I'm setting up NPoco for dependency injection on a Web API + MVC 5 project (using StructureMap) and I'm not sure what the best practice is for managing the database connection. Should I use a singleton, or a per-request scope, something else? The database isn't really being used by the API/MVC controllers themselves, instead it is ultimately being injected into Mediatr CQRS handlers.
Currently I'm using a setup class
public static class DbFactory
{
public static DatabaseFactory Factory { get; set; }
public static void Setup()
{
Factory = DatabaseFactory.Config(x =>
{
x.UsingDatabase(() => new Database("con"));
//x.WithFluentConfig(fluentConfig);
//x.WithMapper(new Mapper());
});
}
}
which is configured with StrucureMap like this
// called from global.asax
DbFactory.Setup();
var container = new Container(cfg =>
{
// ... other stuff
cfg.For<IDatabase>().Use(() => DbFactory.Factory.GetDatabase());
});
Related
In startup.cs I have
services.AddAuthorization(options =>
{
options.AddPolicy("RequireSomething", policy => policy.Requirements.Add(new SomeRequirement()));
});
What if the SomeRequirement -class needs a class that is only available through dependency injection, like below. I can't/don't want to instantiate SomeRequirement.
public class SomeRequirement : AuthorizationHandler<SomeRequirement>, IAuthorizationRequirement
{
ISomething _something;
public SomeRequirement(ISomething something)
{
_something = something;
}
protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, SomeRequirement requirement)
{
//TODO Do stuff
return Task.CompletedTask;
}
}
I suggest there are two solution for this.
I assume that you have concrete implementation of ISomething. If you knew that that initialize that and pass it to parameter as parameter. This is short and sweet solution.
Second solution is bit awkward.
Default DI Container available in ASP.net Core does not support property injection.
Instead of using Default DI Container try to use Autofac or some other DI Container that support property injection.
Update 1: Possible Solution. ( Using Default DI of ASP.net Core)
public class SomeRequirement : AuthorizationHandler<SomeRequirement>, IAuthorizationRequirement
{
ISomething _something;
public SomeRequirement(ISomething something)
{
_something = something;
}
protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, SomeRequirement requirement)
{
//TODO Do stuff
return Task.CompletedTask;
}
}
public interface ISomething
{
}
public class Something : ISomething
{
}
And In ConfigureService
services.AddSingleton<ISomething, Something>();
services.AddScoped(typeof(SomeRequirement));
services.AddAuthorization(options =>
{
options.AddPolicy("RequireSomething", policy => policy.Requirements.Add(services.BuildServiceProvider().GetRequiredService<SomeRequirement>()));
});
Just starting playing with the .Net Core RC2 by migrating a current MVC .Net app I developed. It looks like to me because of the way that configuration is handled with appsettings.json that if I have multiple connection strings I either have to use EF to retrieve a connectionstring or I have to create separate classes named for each connection string. All the examples I see either use EF (which doesn't make sense for me since I will be using Dapper) or the example builds a class named after the section in the config. Am I missing a better solution?
"Data": {
"Server1": {
"ConnectionString": "data source={server1};initial catalog=master;integrated security=True;"
},
"Server2": {
"ConnectionString": "data source={server2};initial catalog=master;integrated security=True;"
}
}
Why would I want to build two classes, one named "Server1" and another "Server2" if the only property each had was a connectionstring?
There are a couple of corrections that I made to Adem's response to work with RC2, so I figured I better post them.
