nhibernate interceptors with domain context - asp.net

Is it possible (in a clean fashion) to create an audit interceptor in hibernate 2.1 and pass in a domain context to it?
What I would like to achieve is to set a Date Time (can be done easy peasy - found loadsa articles after a quick google), but setting an object e.g. a user who created the item, or altered an entity I have yet to find anything which covers this.
Since I will not know the object at application request/start up (which is where i have to register the nhibernate interceptor), does anyone know of a suitable workaround?
Thanks in advance, Mark H

You can store the user in the current session (HttpContext.Session) or use thread local data. It can then be accessed by the listener. If you go for the thread local approach, you will need to set if for each request, for instance with an HttpModule. Not perfect, but that's how I've seen it done in java (not exactly the same, but a similar approach).

Related

Expose the HttpContext in log4net

I have an ASP.NET website and I am doing logging with log4net. As logging requirements change often, I want to enable PMs to modify the information that gets logged and also to be able to log extra information for debugging in production (i.e without having to recompile)
My plan is to expose certain values to log4net, for example the GET / POST params from context. To log such a param, the user would just go to the log4net config and do something like %message{userId}
I have found a way to do it using a property bag on log4net.ThreadContext but I am not sure if this doesn't have side-effects, i.e. the values are persisted for too long.
Another way is to use a forwarding appender, and inject the extra values whenever the logger gets called, but I haven't been able to implement this, there are not enough examples out there.
Any ideas?
Look at my answer to this question. The linked question and answer are specifically about adding the username from HttpContext.Current.User to the logfile, but it should be pretty easy to make a more generic solution that might fit your needs.
It might provide you with some ideas of how to incorporate information from the HttpContext into your log4net logging. There are other good ideas in that thread as well.
You should have a look at NDC (Nested Diagnostic Context) in log4net. This will provide you with to possibility to add information logging messages like setting up a stack:
using(log4net.NDC.Push("My extra info")){
}
All logmessages within the NDC scope will have the inner_context available (pattern layout format):
[%ndc] - %message%newline

NHibernate, Sqlite, missing tables and IOC fun

I'm doing unit testing on a class library that uses NHibernate for persistence. NHibernate is using a Sqlite in-memory database for testing purposes. Under normal circumstances, it's easy to get StructureMap to kick out a session for me.
However, because I'm using the in-memory database to improve testing speed, I need to have a single session available for the duration of a test (because it blows the database away when I create a new one). And there is another wrinkle. The case that is currently burning me is testing a custom NHibernate-based ASP.NET membership provider. These are created apparently once per AppDomain, so I shouldn't inject the session into it, for obvious reasons.
Is there a way in structuremap to tell it to get rid of an instance of a particular type while still maintaining the bits that tell it how to instantiate that type? Really, if I could get away with it, I would just make it act like the HttpScoped object lifetime, but apparently I can only do that within the context of an Http request. Is there a straightforward way to manually control the lifetime of an object coming out of structuremap?
I apologize for the length of this and the possibility that it is a dumb question. I'm solo on this project, so I don't really have anyone to bounce ideas off of.
You could wrap the session in your own ISession implementation which delegates to a real session which lifetime you control. Then register your own ISession as instance.
I ended up making two constructors for my provider along with a private variable of type Func. By default, its value was set to my standard code for creating a session using StructureMap's ObjectFactory.
The overloaded constructor accepted as a parameter an object of type Func. That way, I can inject a strategy for creating an instance of that type if needed, but otherwise don't have to go through any extended effort. In the case of my test, I created the session in the NUnit setup method and destroyed it in the Teardown. I don't love this idea, but I don't currently hate it enough to rip it out....yet.
This got rid of the error I was experiencing in regard to the tables. However, it appears that NHibernate for some reason cannot write to an in-memory sqlite database under the conditions I created. I'm now working on testing to see if I can write to one in the file system. It isn't ideal, but it will be a good long while (I hope), before the performance of writing to disk really starts hurting.

Symfony2: Is better to use session object or my own manager?

