I am trying to Xamarin.uiTest to automate an application and I got this error in very initial stage.
System.InvalidOperationException : Sequence contains no elements
Code: AppInitializer.cs
using System;
using System.IO;
using System.Linq;
using Xamarin.UITest;
using Xamarin.UITest.Queries;
namespace MyXamarinApp1_Test1
{
public class AppInitializer
{
public static IApp StartApp(Platform platform)
{
if (platform == Platform.Android)
{
return ConfigureApp
.Android
//.InstalledApp("com.companyname.MyXamarinApp1")
.ApkFile("C:\\Users\\...\\Desktop\\com.companyname.MyXamarinApp1.apk")
.StartApp();
}
return ConfigureApp
.iOS.StartApp();
}
}
}
Code: Test.cs
using System;
using System.IO;
using System.Linq;
using NUnit.Framework;
using Xamarin.UITest;
using Xamarin.UITest.Queries;
namespace UITest1
{
[TestFixture(Platform.Android)]
[TestFixture(Platform.iOS)]
public class Tests
{
IApp app;
Platform platform;
public Tests(Platform platform)
{
this.platform = platform;
}
[SetUp]
public void BeforeEachTest()
{
app = AppInitializer.StartApp(platform);
}
[Test]
public void AppLaunches()
{
app.Screenshot("First screen.");
}
}
Any idea to resolve the issue is appreciated.
I am using the signed app, could it be an issue.
Xamarin version : 2.0.3
Nunit : 2.6.4
try downgrading or upgrading it to Xamarin 2.2.1 or less and try cleaning solution or delete debug folder and build and run the command in fresh command line window, it may fix.. not 100% sure
I have some class libraries that I use in my ASP.NET Web API app that handle all my backend stuff e.g. CRUD operations to multiple databases like Azure SQL Database, Cosmos DB, etc.
I don't want to re-invent the wheel and able to use them in a new Azure Functions that I'm creating in Visual Studio 2017. All my repository methods use an interface. So, how will I implement dependency injection in my new Azure function?
I'm not seeing any support for DI but I'm a bit confused. It appears Azure Functions are based on the same SDK as WebJobs and I think last year Microsoft had started supporting DI in WebJobs - I know for sure because I implemented it using Ninject.
Is there way around this so that I can use my existing libraries in my new Azure Functions project?
I see these two techniques in addition to the service locator (anti)pattern. I asked the Azure Functions team for their comments as well.
https://blog.wille-zone.de/post/azure-functions-dependency-injection/
https://blog.wille-zone.de/post/azure-functions-proper-dependency-injection/
There is an open feature request on the GitHub pages for Azure Functions concerning this matter.
However, the way I'm approaching this is using some kind of 'wrapper' entry point, resolve this using the service locator and and start the function from there.
This looks a bit like this (simplified)
var builder = new ContainerBuilder();
//register my types
var container = builder.Build();
using(var scope = container.BeginLifetimeScope())
{
var functionLogic = scope.Resolve<IMyFunctionLogic>();
functionLogic.Execute();
}
This is a bit hacky of course, but it's the best there is until there is at the moment (to my knowledge).
I've seen the willie-zone blog mentioned a lot when it comes to this topic, but you don't need to go that route to use DI with Azure functions.
If you are using Version2 you can make your Azure functions non-static. Then you can add a public constructor for injecting your dependencies. The next step is to add an IWebJobsStartup class. In your startup class you will be able to register your services like you would for any other .Net Core project.
I have a public repo that is using this approach here: https://github.com/jedi91/MovieSearch/tree/master/MovieSearch
Here is a direct link to the startup class: https://github.com/jedi91/MovieSearch/blob/master/MovieSearch/Startup.cs
And here is the function: https://github.com/jedi91/MovieSearch/blob/master/MovieSearch/Functions/Search.cs
Hope this approach helps. If you are wanting to keep your Azure Functions static then the willie-zone approach should work, but I really like this approach and it doesn't require any third party libraries.
One thing to note is the Directory.Build.target file. This file will copy your extensions over in the host file so that DI will work once the function is deployed to Azure. Running the function locally does not require this file.
Azure Functions Depdendency Injection was announced at MSBuild 2019. Here's an example on how to do it:
[assembly: FunctionsStartup(typeof(MyNamespace.Startup))]
namespace MyNamespace
{
public class Startup : FunctionsStartup
{
public override void Configure(IFunctionsHostBuilder builder)
{
builder.Services.AddHttpClient();
builder.Services.AddSingleton((s) => {
return new CosmosClient(Environment.GetEnvironmentVariable("COSMOSDB_CONNECTIONSTRING"));
});
builder.Services.AddSingleton<ILoggerProvider, MyLoggerProvider>();
}
}
}
GitHub Example
Documentation
As stated above, it was just announced at Build 2019. It can now be setup almost exactly like you would in an ASP .Net Core app.
