LendController um DTO ergänzt

BuecherwurmAPI.csproj

@@ -4,8 +4,9 @@
     <TargetFramework>netcoreapp3.1</TargetFramework>
   </PropertyGroup>
 
-  <ItemGroup>
-    <PackageReference Include="Microsoft.AspNetCore.Mvc.NewtonsoftJson" Version="3.1.4" />
+  <ItemGroup>
+    <PackageReference Include="AutoMapper.Extensions.Microsoft.DependencyInjection" Version="7.0.0" />
+    <PackageReference Include="Microsoft.AspNetCore.Mvc.NewtonsoftJson" Version="3.1.4" />
   </ItemGroup>
 
 

Controllers/LendController.cs

@@ -2,7 +2,9 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
+using AutoMapper;
 using BuecherwurmAPI.Data;
+using BuecherwurmAPI.DTOs;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.JsonPatch;
 using Microsoft.Extensions.Logging;
@@ -15,10 +17,12 @@ namespace BuecherwurmAPI.Controllers
     public class LendController : ControllerBase
     {
         private readonly ILendRepo _repository;
+        private readonly IMapper _mapper;
         
-        public LendController(ILendRepo repository)
+        public LendController(ILendRepo repository, IMapper mapper)
         {
             _repository = repository;
+            _mapper = mapper;
         }
         
         //GET api/leihvorgang
@@ -30,9 +34,31 @@ namespace BuecherwurmAPI.Controllers
         
         //POST api/leihvorgang
         [HttpPost]
-        public ActionResult<Lend> LendsPost(Lend lend)
+        public ActionResult<LendReadDTO> LendsPost(Lend lend)
         {
-            return Ok(new Lend{Id = lend.Id, Customer = lend.Customer, Returned = lend.Returned, ItemId = lend.ItemId, ReturnDate = lend.ReturnDate});
+            /*
+                Internally a lend is stored with an id
+                but the client shouldn't be allowed to set or change it
+                therefore the package 'AutoMapper' is used to prevent errors
+                that could happen when doing this task manually.
+                It takes the information from the client and maps it to the
+                corresponding internal object which then will be returned.
+                Furthermore it could be used to keep some attributes secret.
+                Another nice effect of this is that the implementation could be changed 
+                while the interface could be retained by some minor changes in the code.
+                
+                DTO stands for Data Transfer Object
+            */
+            var item = new Lend
+            {
+                Id = 256,
+                Customer = lend.Customer,
+                Returned = lend.Returned,
+                ItemId = lend.ItemId,
+                ReturnDate = lend.ReturnDate
+            };
+            return Ok(item);
+            //return Ok(_mapper.Map<LendReadDTO>(item));
         }
 
         //GET api/leihvorgang/{id}

DTOs/LendRead.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace BuecherwurmAPI.DTOs
+{
+    public class LendReadDTO
+    {
+        public int ItemId { get; set;}
+        public DateTime ReturnDate { get; set; }
+        public string Customer { get; set;  }
+        public bool Returned { get; set; }
+    }
+}

Profiles/LendProfile.cs

@@ -0,0 +1,14 @@
+using AutoMapper;
+using BuecherwurmAPI.DTOs;
+using BuecherwurmAPI.Models;
+
+namespace BuecherwurmAPI.Profiles
+{
+    public class LendProfile : Profile
+    {
+        public LendProfile()
+        {
+            CreateMap<Lend, LendReadDTO>();
+        }
+    }
+}

Startup.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
+using AutoMapper;
 using BuecherwurmAPI.Data;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
@@ -32,6 +33,8 @@ namespace BuecherwurmAPI
             // It takes an interface and a specific implementation.
             // That allows to swap the implementation easily.
             services.AddScoped<ILendRepo, MockLendRepo>();
+
+            services.AddAutoMapper(AppDomain.CurrentDomain.GetAssemblies());
         }
 
         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.