Category Archives: Open Source Projects
NBuilder 6.0.0 Released

Thank you to the contributors who submitted pull requests for the issues that were important to them. A summary of the changes for NBuilder 6 are as follows:

  • Breaking Change: WithConstructor
    • No longer takes an Expression<Func<T>>.
    • Takes a Func<T>.
    • Marked [Obsolete] in favor of WithFactory
    • This change was to address an issue in which the constructor expression was not being reevaluated for each item in a list.
  • Feature: @AdemCatamak Added support for IndexOf as part of the ListBuilder implementation.
var products = new Builder()
    .CreateListOfSize<Product>(10)
    .IndexOf(0, 2, 5)
    .With(x => x.Title = "A special title")
    .Build();
  • Feature: @PureKrome Added support for DateTimeKind to RandomGenerator
var result = randomGenerator.Next(DateTime.MinValue, DateTime.MaxValue, DateTimeKind.Utc);
  • Feature: Added DisablePropertyNamingFor(PropertyInfo) overload to BuilderSettings.
  • Feature: Added TheRest as an extension to the ListBuilder.
var results = new Builder()
        .CreateListOfSize<SimpleClass>(10)
        .TheFirst(2)
        .Do(row => row.String1 = "One")
        .TheRest()
        .Do(row => row.String1 = "Ten")
        .Build()
    ;
  • Bug: Last item in enum is never generated when generating property values randomly.
  • Bug: Lost strong name when porting to .NET Standard.
  • Bug: Non-deterministic behavior when calling TheLast multiple times for the same range.
Isg.EntityFramework 0.9.0 Released (Bug Fix)

Release Notes

  • Fixed a bug in TypeInterceptor in which IsTargetEntity() was not being called before passing the handling down the inheritance chain.
Don’t Unit Test NHibernate: Use Generic Repository

I was reading this stack overflow question: How can I solve this: Nhibernate Querying in an n-tier architecture?

The author is trying to abstract away NHibernate and is being counseled rather heavily not to do so. In the comments there are a couple of blog entries by Ayende on this topic:

The false myth of encapsulating data access in the DAL

Architecting in the pit of doom the evils of the repository abstraction layer

Ayende is pretty down on abstracting away NHIbernate. The answers on StackOverflow push the questioner toward just standing up an in-memory Sqlite instance and executing the tests against that.

The Sqlite solution is pretty painful with complex databases. It requires that you set up an enormous amount of data that isn’t really germane to your test in order to satisfy FK and other constraints. The ceremony of creating this extra data clutters the test and obscures the intent. To test a query for employees who are managers, I’d have to create Departments and Job Titles and Salary Types etc., etc., etc.. Dis-like.

What problem am I trying to solve?

In the .NET space developers tend to want to use LINQ to access, filter, and project data. NHibernate (partially) supports LINQ via an extension method off of ISession. Because ISession.Query<T> is an extension method, it is not stubbable with free mocking tools such as RhinoMocks, Moq, or my favorite: NSubstitute. This is why people push you to use the Sqlite solution—because the piece of the underlying interface that you want to use most of the time is not built for stubbing.

I think that a fundamental problem with NHibernate is that it is trying to serve 2 masters. On the one hand it wants to be a faithful port of Hibernate. On the other, it wants to be a good citizen for .NET. Since .NET has LINQ and Java doesn’t, the support for LINQ is shoddy and doesn’t really fit in well the rest of the API design. LINQ support is an “add-on” to the Java api, and not a first-class citizen. I think this is why it was implemented as an extension method instead of as part of the ISession interface.

I firmly disagree with Ayende on Generic Repository. However, I do agree with some of the criticisms he offers against specific implementations. I think his arguments are a little bit of straw man, however. It is possible to do Generic Repository well.

