running on the same machine with your API.
P.S.: I wrote a blogpost on this topic, you might be interested in checking it as well.
Related
I have Xamarin Forms project where I'm trying to POST and GET data to/from a Web API but when I'm making an async/await call, it works on the emulator (not without its original problems!) but when I try it on my actual phone mobile (Samsung S8+), it just hangs indefinitely.
Note that I'm only concentrating on the Android part right now, not iOS, not that the problem should make any difference in either.
This is the code I'm using:
IDataService.cs
Task<TResponse> PostDataAsync<TRequest, TResponse>(string uri, TRequest data)
where TRequest : class
where TResponse : class;
DataService.cs:
public async Task<TResponse> PostDataAsync<TRequest, TResponse>(string
additionalUri, TRequest data)
where TRequest : class
where TResponse : class
{
return await WebClient
.PostData<TRequest, TResponse>
(string.Concat(this.Uri, additionalUri), data);
}
WebClient.cs
using (var client = new HttpClient())
{
var jsonData = JsonConvert.SerializeObject(data);
using (var response = await client.PostAsync(
uri,
new StringContent(jsonData,
Encoding.UTF8,
"application/json" )))
{
if (response.IsSuccessStatusCode)
{
var content = await response.Content.ReadAsStringAsync();
return JsonConvert.DeserializeObject<TResponse>(content);
}
}
}
Method 1:
LoginPageViewModel.cs
public DelegateCommand SignInCommand => _signInCommand ??
(this._signInCommand = new DelegateCommand(SignInCommandAction));
private async void SignInCommandAction()
{
try
{
....
var user = await this._dataService
.PostDataAsync<LoginRequestDto,
LoginResponseDto>(#"Accounts/Login", loginRequestDto);
....
}
...
}
Method2:
LoginPageViewModel.cs
public DelegateCommand SignInCommand => _signInCommand ??
(this._signInCommand =
new DelegateCommand(async () => await SignInCommandAction()));
private async Task SignInCommandAction()
{
try
{
....
var user = await this._dataService
.PostDataAsync<LoginRequestDto,
LoginResponseDto>(#"Accounts/Login", loginRequestDto);
....
}
...
}
The PostDataAsync works with both methods when I call my local web API i.e. http://10.0.2.2/MyApp/api/ but both methods still hangs when calling external my web service from web provider i.e. http://myapp-123-site.atempurl.com/api/ which is a temp url for testing purpose.
The same apply to my GetDataAsync which is not demonstrated in question but I just thought I'd mention it.
Based on the above, you would think that my async/await code is correct since it works when calling the local web api but then what's causing it to hang when calling the remote web api.
As mentioned, I did enable my INTERNET permission in the manifest.
Any suggestions welcomed?
Thanks.
UPDATE-1:
Note that I've just tried to call a GET opertation within the same function and this is working in the emulator but hanging with the actual mobile.
using (var client = new HttpClient())
{
using (var response = await client.GetAsync(uri))
{
if (response.IsSuccessStatusCode)
{
var content = await response.Content.ReadAsStringAsync();
return Newtonsoft.Json.JsonConvert
.DeserializeObject<TResponse>(content);
}
}
}
UPDATE-2:
This is somehow working and I have no idea why! The only thing that comes to mind is that I upgraded my libraries. This included PRISM which may have been at the source of the problem but I have no idea.
Sorry I can't provide more details. I could role back my code and try to see if it's hanging again but I just don't have the time to go and experiment some more considering the amount of time I've already spent on this. Sorry.
The requested url is an IP or a domain name.
If it is ip, only the IP of the public network can be accessed by devices on multiple network segments.
If it is a domain name, it needs to support the domain name resolution service.
If you do not have these environments for a while, you need the IP of the device and the IP of the server on the same network segment.
The PostDataAsync works with both methods when I call my local web API i.e. http://10.0.2.2/MyApp/api/ but both methods still hangs when calling external my web service from web provider i.e. http://myapp-123-site.atempurl.com/api/ which is a temp url for testing purpose.
From this phenomenon , the reason should be the temp url. From this domain name (myapp-123-site.atempurl.com) can not find the right local IP (10.0.2.2).And when you test in local network , I guess this will work.However the network of actual mobile can be not the same with local network , such as using 3G/4G network , then this will not working.
