I am using dapper with the repository pattern in a WebApi Application and I have the following problem.
The Repository Class is as follows
public class Repository : DataConnection, IRepository
{
public Repository(IDbConnection connection)
: base(connection)
{
}
public T GetFirst<T>(object filters) where T : new()
{
//Creates the sql generator
var sqlGenerator = new MicroOrm.Pocos.SqlGenerator.SqlGenerator<T>();
//Creates the query
var query = sqlGenerator.GetSelect(filters);
//Execute the query
return Connection.Query<T>(query, filters).FirstOrDefault();
}
The IRepository Interface has only one method, the GetFirst. A Controller that uses this repository is as follows
public class UsersController : ApiController
{
private IRepository Repository;
public UsersController(IRepository repository)
{
Repository = repository;
}
public User Get(int id)
{
return Repository.GetFirst<User>(new { id });
}
}
I use autofac as DI and in the Application_Start method in Global.asax I use the following code
string connString = ConfigurationManager.ConnectionStrings["DapperDemo"].ConnectionString;
SqlConnection connnection = new SqlConnection(connString);
var builder = new ContainerBuilder();
builder.RegisterType<Repository>().As<IRepository>();
builder.RegisterType<UsersController>().InstancePerRequest();
var container = builder.Build();
var resolver = new AutofacWebApiDependencyResolver(container);
GlobalConfiguration.Configuration.DependencyResolver = resolver;
But it seems that I am missing something cause I get the following error:
An error occurred when trying to create a controller of type 'UsersController'. Make sure that the controller has a parameterless public constructor.
You need to overwrite default controller activator, because it has no knowledge of your DI container.
Add a service class:
public class ServiceActivator : IHttpControllerActivator
{
public ServiceActivator(HttpConfiguration configuration) { }
public IHttpController Create(HttpRequestMessage request
, HttpControllerDescriptor controllerDescriptor, Type controllerType)
{
var controller = ObjectFactory.GetInstance(controllerType) as IHttpController;
return controller;
}
}
Then on Application_Start():
GlobalConfiguration.Configuration.Services.Replace(typeof(IHttpControllerActivator), new ServiceActivator(GlobalConfiguration.Configuration));
I'm using structure map in this example, so just replace it with which ever container you are using.
Related
I need to Mock a DBContext class which in turn uses a Stored procedure & SqlAdapter to fetch result using Nunit and Moq . There is Unity Resolver IOC involved which takes care of DI .
---Web API Controller Class----
IEmployee _employee;
public Controller(IEmployee employee)
{
_employee = employee;
}
Route[employeedetails/get]
[HttpPost]
public EmployeeEntity Get(ParameterObject param)
{
return _employee.Get(param);
}
----------------------------------
Employee implements IEmployee :
--- DataAccess Class which implements the interface----
public class Employee : IEmployee
{
public EmployeeContext _repository;
public Employee(EmployeeContext repository)
{
_repository = repository;
}
public EmployeeEntity Get(ParameterObject param)
{
DataSet dataset= new DataSet();
EmployeeEntity response = new EmployeeEntity();
using(SqlConnection connection =
(SqlConnection)_repository.Database.Connection)
{
connection.Open()
SqlCommand command = connection.CreateCommand();
command.CommandText = "spGetEmployee";
command.CommandType = CommandType.StoredProcedure;
-- Add Parameters using param object --
using(SqlDataAdapter adapter = new SqlDataAdapter(command))
{
adapter.Fill(dataset);
response = MapReponse(dataset);
}
connection.Close();
}
return response;
}
}
-------------------------------------
--------DBContext class -----------
public partial class EmployeeContext : DbContext
{
public EmployeeContext() : base ("name=EmployeeContext")
{
}
}
So I need to Mock the DB functionality using NUnit and Moq .. My code using Unity resolver . Please help I tried many ways . Nothing si working for me ....
I am struggling with wiring dependencies through autofac in my WebApi 2 project. I have a following interface and class that i'd like to inject in my GET and POST controller actions,
public interface IRepository
{
IContext Context
{
get;
}
void SomeOperation();
}
public MyRepository : IRepository
{
IContext _context;
public MyRepository(IContext context)
{
_context = context;
}
public Context
{
get
{
return _context;
}
}
public void SomeOperation
{
// Perform some operation using _context;
}
}
I 'd like IRepository to be injected in controller like this,
public class MyController : ApiController
{
private readonly IRepository _repo;
public ApplicationsController(IRepository repo)
{
_repo = repo;
}
// GET: api/v1/Contexts({contextId})
public IHttpActionResult Get(string contextId)
{
_repo.SomeOperation();
}
}
IContext object to be injected in MyRepository has to be fetched from a factory, something like this
public class ContextFactory
{
Hashtable contextMap;
IContext Get(string contextId)
{
if contextMap.Contains(contextId)
return contextMap[contextId].Value;
else
{
IContextConfiguration configuration = ContextConfigurationFactory.Get(contextId);
IContext context = new ConcreteContext(configuration);
contextMap.Add[contextId, context];
return context;
}
}
}
I am not sure how to wire all the classes and convert logic in factory classes by injecting relationships through Autofac so that context id passed in url is passed to ContextConfigurationFactory.Get and instantiate ConcreteContext object when not found in hash and eventually Autofac injecting right context object in MyRepository before passing it on to Get action in the controller.
