Skip to main content

Unit Of Work injection through Asp.Net Core Dependency Injection

This article is not directly related to UnitOfWork but leveraging Asp.Net Core Dependency Injection to consume Unit Of Work.

In one of the previous article about project architecture, I was not very satisfied with the approach for Unit Of Work implementation for initialization of repository even if with some advantage.

Here is old code for UnitOfWork.

  public sealed partial class MyProjectUnitOfWork   
    : UnitOfWork<DbContext>, IMyProjectUnitOfWork   
   {   
    public MyProjectUnitOfWork(IContextFactory<DbContext> contextFactory)   
     : base(contextFactory)   
    {   
    }   
    /// <summary>   
    /// BookRepository holder   
    /// </summary>   
    private MyProject.DB.Repository.BookRepository _bookRepository;   
    /// <summary>   
    /// Gets the BookRepository repository.   
    /// </summary>   
    /// <value>   
    /// The BookRepository repository.   
    /// </value>   
    MyProject.Interface.Repository.IBookRepository IMyProjectUnitOfWork.BookRepository   
    {   
     get   
     {   
      return _bookRepository =   
      _bookRepository ?? new MyProject.DB.Repository.BookRepository(Context);   
     }   
    }   
   }

The major reason for dissatisfaction was due to direct initialization of those repositories. Even if it lazy initialization and globally at one place but still the direct dependency.

So, what changed in the Asp.Net Core DI that in the earlier code I have not accommodated. Actually it does not change, in fact, the DIs libraries are more feature rich in comparison of Asp.Net Core DI. The only good thing is we would not generally depend on any third party libraries since there is built in the library available with Framework itself. So, this gives freedom to use DI related codes on dependent projects without much worrying about that DI framework could change in future.

After keeping this in mind what all need to be changed:

  1. MyProjectUnitOfWork implementation to get repository in a new way.
  2. Constructor change to resolve service through Service Provider.
  3. Initialization of DIs for repositories.
  4. Making entry point in Startup.cs 

MyProjectUnitOfWork T4 for code generation

 
 <#@ template debug="true" hostSpecific="true" #>  
 <#@ output extension=".cs" #>  
 <#@ Assembly Name="System.Core" #>  
 <#@ import namespace="System" #>  
 <#@ import namespace="EnvDTE" #>  
 <#@ import namespace="EnvDTE80" #>  
 <#@ import namespace="System" #>  
 <#@ import namespace="System.IO" #>  
 <#@ import namespace="System.Diagnostics" #>  
 <#@ import namespace="System.Linq" #>  
 <#@ import namespace="System.Collections" #>  
 <#@ import namespace="System.Collections.Generic" #>   
 <#@ include file="EF.Utility.CS.ttinclude"#>  
 <#@ include file="../../T4Plugin/VisualStudioAutomationHelper.ttinclude" #>  
 <#@ include file="../../T4Plugin/MultiOutput.ttinclude" #>  
 <#  
   var modelProjectNamespace = "MyProject.Model";  
   var modelNamespace = "MyProject.Model.DataModel";  
   var modelNamespaceReplace = "MyProject.Interface.Repository";  
   var repositoryNamespace = "MyProject.DB.Repository";  
   CodeGenerationTools code = new CodeGenerationTools(this);  
   var codeDom = CodeDomProvider.CreateProvider("C#");  
   var modelProject = VisualStudioHelper.GetProject(modelProjectNamespace);  
   var allModelClasses = VisualStudioHelper.GetAllCodeElementsOfType(modelProject.CodeModel.CodeElements, EnvDTE.vsCMElement.vsCMElementClass, false);  
   var types = (from modelClass in allModelClasses.OfType<CodeClass2>()  
       where modelClass.FullName.StartsWith(modelNamespace) &&   
         !modelClass.FullName.EndsWith("MetadataSource")  
       select modelClass  
     ).OrderBy(clas=>clas.FullName);  
 #>  
 //------------------------------------------------------------------------------  
 // <auto-generated>  
 //   This code was generated from a template and will be re-created if deleted  
 //       with default implementation.  
 // </auto-generated>  
 //------------------------------------------------------------------------------  
 using System;  
 using MyProject.Interface.Infrastructure;  
 using Microsoft.EntityFrameworkCore;  
 using Microsoft.Extensions.DependencyInjection;  
 namespace <#=    code.VsNamespaceSuggestion()#>  
 {  
   /// <summary>  
   /// MyProject implementation of Unit of Work  
   /// </summary>  
      public sealed partial class MyProjectUnitOfWork  
           : IMyProjectUnitOfWork  
      {  
     /// <summary>  
     /// The service provider  
     /// </summary>  
     private readonly IServiceProvider ServiceProvider;  
     /// <summary>  
     /// Initializes a new instance of the <see cref="MyProjectUnitOfWork"/> class.  
     /// </summary>  
     /// <param name="dbContext">The database context.</param>  
     /// <param name="serviceProvider">The service provider.</param>  
     public MyProjectUnitOfWork(MyProjectContext dbContext, IServiceProvider serviceProvider)  
       : base(dbContext)  
     {  
       ServiceProvider = serviceProvider;  
     }  
                          <#  
   foreach (var type in types)  
   {  
     var nameSpace = type.Namespace.Name.Replace(modelNamespace,repositoryNamespace);  
     var interfaceNameSpace = type.Namespace.Name.Replace(modelNamespace,modelNamespaceReplace);  
     var name = type.Name + "Repository";  
     var fullName = nameSpace + "." + name;  
           var interfaceFullName = $"{interfaceNameSpace}.I{type.Name}Repository";  
                #>  
           /// <summary>  
           /// <#=      name #> holder  
           /// </summary>  
     private <#=      fullName #> _<#=      code.CamelCase(name) #>;  
     /// <summary>  
     /// Gets the <#=      type.Name #>Repository repository.  
     /// </summary>  
     /// <value>  
     /// The <#=      type.Name #>Repository repository.  
     /// </value>  
     <#=interfaceFullName#> IMyProjectUnitOfWork.<#=      type.Name #>Repository   
     {   
          get  
          {  
                     return ServiceProvider.GetService<<#=      fullName #>>();  
          }  
     }  
      <#}  
      #>}  
 }

