Ninject singleton scope loading - ninject

I am very much new to ASP.NET MVC and I need help loading some types in singleton scope using Ninject.
--- existing code looks as ----
List<Type> types = loading some types into list here.
foreach (var type in types.Where(O => O.Name.StartsWith("I")))
{
Kernel.Bind(type).To(Type.GetType(type.FullName.Replace(".I", ".")));
}
My job is to bind these types in singleton scope and I am not sure how to do that.

After kernel.Bind().To() put .InSingletonScope()

Also have a look at the Ninject conventions extension. It makes stuff like this a lot easier.
For example you could write it like this instead.
kernel.Bind(x =>
x.FromThisAssembly()
.SelectAllClasses()
.Where(types.Contains)
.BindDefaultInterface()
.Configure(b => b.InSingletonScope()));
Depending on how you get your list of types, this might be written even easier. Just check out the documentation and the samples on the wiki.
https://github.com/ninject/ninject.extensions.conventions/wiki

Related

Override lazy loading behavior 'lazy=false'

I would like to override the default lazy loading behavior which is set in mappings as 'lazy=false'. Can't change it as many parts of existing application depend on this setting.
After spent some hours on it I didn't find a solution so I'm asking here.
How to do this?
What I want to achieve is to fine tune my query to load only what is needed.
This is what I've tried already:
Using QueryOver api:
var properties = session.QueryOver<Property>()
.Fetch(prop => prop.Transactions).Eager
.Fetch(prop => prop.Districts).Eager
//I dont want to load those entities below so I mark
//them as lazy - IT DOESN'T WORK
//I can see in SQL that they are getting loaded in separate queries
.Fetch(prop => prop.Districts.First().Aliases).Lazy
.Fetch(prop => prop.Districts.First().PolygonPoints).Lazy
.Skip(i * pageSize)
.Take(pageSize)
.List();
Using Criteria api:
var criteria = session.CreateCriteria<Property>();
criteria.SetFetchMode("Transactions", NHibernate.FetchMode.Join);
criteria.SetFetchMode("Districts", NHibernate.FetchMode.Join);
criteria.SetFetchMode("Districts.Aliases", NHibernate.FetchMode.Select); // tried Lazy too
criteria.SetFetchMode("Districts.PolygonPoints", NHibernate.FetchMode.Select); // tried Lazy too
criteria.AddOrder(NHibernate.Criterion.Order.Asc("Id"));
criteria.SetFirstResult(i * pageSize);
criteria.SetMaxResults(pageSize);
var properties = criteria.List<Property>();
Using any of the above methods 'Aliases' and 'PolygonPoints' are always being loaded when calling List<>(). I don't need them in my process.
I'm using Nhibernate 4.0.
Any ideas?
We cannot override mapping in this case. We can do it opposite way - have lazy in place - and use eager fetching for querying.
The decision process (of reference loading) is done outside of the query, ex post. So it could be pre-loaded, but cannot be avoided.
Solution here could be of two types.
The first is preferred (by me) - do your best and make laziness the default: Ayende -
NHibernate is lazy, just live with it
Use projections. Instruct NHibernate to create just one query, use transformer to get expected object graph - without any proxies in it
There is pretty clear example how to (properly) use projection list even for references:
Fluent NHibernate - ProjectionList - ICriteria is returning null values
And we would also need Custom result transformer, which will ex-post create all the references from the returned data:
Custom DeepResultTransfomer

zend acl dynamic assertions : when/how to load the resource?