Let's simplify this a bit. What you're trying to do is:
Get the context ID from a route parameter.
Use that route parameter in the factory to create a context.
The rest seems pretty much peripheral - the repository, the controller, all that. The crux of the question is that you need to get a route parameter into your factory.
Given that, let's put together some simplified code:
public class ContextFactory
{
public IContext Get(string contextId)
{
return new Context(contextId);
}
}
public interface IContext
{
string Id { get; }
}
public class Context : IContext
{
public Context(string id)
{
this.Id = id;
}
public string Id { get; private set; }
}
That's basically what you have:
An IContext interface that things need.
A ContextFactory that is basically responsible for building these things.
A Context concrete implementation of IContext that is built by the factory.
I would probably do something like this:
var builder = new ContainerBuilder();
builder.RegisterType<ContextFactory>();
builder.Register(ctx =>
{
var routeData = HttpContext.Current.Request.RequestContext.RouteData;
var id = routeData.Values["contextId"] as string;
var factory = ctx.Resolve<ContextFactory>();
return factory.Get(id);
}).As<IContext>()
.InstancePerLifetimeScope();
Now when you resolve IContext it will use your factory, get the current context ID from route data, and pass it through the factory.
I will leave the following for you to look into:
What happens if the route parameter isn't there? (Autofac won't let you return null.)
What happens if the route parameter has invalid data?
The route parameter is pretty hackable, is this a security risk?
...and so on.
public sealed class SessionContext
{
private ISession httpContext;
public SessionContext(ISession httpContext)
{
this.httpContext = httpContext;
}
public string UserType
{
get
{
return httpContext.GetString("_UserType");
}
set
{
httpContext.SetString("_UserType", value);
}
}
...... More properties .....
}
public class HomeController : Controller
{
private AppSettings _appSettings;
private SessionContext session = null;
private readonly IHttpContextAccessor _httpContextAccessor;
private ISession httpContext => _httpContextAccessor.HttpContext.Session;
//I don't like this constructor as it is getting initialize or every controller call.
public HomeController(IOptions<AppSettings> myAppSettings, IHttpContextAccessor httpContextAccessor)
{
_appSettings = myAppSettings.Value;
_httpContextAccessor = httpContextAccessor;
appSettings = new AppSettings(_appSettings); //Should initialize only once.
session = new SessionContext(httpContext);
}
}
I have questions regarding ...
How to initialize and use Custom / Support classes in MVC 6 with Asp.Net Core 2.0
When I Initialize these classes, they getting initialize or every controller call. That is very redundant.
my SessionContext class is getting re-initialize every time. So I am loosing the values when I call this class from another controller.
I tried this approach but, not much of use.
services.AddSingleton();
Move from question to answer:
public void ConfigureServices(IServiceCollection services)
{
services.AddOptions();
services.AddSingleton<SessionContext, SessionContext>();
//calling the extension class to instantiate the classes which we require earlier.
services.AddMyProjectHelper(Configuration)
}
Created a extension class... where it initializes the support classes
public static class MyProjectHelperExtensions
{
public static IServiceCollection AddMyProjectHelper(this IServiceCollection services, IConfiguration configuration)
{
var section = configuration.GetSection("AppSettings");
// we first need to create an instance
var settings = new AppSettings();
// then we set the properties
new ConfigureFromConfigurationOptions<AppSettings>(section).Configure(settings);
var session = services.BuildServiceProvider().GetService<SessionContext>();
// then we register the instance into the services collection
services.AddSingleton<MyProjectHelper>(new MyProjectHelper(settings, session));
return services;
}
}
finally controller ctor uses the DI for the required class. Now I have avoided redundant initialization of support classes.
public SecurityController(MyProjectHelper objHelper, SessionContext sessionContext)
{
session = sessionContext;
projectHelper = projectHelper ?? objHelper;
}
Now, I am able to share the session variables which I have set in my support classes
private SessionContext session = null;
public HomeController(SessionContext sessionContext)
{
session = sessionContext;
}
[Authorize]
public IActionResult Index()
{
if (session.CurrEmployee != null)
{
ViewBag.Name = (session.CurrEmployee.FirstName + " " + session.CurrEmployee.LastName);
return View();
}
}
I am using the following code in a unit test for the test setup:
var simpleEntity = new SimpleEntity();
var complexEntity = new ComplexEntity
{
JoinEntity1List = new List<JoinEntity1>
{
new JoinEntity1
{
JoinEntity2List = new List<JoinEntity2>
{
new JoinEntity2
{
SimpleEntity = simpleEntity
}
}
}
}
};
var anotherEntity = new AnotherEntity
{
ComplexEntity = complexEntity1
};
using (var context = databaseFixture.GetContext())
{
context.Add(anotherEntity);
await context.SaveChangesAsync();
}
When SaveChangesAsync is reached EF throws an ArgumentException with the following message:
An item with the same key has already been added. Key: 1
I'm using a fixture as well for the unit test class which populates the database with objects of the same types, though for this test I want this particular setup so I want to add these new entities to the in memory database. I've tried adding the entities on the DbSet (not the DbContext) and adding all three entities separatly to no avail. I can however add "simpleEntity" separately (because it is not added in the fixture) but EF complains as soon as I try to add "complexEntity" or "anotherEntity".
