I understand this is a very old question, but I still have questions
Imagine that there is a service that works on REST and returns objects DTO & List
public interface ExternalService() {
Dto getDto(String id);
List<Dto> getListDto(String filter);
}
How to properly wrap the result in mono in Spring Service?
public MonoService() {
public void call1 (String id){
Mono.just(getDto(id))
.map()...
}
public void call2 (String id){
Mono.fromCallable(() -> getDto(id))
.subscribeOn(Schedulers.boundedElastic())
.map()...
}
public void call2 (String id){
Mono.just(idIn)
.map(id -> getDto(idIn))
.map()...
}
}
Mono has method fromCallable. Why doesn't Flux have one?
Related
I'm using ASP.NET MVC 4 with Entity Framework 5. I have model classes and Entity Maps to map existing tables to those model classes. All this is setup fine and works great.
Now I want to mock this. I created Unit Of Work that takes the DataContext and uses a Generic Repository. Upon that I built services to be able to get data from many repositories at once and only needing to have one instance of the DataContext. This also works great.
Now to the problem: I want to test the services, with mock data. When I create the Unit Of Work instance, I want to be able to insert a DataContext that is mocked instead of the real DataContext.
I tried to create a IContext interface and let the real and mocked DataContext implement that but ran into problems with DbSet. I tried to use IDbSet and creating a FakeDbSet but without success. I also read on the internet that mocking the context with IDbSet and using a FakeDbSet is a bad approach.
Do you have any idea what would be the best way to achieve this? What I have now is the behavior I would like to keep, but would really like to be able to mock the data from the Model classes in the DataContext.
I'm aware of that Entity Framework already comes with Unit Of Work behavior and that you don't need to add extra behavior on top of that. But I wanted to wrap that inside of another class that keeps track of all the repositories (called UnitOfWork class).
Edit: I wrote two articles explaining my solution with both LINQ and Entity Framework.
http://gaui.is/how-to-mock-the-datacontext-linq/
http://gaui.is/how-to-mock-the-datacontext-entity-framework/
Here's my code:
IRepository.cs
public interface IRepository<T> where T : class
{
void Add(T entity);
void Delete(T entity);
void Update(T entity);
T GetById(long Id);
IEnumerable<T> All();
IEnumerable<T> Find(Expression<Func<T, bool>> predicate);
}
IUnitOfWork.cs
public interface IUnitOfWork : IDisposable
{
IRepository<TEntity> GetRepository<TEntity>() where TEntity : class;
void Save();
}
Repository.cs
public class Repository<T> : IRepository<T> where T : class
{
private readonly IDbContext _context;
private readonly IDbSet<T> _dbset;
public Repository(IDbContext context)
{
_context = context;
_dbset = context.Set<T>();
}
public virtual void Add(T entity)
{
_dbset.Add(entity);
}
public virtual void Delete(T entity)
{
var entry = _context.Entry(entity);
entry.State = System.Data.EntityState.Deleted;
}
public virtual void Update(T entity)
{
var entry = _context.Entry(entity);
_dbset.Attach(entity);
entry.State = System.Data.EntityState.Modified;
}
public virtual T GetById(long id)
{
return _dbset.Find(id);
}
public virtual IEnumerable<T> All()
{
return _dbset;
}
public IEnumerable<T> Find(Expression<Func<T, bool>> predicate)
{
return _dbset.Where(predicate);
}
}
UnitOfWork.cs
public class UnitOfWork<TContext> : IUnitOfWork where TContext : IDbContext, new()
{
private readonly IDbContext _ctx;
private Dictionary<Type, object> _repositories;
private bool _disposed;
public UnitOfWork()
{
_ctx = new TContext();
_repositories = new Dictionary<Type, object>();
_disposed = false;
}
public IRepository<TEntity> GetRepository<TEntity>() where TEntity : class
{
if (_repositories.Keys.Contains(typeof(TEntity)))
return _repositories[typeof(TEntity)] as IRepository<TEntity>;
var repository = new Repository<TEntity>(_ctx);
_repositories.Add(typeof(TEntity), repository);
return repository;
}
public void Save()
{
_ctx.SaveChanges();
}
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
protected virtual void Dispose(bool disposing)
{
if (!this._disposed)
{
if (disposing)
{
_ctx.Dispose();
}
this._disposed = true;
}
}
}
ExampleService.cs
public class ExampleService
{
private IRepository<Example> m_repo;
public ExampleService(IUnitOfWork uow)
{
m_repo = uow.GetRepository<Example>();
}
public void Add(Example Example)
{
m_repo.Add(Example);
}
public IEnumerable<Example> getAll()
{
return m_repo.All();
}
}
ExampleController.cs
public IEnumerable<Example> GetAll()
{
// Create Unit Of Work object
IUnitOfWork uow = new UnitOfWork<AppDataContext>();
// Create Service with Unit Of Work attached to the DataContext
ExampleService service = new ExampleService(uow);
return service.getAll();
}
Your ExampleService class is expecting IUnitOfWork, that means you just need another IUnitOfWork that is a Mock and its GetRepository() method will return an IRepository Mock.