I configured the appsettings.json and created a class like Adem's
{
"ConnectionStrings": {
"DefaultConnectionString": "Default",
"CustomConnectionString": "Custom"
}
}
and
public class ConnectionStrings
{
public string DefaultConnectionString { get; set; }
public string CustomConnectionString { get; set; }
}
most of Adem's code comes out of the box in VS for RC2, so I just added the line below to the ConfigureServices method
services.Configure<Models.ConnectionStrings>(Configuration.GetSection("ConnectionStrings"));
The main missing point is that the connection string has to be passed to the controller (Once you’ve specified a strongly-typed configuration object and added it to the services collection, you can request it from any Controller or Action method by requesting an instance of IOptions, https://docs.asp.net/en/latest/mvc/controllers/dependency-injection.html)
So this goes to the controller,
private readonly ConnectionStrings _connectionStrings;
public HomeController(IOptions<ConnectionStrings> connectionStrings)
{
_connectionStrings = connectionStrings.Value;
}
and then when you instantiate the DAL you pass the appropriate connectionString
DAL.DataMethods dm = new DAL.DataMethods(_connectionStrings.CustomConnectionString);
All the examples show this, they just don't state it, why my attempts to pull directly from the DAL didn't work
I don't like the idea of instantiating the DAL. Rather, I'd do something like this
public class ConnectionStrings : Dictionary<string, string> { }
And something like this in the ctor of the DAL
public Dal(IOptionsMonitor<ConnectionStrings> optionsAccessor, ILogger<Dal> logger)
{
_connections = optionsAccessor.CurrentValue;
_logger = logger;
}
and you'll need to register with IoC
services.Configure<ConnectionStrings>(configuration.GetSection("ConnectionStrings")); /* services is the IServiceCollection */
Now you have all the connection strings in the DAL object. You can use them on each query or even select it by index on every call.
You can use Options to access in DAL layer. I will try to write simple example(RC1):
First you need to create appsettings.json file with below content:
{
"ConnectionStrings": {
"DefaultConnectionString": "Default",
"CustomConnectionString": "Custom"
}
}
Then create a class:
public class ConnectionStrings
{
public string DefaultConnectionString { get; set; }
public string CustomConnectionString { get; set; }
}
And in Startup.cs
private IConfiguration Configuration;
public Startup(IApplicationEnvironment app)
{
var builder = new ConfigurationBuilder()
.SetBasePath(app.ApplicationBasePath)
.AddJsonFile("appsettings.json");
Configuration = builder.Build();
}
public void ConfigureServices(IServiceCollection services)
{
// ....
services.AddOptions();
services.Configure<ConnectionStrings>(Configuration.GetSection("ConnectionStrings"));
}
Finally inject it in the DAL class:
private IOptions<ConnectionStrings> _connectionStrings;
public DalClass(IOptions<ConnectionStrings> connectionStrings)
{
_connectionStrings = connectionStrings;
}
//use it
I have a small MVC application that connects to a single MYSQL database. I had it setup with Ninject to bind the connectionString during the application startup. The code looked like this:
Global.asax.cs:
protected void Application_Start()
{
...
ControllerBuilder.Current.SetControllerFactory(new NinjectControllerFactory());
}
NinjectControllerFactory.cs:
public class NinjectControllerFactory : DefaultControllerFactory
{
...
private class EriskServices : NinjectModule
{
public override void Load()
{
// Bind all the Repositories
Bind<IRisksRepository>().To<MySql_RisksRepository>()
.WithConstructorArgument("connectionString",
ConfigurationManager.ConnectionStrings["dbcMain"]
.ConnectionString);
}
}
}
Today my requirements have changed and I have to now support multiple databases. I would like to have each database connection string defined in the web.config file, like how it was before. The user selects which database they want to connect to during the application login.
What would be the easiest way to bind my repositories after the login? I'm assuming I would need to code the database binding in the login controller.
I am kind of a newbie to Ninject so any examples would be much appreciated!
As always, Thanks for the time and help!
.
I would probably Bind the repository to a Ninject.Activation.IProvider, and then create your own provider that pulls the connectionString from Session
Bind<IRisksRepository>().ToProvider<SessionConnectionProvider>();
then...
public class SessionConnectionProvider : Ninject.Activation.IProvider
{
#region IProvider Members
public object Create( Ninject.Activation.IContext context )
{
// use however you're accessing session here
var conStr = session.ConnectionString;
return new MySql_RisksRepository( conStr );
}
public Type Type
{
get { return typeof( IRisksRepository ); }
}
#endregion
}
I would like to have my own injection attribute so that I am not coupling my code to a particular IOC framework. I have a custom injection attribute that my code uses to denote that a property should be injected.
public class CustomInjectAttribute : Attribute {}
Fictitious example below...
public class Robot : IRobot
{
[CustomInject]
public ILaser Zap { get; set; }
...
