Skip to main content

Auto fluent mapping generation for OpenAccess/Telerik DataAccess through T4

There is two way to map code first with DB related entities. The first is data annotation which is like setting attributes and the other one is fluent mapping. Fluent mapping is very powerful and flexible approach to map entities. The only downside of fluent mapping is incompatibility with client side validation where as MVC has inbuilt functionality to validate on client side with data annotation.

We will look into basic fluent mapping generation along with data annotation if present. Default data annotation is not compatible with Telerik DataAccess/OpenAccess. This article does not gives information about how fluent mapping works or how to generate it but auto generation of fluent mapping by any give model.

Pre-requisites for fluent generation
I have took help of two different libraries to generate fluent mapping for OpenAccess.
- MultiOutput.ttinclude (https://github.com/subsonic/SubSonic-3.0-Templates/blob/master/ActiveRecord/MultiOutput.ttinclude) : This is to generate multiple files through single T4 file.
- VisualStudioAutomationHelper.ttinclude (https://github.com/PombeirP/T4Factories/blob/master/T4Factories.Testbed/CodeTemplates/VisualStudioAutomationHelper.ttinclude) : This will help us in reading existing models and refactoring through EnvDte library.

Guide to be followed for generation:

 Choose the path to include above files (In my case those are kept in T4Plugin):
<#@ include file="../../T4Plugin/VisualStudioAutomationHelper.ttinclude" #>

<#@ include file="../../T4Plugin/MultiOutput.ttinclude" #>

 White-listing and black listing properties
var whiteListPropertyTypes = new List<string>(){};

var blackListedPropertyNames = new List<string>();
In whiteListPropertyTypes list, we can specify the custom types that need to be included. Like some enumeration types. In same way some properties could be excluded by help of blackListedPropertyNames list.

Listing classes for generation of fluent mapping
var codeClass in allClasses.OfType<CodeClass2>()
        .Where(clas=> clas!=null && clas.FullName.StartsWith("T4FluentMapping.DomainModel") &&

        !clas.FullName.EndsWith("MetadataSource"))
This code will list up all classes starts with T4FluentMapping.DomainModel and excludes class ends with MetadataSource.

That is all needed to generate basic fluent mapping. Here the all code goes:
-----------------------------------------------------------------------------------------------
<#@ template  debug="true" hostSpecific="true" #>
<#@ output extension=".cs" #>
<#@ Assembly Name="EnvDTE" #>
<#@ Assembly Name="EnvDTE80" #>
<#@ Assembly name="System.ComponentModel.DataAnnotations" #>
<#@ import namespace="EnvDTE" #>
<#@ import namespace="EnvDTE80" #>
<#@ import namespace="System" #>
<#@ import namespace="System.Linq" #>
<#@ import namespace="System.Collections" #>
<#@ import namespace="System.Collections.Generic" #> 
<#@ import namespace="System.ComponentModel.DataAnnotations" #>
<#@ import namespace="System.Text.RegularExpressions" #>
<#@ include file="../../T4Plugin/VisualStudioAutomationHelper.ttinclude" #>
<#@ include file="../../T4Plugin/MultiOutput.ttinclude" #>

 <#

     // get a reference to the project of this t4 template
    var project = VisualStudioHelper.CurrentProject;

     // get all class items from the code model
    var allClasses = VisualStudioHelper.GetAllCodeElementsOfType(project.CodeModel.CodeElements, EnvDTE.vsCMElement.vsCMElementClass, false);

     // TODO: Extra parameter type to get it listed
    // Ex: Model.Enumeration.DbOperation
var whiteListPropertyTypes = new List<string>(){};
var blackListedPropertyNames = new List<string>();

     // iterate all classes
    foreach(var codeClass in allClasses.OfType<CodeClass2>()
        .Where(clas=> clas!=null && clas.FullName.StartsWith("T4FluentMapping.DomainModel") &&
        !clas.FullName.EndsWith("MetadataSource")))
    {
        var fileName=codeClass.Name+"Mapping.Generated.cs";
        #>
namespace T4FluentMapping.Model.Mapping.FluentMapping
{
    //------------------------------------------------------------------------------
    // <auto-generated>
    //     This code was generated from a template and will be re-created if deleted
    //   with default values if executed.
    // </auto-generated>
    //------------------------------------------------------------------------------
    using Telerik.OpenAccess.Metadata;
    using Telerik.OpenAccess.Metadata.Fluent;

     /// <summary>
    /// Fluent mapping for <see cref="<#=            codeClass.FullName#>"/>
    /// </summary>
    public partial class <#=            codeClass.Name#>Mapping
   : MappingConfiguration<<#=            codeClass.FullName #>>
    {
        /// <summary>
        /// Initializes a basic fluent mappings for <see cref="<#=            codeClass.FullName#>" />
        /// </summary>
   public void InitializeBasicMappings()
   {
   this.MapType(map => new
   {
<#
        // iterate all properties
        var allProperties = VisualStudioHelper.GetAllCodeElementsOfType(codeClass.Members, EnvDTE.vsCMElement.vsCMElementProperty, true);
        foreach(EnvDTE.CodeProperty property in allProperties
.Where(prop=>(prop as CodeProperty2).ReadWrite == vsCMPropertyKind.vsCMPropertyKindReadWrite))
        {
            // for excluding property
            var commentForFieldValue = ((property.Name == "FieldValue" && codeClass.Name == "SystemDataField" )
|| blackListedPropertyNames.Any(propName=>propName == property.Name)
)?"//":String.Empty;
            if (IsPrimitive(property.Type) || whiteListPropertyTypes.Contains(property.Type.AsFullName))
            {
        #>
                <#=commentForFieldValue#>map.<#=property.Name #>,
<#          
            }
            #>
<#
        }
        #>
            }).ToTable("<#= codeClass.Name #>");

