I am trying to set a public property in the service constructor, it is giving null reference exception in the Any() method. If I changed it to readonly field, it is working fine. But I would like to set this property by instantiating the service, could anyone provide insights how this can be achieved.
public class CustomerService : Service
{
private readonly IDbConnection _dbConnection;
public ServiceCommand SelectCommand {get;set;}
public CustomerService(IDBConnection dbConnection)
{
SelectCommand = new ServiceCommand();
_dbConnection = dbConnection;
}
public Customer Any()
{
//selectcommand is null here
}
}
I've partially answered this in this earlier question.
All public properties get injected by the IOC
The reason why SelectCommand property is null is because it's a public property. All of your Services public properties are attempted to be resolved by your Registered dependencies and because you don't have any registered dependencies of type ServiceCommand it is overrided with null. If this was defined in your constructor instead it would've thrown a run-time exception, because it's just a property it's set to null.
If you change the visibility of SelectCommand to be non-public, e.g. protected, private, internal or static it wont be attempted to be injected by the IOC.
Related
I am using Servicestack. I have a base class for my Services, like so:
public abstract class ServiceHandlerBase : Service
and then some methods and properties in there of interest. I already have several methods that accesses the IRequest object, like:
protected AlfaOnline GetContactItem()
{
string deviceUUID = Request.Headers.Get(Constants.DEVICE_UUID); // <-- calling this method from constructor will give NullRef on Request here
string authToken = Request.Headers.Get(Constants.AUTH_TOKEN);
// do stuff
return existingContactItem;
}
which works well inside my service implementations, no problems there.
Now, I wanted to use this exact same method directly from the base class, calling it in the constructor:
public ServiceHandlerBase()
{
AlfaOnline ao = GetContactItem();
}
but I then get a NullReferenceException on the Request object as noted above.
When is the Request object ready to access and use? Because it's not null inside the service implementations.
You can't access any dependencies like IRequest in the constructor before they've been injected, they're only accessible after the Service class has been initialized like when your Service method is called.
You can use a Custom Service Runner to execute custom logic before any Service is Executed, e.g:
public class MyServiceRunner<T> : ServiceRunner<T>
{
public override void OnBeforeExecute(IRequest req, TRequest requestDto) {
// Called just before any Action is executed
}
}
And register it with ServiceStack in your AppHost with:
public override IServiceRunner<TRequest> CreateServiceRunner<TRequest>(ActionContext ctx)
{
return new MyServiceRunner<TRequest>(this, ctx);
}
But if you just want to run some logic for a Service class you can now override OnBeforeExecute() in your base class, e.g:
public abstract class ServiceHandlerBase : Service
{
public override void OnBeforeExecute(object requestDto)
{
AlfaOnline ao = GetContactItem();
}
}
See ServiceFilterTests.cs for a working example.
If you're implementing IService instead of inheriting the Service base class you can implement IServiceBeforeFilter instead.
The new Service Filters is available from v5.4.1 that's now available on MyGet.
I am using primefaces version 5 and I am adding messages regarding to a specific actions like save :
public void save(Tenant tenant) {
tenantDao.save(tenant);
FacesContext.getCurrentInstance().addMessage(null, new FacesMessage("Save success"));
}
Since I had a lot of these actions I tried to simplify this by creating a custom annotation called Message:
#Target(Runtime)
#Retention(Method)
public #interface Message {
String value();
}
and in my dao class :
public class TenantDao {
#Message("Saved Successfully")
public Tenant save(Tenant t) {
return em.save(t);
}
}
To read this annotation I have overridden the ELResolver the method invoke
public Object invoke(ELContext context,
Object base,
Object method,
Class<?>[] paramTypes,
Object[] params) {
Object result = super.invoke(context,method,paramTypes,params);
Method m = base.getClass().getMethod(method,paramTypes);
if(m.getAnnotation(Message.class) != null) {
addMessahe(m.getAnnotation(Message.class).value());
}
return result;
}
This was called in property (rendered, update, ..) but not in action listener
After a lot of debugging I discovered that theactionListener is called from MethodExpression class. So, I wrapped the MethodExpression class, and override the method invoke.
The problem now is that there are no way to retreive the class Method from MethodExpression class, also if I used the expression #{tenantDao.save(tenant)} the method getMethodInfo from MethodExpression will throw an exception.
Are there any way to read tAnnotation from any jsf context ?
I know that using Spring with AOP may solve this but I am not using Spring now.
Thanks
Given below are my different class declarations and how I am trying to setup unity container configuration to get a Interface to Concrete class implementation. The code currently throws either an stackoverflow exception or suggests that a interface cannot be constructed.
Please help me fix, either the class structure or the container configuration.