}
In Ninject, you can setup an injection Heuristic to find that attribute, and inject like;
public class NinjectInjectionHeuristic : NinjectComponent, IInjectionHeuristic, INinjectComponent, IDisposable
{
public new bool ShouldInject(MemberInfo member)
{
return member.IsDefined(typeof(CustomInjectAttribute), true);
}
}
and then register the heuristic with the kernel.
Kernel.Components.Get<ISelector>().InjectionHeuristics.Add(new NinjectInjectionHeuristic());
How would I go about achieving this with StructureMap. I know StructureMap has its own SetterProperties and attributes, but I'm looking for a way to decouple from that as you can with Ninject in the above example.
Use the SetAllProperties() method in your ObjectFactory or Container configuration. For example:
new Container(x =>
{
x.SetAllProperties(by =>
{
by.Matching(prop => prop.HasAttribute<CustomInjectAttribute>());
});
});
This makes use of a handy extension method (that should be in the BCL):
public static bool HasAttribute<T>(this ICustomAttributeProvider provider) where T : Attribute
{
return provider.GetCustomAttributes(typeof (T), true).Any();
}
I'm in my first time with DDD, so I'm begginer! So, let's take it's very simple :D
I developed an application using asp.net mvc 2 , ddd and nhibernate. I have a domain model in a class library, my repositories in another class library, and an asp.net mvc 2 application. My Repository base class, I have a construct that I inject and dependency (my unique ISessionFactory object started in global.asax), the code is:
public class Repository<T> : IRepository<T>
where T : Entidade
{
protected ISessionFactory SessionFactory { get; private set; }
protected ISession Session
{
get { return SessionFactory.GetCurrentSession(); }
}
protected Repository(ISessionFactory sessionFactory)
{
SessionFactory = sessionFactory;
}
public void Save(T entity)
{
Session.SaveOrUpdate(entity);
}
public void Delete(T entity)
{
Session.Delete(entity);
}
public T Get(long key)
{
return Session.Get<T>(key);
}
public IList<T> FindAll()
{
return Session.CreateCriteria(typeof(T)).SetCacheable(true).List<T>();
}
}
And After I have the spefic repositories, like this:
public class DocumentRepository : Repository<Domain.Document>, IDocumentRepository
{
// constructor
public DocumentRepository (ISessionFactory sessionFactory) : base(sessionFactory)
{ }
public IList<Domain.Document> GetByType(int idType)
{
var result = Session.CreateQuery("from Document d where d.Type.Id = :IdType")
.SetParameter("IdType", idType)
.List<Domain.Document>();
return result;
}
}
there is not control of transaction in this code, and it's working fine, but, I would like to make something to control this repositories in my controller of asp.net mvc, something simple, like this:
using (var tx = /* what can I put here ? */) {
try
{
_repositoryA.Save(objA);
_repositoryB.Save(objB);
_repositotyC.Delete(objC);
/* ... others tasks ... */
tx.Commit();
}
catch
{
tx.RollBack();
}
}
I've heared about NHibernateUnitOfWork, but i don't know :(, How Can I configure NHibernateUnitOfWork to work with my repositories ? Should I change the my simple repository ? Sugestions are welcome!
So, thanks if somebody read to here! If can help me, I appretiate!
PS: Sorry for my english!
bye =D
Session is NHibernate's unit of work. But you can always create your own abstraction of it.
using (var tx = Session.BeginTransaction) { ...
There is an excellent library called NCommon (source) that provides a great UnitOfWork implementation built right in. Version 1.1 allows you to do something like:
public class Foo
{
private readonly IRepository<Stuff> _repository;
public Foo(IRepository<Stuff> repository)
{
_repository = repository;
}
public void DoSomething()
{
using (var scope = new UnitOfWorkScope())
{
_repository.Save(a);
scope.Commit();
}
}
}
It integrates with the latest NHibernate and even uses NHibernate.Linq to provide some powerful querying features. You have little or nothing to build yourself and it works great out of the box.
Edit:
I elaborated on my example to show the full recommended way to use NCommon in a project with dependency-injection.
You can make the Session on your Repository a public property. Then you can do the following:
using(var tx = _repository.Session.BeginTransaction())
On a somewhat related note, this should all be inside of a service layer, not in your controller. Then the controller should have references to your services.