I am working on xamarin forms. Where I am consuming the API. When I am running the app in android 5 it is working fine but If I am running 7 + it is giving the error like
Unable to resolve host "almsdev.southeastasia.cloudapp.azure.com": No address associated with hostname.
How to resolve this?
Following is the code snippet:
public async Task<HttpResponseMessage> Login(string EmailOrMobile)
{
try
{
var responseTask = await client.GetAsync(OauthBaseUrl + "OAuthSAAS/MSLogin?UserCredentials=" + EmailOrMobile);
return responseTask;
}
catch (Exception ex)
{
Crashes.TrackError(ex);
return null;
}
}
On button click I am calling above method
private async void fn_Submit_Clicked(object sender, EventArgs e)
{
var response = await _oauthService.Login(txt_credentails.Text.Trim());
}
My Base URL is
http://almsdev.southeastasia.cloudapp.azure.com:81/api/
I am using
Http client = new Http();
Since you are targeting Android 9.0(API level 28) cleartext(non-HTTPS) support is disabled by default.
To overcome this you can: either use HTTPS, or, add configs to allow http traffic.
First, in your Android Project, create a folder: xml and add the file network_security_config
<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
<domain-config cleartextTrafficPermitted="true">
<domain includeSubdomains="true">almsdev.southeastasia.cloudapp.azure.com</domain>
</domain-config>
</network-security-config>
Then, in your Manifest.xml
<application android:label="YourAppName" android:networkSecurityConfig="#xml/network_security_config">
You can read more in the Xamarin Blog Post
Try to Add the login credentials to your Header Http Client.
Related
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.
I created a class that connected to the API to retrieve the required data using httpclient. That file was called in the code behind file of the view and worked perfectly. Than I decided to implement the MVVM approach. As a result, I moved the code that initialized the rest service class to the view-model.
After doing that, i stopped getting the data. To investigate, I stated the the debugging session with the breakpoint placed at the line where i initialize the rest service class. Than i executed that line. By doing that, I found out that a huge android mono exception is thrown and the debugging session if stopped. The app exits the debugging session.
This has happened for the first time since i stated developing my app in Xamarin Forms. I have no idea about why it is breaking like that. Your help will be greatly appreciated.
This is the code that was working properly.
In the view code behind file
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class SubtaskPage : ContentPage
{
protected override void OnAppearing()
{
base.OnAppearing();
PopulateSubtaskData();
}
private async void PopulateSubtaskData()
{
lstSubtasks.IsRefreshing = true;
try
{
RestService rs = new RestService();
SResponse = await rs.GetSubtasksAsync(Convert.ToInt32(Application.Current.Properties["UserId"]));
if (SResponse.Status == 1)
{
lstSubtasks.ItemsSource = SResponse.Subtasks;
}
else
{
await DisplayAlert("Error", SResponse.Message, "Ok");
}
}
catch (Exception E)
{
Debug.WriteLine(#"GetSubtasksAsync -> ERROR {0}", E.Message);
}
lstSubtasks.IsRefreshing = false;
}
}
The rest service class is as follows
This class is in a separate folder named "Services". ip and url have been changed for security reason.
class RestService
{
HttpClient client;
public List<Ticket> Tickets { get; private set; }
string Server1 = "server ip";
string Server2 = "server ip";
public RestService()
{
client = new HttpClient();
client.MaxResponseContentBufferSize = 256000;
}
public async Task<SubtasksResponse> GetSubtasksAsync(int UserId)
{
SubtasksResponse SubtaskResponse = new SubtasksResponse();
string ApiUrl = "URL";
string Url = "";
HttpResponseMessage response;
if (CrossConnectivity.Current.IsConnected)
{
Url = await GetActiveServerAsync();
if (Url != "")
{
var uri = string.Format(Url + ApiUrl, UserId);
try
{
response = await client.GetAsync(uri);
if (response.IsSuccessStatusCode)
{
var content = await response.Content.ReadAsStringAsync();
SubtaskResponse.Subtasks = JsonConvert.DeserializeObject<List<Ticket>>(content);
SubtaskResponse.Status = 1;
}
else
{
SubtaskResponse.Subtasks = null;
SubtaskResponse.Status = 0;
SubtaskResponse.Message = "Attempt to fetch data from server was unsuccessful. Please try again";
}
}
catch (Exception E)
{
SubtaskResponse.Subtasks = null;
SubtaskResponse.Status = 0;
SubtaskResponse.Message = "Error occured while fetching data from the server. Please try again";
}
}
else
{
SubtaskResponse.Subtasks = null;
SubtaskResponse.Status = 0;
SubtaskResponse.Message = "Remote Server Not Responding! Please try again later";
}
}
else
{
SubtaskResponse.Subtasks = null;
SubtaskResponse.Status = 0;
SubtaskResponse.Message = "No Network Connection Found! Please connect to a network and try again";
}
return SubtaskResponse;
}
}
}
This was working fine until I added the view model into the mix.