The above would generate

 //------------------------------------------------------------------------------  
 // <auto-generated>  
 //   This code was generated from a template and will be re-created if deleted  
 //       with default implementation.  
 // </auto-generated>  
 //------------------------------------------------------------------------------  
 using System;  
 using MyProject.Interface.Infrastructure;  
 using Microsoft.EntityFrameworkCore;  
 using Microsoft.Extensions.DependencyInjection;  
 namespace MyProject.DB.Infrastructure  
 {  
   /// <summary>  
   /// MyProject implementation of Unit of Work  
   /// </summary>  
      public sealed partial class MyProjectUnitOfWork  
           : IMyProjectUnitOfWork  
      {  
     /// <summary>  
     /// The service provider  
     /// </summary>  
     private readonly IServiceProvider ServiceProvider;  
     /// <summary>  
     /// Initializes a new instance of the <see cref="MyProjectUnitOfWork"/> class.  
     /// </summary>  
     /// <param name="dbContext">The database context.</param>  
     /// <param name="serviceProvider">The service provider.</param>  
     public MyProjectUnitOfWork(MyProjectContext dbContext, IServiceProvider serviceProvider)  
       : base(dbContext)  
     {  
       ServiceProvider = serviceProvider;  
     }  
           /// <summary>  
           /// BookRepository holder  
           /// </summary>  
     private MyProject.DB.Repository.BookRepository _bookRepository;  
     /// <summary>  
     /// Gets the BookRepository repository.  
     /// </summary>  
     /// <value>  
     /// The BookRepository repository.  
     /// </value>  
     MyProject.Interface.Repository.IBookRepository IMyProjectUnitOfWork.BookRepository   
     {   
          get  
          {  
                     return ServiceProvider.GetService<MyProject.DB.Repository.BookRepository>();  
          }  
     }  
      }  
 }

By looking into the code, it is just using ServiceProvider to get the registered services.

Now, need to write code to register service. This again would be populated through T4 and dependency injection codes.

