Background:
I'm getting a mapping failure when trying to use nHibernate. The application consists of several assemblies. One of the assemblies is a library of useful routines and the other is application code that uses the library. The library assembly adds itself to the nHibernate configuration but since it doesn't know about other assemblies it doesn't add them. My xml mapping file is located in the application assembly. I think it's not finding it because it's not looking in the application assembly.
Question:
Can you map to a class in an arbitrary assembly without adding it to the configuration?
If not, can you add a mapping at run time?
Thanks
p.s.
I did make sure the mapping file was marked as an embedded resource
Update - Apr 3 '09
I changed the underlying library to allow adding assemblies at initialization. That seems to work just great.
You can add mappings at runtime at the moment your session factory is being constructed:
ISessionFactory sf = new Configuration()
.AddFile("Item.hbm.xml")
.AddFile("Bid.hbm.xml")
.BuildSessionFactory();
or with assemblies:
ISessionFactory sf = new Configuration()
.AddAssembly("NHibernate.Auction")
.BuildSessionFactory();
Re your comment - no you cannot add mappings once you constructed your session factory. You can however re-create the session factory. Keep in mind though that it can be expensive operation (a second or so).
Related
In my WCF project I register my interface using Castle Windsor in the global.asax:
Component.For<IStrategy>()
.ImplementedBy<MyStrategy>()
.LifestylePerWcfOperation(),
Then later on in the same file I configure NHibernate using FluentNhibernate using a provider:
FluentConfiguration configuration = Fluently.Configure()
.Database(
MsSqlConfiguration.MsSql2008.ConnectionString(myConnString)
.Provider<ConnectionProvider>())
.Mappings(m => m.FluentMappings.AddFromAssemblyOf<TenantMap>()) etc etc
However this ConnectionProvider is hosted in a common shared dll library as there are other WCF services that need to use it. I want to register this dependency as below but it doesn't work which means I have to manually new up a instance.
public ConnectionProvider()
{
// doesnt work
using (IDependencyScope scope = GlobalConfiguration.Configuration.DependencyResolver.BeginScope())
{
_myStrategy = scope.GetService<IStrategy>();
}
}
Is there anyway to make this work? Its like its lost scope as its in another assembly now. In the same assembly the DependencyScope works fine and creates an instance, but I want to keep it in a shared dll.
EDIT: The error I get is "System.Web.Http.Dependencies.EmptyResolver" on a watch on this bit of code: GlobalConfiguration.Configuration.DependencyResolver
I can see several problems with the code above:
1) You are registering IStrategy,MyStrategy with a per WcfOperation lifestyle. This means that windsor will create a strategy for each WcfOperation. On the otherhand you are trying to manually set the lifestyle of the component by using scope.GetService. For scope.GetService to work you will need a lifestyle scoped.
2) Assuming that the code for ConnectionProvider above is the constructor, it seems that the constructor is trying to get something from the container. This is in general a bad idea, and even worse when using an Ioc container like windsor. Instead pass the IStrategy to the constructor (inject it).
3) Seeing that you are calling the container a constructor here, probably means that you are not adhering to the principle that there should be only 3 calls to the container, 1 to register component, 1 to retrieve a top level component, and 1 to release the container.
I suggest you read a bit more about depedency injection and Ioc containers in general to fully understand how to work with this container.
I have a question using Entity Framework in WCF. I am using .NET 4.5 with EF DbContext.
Here are the things I know to do to use EF in WCF. May be they are insufficient or some are not required.
Create EF ADO.NET Model.
Seperate the POCO classes to a seperate project (ProjectName: Entities) by using DbContext template generator.
Point the TT template of the POCO project to the edmx file in the data project (ProjectName: Data). "..\Data\MyEdmx.edmx"
Add [DataContract(IsReference(True))] and [DataMemeber] attributes in the .TT file of the POCO project so that the classes and properties will have the serialization attributes. Add Runtime.Serialization reference to the project and add the namespace to .TT file. This enables not to lose your attribute declaration while recreating the classes on a save of the .TT file or adding new entities.
Add ProjectName: Entities reference to Data project.
Turn off ProxyCreation and LazyLoading in the Context.tt file in the data project.
Add (ProjectName: Entities) and (ProjectName: Data) to your wcf service project.
Copy the EntityFramework connection string to your WCF project.
All your select methods in the service, must use .Include if you want the navigation objects to be populated. This gives better control when you want to load or or when you want limit data to show. Also, you don't get the child/related automatically due to lazyloading turned off.
Insert or Update or Delete, the service has to create the context and manually set the object state to be modified or added? Otherwise the changes will not be saved. Use the DbContext.Attach to attach and set the state of the entity appropriately Added,Modified, etc.
The problem I had was I could not find a good example of the steps to perform to use EF with WCF. I was able to see only bits and pieces. May be I am a late entrant to the WCF EF world hence could not find.
Not sure if I can use proxies WCF. I haven't understood completely the advantage of proxies yet.
I also read recommendations to use DTO as a layer between EF and the service. This requires a mapper to be in place. I don't know if I need it right away. But the idea is clear that it helps hide any unnecessary database columns showing in the business object. For example, audit columns such as created by, updated by etc we dont to show in the client.