Microsoft Documentation
Short Blog I Wrote
Actually there is a much nicer and simpler way provided out of the box by Microsoft. It is a bit hard to find though. You simply create a start up class and add all required services here, and then you can use constructor injection like in regular web apps and web apis.
This is all you need to do.
First I create my start up class, I call mine Startup.cs to be consistent with Razor web apps, although this is for Azure Functions, but still it's the Microsoft way.
using System;
using com.paypal;
using dk.commentor.bl.command;
using dk.commentor.logger;
using dk.commentor.sl;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Hosting;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using org.openerp;
[assembly:Microsoft.Azure.WebJobs.Hosting.WebJobsStartup(typeof(dk.commentor.starterproject.api.Startup))]
namespace dk.commentor.starterproject.api
{
public class Startup : IWebJobsStartup
{
public void Configure(IWebJobsBuilder builder)
{
builder.Services.AddSingleton<ILogger, CommentorLogger>();
builder.Services.AddSingleton<IPaymentService, PayPalService>();
builder.Services.AddSingleton<IOrderService, OpenERPService>();
builder.Services.AddSingleton<ProcessOrderCommand>();
Console.WriteLine("Host started!");
}
}
}
Next I change the method call in the function from static to non-static, and I add a constructor to the class (which is now also non-static). In this constructor I simply add the services I require as constructor parameters.
using System;
using System.IO;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using dk.commentor.bl.command;
namespace dk.commentor.starterproject.api
{
public class ProcessOrder
{
private ProcessOrderCommand processOrderCommand;
public ProcessOrder(ProcessOrderCommand processOrderCommand) {
this.processOrderCommand = processOrderCommand;
}
[FunctionName("ProcessOrder")]
public async Task<IActionResult> Run([HttpTrigger(AuthorizationLevel.Function, "post", Route = null)] HttpRequest req, ILogger log)
{
log.LogInformation("C# HTTP trigger ProcessOrder called!");
log.LogInformation(System.Environment.StackTrace);
string jsonRequestData = await new StreamReader(req.Body).ReadToEndAsync();
dynamic requestData = JsonConvert.DeserializeObject(jsonRequestData);
if(requestData?.orderId != null)
return (ActionResult)new OkObjectResult($"Processing order with id {requestData.orderId}");
else
return new BadRequestObjectResult("Please pass an orderId in the request body");
}
}
}
Hopes this helps.
I would like to add my 2 cents to it. I used the technique that it's used by Host injecting ILogger. If you look at the Startup project I created GenericBindingProvider that implements IBindingProvider. Then for each type I want to be injected I register it as follow:
builder.Services.AddTransient<IWelcomeService, WelcomeService>();
builder.Services.AddSingleton<IBindingProvider, GenericBindingProvider<IWelcomeService>>();
The downside is that you need to register the type you want to be injected into the function twice.
Sample code:
Azure Functions V2 Dependency Injection sample
I have been using SimpleInjector perfectly fine in Azure Functions. Just create a class (let's call it IoCConfig) that has the registrations and make a static instance of that class in function class so that each instance will use the existing instance.
public interface IIoCConfig
{
T GetInstance<T>() where T : class;
}
public class IoCConfig : IIoCConfig
{
internal Container Container;
public IoCConfig(ExecutionContext executionContext, ILogger logger)
{
var configurationRoot = new ConfigurationBuilder()
.SetBasePath(executionContext.FunctionAppDirectory)
.AddJsonFile("local.settings.json", optional: true, reloadOnChange: true)
.AddEnvironmentVariables()
.Build();
Container = new Container();
Configure(configurationRoot, logger);
}
public IoCConfig(IConfigurationRoot configurationRoot, ILogger logger)
{
Container = new Container();
Configure(configurationRoot, logger);
}
private void Configure(IConfigurationRoot configurationRoot, ILogger logger)
{
Container.RegisterInstance(typeof(IConfigurationRoot), configurationRoot);
Container.Register<ISomeType, SomeType>();
}
public T GetInstance<T>() where T : class
{
return Container.GetInstance<T>();
}
}
Then in root:
public static class SomeFunction
{
public static IIoCConfig IoCConfig;
[FunctionName("SomeFunction")]
public static async Task Run(
[ServiceBusTrigger("some-topic", "%SUBSCRIPTION_NAME%", Connection = "AZURE_SERVICEBUS_CONNECTIONSTRING")]
SomeEvent msg,
ILogger log,
ExecutionContext executionContext)
{
Ensure.That(msg).IsNotNull();
if (IoCConfig == null)
{
IoCConfig = new IoCConfig(executionContext, log);
}
var someType = IoCConfig.GetInstance<ISomeType>();
await someType.Handle(msg);
}
}
AzureFunctions.Autofac is very easy to use.