T4 to generate DI codes for Repositories 

 <#@ template debug="true" hostSpecific="true" #>  
 <#@ output extension=".cs" #>  
 <#@ Assembly Name="System.Core" #>  
 <#@ import namespace="System" #>  
 <#@ import namespace="EnvDTE" #>  
 <#@ import namespace="EnvDTE80" #>  
 <#@ import namespace="System" #>  
 <#@ import namespace="System.IO" #>  
 <#@ import namespace="System.Diagnostics" #>  
 <#@ import namespace="System.Linq" #>  
 <#@ import namespace="System.Collections" #>  
 <#@ import namespace="System.Collections.Generic" #>   
 <#@ include file="EF.Utility.CS.ttinclude"#>  
 <#@ include file="../../../T4Plugin/VisualStudioAutomationHelper.ttinclude" #>  
 <#@ include file="../../../T4Plugin/MultiOutput.ttinclude" #>  
 <#  
   var modelProjectNamespace = "MyProject.Model";  
   var modelNamespace = "MyProject.Model.DataModel";  
   var modelNamespaceReplace = "MyProject.Interface.Repository";  
   var repositoryNamespace = "MyProject.DB.Repository";  
   CodeGenerationTools code = new CodeGenerationTools(this);  
   var codeDom = CodeDomProvider.CreateProvider("C#");  
   var modelProject = VisualStudioHelper.GetProject(modelProjectNamespace);  
   var allModelClasses = VisualStudioHelper.GetAllCodeElementsOfType(modelProject.CodeModel.CodeElements, EnvDTE.vsCMElement.vsCMElementClass, false);  
   var types = (from modelClass in allModelClasses.OfType<CodeClass2>()  
       where modelClass.FullName.StartsWith(modelNamespace) &&   
         !modelClass.FullName.EndsWith("MetadataSource")  
       select modelClass  
     ).OrderBy(clas=>clas.FullName);  
 #>  
 //------------------------------------------------------------------------------  
 // <auto-generated>  
 //   This code was generated from a template and will be re-created if deleted  
 //       with default implementation.  
 // </auto-generated>  
 //------------------------------------------------------------------------------  
 using Microsoft.Extensions.DependencyInjection;  
 namespace <#=    code.VsNamespaceSuggestion()#>  
 {  
   /// <summary>  
   /// Registration of repository with Dependency Injection.  
   /// </summary>  
      public static class ExtensionUnitOfWorkService  
      {  
     /// <summary>  
     /// Registers the repositories.  
     /// </summary>  
     /// <param name="service">The service collection.</param>  
           public static void RegisterRepositories(this IServiceCollection service)  
           {  
 <#  
   foreach (var type in types)  
   {  
     var nameSpace = type.Namespace.Name.Replace(modelNamespace,repositoryNamespace);  
     var interfaceNameSpace = type.Namespace.Name.Replace(modelNamespace,modelNamespaceReplace);  
     var name = type.Name + "Repository";  
     var fullName = nameSpace + "." + name;  
           var interfaceFullName = $"{interfaceNameSpace}.I{type.Name}Repository";  
           #>               service.AddScoped<<#= interfaceFullName #>, <#= fullName #>>();  
 <#  
   }#>          }  
      }  
 }

Once executed it would generate codes to map Repository interfaces with respective classes.

 //------------------------------------------------------------------------------  
 // <auto-generated>  
 //   This code was generated from a template and will be re-created if deleted  
 //       with default implementation.  
 // </auto-generated>  
 //------------------------------------------------------------------------------  
 using Microsoft.Extensions.DependencyInjection;  
 namespace MyProject.DB.Infrastructure.Configuration  
 {  
   /// <summary>  
   /// Registration of repository with Dependency Injection.  
   /// </summary>  
      public static class ExtensionUnitOfWorkService  
      {  
     /// <summary>  
     /// Registers the repositories.  
     /// </summary>  
     /// <param name="service">The service collection.</param>  
           public static void RegisterRepositories(this IServiceCollection service)  
           {  
                service.AddScoped<MyProject.Interface.Repository.IBookRepository, MyProject.DB.Repository.BookRepository>();  
           }  
      }  
 }



Two things are done by now MyProjectUnitOfWork properties implementation to get Repositories from ServiceProvider and then mappings of Repository interface to respective classes on ExtensionUnitOfWorkService class.

DbContext registration and above services registration

 /// <summary>  
 /// DB Configuration.  
 /// </summary>  
 public static class ExtensionRepositoryConfiguration  
 {  
   /// <summary>  
   /// Adds the database configuration to MVC Core.  
   /// </summary>  
   /// <param name="services">The services.</param>  
   /// <param name="configuration">The configuration.</param>  
   /// <param name="connectionName">Name of the connection.</param>  
   public static void AddDb(this IServiceCollection services,  
     IConfigurationRoot configuration, string connectionName)  
   {  
     services.AddDbContext<MyProjectContext>(options =>  
     {  
       options.UseSqlServer(connectionName,  
         serverOption => serverOption.MigrationsAssembly("MyProject.Web"));  
     });  
     services.AddScoped<IMyProjectUnitOfWork>((serv) =>  
     {  
       return new MyProjectUnitOfWork(serv.GetService<MyProjectContext>(), serv);  
     });  
     services.RegisterRepositories();  
   }  
 }


All DIs for Repositories are done by calling RegisterRepositories and general Context injection.