I did not choose to use DataServices as I lose other binding options that I get from WCF. I don't know if it is a good thing to lose the simplicity of DataServices thinking about the future requirements of clients that require/support other binding mechanisms.
Any recommendations is appreciated.
Additional Update
I did find this in MSDN http://msdn.microsoft.com/en-us/library/ee705457(v=vs.100).aspx. Some of the links were pointing to pre-release documentation. But this gives some more ideas for me in using EF and WCF.
This articles shows how to use proxies with WCF, change tracking of POCO. This is a good start for me. If any one has more advise please provide your thoughts.
Update 2
*Another Excellent Link for N-Tier*
http://msdn.microsoft.com/en-us/magazine/dd882522.aspx
I am glad that the time I am spending is really educating me!
I progressed on using EF with WCF after lot of reading here and in other forums.
I followed the steps ahead. I was able to see the advantage of using DTO. This really allows you to hide fields that you don't need to expose to the client or other services. But I am holding back on introducing DTO due to time constraints.
I used context.Attach, context.Add and context.Entry.
I also did a small prototype to use WCF Data Service. That was very fast paced development. I am holding back on using WCF data services for now due to time constraint in learning its features.
We have a dynamically composed application, in which user can add services and operations. This application is installed on a server cluster.
Since adding services to application involves so much writing to web.config, i was wondering if its possible to read system.servicemodel section from a database instead of web.config.
Seems like microsoft's implementation of configuration is very tightly coupled with where its stored.
There is no "out-of-the-box" way to do that. However, it is possible.
Few feet below, Configuration class uses FileStream instance where it actually can use any Stream. That particular step can be replaced with custom implementation of IInternalConfigHost interface (a lot of properties and methods to implement there).
Particularly interesting are OpenStreamForRead and OpenStreamForWrite, both are returning Stream instances. There you can put logic to pull XML of configuration sections from database into ConfigurationSection instances and to put ConfigurationSection instances as XML into database.
The next step is to create an instance of Configuration class. However, here we must get dirty because its constructor never leaves the System.Configuration kingdom. The need to use reflection to reach and use it. I suggest implementation of IInternalConfigConfigurationFactory to wrap the reflection magic.
Configuration Create( Type typeConfigHost,
params object[] hostInitConfigurationParams );
As first parameter pass the type of implemented configuration host.
After we have Configuration instance, we can use it a custom ServiceHost, ChannelFactory<T> and DuplexChannelFactory<T>.
I need to be able to configure my connection string at run time, preferably from a config file would be the simplest solution. However, I can't use ConnectionString.FromAppSetting nor ConnectionString.FromConnectionStringWithKey. My data-access assembly is referenced from console apps, win forms, and web. And while I can add "Settings" to my project, it's only a dll and won't bring that app.config over with it to the actual applications build destination.
I don't expect this is too uncommon. What is typically the way this is handled? Is this a prime example of when to use dependency injection (one that I could configure from a separate file?) I'm feeding the connection string to my 'unit of work' object, but I'd like to do it statically as to build the config and sessionfactory only once.
I can definitely clarify if needed, but I'm not sure the best way to ask.
You can use hibernate.cfg.xml (it works on every plattaform).
Alternatively you can do the following
Inherit DriverConnectionProvider
override the ConnectionString property, and read the connection string from anywhere.
Supply your new connection provider to your nhibernate configuration in code or in xml.
You can use ServiceLocation inside your DriverConnectionProvider or you can use the EnhancedBytecodeProvider on unhaddins. Search Enhanced bytecodeprovider and Fabio Maulo on google.
Here is an example: Dynamically change user info in connection string
I am trying to get test running that uses FluentNHibernate to map my
entities.
I get unknown entity class error.
I have a Domain project that has my entities and the mappings in a seperate
folder in that project.
My test project has the Nhibrenate configuration in the App.Config.
Any ideas please???
Malcolm
EDIT: I have this method that creats the ISessionFactory but I dont think this code is working and this is why it does not recoginze me mappings exist at all. The SessionFacoryCreator is the assembly with my AppConfig and Recipe is my assembly where the Domain objects are. Please HELLLLLLP!!!!
public static ISessionFactory Create()
{
Configuration cfg = new Configuration()
.AddAssembly(typeof(SessionFactoryCreator).Assembly)
.AddAssembly(typeof(Recipe).Assembly);
return cfg.BuildSessionFactory();
}
Have you read the wiki? Your example shows nothing of hooking Fluent NHibernate into the session factory building, that'd be why it isn't working. Start with the Getting Started guide.
How do you add your Entities to the Hibernate framework? Are you using AnnotationConfiguration or just Configuration? If you are using annotations you must add your annotated entity to the framwork. Otherwise, if you are using xml hibernate mapping, the syntax could be worng (iirc)
NHibernate and I keep on getting the following error: MappingException: Unkown Entity Class
If you get MappingException error, there are two things you should check out:
Make sure the name of the *.hbm.xml is spelled correctly — not *.hmb.xml nor *.mbh.xml
Make sure the Build Action property is set to “Embeded Resource.”