Return HTTP Conflict when a route for this user already exists which …

…is exactly the same

src/RoadCaptain.App.Web/Adapters/SqliteRouteStore.cs

@@ -148,6 +148,11 @@ public Models.RouteModel Store(CreateRouteModel createModel, User user)
         {
             var route = RouteStorageModelFrom(createModel, user);
 
+            if (_roadCaptainDataContext.Routes.Any(r => r.Hash == route.Hash && r.UserId == route.UserId))
+            {
+                throw new DuplicateRouteException();
+            }
+
             _roadCaptainDataContext.Routes.Add(route);
             _roadCaptainDataContext.SaveChanges();
 

src/RoadCaptain.App.Web/Controllers/RoutesController.cs

@@ -84,7 +84,19 @@ public IActionResult CreateRoute([FromBody] CreateRouteModel createRoute)
                     (int)HttpStatusCode.BadRequest, "Invalid user"));
             }
 
-            return Ok(_routeStore.Store(createRoute, user));
+            try
+            {
+                return Ok(_routeStore.Store(createRoute, user));
+            }
+            catch (DuplicateRouteException e)
+            {
+                _monitoringEvents.Error(e, "Duplicate route exists");
+
+                return Conflict(ProblemDetailsFactory.CreateProblemDetails(
+                    HttpContext,
+                    (int)HttpStatusCode.Conflict,
+                    "Duplicate route exists"));
+            }
         }
 
         [HttpPut("{id:long}", Name = "UpdateRouteById")]

src/RoadCaptain.App.Web/DuplicateRouteException.cs

@@ -0,0 +1,10 @@
+namespace RoadCaptain.App.Web
+{
+    public class DuplicateRouteException : Exception
+    {
+        public DuplicateRouteException() 
+            : base("Another route exists that is exactly the same")
+        {
+        }
+    }
+}