For example (not really a Mock but In-Memory stub):
public InMemoryRepository<T> : IRepository<T> where T : class
{
........
}
public InMemoryUnitOfWork : IUnitOfWork
{
public IRepository<TEntity> GetRepository<TEntity>() where TEntity : class
{
return new InMemoryRepository<TEntity>();
}
}
Then:
public IEnumerable<Example> GetAll()
{
// Create Unit Of Work object
IUnitOfWork uow = new InMemoryUnitOfWork();
// Create Service with Unit Of Work
ExampleService service = new ExampleService(uow);
return service.getAll();
}
You can follow the following link it is very helpful.
Generic Repository Pattern in MVC3 Application with Entity Framework
Entity Framework and Data Patterns
I am developing a (hopefully) RESTful API using ServiceStack.
I noticed that most of my services look the same, for example, a GET method will look something like this:
try
{
Validate();
GetData();
return Response();
}
catch (Exception)
{
//TODO: Log the exception
throw; //rethrow
}
lets say I got 20 resources, 20 request DTOs, so I got about 20 services of the same template more or less...
I tried to make a generic or abstract Service so I can create inheriting services which just implement the relevant behavior but I got stuck because the request DTOs weren't as needed for serialization.
Is there any way to do it?
EDIT:
an Example for what I'm trying to do:
public abstract class MyService<TResponse,TRequest> : Service
{
protected abstract TResponse InnerGet();
protected abstract void InnerDelete();
public TResponse Get(TRequest request)
{
//General Code Here.
TResponse response = InnerGet();
//General Code Here.
return response;
}
public void Delete(TRequest request)
{
//General Code Here.
InnerDelete();
//General Code Here.
}
}
public class AccountService : MyService<Accounts, Account>
{
protected override Accounts InnerGet()
{
throw new NotImplementedException();//Get the data from BL
}
protected override void InnerDelete()
{
throw new NotImplementedException();
}
}
To do this in the New API we've introduced the concept of a IServiceRunner that decouples the execution of your service from the implementation of it.
To add your own Service Hooks you just need to override the default Service Runner in your AppHost from its default implementation:
public virtual IServiceRunner<TRequest> CreateServiceRunner<TRequest>(ActionContext actionContext)
{
return new ServiceRunner<TRequest>(this, actionContext); //Cached per Service Action
}
With your own:
public override IServiceRunner<TRequest> CreateServiceRunner<TRequest>(ActionContext actionContext)
{
return new MyServiceRunner<TRequest>(this, actionContext); //Cached per Service Action
}
Where MyServiceRunner is just a custom class implementing the custom hooks you're interested in, e.g:
public class MyServiceRunner<T> : ServiceRunner<T> {
public override void OnBeforeExecute(IRequestContext requestContext, TRequest request) {
// Called just before any Action is executed
}
public override object OnAfterExecute(IRequestContext requestContext, object response) {
// Called just after any Action is executed, you can modify the response returned here as well
}
public override object HandleException(IRequestContext requestContext, TRequest request, Exception ex) {
// Called whenever an exception is thrown in your Services Action
}
}
Also for more fine-grained Error Handling options check out the Error Handling wiki page.
My solution was to add an additional layer where I can handle Logic per entity:
Base Logic Sample:
public interface IEntity
{
long Id { get; set; }
}
public interface IReadOnlyLogic<Entity> where Entity : class, IEntity
{
List<Entity> GetAll();
Entity GetById(long Id);
}
public abstract class ReadOnlyLogic<Entity> : IReadOnlyLogic<Entity> where Entity : class, IEntity, new()
{
public IDbConnection Db { get; set; }
#region HOOKS
protected SqlExpression<Entity> OnGetList(SqlExpression<Entity> query) { return query; }
protected SqlExpression<Entity> OnGetSingle(SqlExpression<Entity> query) { return OnGetList(query); }
#endregion
public List<Entity> GetAll()
{
var query = OnGetList(Db.From<Entity>());
return Db.Select(query);
}
public Entity GetById(long id)
{
var query = OnGetSingle(Db.From<Entity>())
.Where(e => e.Id == id);
var entity = Db.Single(query);
return entity;
}
}
Then we can use hooks like:
public interface IHello : IReadOnlyLogic<Hello> { }
public class HelloLogic : ReadOnlyLogic<Hello>, IHello
{
protected override SqlExpression<Hello> OnGetList(SqlExpression<Hello> query)
{
return query.Where(h => h.Name == "Something");
}
}
Finally our service only calls our logic:
public class MyServices : Service
{
IHello helloLogic;
public object Get()
{
return helloLogic.GetAll();
}
}
I have a Product Service. On each call to Service, I want to call a method. In this case, I am logging. I am looking for a way, not to write the using statement in each method. But I still want the Logging to happen on each call. How do I do this?
