Add dependency Injection

Controllers/GerbilsController.cs

@@ -8,11 +8,11 @@ namespace GerbilManager.Controllers
     [Route("gerbils")]
     public class GerbilsController : ControllerBase
     {
-        private readonly InMemGerbilRepository repository;
+        private readonly IGerbilRepository repository;
 
-        public GerbilsController()
+        public GerbilsController(IGerbilRepository repo)
         {
-            repository = new InMemGerbilRepository();
+            this.repository = repo;
         }
 
         //GET /gerbils
@@ -22,5 +22,18 @@ namespace GerbilManager.Controllers
             var items = repository.GetGerbils();
             return items;
         }
+
+        //GET /gerbils
+        [HttpGet("{id}")]
+        public ActionResult<Gerbil> GetGerbil(Guid id)
+        {
+            var item = repository.GetGerbil(id);
+
+            if(item is null)
+            {
+                return NotFound();
+            }
+            return item;
+        }
     }
 }

Program.cs

@@ -1,3 +1,5 @@
+using GerbilManager.Repositories;
+
 var builder = WebApplication.CreateBuilder(args);
 
 // Add services to the container.
@@ -7,6 +9,8 @@ builder.Services.AddControllers();
 builder.Services.AddEndpointsApiExplorer();
 builder.Services.AddSwaggerGen();
 
+builder.Services.AddSingleton<IGerbilRepository, InMemGerbilRepository>();
+
 var app = builder.Build();
 
 // Configure the HTTP request pipeline.

Repositories/IGerbilRepository.cs

@@ -0,0 +1,11 @@
+using GerbilManager.Models;
+
+namespace GerbilManager.Repositories
+{
+    public interface IGerbilRepository
+    {
+        IEnumerable<Gerbil> GetGerbils();
+
+        Gerbil GetGerbil(Guid id);
+    }
+}

Repositories/InMemGerbilRepository.cs

@@ -2,8 +2,7 @@ using GerbilManager.Models;
 
 namespace GerbilManager.Repositories
 {
-
-    public class InMemGerbilRepository
+    public class InMemGerbilRepository : IGerbilRepository
     {
         private readonly List<Gerbil> _gerbilList = new()
         {
@@ -19,5 +18,5 @@ namespace GerbilManager.Repositories
 
         public Gerbil GetGerbil(Guid id) => _gerbilList.SingleOrDefault(x => x.Id == id);
     }
-    
+
 }