I prefer to keep my IRepository interface simple:

    public interface IRepository : IDisposable
    {
        IQueryable<T> Find<T>() where T: class;

        T Get<T>(object key) where T : class;

        void Save<T>(T value) where T: class;

        void Delete<T>(T value) where T: class;

        ITransaction BeginTransaction();

        IDbConnection GetUnderlyingConnection();
    }

 

Here are some of my guidelines when using a Generic Repository abstraction:

  • My purpose in using Generic Repository is not to “hide” the ORM, but
    • to ease testability.
    • to provide a common interface for accessing multiple types of databases (e.g., I have implemented IRepository against relational and non-relational databases) Most of my storage operations follow the Retrieve-Modify-Persist pattern, so Find<T>, Get<T>, and Save<T> support almost everything I need.
  • I don’t expose my data models outside of self-contained operations, so Attach/Detach are not useful to me.
  • If I need any of the other advanced ORM features, I’ll use the ORM directly and write an appropriate integration test for that functionality.
    • I don’t use Attach/Detach, bulk operations, Flush, Futures, or any other advanced features of the ORM in my IRepository interface. I prefer an interface that is clean, simple, and useful in 95% of my scenarios.
  • I implemented Find<T> as an IQueryable<T>. This makes it easy to use the Specification pattern to perform arbitrary queries. I wrote a specification package that targets LINQ for this purpose.
    • In production code it is usually easy enough to append where-clauses to the exposed IQueryable<T>
    • For dynamic user-driven queries I will write a class that will convert a flat request contract into the where-clause needed by the operation.
  • I expose the underlying connection so that if someone needs to execute a sproc or raw sql there is a convenient way of doing that.
Isg.EntityFramework 0.8.0 Released

InterceptionContext is now passed to TypeInterceptor methods and ChangeInterceptor methods. This may result in breaking changes depending on if and how you have inherited those classes, but I’ve done my best to preserve existing behavior. I marked the obsolete methods as such.

The purpose of this change is enable the scenario where you want to write a log-record back to the database when a record is saved or deleted.

Update:

0.8.0 did not contain the updated assemblies.

0.8.1 does.

What happened?

My build server is configured so that it only creates and publishes packages from the last pinned build. I forgot to pin the build that has the changes. I’ve pinned the build and republished 0.8.1. I’ve created a workitem for myself to separate package creation from package publication so that I can inspect the package before it’s sent to Nuget.

Isg.EntityFramework 0.7.0 Released–Bug Fix

Issues Fixed

  1. ChangeInterceptor.OnAfter not working correctly.

The cause of the bug is that EntityFramework resets the EntityState to UnChanged after writing the object to the database. This means that I cannot tell which operation was performed on the entity unless I memoize the state before the operation. The effect of this change is that I can no longer get the EntityState of the item before the operation from the DbEntityEntry.

Breaking Changes

If you are inheriting from TypeInterceptor or ChangeInterceptor the signature of OnBefore and OnAfter has changed.

The new signatures are

 protected override void OnBefore(DbEntityEntry item, EntityState state)
 protected override void OnAfter(DbEntityEntry item, EntityState state)

Isg.EntityFramework 0.6.0 Released

Breaking Changes

New Features

 

Isg.EntityFramework.Interceptors.Auditable

If you have a class that implements IAuditable the AuditableChangeInterceptor will use IPrincipal and IClock to assign audit fields. If you are inserting a new record, CreateUser and UpdateUser will be set to IPrincipal.Identity.Name, and CreateDate and UpdateDate will be set to IClock.Now. If you are updating an existing record, only the Update fields will be modified.

    public interface IAuditable
    {
        DateTime CreateDate { get; set; }
        string CreateUser { get; set; }

        DateTime UpdateDate { get; set; }
        string UpdateUser { get; set; }
    }
Isg.EntityFramework.ObservableProvider

The Problem

I’ve been struggling for awhile to figure out how to get Entity Framework to set and unset application roles in Sql Server when opening and before closing a connection. The problem is that ConnectionState does not provide a Closing state that fires before a connection is closed.

