Skip to main content

Strongly typed Application configuration through EF SQL DB

The idea is to create a strongly typed application configuration by constructing concrete class and get the values populated from the database so that it is easier to change. This would allow admin to directly modify DB values for configuration.

So, let's start with what we need.

Application setting classes as needed

Classes for application setting. It is just a POCO implementation.

   /// <summary>  
   /// Entire application settings  
   /// </summary>  
   public class Setting  
   {  
     /// <summary>  
     /// Gets or sets the setting version.  
     /// </summary>  
     /// <value>  
     /// The setting version.  
     /// </value>  
     public int SettingVersion { get; set; }  
     /// <summary>  
     /// Gets or sets the name of the application.  
     /// </summary>  
     /// <value>  
     /// The name of the application.  
     /// </value>  
     public string ApplicationName { get; set; }  
     /// <summary>  
     /// Gets or sets the LDAP.  
     /// </summary>  
     /// <value>  
     /// The LDAP.  
     /// </value>  
     public LdapSetting Ldap { get; set; }  
   }  

   /// <summary>  
   /// LDAP settings  
   /// </summary>  
   public class LdapSetting  
   {  
     /// <summary>  
     /// Gets or sets the domain host.  
     /// </summary>  
     /// <value>  
     /// The domain host.  
     /// </value>  
     public string DomainHost { get; set; }  
     /// <summary>  
     /// Gets or sets the name of the domain.  
     /// </summary>  
     /// <value>  
     /// The name of the domain.  
     /// </value>  
     public string DomainName { get; set; }  
   }  

DB Model to hold above values

The entire thing would be saved as a key and value so we can create a simple DB model for same.

   public class ConfigurationValue  
   {  
     /// <summary>  
     /// Gets or sets the identifier.  
     /// </summary>  
     /// <value>  
     /// The identifier.  
     /// </value>  
     public int Id { get; set; }  
     /// <summary>  
     /// Gets or sets the key.  
     /// </summary>  
     /// <value>  
     /// The key.  
     /// </value>  
     public string Key { get; set; }  
     /// <summary>  
     /// Gets or sets the value.  
     /// </summary>  
     /// <value>  
     /// The value.  
     /// </value>  
     public string Value { get; set; }  
   }  

   public class MyAppContext  
     : DbContext  
   {  
     /// <summary>  
     /// Initializes a new instance of the <see cref="GemsContext"/> class.  
     /// </summary>  
     /// <param name="option">Database context options.</param>  
     public MyAppContext(DbContextOptions option)  
       : base(option)  
     {  
     }  
     /// <summary>  
     /// Gets or sets the configurations.  
     /// </summary>  
     /// <value>  
     /// The configurations.  
     /// </value>  
     public DbSet<ConfigurationValue> Configurations { get; set; }  
   }  

Configuration Provider

The next thing is to create a provider for custom configuration to match with our requirement. This would basically read information from DB and set the values to class. Also, we can create default values if it does not exists.