Just add a config file:
public class DIConfig
{
public DIConfig(string functionName)
{
DependencyInjection.Initialize(builder =>
{
builder.RegisterType<Sample>().As<ISample>();
...
}, functionName);
}
}
Add the DependencyInjectionConfig attribute then inject:
[DependencyInjectionConfig(typeof(DIConfig))]
public class MyFunction
{
[FunctionName("MyFunction")]
public static HttpResponseMessage Run([HttpTrigger(AuthorizationLevel.Function, "get", Route = null)]HttpRequestMessage request,
TraceWriter log,
[Inject]ISample sample)
{
https://github.com/introtocomputerscience/azure-function-autofac-dependency-injection
I think this is a better solution:
https://github.com/junalmeida/autofac-azurefunctions
https://www.nuget.org/packages/Autofac.Extensions.DependencyInjection.AzureFunctions
Install the NuGet in your project and then make a Startup.cs and put this in it:
[assembly: FunctionsStartup(typeof(Startup))]
public class Startup
{
public override void Configure(IFunctionsHostBuilder builder)
{
builder
.UseAppSettings() // this is optional, this will bind IConfiguration in the container.
.UseAutofacServiceProviderFactory(ConfigureContainer);
}
private void ConfigureContainer(ContainerBuilder builder)
{
// do DI registration against Autofac like normal! (builder is just the normal ContainerBuilder from Autofac)
}
...
Then in your function code you can do normal constructor injection via DI:
public class Function1 : Disposable
{
public Function1(IService1 service1, ILogger logger)
{
// logger and service1 injected via autofac like normal
// ...
}
[FunctionName(nameof(Function1))]
public async Task Run([QueueTrigger("myqueue-items", Connection = "AzureWebJobsStorage")]string myQueueItem)
{
//...
Support for Dependency injection begins with Azure Functions 2.x which means Dependency Injection in Azure function can now leverage .NET Core Dependency Injection features.
Before you can use dependency injection, you must install the following NuGet packages:
Microsoft.Azure.Functions.Extensions
Microsoft.NET.Sdk.Functions
Having Dependency Injection eases things like DBContext, Http client usage (Httpclienfactory), Iloggerfactory, cache support etc.
Firstly, update the Startup class as shown below
namespace DemoApp
{
public class Startup: FunctionsStartup
{
public override void Configure(IFunctionsHostBuilder builder)
{
builder.Services.AddScoped<IHelloWorld, HelloWorld>();
// Registering Serilog provider
var logger = new LoggerConfiguration()
.WriteTo.Console()
.CreateLogger();
builder.Services.AddLogging(lb => lb.AddSerilog(logger));
//Reading configuration section can be added here etc.
}
}
}
Secondly, Removal of Static keyword in Function class and method level
public class DemoFunction
{
private readonly IHelloWorld _helloWorld;
public DemoFunction(IHelloWorld helloWorld)
{
_helloWorld = helloWorld;
}
[FunctionName("HttpDemoFunction")]
public async Task<IActionResult> Run(
[HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
ILogger log)
{
log.LogInformation("C# HTTP trigger function processed a request.");
}
If we look into above e.g. IHelloWorld is injected using .NET Core DI
**Note:**In-spite of having latest version of Azure function v3 for Dependency Injection to enable few steps are manual as shown above
Sample code on github can be found here
I am developing a real time application based on signal R . I am using .NET framework 4 , Signal R version 1.2.2 in VS 2010.I am getting a Hub reference error stating
Uncaught Error: SignalR: Error loading hubs. Ensure your hubs reference is correct, e.g. <script src='/signalr/hubs'></script>.
I got a solution to add the Hub reference in global file. But since i am using DNN framework it contains multiple projects and have a common global file.
