I'm using Ninject 2.0 with an MVC 2/EF 4 project in order to inject my repositories into my controllers. I've read that when doing something like that, one should bind using InRequestScope(). When I do that, I get a new repository per request, but the old repositories aren't being disposed. Since the old repositories are remaining in memory, I get conflicts with multiple ObjectContexts existing at the same time.
My concrete repositories implement IDisposable:
public class HGGameRepository : IGameRepository, IDisposable
{
// ...
public void Dispose()
{
if (this._siteDB != null)
{
this._siteDB.Dispose();
}
}
}
And my Ninject code:
public class NinjectControllerFactory : DefaultControllerFactory
{
private IKernel kernel = new StandardKernel(new HandiGamerServices());
protected override IController GetControllerInstance(System.Web.Routing.RequestContext requestContext, Type controllerType)
{
try
{
if (controllerType == null)
{
return base.GetControllerInstance(requestContext, controllerType);
// return null;
}
}
catch (HttpException ex)
{
if (ex.GetHttpCode() == 404)
{
IController errorController = kernel.Get<ErrorController>();
((ErrorController)errorController).InvokeHttp404(requestContext.HttpContext);
return errorController;
}
else
{
throw ex;
}
}
return (IController)kernel.Get(controllerType);
}
private class HandiGamerServices : NinjectModule
{
public override void Load()
{
Bind<HGEntities>().ToSelf().InRequestScope();
Bind<IArticleRepository>().To<HGArticleRepository>().InRequestScope();
Bind<IGameRepository>().To<HGGameRepository>().InRequestScope();
Bind<INewsRepository>().To<HGNewsRepository>().InRequestScope();
Bind<ErrorController>().ToSelf().InRequestScope();
}
}
}
What am I doing wrong?
I'm quite sure that you are wrong about the guess that your objects are not disposed. This just does not happen when you think it will happen. But the fact that this does happen later should not give you any problems with ObjectContexts unless you are doing something wrong. With a high load you will have a lot of ObjectContexts at the same time anyway.
What can become a problem though is that the memory usage increases. That's why the request scope needs to be released actively. The Ninject MVC extensions will take care of that. Otherwise have a look at the OnePerRequestModule to see how it is done:
https://github.com/ninject/Ninject.Web.Common/blob/master/src/Ninject.Web.Common/OnePerRequestHttpModule.cs
Related
The task is to call a database, retrieve certain records update and save them.
As the amount of records if fairly large we want to do this Async, however, this doesn't seem to be implemented correctly.
The main class:
#SpringBootApplication
#EnableAsync
MainApplication() {
#Bean("threadPoolExecutor")
public TaskExecutor getAsyncExecutor(){
ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
executor.setCorePoolSize(DataSourceConfig.getTHREAD_POOL_SIZE());
executor.setMaxPoolSize(DataSourceConfig.getTHREAD_POOL_SIZE());
executor.setWaitForTasksToCompleteOnShutdown(true);
executor.setThreadNamePrefix("RetryEnhancement-");
return executor;
}
}
Method in the first service:
#Service
public class FirstService() {
#Transactional
public void fullProcess() {
for(int counter = 0; counter < ConfigFile.getTHREADS(); counter++){
secondaryService.threads();
}
}
}
Method in the second service:
#Service
public class SecondService () {
#Async("threadPoolExecutor")
public void threads() {
while(thirdService.threadMethod()) {
//doNothing
}
}
}
Method in the third service:
#Service
public class ThirdService() {
#Transactional
public boolean threads() {
Record record = repository.fetchRecord();
if(record!=null) {
updateRecord(record);
saveRecord(record);
return true;
} else {
return false;
}
}
}
Repository:
public interface repository extends CrudRepository<Record, long> {
#Lock(LockModeType.PESSIMISTIC_WRITE)
Record fetchRecord();
}
The issue I'm finding is that, while the code executes perfectly fine, it seems to have a Synchronous execution (found by adding a .sleep and watching the execution in the logger).
The seperate threads seem to be waiting until the other is executed.
I'm probably doing something wrong and if another thread already explains the issue, than please refer it, though I have not been able to find this issue in a different thread.
Your solution is way to complex. Ditch all of that and just inject the TaskExecutor and do the updateRecord in a separate thread (you might need to retrieve it again as you are now using a different thread and thus connection.
