Add Dataloaders and error handling

Author: myty

.editorconfig

@@ -59,22 +59,12 @@ dotnet_naming_symbols.constant_fields.applicable_kinds   = field
 dotnet_naming_symbols.constant_fields.required_modifiers = const
 dotnet_naming_style.pascal_case_style.capitalization = pascal_case
 
-# static fields should have s_ prefix
-dotnet_naming_rule.static_fields_should_have_prefix.severity = suggestion
-dotnet_naming_rule.static_fields_should_have_prefix.symbols  = static_fields
-dotnet_naming_rule.static_fields_should_have_prefix.style    = static_prefix_style
-dotnet_naming_symbols.static_fields.applicable_kinds   = field
-dotnet_naming_symbols.static_fields.required_modifiers = static
-dotnet_naming_symbols.static_fields.applicable_accessibilities = private, internal, private_protected
-dotnet_naming_style.static_prefix_style.required_prefix = s_
-dotnet_naming_style.static_prefix_style.capitalization = camel_case
-
 # internal and private fields should be _camelCase
 dotnet_naming_rule.camel_case_for_private_internal_fields.severity = suggestion
 dotnet_naming_rule.camel_case_for_private_internal_fields.symbols  = private_internal_fields
 dotnet_naming_rule.camel_case_for_private_internal_fields.style    = camel_case_underscore_style
 dotnet_naming_symbols.private_internal_fields.applicable_kinds = field
-dotnet_naming_symbols.private_internal_fields.applicable_accessibilities = private, internal
+dotnet_naming_symbols.private_internal_fields.applicable_accessibilities = private
 dotnet_naming_style.camel_case_underscore_style.required_prefix = _
 dotnet_naming_style.camel_case_underscore_style.capitalization = camel_case
 

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

@@ -0,0 +1,42 @@
+using System;
+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;
+
+namespace OpenBreweryDB.API.GraphQL.Breweries.Dataloaders
+{
+    public class BreweryByIdDataLoader : BatchDataLoader<long, Brewery>
+    {
+        private readonly IBreweryConductor _breweryConductor;
+
+        public BreweryByIdDataLoader(IBreweryConductor breweryConductor)
+        {
+            _breweryConductor = breweryConductor ?? throw new ArgumentNullException(nameof(breweryConductor));
+        }
+
+        protected override async Task<IReadOnlyDictionary<long, Brewery>> LoadBatchAsync(
+            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));
+            }
+
+            if (breweryResult.Errors?.Any() == true)
+            {
+                throw new ResultException(breweryResult.Errors);
+            }
+
+            return null;
+        }
+    }
+}

…PI/GraphQL/Breweries/BreweryResolvers.cs …/Breweries/Resolvers/BreweryResolvers.csdotnet/OpenBreweryDB.API/GraphQL/Breweries/BreweryResolvers.cs renamed to dotnet/OpenBreweryDB.API/GraphQL/Breweries/Resolvers/BreweryResolvers.cs dotnet/OpenBreweryDB.API/GraphQL/Breweries/BreweryResolvers.cs renamed to dotnet/OpenBreweryDB.API/GraphQL/Breweries/Resolvers/BreweryResolvers.cs

@@ -6,40 +6,13 @@
 using OpenBreweryDB.Core.Conductors.Breweries.Interfaces;
 using OpenBreweryDB.Data.Models;
 using System.Threading.Tasks;
-using GeoCoordinatePortable;
 using System.Collections.Generic;
 
 namespace OpenBreweryDB.API.GraphQL.Resolvers
 {
-    public static class BreweryResolvers
+    public class BreweryResolvers
     {
-        public static async Task<Brewery> BreweryNodeResolver(IResolverContext ctx, long id)
-        {
-            var breweryConductor = ctx.Service<IBreweryConductor>();
-
-            var breweryResult = breweryConductor.Find(id);
-
-            if (!breweryResult.HasErrorsOrResultIsNull())
-            {
-                return await Task.FromResult(breweryResult.ResultObject);
-            }
-
-            foreach (var err in breweryResult.Errors)
-            {
-                ctx.ReportError(
-                    ErrorBuilder.New()
-                        .SetCode(err.Key)
-                        .SetPath(ctx.Path)
-                        .AddLocation(ctx.FieldSelection)
-                        .SetMessage(err.Message)
-                        .Build()
-                );
-            }
-
-            return null;
-        }
-
-        public static async Task<IEnumerable<Brewery>> NearbyBreweriesResolver(IResolverContext ctx)
+        public async Task<IEnumerable<Brewery>> GetNearbyBreweriesAsync(IResolverContext ctx)
         {
             var brewery = ctx.Parent<Brewery>();
 

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

@@ -1,5 +1,7 @@
+using HotChocolate.Resolvers;
 using HotChocolate.Types;
 using HotChocolate.Types.Relay;
+using OpenBreweryDB.API.GraphQL.Breweries.Dataloaders;
 using OpenBreweryDB.API.GraphQL.Resolvers;
 using OpenBreweryDB.Data.Models;
 using System;
@@ -14,7 +16,9 @@ protected override void Configure(IObjectTypeDescriptor<Brewery> descriptor)
             descriptor
                 .Name("Brewery")
                 .Description("A brewery of beer")
-                .AsNode().IdField(t => t.Id).NodeResolver((ctx, id) => BreweryResolvers.BreweryNodeResolver(ctx, id));
+                .AsNode()
+                .IdField(t => t.Id)
+                .NodeResolver((ctx, id) => ctx.DataLoader<BreweryByIdDataLoader>().LoadAsync(id, ctx.RequestAborted));
 
             descriptor.Field("nearby")
                 .Argument(
@@ -23,7 +27,7 @@ protected override void Configure(IObjectTypeDescriptor<Brewery> descriptor)
                         .Type<IntType>()
                         .Description("limit the nearby breweries to search radius, defaults to 25 milles")
                 )
-                .Resolver(BreweryResolvers.NearbyBreweriesResolver);
+                .ResolveWith<BreweryResolvers>(r => r.GetNearbyBreweriesAsync(default));
 
             descriptor.Field(t => t.BreweryType)
                 .Type<NonNullType<StringType>>()

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

@@ -0,0 +1,16 @@
+using System.Linq;
+using AndcultureCode.CSharp.Core.Interfaces;
+
+namespace OpenBreweryDB.API.GraphQL.Errors
+{
+    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)
+                : error;
+        }
+    }
+}

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

@@ -0,0 +1,16 @@
+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)
+        {
+            Errors = errors;
+        }
+
+        public List<IError> Errors { get; }
+    }
+}

dotnet/OpenBreweryDB.API/Startup.cs

@@ -23,6 +23,7 @@
 using OpenBreweryDB.Core.Conductors.Users.Interfaces;
 using OpenBreweryDB.API.GraphQL.Users;
 using OpenBreweryDB.API.GraphQL.Reviews;
+using OpenBreweryDB.API.GraphQL.Errors;
 
 namespace OpenBreweryDB.API
 {
@@ -48,6 +49,8 @@ public void ConfigureServices(IServiceCollection services)
 
             services
                 .AddInMemorySubscriptions()
+                .AddErrorFilter<ResultErrorFilter>()
+                .AddDataLoaderRegistry()
                 .AddGraphQL(sp => SchemaBuilder.New()
                 .EnableRelaySupport()
                 .AddServices(sp)