It was suggested to me to turn of connection pooling. Errrr, no. We want connection pooling for our applications. I also don’t want to have to manually open and close the connection every time I create a DbContext. That’s just messy and irritating.

The next obvious thing to do would be to create a DbConnectionDecorator to wrap the existing database connection and expose the Closing event. This proved to be very difficult because Entity Framework does not expose when and how it opens connections.

Grrrrrr.

The Solution

What’s that you say? I can implement my own EntityFramework Provider? There’s a provider wrapper toolkit I can plug into to do this? Awesome!

Oh wait—that looks really, really, REALLY complicated? You mean I can’t just decorate a single object? I have to decorate a whole family of objects?

Hmmmm.

Alright, tell you what I’ll do. I’ll implement the provider wrapper using the toolkit as best I can—but then I’m going to strip away everything I don’t actually need. Besides, if I just make the various data related events observable, it’s nothing to Trace the output. And Cacheing can easily be added as a IDbContext Decorator anyway. I don’t really get why that should be done at the Provider level.

Configuring Your Application to use the Provider

To use the new provider, first install the package. At application startup, you’ll need to register the provider and tell it which other provider you are wrapping. The registration process will set the ObservableConnectionFactory as the default connection factory used by EF unless you pass the optional setAsDefault:false.

Consuming the Provider Events

ObservableConnection exposes several new events, including Opening, Opened, Failed, Closing, and Closed. However, to subscribe to those events directly requires that you cast the DbConnection exposed by EF to ObservableDbConnection, which strikes me as a little cumbersome (not to mention a violation of the LSP). My first use case demands that I handle the Opening and Closing events the same way for every DbConnection application-wide. To that end, ObservableDbConnection (and ObservableDbCommand) pushes its event messages onto a static class called Hub.

Guarantees

This code is brand-spanking new and it hasn’t had time to bake yet. I’m using it, but it’s entirely possible that there are unforeseen problems. Feel free to report issues to and/or contribute to the open-source project on BitBucket. Until then, know that it has been rigorously test and that it works on my machine.

works on my machine, starburst

Simple.Validation 0.6.1 Released

What’s new?

Testability has been kind of an issue for us with code that relies on the static Validator class. To improve the situation, I added IValidationEngine as an alternative. Validator is still fully backwards compatible

  • Addition of the IValidationEngine interface
  • The DefaultValidationEngine requires an instance of IValidatorProvider for its constructor
  • Validator.SetValidatorProvider() has been marked obsolete. You can still use it, but it will have the side-effect of over-setting Validator.ValidationEngine to a new instance of DefaultValidationEngine.
  • Added a NinjectModule to Simple.Validation.Ninject that configures the DefaultValidationEngine and DefaultValidatorProvider automatically.
Simple.Validation 0.5.0 Released

New Feature

Message() method has been overloaded to accept a function to build the validation message while the object/property is being validated.

Example:

var validator = Properties<Employee>
    .For(e => e.FirstName)
    .Required()
    .Message((context, value) =>
        {
             customMessage = string.Format("Custom Message format '{0}'", value);
             return customMessage;
        });
Isg.EntityFramework 0.5.1 – Release Notes

I’ve added a LookUp property to the InterceptionContext to make it easier to see which rows were affected during the After() interception phase.

    public class InterceptionContext
    {
        public DbContextBase DbContext { get; internal set; }
        public ObjectContext ObjectContext { get; internal set; }
        public ObjectStateManager ObjectStateManager { get; internal set; }
        public DbChangeTracker ChangeTracker { get; internal set; }
        public IEnumerable<DbEntityEntry> Entries { get; internal set; }
        public ILookup<EntityState, DbEntityEntry> EntriesByState { get; internal set; }

... snipped for brevity

EntriesByState is populated prior to the call to Before(). Added and Modified entities will have their EntityState reverted to UnChanged after SaveChanges() is called. EntriesByState preserves the original state of the entities so that After() interceptors can make use of new Id’s and such.

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