This is a Xamarin solution and I am getting the error found in this message's title. Of course, I can easily confirm that there is a Proxy property on HttpClientHandler in the PCL project. And the solution builds without error. Only when I run does it produce this error (on either Droid or iOS) and does so at the point where it invokes the method in the PCL which instantiates the HttpClient. Note that it doesn't even get to that method. The error appears on the application start-up method; e.g., UIApplication.Main()
If I comment out the handler and instantiate HttpClient without a handler, it works fine as long as I'm on the open internet. But I'm trying to get this to work from behind a proxy.
Further investigation showed that the device projects had no references to System.Net.Http. So I added these -- and it indicates Xamarin.iOS and Xamarin.Android as the packages -- but it still produces the error.
I'm not clear what the error is telling me but I believe it means that the device project can't see System.Net.Http.HttpClientHandler?
private HttpClient GetHttpClient()
{
WebProxy proxy = new WebProxy(ProxyConfig.Url)
{
Credentials = new NetworkCredential(ProxyConfig.Username, ProxyConfig.Password)
};
// At runtime, when GetHttpClient is invoked, it says it cannot find the Proxy setter
HttpClientHandler handler = new HttpClientHandler
{
Proxy = proxy,
UseProxy = true,
PreAuthenticate = true,
UseDefaultCredentials = false,
};
HttpClient client = new HttpClient(handler);
// This works when not behind a proxy
//HttpClient client = new HttpClient();
return client;
}
public async Task GetWeatherAsync(double longitude, double latitude, string username)
{
// MissingMethodException is thrown at this point
var client = GetHttpClient();
client.BaseAddress = new Uri(string.Format("http://api.geonames.org/findNearByWeatherJSON?lat={0}&lng={1}&username={2}", latitude, longitude, username));
try
{
var response = await client.GetAsync(client.BaseAddress);
if (response.IsSuccessStatusCode)
{
var JsonResult = response.Content.ReadAsStringAsync().Result;
var weather = JsonConvert.DeserializeObject<WeatherResult>(JsonResult);
SetValues(weather);
}
else
{
Debug.WriteLine(response.RequestMessage);
}
}
catch (HttpRequestException ex)
{
Debug.WriteLine(ex.Message);
}
catch (System.Net.WebException ex)
{
Debug.WriteLine(ex.Message);
}
catch (Exception ex)
{
Debug.WriteLine(ex.Message);
}
}
Add the Microsoft.Net.Http NuGet package to your platform project too. If you run into an issue adding this, try installing the latest Microsoft.Bcl.Build package first. Then, after that is installed, add the HTTP package.
I am trying to develop a web-socket server app for my UWP Windows 10 App.
This is my code:
class Server
{
public async void Start()
{
MessageWebSocket webSock = new MessageWebSocket();
//In this case we will be sending/receiving a string so we need to set the MessageType to Utf8.
webSock.Control.MessageType = SocketMessageType.Utf8;
//Add the MessageReceived event handler.
webSock.MessageReceived += WebSock_MessageReceived;
//Add the Closed event handler.
webSock.Closed += WebSock_Closed;
Uri serverUri = new Uri("ws://127.0.0.1/motion");
try
{
//Connect to the server.
await webSock.ConnectAsync(serverUri);
//Send a message to the server.
await WebSock_SendMessage(webSock, "Hello, world!");
}
catch (Exception ex)
{
//Add code here to handle any exceptions
}
}
//The MessageReceived event handler.
private void WebSock_MessageReceived(MessageWebSocket sender, MessageWebSocketMessageReceivedEventArgs args)
{
DataReader messageReader = args.GetDataReader();
messageReader.UnicodeEncoding = Windows.Storage.Streams.UnicodeEncoding.Utf8;
string messageString = messageReader.ReadString(messageReader.UnconsumedBufferLength);
//Add code here to do something with the string that is received.
}
//The Closed event handler
private void WebSock_Closed(IWebSocket sender, WebSocketClosedEventArgs args)
{
//Add code here to do something when the connection is closed locally or by the server
}
//Send a message to the server.
private async Task WebSock_SendMessage(MessageWebSocket webSock, string message)
{
DataWriter messageWriter = new DataWriter(webSock.OutputStream);
messageWriter.WriteString(message);
await messageWriter.StoreAsync();
}
}
It errors here:
await webSock.ConnectAsync(serverUri);
with this error:
Not found (404). (Exception from HRESULT: 0x80190194)
I don't have any personal experience with it, but you might want to give IotWeb HTTP Server a try. It seems to be a portable embedded HTTP and web socket server that also supports UWP and can be run inside Windows Store and Windows 10 IoT Core applications.