Something like this should do the trick
private final TaskExecutor executor; // injected through constructor
public void process() {
Stream<Record> records = repository.fetchRecords(); // Using a stream gives you a lazy cursor!
records.forEach(this::processRecord);
}
private void processRecord(Record record) {
executor.submit({
updateRecord(record);
saveRecord(record);
});
}
You might want to put the processRecord into another object and make it #Transactional or wrap it in a TransactionTemplate to get that behavior.
I am configuring logging for my application and for logging I am using log4net and castle windsor for DI.
I want logging framework to be wrap inside custom implementation so it can be changed in future.
public interface ICustomLogger
{
void Debug(object message, Exception ex = null);
void Info(object message, Exception ex = null);
void Warn(object message, Exception ex = null);
void Error(object message, Exception ex = null);
void Fatal(object message, Exception ex = null);
}
public class CustomLogger : ICustomLogger
{
private readonly log4net.ILog _log;
private readonly log4net.ILog _log1;
public CustomLogger()
{
//approach1
var stack = new StackTrace();
var frame = stack.GetFrame(1);
var method = frame.GetMethod();
Type type = method.DeclaringType;
_log = log4net.LogManager.GetLogger(type);
//approach2
var dtype = System.Reflection.MethodBase.GetCurrentMethod().DeclaringType;
_log1 = log4net.LogManager.GetLogger(dtype);
}
public CustomLogger(string name)
{
_log = log4net.LogManager.GetLogger(name);
}
public CustomLogger(Type type)
{
_log = log4net.LogManager.GetLogger(type);
}
public void Debug(object message, Exception ex = null)
{
if (_log.IsDebugEnabled)
{
if (ex == null)
{
_log.Debug(message);
}
else
{
_log.Debug(message, ex);
}
}
}
public void Info(object message, Exception ex = null)
{
if (_log.IsInfoEnabled)
{
if (ex == null)
{
_log.Info(message);
}
else
{
_log.Info(message, ex);
}
}
}
public void Warn(object message, Exception ex = null)
{
if (_log.IsWarnEnabled)
{
if (ex == null)
{
_log.Warn(message);
}
else
{
_log.Warn(message, ex);
}
}
}
public void Error(object message, Exception ex = null)
{
if (_log.IsErrorEnabled)
{
if (ex == null)
{
_log.Error(message);
}
else
{
_log.Error(message, ex);
}
}
}
public void Fatal(object message, Exception ex = null)
{
if (_log.IsFatalEnabled)
{
if (ex == null)
{
_log.Fatal(message);
}
else
{
_log.Fatal(message, ex);
}
}
}
}
To register this custom implementation with DI...
container.Register(Component.For<ICustomLogger>()
.ImplementedBy<CustomLogger>()
.LifeStyle.Transient);
Problem comes when I ask DI to resolve logger, then it always return logger for Customlogger type not the class where I want to use it.
class ABC
{
ICustomLogger _logger;
public ABC(ICustomLogger logger)
{
_logger = logger; // type of this logger is CustomLogger not ABC
}
}
Both the approach are not working to resolve logger as ABC.
Can anyone help me to understand what's wrong here and how to fix the issue.
You can do this via a custom dependency resolver.
You first need to create an implementation of ISubDependencyResolver that can resolve dependencies of type ICustomLogger:
public class LoggerResolver : ISubDependencyResolver
{
public bool CanResolve(
CreationContext context,
ISubDependencyResolver contextHandlerResolver,
ComponentModel model,
DependencyModel dependency)
{
//We can only handle dependencies of type ICustomLogger
return dependency.TargetType == typeof (ICustomLogger);
}
public object Resolve(
CreationContext context,
ISubDependencyResolver contextHandlerResolver,
ComponentModel model,
DependencyModel dependency)
{
//We pass the requested type, e.g. ABC, to the constructor of CustomLogger
return new CustomLogger(context.RequestedType);
}
}
You then need to register this resolver with the container like this:
container.Kernel.Resolver.AddSubResolver(new LoggerResolver());
For your specific question - in both approaches you never really leave the "scope" of your class. With the first you are creating a new StackTrace and in the other the declaring type of a constructor is that class itself.