 // Data annotation mappings
<#
// For data annotation attribute mapping
foreach(EnvDTE.CodeProperty property in allProperties)
{
if(IsType(property.Type,typeof(bool)))
{
#>this.HasProperty(model => model.<#=property.Name#>).HasColumnType("bit");
<#
}

 foreach(var attribute in GetAttributes(property))
{
if(attribute.Name == "Required")
{
#>this.HasProperty(model => model.<#=property.Name#>).IsNotNullable();
<#
}
if(attribute.Name == "MaxLength")
{
#>this.HasProperty(model => model.<#=property.Name#>).HasColumnType("varchar").HasLength(<#=attribute.Value#>);
<#
}
if(attribute.Name == "StringLength")
{
#>this.HasProperty(model => model.<#=property.Name#>).HasColumnType("varchar").HasLength(<#=attribute.Value#>);
<#
}
}
if(whiteListPropertyTypes.Contains(property.Type.AsFullName))
{
#>this.HasProperty(model => model.<#=property.Name#>);
<#
}
if(IsNullable(property.Type))
{
#>this.HasProperty(model => model.<#=property.Name#>).IsNullable();
<#
}
}#>
}
    }
}
<#
    SaveOutput(fileName);
DeleteOldOutputs();
    }
#>

 <#+
    // Support C# and VB syntax
    private static readonly Regex _unwrapNullableRegex = new Regex(@"^System.Nullable(<|\(Of )(?<UnderlyingTypeName>.*)(>|\))$");

 private static Type[] _primitiveList;

 private static void InitializePrimitives()
{
if(_primitiveList == null)
{
var types = new[]
{
typeof (Enum),
typeof (String),
typeof (Char),

 typeof (Boolean),
typeof (Byte),
typeof (Int16),
typeof (Int32),
typeof (Int64),
typeof (Single),
typeof (Double),
typeof (Decimal),

 typeof (SByte),
typeof (UInt16),
typeof (UInt32),
typeof (UInt64),

 typeof (DateTime),
typeof (DateTimeOffset),
typeof (TimeSpan),
};
var nullTypes = from t in types
where t.IsValueType
select typeof (Nullable<>).MakeGenericType(t);

 _primitiveList = types.Concat(nullTypes).ToArray();
}
}
   /// <summary>
    /// Determines whether the supplied CodeTypeRef represents a primitive .NET type, e.g.,
    /// byte, bool, float, etc.
    /// </summary>
    public static bool IsPrimitive(CodeTypeRef codeTypeRef)
    {
InitializePrimitives();
return _primitiveList.Any(item => item.FullName == codeTypeRef.AsFullName || _unwrapNullableRegex.Match(codeTypeRef.AsFullName).Success);
    }

 public static bool IsNullable(CodeTypeRef codeTypeRef)
    {
return _unwrapNullableRegex.Match(codeTypeRef.AsFullName).Success;
    }

 public static IEnumerable<CodeAttribute> GetAttributes(CodeProperty codeProperty)
{
return codeProperty.Attributes.OfType<CodeAttribute>().ToList();
}

     public static bool IsType<T>(CodeTypeRef codeTypeRef)
    {
        return IsType(codeTypeRef , typeof(T));
    }
 
public static bool IsType(CodeTypeRef codeTypeRef, Type type)
    {
return codeTypeRef.AsFullName == type.ToString() || codeTypeRef.AsFullName == "System.Nullable<"+ type.ToString()+ ">";
    }
 #>
-----------------------------------------------------------------------------------------------



Labels

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

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 Argume...
Post a 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

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

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

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...
2 comments
Read more

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 qu...
Post a Comment
Read more

Dependency Injection through XML configuration and XML transformation through SlowCheetah

Dependency Injection (DI) is a design pattern to change definition by substituting object without changing code for the application. The most popular DI type is to construct classes based on certain interface and pass actual object on constructor level. What are we trying to do? We will be looking into a way to achieve dependency injection through XML configuration based on  build selection . The implemented classes derived through interface will get switched based on build selection. Where to use it? I really hate making dependencies with something specific which can be changed later on. In my case, Azure environment. I believe Azure is more like a platform where we can host the application rather then integrating the application with Azure. What if client decided to switch to other hosting environment, in that case we got to change every piece of code wherever Azure SDKs are referred. The above one is merely an example. We can use this approach on many other item as wel...
Post a Comment
Read more

Custom authorization based on dotnet core policy with Attribute filter

Around 2.5 years back I had written about custom authorization on MVC  Custom authorization on class, action/function, code, area level under Asp.Net MVC application , there are few approaches which are changed in Core version for authorization. Like Authorization filter approach is discouraged since it cannot be unit tested. I believe this is right step but also global or basic authentication could still be driven by Attribute due to enhancing simplicity on codes by focusing on the primary objective rather than writing authorization check everywhere. The whole approach and usage remain same from the original Post, in this, we would be just looking into making it compatible with dotnet Core MVC. You would need to go through earlier Post to understand the approach that was taken for authorization of a user. Also, can go through official post: https://docs.microsoft.com/en-us/aspnet/core/security/authorization/policies to understand new approach. More of all we need to create...
Post a Comment
Read more