EFConfigProvider

   /// <summary>  
   /// EF configuration provider for the application.  
   /// </summary>  
   /// <seealso cref="ConfigurationProvider" />  
   public class EFConfigProvider  
     : ConfigurationProvider  
   {  
     /// <summary>  
     /// Gets or sets the name of the hosting environment.  
     /// </summary>  
     /// <value>  
     /// The name of the hosting environment.  
     /// </value>  
     private readonly string EnvironmentName;  
     /// <summary>  
     /// The default values for settings  
     /// </summary>  
     private Lazy<Dictionary<string, string>> DefaultValues;  
     /// <summary>  
     /// Initializes a new instance of the <see cref="EFConfigProvider"/> class.  
     /// </summary>  
     /// <param name="dbContextBuilderAction">The database context builder action.</param>  
     /// <param name="environmentName">Name of the hosting environment.</param>  
     public EFConfigProvider(Action<DbContextOptionsBuilder> dbContextBuilderAction, string environmentName)  
     {  
       DbContextBuilderAction = dbContextBuilderAction;  
       EnvironmentName = environmentName;  
       InitDefaultValues(environmentName);  
     }  
     /// <summary>  
     /// Gets the database context builder action.  
     /// </summary>  
     /// <value>  
     /// The database context builder action.  
     /// </value>  
     private Action<DbContextOptionsBuilder> DbContextBuilderAction { get; }  
     /// <summary>  
     /// Loads (or reloads) the data for this provider.  
     /// </summary>  
     public override void Load()  
     {  
       var builder = new DbContextOptionsBuilder<MyAppContext>();  
       DbContextBuilderAction(builder);  
       using (var dbContext = new MyAppContext(builder.Options))  
       {  
         dbContext.Database.EnsureCreated();  
         Data = !dbContext.Configurations.Any()  
           ? CreateAndSaveDefaultValues(dbContext)  
           : EnsureAllSync(dbContext.Configurations.ToDictionary(c => c.Key, c => c.Value), dbContext);  
       }  
     }  
     /// <summary>  
     /// Creates the and save default values.  
     /// </summary>  
     /// <param name="dbContext">The database context.</param>  
     /// <returns>Data feeds for IOption.</returns>  
     private IDictionary<string, string> CreateAndSaveDefaultValues(  
       MyAppContext dbContext)  
     {  
       AddInDb(DefaultValues.Value, dbContext);  
       return DefaultValues.Value;  
     }  
     private void AddInDb(IDictionary<string, string> configurations, MyAppContext dbContext)  
     {  
       dbContext.Configurations.AddRange(configurations  
         .Select(kvp => new ConfigurationValue { Key = kvp.Key, Value = kvp.Value }));  
       dbContext.SaveChanges();  
     }  
     /// <summary>  
     /// Ensures all values are present.  
     /// </summary>  
     /// <param name="dbValues">The database values.</param>  
     /// <param name="dbContext">The database context.</param>  
     /// <returns>Synced dictionary.</returns>  
     private IDictionary<string, string> EnsureAllSync(IDictionary<string, string> dbValues, MyAppContext dbContext)  
     {  
       // Find item which does not exist in DB values, for anything added later stage.  
       var newItems = DefaultValues.Value.Where(item => !dbValues.Keys.Contains(item.Key))  
         .ToDictionary(item => item.Key, item => item.Value);  
       if (newItems.Any())  
       {  
         AddInDb(newItems, dbContext);  
         return dbValues  
           .Concat(newItems.Select(item => new KeyValuePair<string, string>(item.Key, item.Value)))  
           .ToDictionary(item => item.Key, item => item.Value);  
       }  
       return dbValues;  
     }  
     /// <summary>  
     /// Initializes the default values.  
     /// </summary>  
     /// <param name="environmentName">Name of the environment.</param>  
     private void InitDefaultValues(string environmentName)  
     {  
       // Can be done based on environment name.  
       DefaultValues = new Lazy<Dictionary<string, string>>(() =>  
       {  
         return new Dictionary<string, string>  
        {  
           { nameof(Setting.SettingVersion), "1" },  
           { nameof(Setting.ApplicationName), $"App - {environmentName}" },  
           { $"{nameof(Setting.Ldap)}:{nameof(LdapSetting.DomainHost)}", "NA" },  
           { $"{nameof(Setting.Ldap)}:{nameof(LdapSetting.DomainName)}", "NA" }  
        };  
       });  
     }  
   }  

- EnvironmentName is just to know which hosting environment configuration belongs to like Development, Testing or whatever you might have configured.
- EnsureAllSync is for handling any new addition of configuration/properties added at a later stage. This would add into the database automatically.
- InitDefaultValues is to generate default values if records are not available in DB. Also, we can identify the environment and can have a different set of values based on environment. I would recommend using enum in that situation.
- You might be a bit skeptic about how the default values are used. It is basically required by dotnet itself to read as IDictionary, in which the configurations are put by using : deliminator. So, the text name has to be used based on the class property. I have used nameof operator to keep it strongly typed, magic strings are always a problem in refactoring.