RouteTable.Routes.MapHubs("/myhubs", new HubConfiguration());
i tried adding this piece of code there, but it too didn't works..
my hub class
public class ChatHub : Hub
{
public void Send(string message)
{
Clients.Others.receive(message);
}
}
And start up class is
[assembly: OwinStartup(typeof(DotNetNuke.Modules.VideoChat.Startup))]
namespace DotNetNuke.Modules.VideoChat
{
public class Startup
{
public void Configuration(IAppBuilder app)
{
app.MapHubs();
}
}
}
i am using jquery on client side.
var chat = $.connection.chatHub;
$.connection.hub.start().done(function () {}
Can anyone suggest a way around
You need to follow these steps:
Create a Hub class on the server that inherits the Hub class from SignalR
Create client proxy for the Hub class (using .NET class or javascript code)
Startup the Hub on the server using MapHubs() (obsolete)
Your question does not give enought information. Is it a web application? Are you using javascript or .NET on the client side?
See this post: SignalR hubclass in classlibrary
EDIT
Here is what you should have in your Startup class now that I see that you are using OWIN:
[assembly: OwinStartup("StartupConfiguration", typeof(DotNetNuke.Modules.VideoChat.Startup))]
namespace DotNetNuke.Modules.VideoChat
{
public class Startup
{
public void Configuration(IAppBuilder app)
{
// SignalR Hub Startup
var hubConfiguration = new HubConfiguration();
hubConfiguration.EnableDetailedErrors = true;
hubConfiguration.EnableJavaScriptProxies = true;
hubConfiguration.EnableJSONP = false;
app.MapSignalR(hubConfiguration);
}
}
}
In your web.config, add these lines:
<appSettings>
<add key="owin:appStartup" value="StartupConfiguration" />
<add key="owin:AutomaticAppStartup " value="true" />
</appSettings>
I am using signalR 1.0.0 rc2 and have the code as following:
using System.Web;
using System.Threading.Tasks;
using Microsoft.AspNet.SignalR;
using Microsoft.AspNet.SignalR.Hubs;
[HubName("chat")]
public class Chat : Hub
{
public Chat()
{
}
[HubMethodName("send")]
public void Send(string message,string connectionId)
{
Clients.All(message);
}
}
and i have the client side js :
$(function () {
var myHub= $.connection.chat;
}
here i get the chat undefined.
i looked at the signalr/hubs and found
$.extend(signalR, {
//here should have extended hub methods but has nothing
});
what is the problem here is the hub not being initilized .I haven't included
RouteTable.Routes.MapHubs() in global.asax.cs (is it necessary to include this line?) . also when i include this line i get an error :
Method not found: 'Void Microsoft.AspNet.SignalR.DependencyResolverExtensions.InitializePerformanceCoun>ters(Microsoft.AspNet.SignalR.IDependencyResolver, System.String,System.Threading.CancellationToken)'.
thanks .
Is it possible to host SignalR as a part of WCF websocket service and not as a part of ASP.net web site. I am aware about pushing mesage from a web service to signalR clients but is it also possible tht when the socket connection is opened from browser it maps to a web serivce contract?
You can self-host the SignalR server:
Taken from (https://github.com/SignalR/SignalR/wiki/QuickStart-Hubs):
Getting Started
To get started, Install the following packages:
Install-Package Microsoft.Owin.Hosting -pre
Install-Package Microsoft.Owin.Host.HttpListener -pre
Install-Package Microsoft.AspNet.SignalR.Owin -pre
using System;
using Microsoft.AspNet.SignalR;
using Microsoft.Owin.Hosting;
using Owin;
namespace SignalR.Hosting.Self.Samples
{
class Program
{
static void Main(string[] args)
{
string url = "http://172.0.0.01:8080";
using (WebApplication.Start<Startup>(url))
{
Console.WriteLine("Server running on {0}", url);
Console.ReadLine();
}
}
}
class Startup
{
public void Configuration(IAppBuilder app)
{
// This will map out to http://localhost:8080/signalr by default
// This means a difference in the client connection.
app.MapHubs();
}
}
public class MyHub : Hub
{
public void Send(string message)
{
Clients.All.addMessage(message);
}
}
}
You can host the SignarR hub in any .Net application, like:
public class Program
{
public static void Main(string[] args)
{
// Connect to the service
var hubConnection = new HubConnection("http://localhost/mysite");
// Create a proxy to the chat service
var chat = hubConnection.CreateProxy("chat");
// Print the message when it comes in
chat.On("addMessage", message => Console.WriteLine(message));
// Start the connection
hubConnection.Start().Wait();
string line = null;
while((line = Console.ReadLine()) != null)
{
// Send a message to the server
chat.Invoke("Send", line).Wait();
}
}
}
Ref: https://github.com/SignalR/SignalR/wiki/QuickStart-Hubs
If there any specific reason you want to use WCF? you can write your service as SignarR hub only.