public class ProductService : IProductService
{
public IList<Product> GetProductsByBrand(int BrandID)
{
using (new Logging())
{
// Get a list of products By Brand
}
return new List<Product>();
}
public IList<Product> Search(string ProductName)
{
using (new Logging())
{
// Search
}
return new List<Product>();
}
public static string OrderProducts(IList<Order> Orders, Payment paymentDetials)
{
string AuthCode;
using (new Logging())
{
// Order and get the AuthCode
}
AuthCode = "";
return AuthCode;
}
}
Have you heard of AOP (Aspect Oriented Programming)? It's a way of implementing cross cutting concerns as reusable Aspects that wrap around the target type and perform additional processing before or after the method that they are wrapping.
http://en.wikipedia.org/wiki/Decorator_pattern
Within a WCF environment this is typically done by applying "Behaviors" to your service class. In this case I would suggest the IOperationBehavior interface using an attribute that implements IParameterInspector in order to look at the parameters before they are passed the service instance is created and called. Here is a link to a useful article that goes into more depth regarding your options for extending the wcf message pipeline.
http://msdn.microsoft.com/en-us/magazine/cc163302.aspx
//Attribute class
public class LogOperationBehavior : Attribute, IOperationBehavior, IParameterInspector {
public void AddBindingParameters(OperationDescription operationDescription, System.ServiceModel.Channels.BindingParameterCollection bindingParameters) {
return;
}
public void ApplyClientBehavior(OperationDescription operationDescription, System.ServiceModel.Dispatcher.ClientOperation clientOperation) {
//clientOperation.ParameterInspectors.Add(new ClientParameterInspector());
}
public void ApplyDispatchBehavior(OperationDescription operationDescription, System.ServiceModel.Dispatcher.DispatchOperation dispatchOperation) {
dispatchOperation.ParameterInspectors.Add(this);
}
public void Validate(OperationDescription operationDescription) {
return;
}
#region IParameterInspector Members
public void AfterCall(string operationName, object[] outputs, object returnValue, object correlationState) {
//perform logging after
}
public object BeforeCall(string operationName, object[] inputs) {
//perform logging before
return null;
}
#endregion
}
public class BusinessOperation : IBusinessOperation {
//Apply to your service via an attribute
[LogOperationBehavior]
public DivideResponse DivideTwoNumbers(DivideRequest dr) {
return new DivideResponse() {
Answer = dr.Numerator/ dr.Demoninator2,
};
}
Have you considered creating a logging proxy? It would look something like this:
public class LoggingProductService : IProductService
{
private readonly IProductService _core;
public LoggingProductService(IProductService core)
{
_core = core;
}
public IList<Product> GetProductsByBrand(int BrandID)
{
Log("Getting products for brand " + BrandId);
return _core.GetProductsByBrand(BrandId);
}
//other IProductService methods here, all logging and delegating to _core
private void Log(string message)
{
using (var log = new Logging())
{
log.Write(message);
}
}
}
Of course, I don't entirely understand your Logging interface, so fill in the appropriate guesses with correct code. You also may not want to create and Dispose a Logging that often, I don't know.
You can create a dynamic proxy. See this article for instructions. http://www.drdobbs.com/windows/184405378
First the code:
[ServiceContract]
public interface IWorker
{
[OperationContract]
void Process(XmlElement data);
[OperationContract]
void Update(Rule rule);
}
[DataContract]
public class Rule
{
[OperationContract]
public string Expression { get; set; }
[OperationContract]
public List<IAction> Actions { get; set; }
}
public interface IAction
{
void Execute(XmlElement data);
}
A dispatcher encodes data as xml and sends it to an IWorker instance where each expression is evaluated. When an IWorker instance evaluates an expression as true, IAction.Execute is called and the xml/data is passed.
What's the best way to serialize Rule.Actions? I've started writing a custom serializer but I'd prefer to see if there is an easier way.
Thanks.
