add customizable resource expressions

Author: jaredcnance

JsonApiDotNetCore/Abstractions/JsonApiContext.cs

@@ -24,7 +24,7 @@ public JsonApiContext(HttpContext httpContext, Route route, object dbContext, Js
 
     public Type GetJsonApiResourceType()
     {
-      return Configuration.ResourceMapDefinitions[Route.BaseModelType];
+      return Configuration.ResourceMapDefinitions[Route.BaseModelType].Item1;
     }
 
     public string GetEntityName()

JsonApiDotNetCore/Configuration/IJsonApiModelConfiguration.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using AutoMapper;
 using JsonApiDotNetCore.Abstractions;
 
 namespace JsonApiDotNetCore.Configuration
@@ -23,10 +24,11 @@ public interface IJsonApiModelConfiguration
     /// <summary>
     /// Define explicit mapping of a model to a class that implements IJsonApiResource
     /// </summary>
-    /// <param name="modelType"></param>
-    /// <param name="resourceType"></param>
+    /// <typeparam name="TModel"></typeparam>
+    /// <typeparam name="TResource"></typeparam>
+    /// <param name="mappingExpression"></param>
     /// <exception cref="ArgumentException"></exception>
-    void AddResourceMapping(Type modelType, Type resourceType);
+    void AddResourceMapping<TModel, TResource>(Action<IMappingExpression> mappingExpression);
 
     /// <summary>
     /// Specifies a controller override class for a particular model type.

JsonApiDotNetCore/Configuration/JsonApiConfigurationBuilder.cs

@@ -3,6 +3,7 @@
 using JsonApiDotNetCore.Routing;
 using Microsoft.EntityFrameworkCore;
 using System.Linq;
+using System.Linq.Expressions;
 using AutoMapper;
 using JsonApiDotNetCore.Abstractions;
 using JsonApiDotNetCore.Attributes;
@@ -68,10 +69,10 @@ private void SetupResourceMaps()
       {
         foreach (var definition in Config.ResourceMapDefinitions)
         {
-          cfg.CreateMap(definition.Key, definition.Value);
+          var mappingExpression = cfg.CreateMap(definition.Key, definition.Value.Item1);
+          definition.Value.Item2?.Invoke(mappingExpression);
         }
       });
-
       Config.ResourceMapper = mapConfiguration.CreateMapper();
     }
 
@@ -87,7 +88,7 @@ private void LoadDefaultResourceMaps()
         // do not overwrite custom definitions
         if(!Config.ResourceMapDefinitions.ContainsKey(modelType.UnderlyingSystemType))
         {
-          Config.ResourceMapDefinitions.Add(modelType.UnderlyingSystemType, resourceType);
+          Config.ResourceMapDefinitions.Add(modelType.UnderlyingSystemType, new Tuple<Type, Action<IMappingExpression>>(resourceType, null));
         }
       }
     }

JsonApiDotNetCore/Configuration/JsonApiModelConfiguration.cs

@@ -18,21 +18,23 @@ public class JsonApiModelConfiguration : IJsonApiModelConfiguration
     public IMapper ResourceMapper;
     public Type ContextType { get; set; }
     public List<RouteDefinition> Routes = new List<RouteDefinition>();
-    public Dictionary<Type, Type>  ResourceMapDefinitions = new Dictionary<Type, Type>();
+    public Dictionary<Type, Tuple<Type, Action<IMappingExpression>>>  ResourceMapDefinitions = new Dictionary<Type, Tuple<Type, Action<IMappingExpression>>>();
     public Dictionary<Type, Type> ControllerOverrides = new Dictionary<Type, Type>();
 
     public void SetDefaultNamespace(string ns)
     {
       Namespace = ns;
     }
 
-    // TODO: change to AddResourceMapping(Type, Type)
-    public void AddResourceMapping(Type modelType, Type resourceType)
+    public void AddResourceMapping<TModel, TResource>(Action<IMappingExpression> mappingExpression)
     {
+      var resourceType = typeof(TResource);
+      var modelType = typeof(TModel);
+
       if (!resourceType.GetInterfaces().Contains(typeof(IJsonApiResource)))
         throw new ArgumentException("Specified type does not implement IJsonApiResource", nameof(resourceType));
 
-      ResourceMapDefinitions.Add(modelType, resourceType);
+      ResourceMapDefinitions.Add(modelType, new Tuple<Type, Action<IMappingExpression>>(resourceType, mappingExpression));
     }
 
     public void UseController(Type modelType, Type controllerType)

JsonApiDotNetCoreExample/Startup.cs

@@ -41,6 +41,10 @@ public void ConfigureServices(IServiceCollection services)
               config.SetDefaultNamespace("api/v1");
               config.UseContext<ApplicationDbContext>();
               config.UseController(typeof(TodoItem), typeof(TodoItemsController));
+              config.AddResourceMapping<Person, PersonResource>(map =>
+              {
+                map.ForMember("Name", opt => opt.MapFrom(src => $"{((Person)src).Name}_1"));
+              });
             });
         }
 

README.md

@@ -49,11 +49,19 @@ public class PersonResource : IJsonApiResource
 }
 ``` 
 
-We use [AutoMapper](http://automapper.org/) as the mapping tool. 
-You can specify a custom mapping configuration in your `Startup` class like so:
+We use [AutoMapper](http://automapper.org/) to map from the context model to the JsonApiResource. 
+The below snippet shows how you can specify a custom mapping expression in your `Startup` class that will apped '_1' to the resource name.
+Check out [AutoMapper's Wiki](https://github.com/AutoMapper/AutoMapper/wiki) for detailed mapping options.
 
 ```
-// not implemented
+services.AddJsonApi(config => {
+  ...
+  config.AddResourceMapping<Person, PersonResource>(map =>
+  {
+    map.ForMember("Name", opt => opt.MapFrom(src => $"{((Person)src).Name}_1"));
+  });
+  ...
+});
 ```
 
 ## Overriding controllers