Configuration Source

Now, the custom provider needs to be added into configuration source i:e IConfigurationSource, which would simply create an instance of the provider.

  /// <summary>  
   /// Application Configuration source.  
   /// </summary>  
   /// <seealso cref="IConfigurationSource" />  
   public class EFConfigSource  
     : IConfigurationSource  
   {  
     /// <summary>  
     /// The database context builder action  
     /// </summary>  
     private readonly Action<DbContextOptionsBuilder> DbContextBuilderAction;  
     /// <summary>  
     /// The hosting environment name  
     /// </summary>  
     private readonly string EnvironmentName;  
     /// <summary>  
     /// Initializes a new instance of the <see cref="EFConfigSource"/> class.  
     /// </summary>  
     /// <param name="optionsAction">The options action.</param>  
     /// <param name="environmentName">Name of the hosting environment.</param>  
     public EFConfigSource(Action<DbContextOptionsBuilder> optionsAction, string environmentName)  
     {  
       DbContextBuilderAction = optionsAction;  
       EnvironmentName = environmentName;  
     }  
     /// <summary>  
     /// Builds the <see cref="T:Microsoft.Extensions.Configuration.IConfigurationProvider" /> for this source.  
     /// </summary>  
     /// <param name="builder">The <see cref="T:Microsoft.Extensions.Configuration.IConfigurationBuilder" />.</param>  
     /// <returns>  
     /// An <see cref="T:Microsoft.Extensions.Configuration.IConfigurationProvider" />  
     /// </returns>  
     public IConfigurationProvider Build(IConfigurationBuilder builder)  
     {  
       return new EFConfigProvider(DbContextBuilderAction, EnvironmentName);  
     }  
   }  

Final configuration on Startup.cs with help of some extension class

By doing above we have done most of the task,  just we need to create extension class and register on startup.cs

Extension configuration that would be used on StartUp.cs

   /// <summary>  
   /// EF configuration helper.  
   /// </summary>  
   public static class ExtensionEfConfig  
   {  
     /// <summary>  
     /// Adds the entity framework configuration.  
     /// </summary>  
     /// <param name="builder">The builder.</param>  
     /// <param name="setup">The setup.</param>  
     /// <param name="environmentName">Name of the environment.</param>  
     /// <returns><see cref="IConfigurationBuilder"/> after creation of EF config provider.</returns>  
     public static IConfigurationBuilder AddEntityFrameworkConfig(  
           this IConfigurationBuilder builder, Action<DbContextOptionsBuilder> setup, string environmentName)  
     {  
       return builder.Add(new EFConfigSource(setup, environmentName));  
     }  
     /// <summary>  
     /// Adds the configurations.  
     /// </summary>  
     /// <param name="services">The services.</param>  
     /// <param name="configuration">The configuration root.</param>  
     public static void AddConfigurations(this IServiceCollection services, IConfigurationRoot configuration)  
     {  
       services.Configure<Setting>(configuration);  
       services.Configure<LdapSetting>(configuration.GetSection(nameof(Setting.Ldap)));  
     }  
   }  

In this, I have used two functions. The first one is to construct configuration builder and the second one is to get the class registered through IOptions.
You can see the both dependencies are registered by the master class and child class by getting a subsection of configuration.

Startup.cs

     private readonly string SqlConnectionString;  
     public Startup(IHostingEnvironment env)  
     {  
       SqlConnectionString = $"SqlDatabase{env.EnvironmentName}";  
       Func<IConfigurationBuilder> getConfig = () =>  
       new ConfigurationBuilder()  
         .SetBasePath(env.ContentRootPath)  
         .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)  
         .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)  
         .AddEnvironmentVariables();  
       var defaultConfig = getConfig().Build();  
       Configuration = getConfig()  
         .AddEntityFrameworkConfig(options =>  
           options.UseSqlServer(defaultConfig.GetConnectionString(SqlConnectionString)), env.EnvironmentName  
         ).Build();  
     }  

 services.AddConfigurations(Configuration);  


- The defaultConfig would get information from existing configurations available, and the second one is final one which would include DB values as well. Created a helper anonymous function for same.
- Now, DI for configuration is as simple as calling a function.

