add dataloader

Author: myty

dotnet/OpenBreweryDB.API/GraphQL/Breweries/Dataloaders/BreweryByIdDataLoader.cs

@@ -2,16 +2,18 @@
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
-using HotChocolate.DataLoader;
 using OpenBreweryDB.Core.Conductors.Breweries.Interfaces;
 using OpenBreweryDB.Data.Models;
 using AndcultureCode.CSharp.Core.Extensions;
 using System.Linq;
 using OpenBreweryDB.API.GraphQL.Errors;
+using GreenDonut;
+using ACModels = AndcultureCode.CSharp.Core.Models;
+using AndcultureCode.CSharp.Core.Enumerations;
 
 namespace OpenBreweryDB.API.GraphQL.Breweries.Dataloaders
 {
-    public class BreweryByIdDataLoader : BatchDataLoader<long, Brewery>
+    public class BreweryByIdDataLoader : DataLoaderBase<long, Brewery>
     {
         private readonly IBreweryConductor _breweryConductor;
 
@@ -20,23 +22,34 @@ public BreweryByIdDataLoader(IBreweryConductor breweryConductor)
             _breweryConductor = breweryConductor ?? throw new ArgumentNullException(nameof(breweryConductor));
         }
 
-        protected override async Task<IReadOnlyDictionary<long, Brewery>> LoadBatchAsync(
+        protected override async Task<IReadOnlyList<Result<Brewery>>> FetchAsync(
             IReadOnlyList<long> keys,
             CancellationToken cancellationToken)
         {
             var breweryResult = _breweryConductor.FindAll(b => keys.Contains(b.Id));
 
             if (!breweryResult.HasErrorsOrResultIsNull())
             {
-                return await Task.FromResult(breweryResult.ResultObject.ToDictionary(t => t.Id));
+                return breweryResult.ResultObject
+                    .Select(Result<Brewery>.Resolve)
+                    .ToList();
             }
 
             if (breweryResult.Errors?.Any() == true)
             {
-                throw new ResultException(breweryResult.Errors);
+                return breweryResult
+                    .Errors
+                    .Select(e => Result<Brewery>.Reject(new ResultException(e)))
+                    .ToList();
             }
 
-            return null;
+            return await Task.FromResult(new List<Result<Brewery>> {
+                Result<Brewery>.Reject(new ResultException(new ACModels.Error {
+                    ErrorType = ErrorType.Error,
+                    Key = "NotFound",
+                    Message = "Resource Not Found"
+                }))
+            });
         }
     }
 }

dotnet/OpenBreweryDB.API/GraphQL/Breweries/Types/BreweryType.cs

@@ -18,7 +18,9 @@ protected override void Configure(IObjectTypeDescriptor<Brewery> descriptor)
                 .Description("A brewery of beer")
                 .AsNode()
                 .IdField(t => t.Id)
-                .NodeResolver((ctx, id) => ctx.DataLoader<BreweryByIdDataLoader>().LoadAsync(id, ctx.RequestAborted));
+                .NodeResolver((ctx, id) => ctx
+                    .DataLoader<BreweryByIdDataLoader>()
+                    .LoadAsync(id, ctx.RequestAborted));
 
             descriptor.Field("nearby")
                 .Argument(

dotnet/OpenBreweryDB.API/GraphQL/Errors/ResultErrorFilter.cs

@@ -1,4 +1,3 @@
-using System.Linq;
 using AndcultureCode.CSharp.Core.Interfaces;
 
 namespace OpenBreweryDB.API.GraphQL.Errors
@@ -8,8 +7,8 @@ public class ResultErrorFilter : HotChocolate.IErrorFilter
         public HotChocolate.IError OnError(HotChocolate.IError error)
         {
             return error.Exception is ResultException resultException
-                && resultException.Errors.FirstOrDefault() is IError firstError
-                ? error.WithCode(firstError.Key).WithMessage(firstError.Message)
+                && resultException.Error is IError resultError
+                ? error.WithCode(resultError.Key).WithMessage(resultError.Message)
                 : error;
         }
     }

dotnet/OpenBreweryDB.API/GraphQL/Errors/ResultException.cs

@@ -1,16 +1,15 @@
 using System;
-using System.Collections.Generic;
 using AndcultureCode.CSharp.Core.Interfaces;
 
 namespace OpenBreweryDB.API.GraphQL.Errors
 {
     public class ResultException : Exception
     {
-        public ResultException(List<IError> errors)
+        public ResultException(IError error)
         {
-            Errors = errors;
+            Error = error;
         }
 
-        public List<IError> Errors { get; }
+        public IError Error { get; }
     }
 }