This is how I am calling the function in the view model.
async Task<SubtasksResponse> PopulateSubtaskList()
{
RestService rs = new RestService();
IsBusy = true;
_subtaskList = await rs.GetSubtasksAsync(Convert.ToInt32(Application.Current.Properties["UserId"]));
IsBusy = false;
return _subtaskList;
}
"RestService rs = new RestService();" this is the line where the code breaks.
Here is the image of the exception that occurs when the code breaks.
Hope you get the clear picture of the situation. Please let me know if additional information is required.
Thanks
Don't do this. If you want to call rest from a mvvm Xamarin Forms app I can advice Refit. All the difficult work is already done for you and abstracted away. With a few lines of code you are up and running.
BTW the error message you are showing probably has nothing to do with your code but is a bug in a recent Xamarin version. See here: https://bugzilla.xamarin.com/show_bug.cgi?id=56787
Found the answer on this page (https://releases.xamarin.com/common-issues-in-the-xamarin-15-2-2-release-being-tracked-by-the-xamarin-team/).
The solution is as follows
Download the missing Mono.Posix file and unzip the archive.
Right-click the Mono.Posix.dll file in Explorer and select Properties.
Check the Digital Signatures tab to ensure the file shows a valid Xamarin Inc. signature.
At the bottom of the General tab, if an Unblock checkbox appears, enable it and select OK. (This checkbox appears depending on how the file was downloaded.)
For Visual Studio 2017, copy the Mono.Posix.dll file into the “Xamarin.VisualStudio” extension directory. For example, for a default installation of the Enterprise edition, copy the file into:
C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\Common7\IDE\Extensions\Xamarin.VisualStudio
For Visual Studio 2015, copy the file into the “Xamarin\Xamarin” extension directory:
C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\Extensions\Xamarin\Xamarin\
Quit and restart Visual Studio.
For more detail, visit the link given above.
I have a very simple REST query to our WebAPI back end (used by a number of applications) and it works fine under Android and Windows but in iOS it fails with an "Object reference not set to an instance of an object" error. In the code below, both moHttpClient and loUri are instantiated. I've tried wrapping the call to GetEmployeeRecord in Device.BeginInvokeOnMainThread but that doesn't help either. I have upgraded to the latest stable version of Xamarin in Visual Studio and on my Mac. Why is it working in the other OSs but not iOS?
private async void btnTest_Clicked(object sender, EventArgs e)
{
await GetEmployeeRecord();
}
private async Task GetEmployeeRecord()
{
try
{
var loUri = new Uri("https://my.website.com/mobile.webapp/api/employees?key=6c6f2c06-a444-4e54-bd77-b5f594c29910");
var loResponse = await moHttpClient.GetAsync(loUri);
if (loResponse.IsSuccessStatusCode)
{
var lcJson = await loResponse.Content.ReadAsStringAsync();
await DisplayAlert("Employee", lcJson, "OK");
}
}
catch (Exception ex)
{
Device.BeginInvokeOnMainThread(() =>
{
DisplayAlert("Get Employee Record", ex.Message, "OK");
});
}
}
Using a breakpoint at the GetAsync line, both moHttpClient and loUri are instantiated. However, mousing over GetAsync gives a message that GetAsync is an unknown member. How can that be?
I just checked and it seems this Unknown member occurs with Android too. But with Android it actually executes.
In order to get the http query to work for iOS I had to install the NuGet package Microsoft.Net.Http in the PCL project, which is where the code is running.
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 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;