Judging from its repository, it's rather new and not exactly mature, nor does it have a lot of documentations or samples available. There's a NuGet package available, though.
Unfortunately I didn't manage to find any other alternative yet.
The code
await webSock.ConnectAsync(serverUri);
Is try to connect to existing server at ws://127.0.0.1/motion, Not to deploy a server on this address.
You can look for ways to build a c# WebSocket server at the follwing links:
https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API/Writing_WebSocket_server
http://www.codeproject.com/Articles/57060/Web-Socket-Server
i am developing an app using "Xamarin Forms", and i'm using Visual Studio 2013 to develop the app.
Here my problem is,
in my app i'm using restful services to Post/Get the data.
The entire code wrote in "Xamarin Shared Project"
Here is my code:
using System.Threading.Tasks;
using System.Net.Http;
namespace Sher.Services
{
public class CustomerService : ICustomerService
{
public async Task<string> TopEntries(String uri)
{
var client = new HttpClient();
var result = await client.GetStringAsync(uri); //"http://api.ihackernews.com/page"
return result;
}
}
public interface ICustomerService
{
Task<string> TopEntries();
}
}
Here i'm facing small problem.
i am able to call the service method and the service method execute in my server.
But the return result is gives always "NULL". i don't know why.
can any one help me to solve this problem.
Thanks in advance.
Yup, this is how async methods work. When an async call (await keyword) is made they exit and continue from that point when async calls is completed.
Try putting a breakpoint in "return result;" line.
I am trying to create a Windows Store App using a WebApi Odata controller. After some effort I have all the Get requests working, I am now moving onto the CRUD methods, and am getting the following Exception on the EndSaveChanges of the Data Service Context.
<?xml version="1.0" encoding="utf-8"?>
<m:error xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata">
<m:code />
<m:message xml:lang="en-US">No HTTP resource was found that matches the request URI 'http://localhost:56317/odata/ESFClients(guid'f04ad636-f896-4de4-816c-388106cd39ce')'.</m:message>
<m:innererror>
<m:message>No routing convention was found to select an action for the OData path with template '~/entityset/key'.</m:message>
<m:type></m:type>
<m:stacktrace></m:stacktrace>
</m:innererror>
</m:error>
Now I think this is a bug in WebApi from this http://aspnetwebstack.codeplex.com/workitem/822 and its hiding the actual error. To make sure it wasn't my Odata Endpoint I created a quick console app to get an entry, update it and Patch it back, which worked all ok. My WebApi Odata Controller derives from ODataController with
public HttpResponseMessage Patch([FromODataUri] Guid key, Delta<ESFClient> patch)
As the method.
In my windows application I have a extension method on the DataServiceContext for the Save Changes.
public static async Task<DataServiceResponse> SaveChangesAsync(this DataServiceContext context, SaveChangesOptions options)
{
var queryTask = Task.Factory.FromAsync<DataServiceResponse>(context.BeginSaveChanges(options, null, null),
queryAsyncResult =>
{
var results = context.EndSaveChanges(queryAsyncResult);
return results;
});
return await queryTask;
}
And calling the update like so from a blank Windows Store XAML page.
public async Task UpdateWeekNo()
{
var container = new ESFOdataService.Container(new Uri("http://localhost:56317/odata/"));
var clients = (DataServiceQuery<ESFClient>)from p in container.ESFClients where p.UserID == new Guid("f04ad636-f896-4de4-816c-388106cd39ce") select p;
var result = await clients.ExecuteAsync();
var updatedClient = result.Single();
if (updatedClient != null)
{
updatedClient.WeekNo = 19;
container.UpdateObject(updatedClient);
await container.SaveChangesAsync(SaveChangesOptions.PatchOnUpdate); // Use PATCH not MERGE.
}
}
So does anyone come across the same issue, or know how I can find out the actual error. One interesting point is that if I debug the controller while running the Windows App, the patch method does not get called.
Ok, so I have finally solved this. Just a recap for those who could experience the same issue. I have an Odata WebApi controller, Windows 8 Store Application using WCF Client Library, with the reference created from Add Service Reference. When trying to update (patch) a record an exception was being thrown at the EndSaveChanges. This is because for some reason Post Tunneling is enabled by default on my context. Setting this to false allowed everything to work.
Context.UsePostTunneling = false;
Context.IgnoreResourceNotFoundException = true;