It seems like EF in memory database cannot handle several Add's over different instances of the context. Is there any workaround for this or am I doing something wrong in my setup?
The databaseFixture in this case is an instance of this class:
namespace Test.Shared.Fixture
{
using Data.Access;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
public class InMemoryDatabaseFixture : IDatabaseFixture
{
private readonly DbContextOptions<MyContext> contextOptions;
public InMemoryDatabaseFixture()
{
var serviceProvider = new ServiceCollection()
.AddEntityFrameworkInMemoryDatabase()
.BuildServiceProvider();
var builder = new DbContextOptionsBuilder<MyContext>();
builder.UseInMemoryDatabase()
.UseInternalServiceProvider(serviceProvider);
contextOptions = builder.Options;
}
public MyContext GetContext()
{
return new MyContext(contextOptions);
}
}
}
You can solve this problem by using Collection Fixtures so you can share this fixture across several test classes. This way you don't build you context several times and thus you won't get this exception:
Some information about collection Fixture
My own example:
[CollectionDefinition("Database collection")]
public class DatabaseCollection : ICollectionFixture<DatabaseFixture>
{ }
[Collection("Database collection")]
public class GetCitiesCmdHandlerTests : IClassFixture<MapperFixture>
{
private readonly TecCoreDbContext _context;
private readonly IMapper _mapper;
public GetCitiesCmdHandlerTests(DatabaseFixture dbFixture, MapperFixture mapFixture)
{
_context = dbFixture.Context;
_mapper = mapFixture.Mapper;
}
[Theory]
[MemberData(nameof(HandleTestData))]
public async void Handle_ShouldReturnCountries_AccordingToRequest(
GetCitiesCommand command,
int expectedCount)
{
(...)
}
public static readonly IEnumerable<object[]> HandleTestData
= new List<object[]>
{
(...)
};
}
}
Good luck,
Seb
My Entity framework context is as following
public partial class MyContext : DbContext, IMyContext
{
static MyContext()
{
System.Data.Entity.Database.SetInitializer<MyContext>(null);
}
public MyContext()
: base("Name=MyContext")
{
}
I am resolving it through autofac in the following way
builder.RegisterType(typeof(MainContext)).As(typeof(DbContext)).InstancePerLifetimeScope();
builder.RegisterType<MainContext>().As<IMainContext>().InstancePerRequest();
This db context gets called in repository layer
#region Fields
private readonly IMyContext _context;
#endregion
#region Constructors and Destructors
public EmployeeRepository(IMyContext context)
{
_context = context;
}
#endregion
public void Create(Employee emp)
{
this._context.Employee.Add(emp);
}
Now my issue is , I want to set the connection string dynamically per call. The connection string will be passed through a webapi which i want to pass on to this context. Can anyone help me how can i do that? I am confused about autofac here. Secondly how can i make sure each call sets connection string and does not cache it.
You can use a factory that will build the context and set the connectionstring for you.
public interface IContextFactory
{
IContext GetInstance();
}
public class MyContextFactory : IContextFactory
{
public IContext GetInstance()
{
String connectionString = this.GetConnectionString(HttpContext.Current);
return new MyContext(connectionString);
}
private String GetConnectionString(HttpContext context)
{
// do what you want
}
}
builder.RegisterType<MyContextFactory>()
.As<IContextFactory>()
.InstancePerRequest();
builder.Register(c => c.Resolve<IContextFactory>().GetInstance())
.As<IContext>()
.InstancePerRequest();
If you can't get connectionstring based on HttpContext, you can change contextFactory implementation to expect initialization by WebAPI before creating the instance. For example :
public interface IContextFactory
{
IContext GetInstance();
void Initialize(String connectionString);
}
public class MyContextFactory : IContextFactory
{
private String _connectionString;
public void Initialize(String connectionString)
{
this._connectionString = connectionString;
}
public IContext GetInstance()
{
if (this._connectionString == null)
{
throw new Exception("connectionString not initialized");
}
return new MyContext(this._connectionString);
}
}
At the beginning of your web API call (through attribute for example), you can call the Initialize method. Because the factory is InstancePerRequest you will have one instance for the duration of the request.
By the way, I'm not sure to understand this registration
builder.RegisterType(typeof(MainContext)).As(typeof(DbContext)).InstancePerLifetimeScope();
builder.RegisterType<MainContext>().As<IMainContext>().InstancePerRequest();
It looks buggy because you will have 2 different registration of the same type and not for the same scope, is it intended ? Furthermore, it doesn't sound a good idea to register a DbContext, do you need this registration ?
The following registration looks better :
builder.RegisterType<MainContext>()
.As<IMainContext>()
.As<DbContext>()
.InstancePerRequest();