Finally, on Startup.cs, need to call this.

 services.AddDb(Configuration, Configuration.GetConnectionString("SqlDatabaseDevelopment"));


SOURCE CODE: https://github.com/viku85/RepositoryUnitOfWorkDiSample

Labels:

Comments

Post a Comment

Popular posts from this blog

Making FluentValidation compatible with Swagger including Enum or fixed List support

FluentValidation is not directly compatible with Swagger API to validate models. But they do provide an interface through which we can compose Swagger validation manually. That means we look under FluentValidation validators and compose Swagger validator properties to make it compatible. More of all mapping by reading information from FluentValidation and setting it to Swagger Model Schema. These can be done on any custom validation from FluentValidation too just that proper schema property has to be available from Swagger. Custom validation from Enum/List values on FluentValidation using FluentValidation.Validators; using System.Collections.Generic; using System.Linq; using static System.String; /// <summary> /// Validator as per list of items. /// </summary> /// <seealso cref="PropertyValidator" /> public class FixedListValidator : PropertyValidator { /// <summary> /// Gets the valid items /// <...
1 comment
Read more

Elegantly dealing with TimeZones in MVC Core / WebApi

In any new application handling TimeZone/DateTime is mostly least priority and generally, if someone is concerned then it would be handled by using DateTime.UtcNow on codes while creating current dates and converting incoming Date to UTC to save on servers. Basically, the process is followed by saving DateTime to UTC format in a database and keep converting data to native format based on user region or single region in the application's presentation layer. The above is tedious work and have to be followed religiously. If any developer misses out the manual conversion, then that area of code/view would not work. With newer frameworks, there are flexible ways to deal/intercept incoming or outgoing calls to simplify conversion of TimeZones. These are steps/process to achieve it. 1. Central code for storing user's state about TimeZone. Also, central code for conversion logic based on TimeZones. 2. Dependency injection for the above class to ...
4 comments
Read more

Handling JSON DateTime format on Asp.Net Core

This is a very simple trick to handle JSON date format on AspNet Core by global settings. This can be applicable for the older version as well. In a newer version by default, .Net depends upon Newtonsoft to process any JSON data. Newtonsoft depends upon Newtonsoft.Json.Converters.IsoDateTimeConverter class for processing date which in turns adds timezone for JSON data format. There is a global setting available for same that can be adjusted according to requirement. So, for example, we want to set default formatting to US format, we just need this code. services.AddMvc() .AddJsonOptions(options => { options.SerializerSettings.DateTimeZoneHandling = "MM/dd/yyyy HH:mm:ss"; });
1 comment
Read more

Storing and restoring Kendo Grid state from Database

There is no any built in way to store entire grid state into database and restore back again with all filters, groups, aggregates, page and page size. At first, I was trying to restore only filters by looking through DataSourceRequest. DataSourceRequest is kind of communication medium between client and server for the operation we do on grid. All the request comes via DataSourceRequest. In previous approach, I was trying to store IFileDescriptor interface which come with class FileDescriptor by looping through filters and serializing into string for saving into database but this IFileDescriptor can also contain CompositeFilterDescriptor which can be nested in nested object which are very tricky to handle. So, I had decompiled entire Kendo.MVC library and found out that all Kendo MVC controls are derived from “JsonObject”. It is there own implementation with ”Serialize” abstract function and “ToJson” function. In controls they are overriding “Serialize” method which depicts t...
Post a Comment
Read more

Trim text in MVC Core through Model Binder

Trimming text can be done on client side codes, but I believe it is most suitable on MVC Model Binder since it would be at one place on infrastructure level which would be free from any manual intervention of developer. This would allow every post request to be processed and converted to a trimmed string. Let us start by creating Model binder using Microsoft.AspNetCore.Mvc.ModelBinding; using System; using System.Threading.Tasks; public class TrimmingModelBinder : IModelBinder { private readonly IModelBinder FallbackBinder; public TrimmingModelBinder(IModelBinder fallbackBinder) { FallbackBinder = fallbackBinder ?? throw new ArgumentNullException(nameof(fallbackBinder)); } public Task BindModelAsync(ModelBindingContext bindingContext) { if (bindingContext == null) { throw new ArgumentNullException(nameof(bindingContext)); } var valueProviderResult = bindingContext.ValueProvider.GetValue(bin...
1 comment
Read more