But you implemented a constructor that can receive a type so why not use it. Currently your CustomLogger is registered with your default constructor:
//There is no place here that you tell castle to resolve using the constructor
//that receives `ABS`
container.Register(Component.For<ICustomLogger>()
.ImplementedBy<CustomLogger>()
.LifeStyle.Transient);
See Castle Windsor passing constructor parameters to understand how to pass the parameters and that way invoke the constructor you want
In addition - Worth re-thinking:
Though it is a good idea to create such abstraction between your code and external source in this case I would not do it and I will explain why:
From my experience one doesn't really change the logging framework after the code is up and running. Especially since you are working with a mature and excellent framework - Log4Net. It has many built in abilities and is very adaptable for ones needs: From different formatting of the messaged to outputting the logs to different sources such as databases, files and if I'm not wrong there are also appenders for things like elastic search.
You are using Castle Windsor which has a good integration with Log4Net and has for you a ready made Logging Facility to Log4Net. See this question for how simple it is to add it.
Last point is that if you already write good SOLID code and pass your logger as ILogger to all the components (and not a specific implementation) all they will probably do is call the different Debug/Info/Warn/Error/Fatal methods - which any other mature logging framework will have. So on the day you will have to change (which I think won't happen) you can write an interface that looks like the Log4Net's interface and an implementation that will adapt that to your new logging framework.
With MVC4 I was able to create and register a global action filter that would check the model state prior to the action's execution and return the serialized ModelState before any damage could be done.
public override void OnActionExecuting(System.Web.Http.Controllers.HttpActionContext actionContext)
{
if (!actionContext.ModelState.IsValid)
{
actionContext.Request.CreateErrorResponse(HttpStatusCode.BadRequest, actionContext.ModelState);
}
}
However, with MVC5, I am having trouble finding Request and therefore CreateErrorResponse
public override void OnActionExecuting(ActionExecutingContext nActionExecutingContext)
{
if (!nActionExecutingContext.Controller.ViewData.ModelState.IsValid)
{
nActionExecutingContext.Result = // Where is Request.CreateErrorResponse ?
}
}
I realize that I could create a custom response class to assign to Result but I'd rather use what's built-in if CreateErrorResponse is still available.
Any idea where I can find it relative to an ActionExecutingContext in MVC5 / Web API 2?
I know this is an old question but I recently had the same problem and solved it using
public override void OnActionExecuting(ActionExecutingContext context)
{
if (!context.ModelState.IsValid)
{
context.Result = new BadRequestObjectResult(context.ModelState);
}
}
I am new at this (I'm still learning), I would appreciate very much if you Jedi masters out there can help me out with the question and concern that I have.
I want to use Ninject and I have the codes below, I would like to know whether my objects will get disposed properly and garbage collected.
For Ninject's default Transient Scope, I read that "Lifetime is not managed by the Kernel (the Scope object is null) and will never be Disposed."
If I would to use my codes in production, especially when I get lots of concurrent calls to my WebApi (POST), will it cause any problems like Memory Leak, etc?
What would be the best Ninject's Object scope to use for this situation?
By the way, if I don't specify the object scope like "kernel.Bind().To();", will it default to TransientScope?
public class VehicleClassRepository : IVehicleClassRepository
{
SomeDataContext context = new SomeDataContext();
public IQueryable<VehicleClass> All
{
get { return context.VehicleClasses; }
}
public IQueryable<VehicleClass> AllIncluding(params Expression<Func<VehicleClass, object>>[] includeProperties)
{
IQueryable<VehicleClass> query = context.VehicleClasses;
foreach (var includeProperty in includeProperties) {
query = query.Include(includeProperty);
}
return query;
}
public VehicleClass Find(int id)
{
return context.VehicleClasses.Find(id);
}
public void InsertOrUpdate(VehicleClass vehicleclass)
{
if (vehicleclass.VehicleClassId == default(int)) {
// New entity
context.VehicleClasses.Add(vehicleclass);
} else {
// Existing entity
context.Entry(vehicleclass).State = EntityState.Modified;
}
}
public void Delete(int id)
{
var vehicleclass = context.VehicleClasses.Find(id);
context.VehicleClasses.Remove(vehicleclass);
}
public void Save()
{
context.SaveChanges();
}
public void Dispose()
{
context.Dispose();
}
}
public interface IVehicleClassRepository : IDisposable
{
IQueryable<VehicleClass> All { get; }
IQueryable<VehicleClass> AllIncluding(params Expression<Func<VehicleClass, object>>[] includeProperties);
VehicleClass Find(int id);
void InsertOrUpdate(VehicleClass vehicleclass);
void Delete(int id);
void Save();
}
In my NinjectWebCommon.cs:
private static void RegisterServices(IKernel kernel)
{
kernel.Bind<IVehicleClassRepository>().To<VehicleClassRepository>();
}
In my WebApi's VehicleClassController.cs:
public HttpResponseMessage Post(VehicleClass value)
{
if (value == null)
{
return new HttpResponseMessage(HttpStatusCode.BadRequest);
}
else
{
vehicleclassRepository.InsertOrUpdate(value);
vehicleclassRepository.Save();
return new HttpResponseMessage(HttpStatusCode.Created);
}
}
Late answer (almost 2 years) but in case others read this...