Related to that question.
I've understood that I have to create some services for handle my entity and so on. That's because I have to "move" my logic away from controllers and place into "managers" (i.e. services)
Now I have a service that have some logic into it. In that service I, depending on user, return a list of "associated object" - say that those object are sport's team.
Let's say that first element of my list (generated from a repository somehow) is the "default" team and say that I have a page were I can change it FOR all session long.
After log out or sessions stale, I want to return at "default" situation.
So my idea was: "since I've wrote a manager for this entity, I'll write a private attribute in this class where load (from db) this property and store (temporarily, with setter method) my changes."
This doesn't affect my db and I can keep my information for all session long.
But a thought came into my mind: how about session object? (is a service, if I didn't understood wrong)
Is my solution a good solution, or is better to store my information into session object?
From my point of view it's the same except that I can read session's variables directly from twig by using app.session. Am I wrong?
Moreover, if I'm not wrong, how can I access my object properties from twig without each time pass them from controller? (is much like having a global variable that I want to display everywhere into my application pages).
Edit:
More information can be found in this chat transcript.
If you want to store a variable for the duration of a session (for example, login until logout or as long as the user doesn't close his browser window) you have to store it in the session object. If you want to store a variable for the duration of a request, you can store it in the manager service.
However, you can use the manager service to load the session variable and make it available to the controller.
Just like it is a good idea to decouple the controller from the database/Doctrine it is also a good idea to decouple the controller from the session.
Update: As mentioned in the comments when looking at REST it is not a good idea to do the session stuff in the service. However, you should still store the variables in the session and use the controller to set the value in the service.

Attaching an event listener to all URLRequest's

We have a flex application that connects to a proxy server which handles authentication. If the authentication has timeout out the proxy server returns a json formatted error string. What I would like to do is inspect every URLRequest response and check if there's an error message and display it in the flex client then redirect back to login screen.
So I'm wondering if its possible to create an event listener to all URLRequests in a global fashion. Without having to search through the project and add some method to each URLRequest. Any ideas if this is possible?
Unless you're only using one service, there is no way to set a global URLRequest handler. If I were you, I'd think more about architecting your application properly by using a delegate and always checking the result through a particular service which is used throughout the app.
J_A_X has some good suggestions, but I'd take it a bit farther. Let me make some assumptions based on the limited information you've provided.
The services are scattered all over your application means that they're actually embedded in multiple Views.
If your services can all be handled by the same handler, you notionally have one service, copied many times.
Despite what you see in the Adobe examples showing their new Service generation code, it's incredibly bad practice to call services directly from Views, in part because of the very problem you are seeing--you can wind up with lots of copies of the same service code littered all over your application.
Depending on how tightly interwoven your application is (believe me, I've inherited some pretty nasty stuff, so I know this might be easier said than done), you may find that the easiest thing is to remove all of those various services and replace them by having all your Views dispatch a bubbling event that gets caught at the top level. At the top level, you respond to that event by calling one instance of your service, which is again handled in one place.
You may or may not choose to wrap that single service in a delegate, but once you have your application archtected in a way where the service is decoupled from your Views, you can make that choice at any time.
Would you be able to extend the class and add an event listener in the object's constructor? I don't like this approach but it could work.
You would just have to search/replace the whole project.

ObjectContext in ASP.Net

I'm working with a project in ASP.Net using Webforms. I'm using Entity Framework to save data on Microsoft SQL.
My question is:
Is possible to use a Static class to keep the ObjectContext of EF live and put/get entities NOT saved inside the ObjectContext?
I want to create an Object, then added with AddObject on the ObjectContext, But NOT to do the Savechanges. All this in one webform. And then, in other webform, access to the ObjectContext and get the Object when added.
It is this possible?
My rules to using ObjectContext:
Do not use static context.
Do not share context.
You are trying to violate both rules. If you do that your application will have undeterministic behavior. Create new ObjectContext instance for each request. It is the same as openning new connection and starting new transaction in the request instead of sharing one connection and one transaction among all of them.
Further explanation also here. Also check linked question in right column and you will see what type of problems people have just because of violating one or both mentioned rules.
Also in web application it becames even more interesting because ObjectContext is not thread safe.
You could add it to the application items collection. See this blog post for syntax and such.
http://www.informit.com/articles/article.aspx?p=27315&seqNum=3
Generally, you don't want to. An ObjectContext is intended to be a unit of work, alive for a single set of related transactions. In an ASP.NET application, that generally corresponds to a single request.
If you must keep it alive for multiple requests, I wouldn't use either a static class, nor the application context. Instead, I'd recommend using the Cache, and then attaching the callbacks to it that let you ensure all your transactions are committed before it gets evicted, just in case.

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