I dont think you can use interfaces in DataContracts (someone correct me if im wrong, but i assume thats like trying to use a generic too). What I do, is have a parent class, then add the KnownType attribute. For instance
[DataContract]
public class Action
{
//members and properties
}
[DataContract]
public class SomeOtherAction:Action
{
//more implimentation
}
[DataContract]
[KnownType(typeof(SomeOtherAction))]
public class Rule
{
[DataMember]
List<Action> Actions{get;set;}
}
Now you can stuff any object that inherits from the parent Action object in to the Actions list, and it will properly serialize all their respective class properties (as long as the object is listed as a knowntype).
*I used "Action" name as an example to relate to yours, obviously Action is a keyword in .NET
Serialization is the process of converting between an object data and bytes which can be transferred over the wire. Interfaces define behavior, so by default WCF can't serialize such data. If you have the exact same assemblies on the client and the server, however, you can use the NetDataContractSerializer, which will essentially serialize (and be able to serialize) all the type information for the objects being serialized, so it can be recreated at the other side.
The code below shows how to use the NetDataContractSerializer in a service for that (based on the main example for this, the post from Aaron Skonnard at http://www.pluralsight-training.net/community/blogs/aaron/archive/2006/04/21/22284.aspx)
public class StackOverflow_6932356
{
[ServiceContract]
public interface IWorker
{
[OperationContract]
void Process(XmlElement data);
[OperationContract]
void Update(Rule rule);
}
[DataContract]
public class Rule
{
[DataMember]
public string Expression { get; set; }
[DataMember]
public List<IAction> Actions { get; set; }
}
public interface IAction
{
void Execute(XmlElement data);
}
public class Service : IWorker
{
static List<IAction> AllActions = new List<IAction>();
public void Process(XmlElement data)
{
foreach (var action in AllActions)
{
action.Execute(data);
}
}
public void Update(Rule rule)
{
AllActions = rule.Actions;
}
}
public class Action1 : IAction
{
public void Execute(XmlElement data)
{
Console.WriteLine("Executing {0} for data: {1}", this.GetType().Name, data.OuterXml);
}
}
public class Action2 : IAction
{
public void Execute(XmlElement data)
{
Console.WriteLine("Executing {0} for data: {1}", this.GetType().Name, data.OuterXml);
}
}
class NetDataContractSerializerOperationBehavior : DataContractSerializerOperationBehavior
{
public NetDataContractSerializerOperationBehavior(OperationDescription operationDescription)
: base(operationDescription) { }
public override XmlObjectSerializer CreateSerializer(Type type, string name, string ns, IList<Type> knownTypes)
{
return new NetDataContractSerializer(name, ns);
}
public override XmlObjectSerializer CreateSerializer(Type type, XmlDictionaryString name, XmlDictionaryString ns, IList<Type> knownTypes)
{
return new NetDataContractSerializer(name, ns);
}
}
static void ReplaceDCSOB(ServiceEndpoint endpoint)
{
foreach (var operation in endpoint.Contract.Operations)
{
for (int i = 0; i < operation.Behaviors.Count; i++)
{
if (operation.Behaviors[i] is DataContractSerializerOperationBehavior)
{
operation.Behaviors[i] = new NetDataContractSerializerOperationBehavior(operation);
break;
}
}
}
}
public static void Test()
{
string baseAddress = "http://" + Environment.MachineName + ":8000/Service";
ServiceHost host = new ServiceHost(typeof(Service), new Uri(baseAddress));
ServiceEndpoint endpoint = host.AddServiceEndpoint(typeof(IWorker), new BasicHttpBinding(), "");
ReplaceDCSOB(endpoint);
host.Open();
Console.WriteLine("Host opened");
var factory = new ChannelFactory<IWorker>(new BasicHttpBinding(), new EndpointAddress(baseAddress));
ReplaceDCSOB(factory.Endpoint);
var proxy = factory.CreateChannel();
proxy.Update(new Rule
{
Expression = "Expr",
Actions = new List<IAction> { new Action1(), new Action2() }
});
XmlDocument doc = new XmlDocument();
doc.LoadXml("<root><foo>bar</foo></root>");
proxy.Process(doc.DocumentElement);
((IClientChannel)proxy).Close();
factory.Close();
Console.Write("Press ENTER to close the host");
Console.ReadLine();
host.Close();
}
}
Let's say I am using the new WCF Web API to build a RESTful service and, in my service, I have a section of the URI that will describe the target resource, but is used on (nearly) all methods of the contract. For example, if I have a User service that deals with eCommerce and may look like:
[ServiceContract]
public class MyUserService
{
private MyUserRepository _UserRepo;
private MyOrganizationRepository _OrgRepo;
[WebGet (UriTemplate = "{OrganizationName}/Users")]
public IEnumerable<User> GetUsers (string OrganizationName)
{
IEnumerable<User> Users = null;
var Organization = _OrgRepo.GetOrgByName (OrganizationName);
if (Organization != null)
{
Users = Organization.GetUsers ();
}
else
{
throw new WebFaultException<string> ("Organization not found.", HttpStatusCode.NotFound);
}
return Users;
}
[WebInvoke (UriTemplate = "{OrganizationName}/Users", /*yada...yada...yada*/)]
public User AddNewUser (string OrganizationName, User User)
{
// Find the organization, like above, and throw if null.