i'm creating a zend framework 2 application and i'm sort of trying to implement what is explained here:
http://ralphschindler.com/2009/08/13/dynamic-assertions-for-zend_acl-in-zf
The demonstration that the code works is really nice, but it doesn't really apply to how a framework (utilizing mvc) works. Or maybe i'm just on the wrong track...
i've created a RouteListener like this :
class RouteListener implements ListenerAggregateInterface
{
public function attach(EventManagerInterface $events)
{
$this->listeners[] = $result = $events->attach(
MvcEvent::EVENT_DISPATCH, array($this, "checkAcl"), 100
);
}
}
the method checkAcl then checks if you're allowed to do what you want to do.
The resource and action are determined like this:
$resource = $routeMatch->getParam("controller");
$action = $routeMatch->getParam("action");
And the role is determined by the identity stored in the session (which implements Zend\Permissions\Acl\Role\RoleInterface)
Following the example: how do i determine if a user is allowed to edit a certain blog-post?
By the time acl is doing it's checking, the controller hasn't loaded the blogpost yet, so i'm not sure how to approach this. Unless i duplicate the retrieval of the blogpost in the assertion, but that i'm hoping there is a better way.
I'm also using doctrine for my persistence layer and in the end i've solved this problem using doctrine's Lifecycle Events. This allows you to trigger the acl-check whenever you want: when a entity (p.e. a blog-post) is loaded, or saved, etc.

ContentHandler issues (circular reference) in Orchard

crosspost: https://orchard.codeplex.com/discussions/459007
First question I have is what would be the repercussions of having 2 PartHandlers for the same Part in 2 different modules?
I got into this predicament because I have to run a method once a specific Content Type is created. It would be as easy to hook onto OnCreated for the part, however, here is my scenario:
Module A contains the part and the original handler
Module B contains the service where the method is
Module B has a reference to Module A
Therefore, I am unable to reference Module B within Module A (circular reference). So what I did was to copy the exact same PartHandler in Module A and placed it in Module B.
Would anything be wrong with that?
Then comes my second question, which I think could solve all these problems: Can we create a PartHandler for the Content Item's default Content Part? (i.e. the part where all custom fields are attached to)
This would definately make things easier as I could consolidate stuff that need to run there.
UPDATE 1 (to better explain question 2)
ContentDefinitionManager.AlterPartDefinition("EventItem",
builder => builder
.WithField("StartDate", cfg => cfg
.OfType("DateTimeField")
.WithDisplayName("Start Date")
.WithSetting("DateTimeFieldSettings.Display", "DateOnly")
.WithSetting("DateTimeFieldSettings.Required", "true"))
.WithField("StartTime", cfg => cfg
.OfType("DateTimeField")
.WithDisplayName("Start Time")
.WithSetting("DateTimeFieldSettings.Display", "TimeOnly"))
.WithField("EndDate", cfg => cfg
.OfType("DateTimeField")
.WithDisplayName("End Date")
.WithSetting("DateTimeFieldSettings.Display", "DateOnly"))
.WithField("EndTime", cfg => cfg
.OfType("DateTimeField")
.WithDisplayName("End Time")
.WithSetting("DateTimeFieldSettings.Display", "TimeOnly"))
.WithField("Intro", cfg => cfg
.OfType("TextField")
.WithDisplayName("Intro")
.WithSetting("TextFieldSettings.Flavor", "textarea"))
ContentDefinitionManager.AlterTypeDefinition(
"EventItem"
, cfg =>
cfg
.DisplayedAs("Event Item")
.WithPart("TitlePart")
.WithPart("EventItem")
.WithPart("LocationPart")
.WithPart("AutoroutePart", builder => builder
.WithSetting("AutorouteSettings.AllowCustomPattern", "true")
.WithSetting("AutorouteSettings.AutomaticAdjustmentOnEdit", "false")
.WithSetting("AutorouteSettings.PatternDefinitions", "[{Name:'Title', Pattern: 'learn/events/{Content.Slug}', Description: 'learn/events/event-title'}]")
.WithSetting("AutorouteSettings.DefaultPatternIndex", "0"))
.WithPart("CommonPart")
.Draftable()
.Creatable()
);
I'm talking about creating a ContentHandler for the EventItem part which holds all the custom fields. How can I go about it when EventItemPart is not defined in any class in the solution?
The following below won't work since it can't find the class EventItemPart:
OnCreated<EventItemPart>((context, keynotes) =>
questionService.SetDefaultQuestions(context.ContentItem));
Cross-answer as well.
Bertrand's perfectly right. Why do you need to reference B in A in first place? If the service from B needs A and A needs this service, then it belongs to A (at least the interface - contract).
You can always split interface and actual implementation for your service, having one in different module than another. If implementation of your service requires stuff from B, then put the interface in A, but actual implementation in B. This way A doesn't even need to know about the existence of B, but still be able to use the service via it's interface - it's the beauty of IoC pattern and Orchard modularity:)
You may use ContentPart or IContent as a type argument in handler generic methods. It's perfectly valid. This way you'd be able to plug in to events on all items, and perform custom filtering afterwards (based on type name, some field existence etc.). In your case it may look like:
OnCreated<ContentPart>((context, part) =>
{
if(part.ContentItem.ContentType != "EventItem") return;
questionService.SetDefaultQuestions(context.ContentItem);
});
Update: no need to do this: .WithPart("EventItem"). This 'fake' part will be automatically added by framework.
Cross-answer:
none
However, repeating yourself is almost always wrong, especially if it's done for a bad reason. Why is are the service and the part in two different modules? Why does A need B? A circular reference indicates tight coupling. If the tight coupling is justified, then it should happen in a single module. If it's not, then you need to re-do your design to remove it.
You can create a handler for anything, but your explanation of your scenario is way to vague and abstract to give any useful advice.