Although it's true that the garbage collector will eventually dispose of your VehicleClassRepository instance, you'll very likely run into problems before then.
Your data context likely holds an open db connection until it's disposed. The db connection probably comes from a pool of db connections.
So long before the CLR ends up garbage collecting these (which would also dispose them), incoming requests end up blocking while trying to get a db connection but there are none available.
I've encountered this type of behavior and learned from it the hard way. So the VehicleClassRepository should be scoped in dependency scope so that you get one per call and more importantly, it'll get disposed immediately after the call is done.
In my MVC 2 project, I originally used Ninject 2 and wrote this version of the NinjectControllerFactory:
public class NinjectControllerFactory : DefaultControllerFactory
{
private IKernel kernel = new StandardKernel(new HandiGamerServices());
protected override IController GetControllerInstance(System.Web.Routing.RequestContext requestContext, Type controllerType)
{
try
{
if (controllerType == null)
{
return base.GetControllerInstance(requestContext, controllerType);
// return null;
}
}
catch (HttpException ex)
{
if (ex.GetHttpCode() == 404)
{
IController errorController = kernel.Get<ErrorController>();
((ErrorController)errorController).InvokeHttp404(requestContext.HttpContext);
return errorController;
}
else
{
throw ex;
}
}
return (IController)kernel.Get(controllerType);
}
Of most importance is the retrieval of my ErrorController, which allows me to gracefully handle a multitude of HTTP errors.
The problem is that I upgraded to the MVC 2 extension via Nuget, so a NinjectControllerFactory is already provided. Would it be possible to use my own override of GetControllerInstance? If so, how?
I do exactly this, and for precisely the same reason. In Global.asax.cs, I add this to my OnApplicationStarted override (declared virtual in NinjectHttpApplication):
ControllerBuilder.Current.SetControllerFactory(
new MyControllerFactory(ControllerBuilder.Current.GetControllerFactory()));
This means you're creating your own controller factory, but providing it with the default implementation to do the heavy lifting.
Then define your controller factory like so:
public class MyControllerFactory : IControllerFactory
{
private IControllerFactory defaultFactory;
public MyControllerFactory(IControllerFactory defaultFactory)
{
this.defaultFactory = defaultFactory;
}
public IController CreateController(RequestContext requestContext, string controllerName)
{
try
{
var controller = defaultFactory.CreateController(requestContext, controllerName);
return controller;
}
catch (HttpException e)
{
// Pasted in your exception handling code here:
if (ex.GetHttpCode() == 404)
{
IController errorController = kernel.Get<ErrorController>();
((ErrorController)errorController).InvokeHttp404(requestContext.HttpContext);
return errorController;
}
else
{
throw ex;
}
}
}
public SessionStateBehavior GetControllerSessionBehavior(RequestContext requestContext, string controllerName)
{
return defaultFactory.GetControllerSessionBehavior(requestContext, controllerName);
}
public void ReleaseController(IController controller)
{
defaultFactory.ReleaseController(controller);
}
}
As you can see, we're just using the default (Ninject) controller factory for most purposes unless it can't find the page. For obtaining the error controller, you can either pass in the kernel as you were already doing, or just call defaultFactory.CreateController using the error controller name.