Usage

The last thing is how to use, we can have DI with IOptions to consume what we started with simple POCOs.

   public class HomeController  
     : Controller  
   {  
     public HomeController(IOptions<LdapSetting> ldapSetting, IOptions<Setting> wholeSettings)  
     {  
       Debugger.Break();  
     }  
   }  


Whole code base can be found on:



Comments

Popular posts from this blog

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 be able to use global

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

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 /// <

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"; });

Kendo MVC Grid DataSourceRequest with AutoMapper

Kendo Grid does not work directly with AutoMapper but could be managed by simple trick using mapping through ToDataSourceResult. The solution works fine until different filters are applied. The problems occurs because passed filters refer to view model properties where as database model properties are required after AutoMapper is implemented. So, the plan is to intercept DataSourceRequest  and modify names based on database model. To do that we are going to create implementation of  CustomModelBinderAttribute to catch calls and have our own implementation of DataSourceRequestAttribute from Kendo MVC. I will be using same source code from Kendo but will replace column names for different criteria for sort, filters, group etc. Let's first look into how that will be implemented. public ActionResult GetRoles([MyDataSourceRequest(GridId.RolesUserGrid)] DataSourceRequest request) { if (request == null) { throw new ArgumentNullExce

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

Kendo MVC Grid DataSourceRequest with AutoMapper - Advance

The actual process to make DataSourceRequest compatible with AutoMapper was explained in my previous post  Kendo MVC Grid DataSourceRequest with AutoMapper , where we had created custom model binder attribute and in that property names were changed as data models. In this post we will be looking into using AutoMapper's Queryable extension to retrieve the results based on selected columns. When  Mapper.Map<RoleViewModel>(data)  is called it retrieves all column values from table. The Queryable extension provides a way to retrieve only selected columns from table. In this particular case based on properties of  RoleViewModel . The previous approach that we implemented is perfect as far as this article ( 3 Tips for Using Telerik Data Access and AutoMapper ) is concern about performance where it states: While this functionality allows you avoid writing explicit projection in to your LINQ query it has the same fatal flaw as doing so - it prevents the query result from

OpenId Authentication with AspNet Identity Core

This is a very simple trick to make AspNet Identity work with OpenId Authentication. More of all both approach is completely separate to each other, there is no any connecting point. I am using  Microsoft.AspNetCore.Authentication.OpenIdConnect  package to configure but it should work with any other. Configuring under Startup.cs with IAppBuilder app.UseCookieAuthentication(new CookieAuthenticationOptions { AuthenticationScheme = CookieAuthenticationDefaults.AuthenticationScheme, LoginPath = new PathString("/Account/Login"), CookieName = "MyProjectName", }) .UseIdentity() .UseOpenIdConnectAuthentication(new OpenIdConnectOptions { ClientId = "<AzureAdClientId>", Authority = String.Format("https://login.microsoftonline.com/{0}", "<AzureAdTenant>"), ResponseType = OpenIdConnectResponseType.IdToken, PostLogoutRedirectUri = "<my website url>",

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) { MyProject

MongoDB navigation property or making it behave as ORM in .Net

This is an implementation to make models to have  navigation properties work like ORM does for us. What actually happens in ORM to make navigation properties work? Entity Framework has proxy classes implementation to allow lazy loading and eager loading implementation. While creating proxy classes it also changes definitions for actual classes to make navigation properties work to get values based on Model's for navigation properties. Most of ORMs work in same fashion like Telerik DataAccess has enhancer tool which changes class definition at compile time to enable navigation properties. In this implementation, we would retain the original class but we would have extension methods to allow initializing properties to have navigation proprieties work. Let's first create desire model on which we need to implement. I am picking up simple one-to-many relationship example from Person to Address. public class Person { public int PersonId { get; set; }