LDAP with ASP.Net Identity Core in MVC with project.json

Lightweight Directory Access Protocol (LDAP), the name itself explain it. An application protocol used over an IP network to access the distributed directory information service. The first and foremost thing is to add references for consuming LDAP. This has to be done by adding reference from Global Assembly Cache (GAC) into project.json "frameworks": { "net461": { "frameworkAssemblies": { "System.DirectoryServices": "4.0.0.0", "System.DirectoryServices.AccountManagement": "4.0.0.0" } } }, These  System.DirectoryServices  and  System.DirectoryServices.AccountManagement  references are used to consume LDAP functionality. It is always better to have an abstraction for irrelevant items in consuming part. For an example, the application does not need to know about PrincipalContext or any other dependent items from those two references to make it extensible. So, we can begin wi...
Post a Comment
Read more

Configuring Ninject, Asp.Net Identity UserManager, DataProtectorTokenProvider with Owin

It can be bit tricky to configure both Ninject and Asp.Net Identity UserManager if some value is expected from DI to configure UserManager. We will look into configuring both and also use OwinContext to get UserManager. As usual, all configuration need to be done on Startup.cs. It is just a convention but can be used with different name, the important thing is to decorate class with following attribute to make it Owin start-up: [assembly: OwinStartup(typeof(MyProject.Web.Startup))] Ninject configuration Configuring Ninject kernel through method which would be used to register under Owin. Startup.cs public IKernel CreateKernel() { var kernel = new StandardKernel(); try { //kernel.Bind<IHttpModule>().To<HttpApplicationInitializationHttpModule>(); // TODO: Put any other injection which are required. return kernel; } catch { kernel.Dispose(); thro...
Post a Comment
Read more

Data seed for the application with EF, MongoDB or any other ORM.

Most of ORMs has moved to Code first approach where everything is derived/initialized from codes rather than DB side. In this situation, it is better to set data through codes only. We would be looking through simple technique where we would be Seeding data through Codes. I would be using UnitOfWork and Repository pattern for implementing Data Seeding technique. This can be applied to any data source MongoDB, EF, or any other ORM or DB. Things we would be doing. - Creating a base class for easy usage. - Interface for Seed function for any future enhancements. - Individual seed classes. - Configuration to call all seeds. - AspNet core configuration to Seed data through Seed configuration. Creating a base class for easy usage public abstract class BaseSeed<TModel> where TModel : class { protected readonly IMyProjectUnitOfWork MyProjectUnitOfWork; public BaseSeed(IMyProjectUnitOfWork MyProjectUnitOfWork) { ...
Post a Comment
Read more

A wrapper implementation for Kendo Grid usage

A wrapper implementation for any heavily used item is always a good practice. Whatever is not written by us and used at a lot of places should be wrapped within specific functionality to keep it future proof and easily changeable. This also encourages DRY principle to keep our common setting at a central place. Kendo UI items are enormous in configuration, one of an issue I find people keep repeating codes for Kendo Grid configuration. They have built very flexible system to have any configuration, but in most of the cases, we do not need all of those complicated configuration. We would try to see a simpler configuration of same. The actual core implementation is bit complex, but we do not have to bother about it once done since the focus is just on usage only. I recommend doing this practice for as simple as jQuery events, form handling or as simple as any notification system. This just won't make things simple but makes codes much more manageable, easy understand, read or open f...
Post a Comment
Read more

Using Redis distributed cache in dotnet core with helper extension methods

Redis cache is out process cache provider for a distributed environment. It is popular in Azure Cloud solution, but it also has a standalone application to operate upon in case of small enterprises application. How to install Redis Cache on a local machine? Redis can be used as a local cache server too on our local machines. At first install, Chocolatey https://chocolatey.org/ , to make installation of Redis easy. Also, the version under Chocolatey supports more commands and compatible with Official Cache package from Microsoft. After Chocolatey installation hit choco install redis-64 . Once the installation is done, we can start the server by running redis-server . Distributed Cache package and registration dotnet core provides IDistributedCache interface which can be overrided with our own implementation. That is one of the beauties of dotnet core, having DI implementation at heart of framework. There is already nuget package available to override IDistributedCache i...
3 comments
Read more