Ninject - How to dynamically select an implementation to bind to an interface

I'm currently using Ninject to create instances of interfaces in a WCF Services application.
Bind<IObjA>().To<ObjA>().InRequestScope();
Bind<IObjB>().To<ObjB>().InRequestScope();
Bind<IObjC>().To<ObjC>().InRequestScope();
It works great, but we are going to have several implementations of IObjC. What options do I have for continuing fluid assignment of implementation to interface for IObjA/IObjB but allowing for configurable assignment for IObjC?
I found a related question on SO but I don't know if I can support both a fluid and a configurable approach simultaneously.
For example, can I use Ninject.extensions.xml for IObjC while continuing to use the above approach for IObjA and IObjB?
Is it advisable to have conditional assignment for IObjC? That seems dirty but at the same time appears very simple.
if (condition1)
Bind<IObjC>().To<ObjC1>().InRequestScope();
else if (condition 2)
Bind<IObjC>().To<ObjC2>().InRequestScope();
Also, I know other frameworks like Castle support XML configuration but I would like to continue using Ninject.
1 - your bindings to IObjC have nothing to do with any other bindings. it doesn't matter where, when, or how you bind other services.
2 - you can use the XML extensions, but I would ask why you think you need it to be configurable.
3 - there are 2 possibilities for your conditional. first is that you want to make a decision at startup to determine whether to use ObjC1 for the entire lifetime of the app, or ObjC2. if that's the case, your code is ok. however, if you want to dynamically decided which object to use each time you resolve the binding, you will need to put the condition inside your binding, like so:
Bind<IObjC>().ToMethod( ctx => condition ? ctx.Kernel.Get<ObjC1>() : ctx.Kernel.Get<ObjC2>() );
alternately, you can use Named bindings:
Bind<ILog>().ToConstant( LogManager.GetLogger( "Accounting" ) ).Named( "Accounting" );
or "When" conditions to help:
Bind<ILog>().ToConstant( LogManager.GetLogger( "Background" ) ).When( context => context.Target != null && context.Target.Name == "backgroundLogger" );

NHibernate DTO Parent child relation

I have som entities and now want to make some DTO´s based on there entities using nhibernate.
I have a Service - Allocation -Ressource where allocation describes how the ressource is allocated for the service.
I want a DTO like
ServiceDTO
-Name
-RessourceDTO
where RessourceDTO also has a name.
In the examples I have see for NHibernate projection/DTO you either use properties or constructor. If I use The Constructor approach I would have something like
ServiceDTO(Name, List
But I can't figure out how to make this work.
Another approach is to extract all the services and then loop through them and hit the database each time, or extract a larger result and then make the DTO's
What is the best approach? I going to hide all of this inside a repository.
How about
public ServiceDTO GetDTOFor(int Id);
{
var service = Session.CreateCriteria<Service>()
.Add(Restrictions.Eq("Id", id)
.SetFetchMode("Resources", fetchmode.eager) // eager load resources
.uniqueResult<Service>();
return new ServiceDTO(service.Name, service.Resources.ToList()) // Copy the Resources
}