I am developing asp.net core 3.1 GraphQL based APIs. I used the below reference article to setup automatic DI configuration in the API layer and have used the nuget package : NetCore.AutoRegisterDi
https://www.thereformedprogrammer.net/asp-net-core-fast-and-automatic-dependency-injection-setup/
Here goes the code details:
Code:
Startup.cs:
public virtual void ConfigureServices(IServiceCollection services) => services
.AddGraphQLResolvers()
.AddProjectRepositories();
ProjectServiceCollectionExtensions.cs
public static class ProjectServiceCollectionExtensions
{
public static IServiceCollection AddProjectRepositories(this IServiceCollection services) =>
services.RegisterAssemblyPublicNonGenericClasses(Assembly.GetAssembly(typeof(CommonService)))
.Where(c => c.Name.EndsWith("Persistence"))
.AsPublicImplementedInterfaces(ServiceLifetime.Scoped);
public static IServiceCollection AddGraphQLResolvers(this IServiceCollection services) =>
services
.AddScoped<ICountriesResolver, CountriesResolver>()
.AddScoped<ICountryGroupsResolver, CountryGroupsResolver>()
.AddScoped<IDisclaimerResolver, DisclaimerResolver>();
}
Here in the above CommonService is part of the Service Layer that ends with Persistence.
CountriesResolver.cs
public class CountriesResolver : Resolver, ICountriesResolver
{
private readonly ICountryService _countryService;
private readonly IHttpContextAccessor _accessor;
private readonly IDataLoaderContextAccessor _dataLoaderContextAccessor;
public CountriesResolver(ICountryService countryService, IHttpContextAccessor accessor, IDataLoaderContextAccessor dataLoaderContextAccessor)
{
_countryService = countryService ?? throw new ArgumentNullException(nameof(countryService));
_accessor = accessor;
_dataLoaderContextAccessor = dataLoaderContextAccessor;
}
public void Resolve(GraphQLQuery graphQLQuery)
{
var language = _accessor.HttpContext.Items["language"] as LanguageDTO;
graphQLQuery.FieldAsync<ResponseGraphType<CountryResultType>>("countriesresponse", arguments: new QueryArguments(new QueryArgument<IdGraphType>{Name = "pageNo", Description = "page number"}, new QueryArgument<IdGraphType>{Name = "pageSize", Description = "page size"}), resolve: async context =>
{
var pageNo = context.GetArgument<int>("pageNo") == 0 ? 1 : context.GetArgument<int>("pageNo");
var pageSize = context.GetArgument<int>("pageSize") == 0 ? 100 : context.GetArgument<int>("pageSize");
if (language != null)
{
var loader = _dataLoaderContextAccessor.Context.GetOrAddLoader("GetAllCountries", () => _countryService.GetAllCountriesAsync(language, pageNo, pageSize));
var list = await context.TryAsyncResolve(async c => await loader.LoadAsync());
return Response(list);
}
return null;
}
, description: "All Countries data");
}
}
ICommonService.cs
using Author.Query.Persistence.DTO;
using System.Threading.Tasks;
namespace Author.Query.Persistence.Interfaces
{
public interface ICommonService
{
LanguageDTO GetLanguageFromLocale(string locale);
Task<LanguageDTO> GetLanguageFromLocaleAsync(string locale);
}
}
CommonService.cs
namespace Author.Query.Persistence
{
public class CommonService : ICommonService
{
private readonly AppDbContext _dbContext;
private readonly IOptions<AppSettings> _appSettings;
private readonly IMapper _mapper;
private readonly ICacheService<Languages, LanguageDTO> _cacheService;
public CommonService(AppDbContext dbContext, IOptions<AppSettings> appSettings, IMapper mapper, ICacheService<Languages, LanguageDTO> cacheService)
{
_dbContext = dbContext ?? throw new ArgumentNullException(nameof(dbContext));
_appSettings = appSettings;
_mapper = mapper ?? throw new ArgumentNullException(nameof(mapper));
_cacheService = cacheService ?? throw new ArgumentNullException(nameof(cacheService));
}
//public Languages GetLanguageFromLocale(string locale)