CodesController Class -
public class CodesController : ApiController
{
private readonly IUnitOfWorkAsync unitOfWork;
private readonly ICodeRepository repository;
public CodesController(IUnitOfWorkAsync unitOfWork, ICodeRepository codeRepository)
{
if (unitOfWork == null)
{
throw new ArgumentNullException("unitOfWork");
}
this.unitOfWork = unitOfWork;
this.repository = codeRepository;
}
//Other class level methods here
}
CodeRepository class -
public class CodeRepository : ICodeRepository
{
private readonly ICodeRepository codeRepository;
public CodeRepository(ICodeRepository repository)
{
this.codeRepository = repository;
}
public virtual async Task<IEnumerable<Code>> GetCodeAsync(string codeKey)
{ //Some implementation here}
}
ICodeRepository Interface -
public interface ICodeRepository : IRepositoryAsync<Code>
{
Task<IEnumerable<Code>> GetCodeAsync(string codeKey);
}
IRepositoryAsync Interface -
public interface IRepositoryAsync<TEntity> : IRepository<TEntity> where TEntity : class, IPersistenceHint
{
Task<bool> DeleteAsync(params object[] keyValues);
Task<bool> DeleteAsync(CancellationToken cancellationToken, params object[] keyValues);
Task<TEntity> FindAsync(params object[] keyValues);
Task<TEntity> FindAsync(CancellationToken cancellationToken, params object[] keyValues);
}
Unity Container Configuration-
container.RegisterType<IUnitOfWorkAsync, UnitOfWork>(
"test",
new TransientLifetimeManager(),
new InjectionConstructor(container.Resolve<IDataContextAsync>("test")));
container.RegisterType<ICodeRepository, CodeRepository>();
container.RegisterType<CodesController, CodesController>();
With this given configuration and class structure, based on my experimentation with container config, I get following exception -
JSON
exceptionMessage=An error occurred when trying to create a controller of type 'CodesController'. Make sure that the controller has a parameterless public constructor.
exceptionType=System.InvalidOperationException
innerException
exceptionMessage=Type '<Namespace>.Api.Controllers.CodesController' does not have a default constructor
stackTrace= at System.Linq.Expressions.Expression.New(Type type)
at System.Web.Http.Internal.TypeActivator.Create[TBase](Type instanceType)at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.GetInstanceOrActivator(HttpRequestMessage request, Type controllerType, Func`1& activator)
at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType)
Please suggest, if anything is wrong here, so that I can fix the same. Already struggling many days on this.
You're injecting ICodeRepository to CodeRepository, which probably causes to stackoverflow exception, since it will keep generating ICodeRepositories. It will generate a recursive call. Somewhat like this one:
public class BaseFoo
{
public BaseFoo(BaseFoo foo){ }
}
public class Foo : BaseFoo
{
public Foo() : base(new Foo()) { }
}
And regarding the "does not have a default constructor"-exception, have you registered a DependencyResolver for Web API? See one of these questions for more detailed information how to do it:
Using Unity with Web Api 2 gives error does not have a default constructor
Unity.WebApi | Make sure that the controller has a parameterless public constructor
ASP.Net MVC 4 Web API controller dosn't work with Unity.WebApi
As a side note, you shouldn't have to register the CodesController in your unity registration.
I've extended the CredentialsAuthProvider provided by service-stack to allow me to authenticate against a Active-Directory instance. The AD access logic is encapsulated within a custom class called AdManager (see below)
e.g.:
public class AdCredentialsAuthProvider : CredentialsAuthProvider
{
public override bool TryAuthenticate(IServiceBase authService,
string userName,
string password)
{
IAdManager manager = new AdManager();
return manager.Authenticate(userName, password);
}
...
Question:
I was hoping I could register the AdManager using service-stacks built-in IoC "Funq.Container" within my extended "AppHostBase" and access it from within my custom CredentialsAuthProvider? I tried registering it but have not found a way of accessing the IoC (or my registered AdManager object) via the service-stack built in framework.
Am I missing something?
Thanks
You can access the IOC from within the AuthProvider with the supplied IServiceBase, e.g:
var addManager = authService.TryResolve<IAdManager>();
Anywhere else you can always resolve dependencies using the Singleton:
var addManager = HostContext.TryResolve<IAdManager>();
Otherwise if you know it's in an ASP.NET Web Host you also access it via your AppHost singleton:
var addManager = AppHostBase.Instance.Resolve<IAdManager>();
Service Stack uses property injection as well. I have used property injection when extending the Service class provided by Service stack.
public class MyService : Service
{
public MyService(IDb db)
{
//db constructor inject
}
public IValidator<MyData> MyDataValidator { get; set; }
public object Get(MyData request)
{
//MyDataValidator is property injected
}
}
I believe the same logic can be applied to the AuthProvider. But I havent tested it.
I am trying to use the Cache facilities of Service Stack. These are accessed through the
RequestContext, which is injected by the IOC in your Service.
This works as expected if you are using the default Funq IOC, it does not work when you hook AutoFac, RequestContext is null and I am not sure how to configure autofac to build it. Any clues here? My AutoFac configuration:
var builder = new ContainerBuilder();
//Now register all dependencies to your custom IoC container
builder.RegisterAssemblyTypes(new[] { typeof(AppHost).Assembly })
.PropertiesAutowired(PropertyWiringFlags.AllowCircularDependencies)
.AsImplementedInterfaces()
.SingleInstance();
container.Register<ICacheClient>(new MemoryCacheClient());
IContainerAdapter adapter = new AutofacIocAdapter(builder.Build());
container.Adapter = adapter;
EDIT:
My Service already extends ServiceStack.ServiceInterface.Service:
public class UserDetailsService : ServiceStack.ServiceInterface.Service
which implements IRequiresRequestContext, RequestContext is null. If I remove autofac then it works as expected. With Autofac RequestContext is null
RequestContext is not meant to be injected by an IOC, it's a special property that is set by ServiceStack if your Service requests it by implementing the IRequiresRequestContext interface. E.g.
public class MyClass : IService, IRequiresRequestContext {
//injected by ServiceStack at run-time (per request)
public IRequestContext RequestContext { get; set; }
}
This is the same mechanism how the RequestContext property gets populated in the convenient default Service base class in ServiceStack.