}
}
If I have to continually load the organization and test for null, this will bog down my code and is not very DRY. (So tempted to spell out DRY...) What I would like to do is load up a property in the MyUserService class that is populated when {OrganizationName} is included in the URI and throw a WebFaultException otherwise. Because this is apart of the URI, what would be the best way to accomplish this?
EDIT:
For those that may be interested, here is an example of the HttpOperationHandler I came up with. There doesn't seem to be a whole lot of information out there covering this. I also found more information about Processors that will be coming with the WCF Web Api suite and it looks like they will handle this sort of thing better replace HttpOperationHandlers and it seems they may be easier to use. (This is just a for-instance to cover some things I found hard to find. I wrote it up a bit differently in my application.)
using Microsoft.ApplicationServer.Http.Dispatcher; // For HttpOperationHandler
using Microsoft.ApplicationServer.Http.Description; // For HttpOperationHandlerFactory
public class OrganizationHandler : HttpOperationHandler<string, Organization>
{
private Repository<Organization> _OrganizationRepository;
public OrganizationHandler (UnitOfWork Work)
: base ("OrganizationName")
{
_OrganizationRepository = Work.Organizations;
}
public override Organization OnHandle (string OrganizationName)
{
var Result = _OrganizationRepository
.Get (O => O.UrlSafeName.Equals (OrganizationName,
StringComparison.InvariantCultureIgnoreCase));
if (Result == null)
{
throw new WebFaultException<string> ("Organization not found.");
}
return Result;
}
}
public class OrganizationHandlerFactory : HttpOperationHandlerFactory
{
private UnitOfWork _Work;
public OrganizationHandlerFactory (UnitOfWork Work)
{
_Work = Work;
}
protected override Collection<HttpOperationHandler> OnCreateRequestHandlers
(ServiceEndpoint endpoint, HttpOperationDescription operation)
{
var Collection = base.OnCreateRequestHandlers (endpoint, operation);
if (operation.InputParameters.Any (IP => IP.Type.Equals (typeof (Organization))))
{
var Binding = endpoint.Binding as HttpBinding;
if (Binding != null)
{
Collection.Add (new OrganizationHandler (_Work));
}
}
return Collection;
}
}
And then to wire it up in Global.asax (I am using Ninject for IoC):
// Add this reference to get the MapServiceRoute<T> extension
using Microsoft.ApplicationServer.Http.Activation;
public class Global : HttpApplication
{
protected void Application_Start (object sender, EventArgs e)
{
var Kernel = BuildKernel ();
var Config = HttpHostConfiguration.Create ()
.SetOperationHandlerFactory
(Kernel.Get (typeof (OrganizationHandlerFactory)) as OrganizationHandlerFactory)
.SetResourceFactory (new NinjectResourceFactory (Kernel));
RouteTable.Routes.MapServiceRoute<OrganizationService> ("Organizations", Config);
}
protected IKernel BuildKernel ()
{
IKernel Kernel = new Ninject.StandardKernel ();
// Load up the Kernel
return Kernel;
}
}
public class NinjectResourceFactory : IResourceFactory
{
private readonly IKernel _Kernel;
public NinjectResourceFactory (IKernel Kernel)
{
_Kernel = Kernel;
}
public object GetInstance (Type serviceType, InstanceContext instanceContext, HttpRequestMessage request)
{
return Resolve (serviceType);
}
public void ReleaseInstance (InstanceContext instanceContext, object service)
{
throw new NotImplementedException ();
}
private object Resolve (Type type)
{
return _Kernel.Get (type);
}
}
And here it is in my Service:
[ServiceContract]
[ServiceBehavior (InstanceContextMode = InstanceContextMode.PerCall)]
public class OrganizationService
{
[WebGet (UriTemplate = "{OrganizationName}/Products")]
public IEnumerable<Product> GetProducts (Organization Organization)
{
return Organization.Products;
}
}
This is exactly what OperationHandlers are for. You create a single OperationHandler that converts the URI parameter into a strongly typed object that you can just accept as a parameter on the operation.