public LanguageDTO GetLanguageFromLocale(string locale)
{
return GetLanguagesByFilter(GetFilterValues(locale, true).ToArray());
}
}
}
ICountryService.cs
namespace Author.Query.Persistence.Interfaces
{
public interface ICountryService
{
Task<CountryResult> GetAllCountriesAsync(LanguageDTO language, int pageNo, int pageSize);
Task<CountryDTO> GetCountryAsync(LanguageDTO language, int countryId);
}
}
CountryService.cs
namespace Author.Query.Persistence
{
public class CountryService : ICountryService
{
private readonly AppDbContext _dbContext;
private readonly IOptions<AppSettings> _appSettings;
private readonly ICacheService<Images, ImageDTO> _cacheService;
public CountryService(TaxathandDbContext dbContext, IOptions<AppSettings> appSettings, ICacheService<Images, ImageDTO> cacheService)
{
_dbContext = dbContext ?? throw new ArgumentNullException(nameof(dbContext));
_cacheService = cacheService ?? throw new ArgumentNullException(nameof(cacheService));
_appSettings = appSettings;
}
public async Task<CountryResult> GetAllCountriesAsync(LanguageDTO language, int pageNo, int pageSize)
{
var localeLangId = language.LanguageId;
var dftLanguageId = int.Parse(_appSettings.Value.DefaultLanguageId);
// By default pick the localLanguage value
var countries = await GetAllCountriesDataAsync(localeLangId, pageNo, pageSize);
// If localLanguage data is not available then pull the data based on default language
if (countries.Countries.Count == 0)
{
countries = await GetAllCountriesDataAsync(dftLanguageId, pageNo, pageSize);
}
return countries;
}
public async Task<CountryDTO> GetCountryAsync(LanguageDTO language, int countryId)
{
var localeLangId = language.LanguageId;
var dftLanguageId = int.Parse(_appSettings.Value.DefaultLanguageId);
//var country = new CountryDTO();
// By default pick the localLanguage value
var country = await GetCountryDetailsAsync(countryId, localeLangId);
// If localLanguage data is not available then pull the data based on default language
if (country == null)
{
country = await GetCountryDetailsAsync(countryId, dftLanguageId);
}
return country;
}
private async Task<CountryDTO> GetCountryDetailsAsync(int countryId, int languageId)
{
var images = await _cacheService.GetAllAsync("imagesCacheKey");
var country = await _dbContext.Countries.AsNoTracking().FirstOrDefaultAsync(c => c.CountryId.Equals(countryId) && c.IsPublished.Equals(true) && c.LanguageId.Equals(languageId));
if (country == null)
{
return null;
}
var countryDTO = new CountryDTO{Uuid = country.CountryId, PNGImagePath = images.FirstOrDefault(im => im.ImageId.Equals(country.PNGImageId)).FilePath, SVGImagePath = images.FirstOrDefault(im => im.ImageId.Equals(country.SVGImageId)).FilePath, DisplayName = country.DisplayName, DisplayNameShort = country.DisplayName, Name = Helper.ReplaceChars(country.DisplayName), Path = Helper.ReplaceChars(country.DisplayName), CompleteResponse = true};
return countryDTO;
}
private async Task<CountryResult> GetAllCountriesDataAsync(int languageId, int pageNo, int pageSize)
{
var countryList = new CountryResult();
var images = await _cacheService.GetAllAsync("imagesCacheKey");
var countries = await _dbContext.Countries.Where(cc => cc.IsPublished.Equals(true) && cc.LanguageId.Equals(languageId)).Select(c => new
{
c.CountryId, c.DisplayName, c.PNGImageId, c.SVGImageId
}
).OrderByDescending(c => c.CountryId).Skip((pageNo - 1) * pageSize).Take(pageSize).AsNoTracking().ToListAsync();
if (countries.Count == 0)
{
return null;
}
countryList.Countries.AddRange(countries.Select(co => new CountryDTO{Uuid = co.CountryId, PNGImagePath = images.FirstOrDefault(im => im.ImageId.Equals(co.PNGImageId)).FilePath, SVGImagePath = images.FirstOrDefault(im => im.ImageId.Equals(co.SVGImageId)).FilePath, DisplayName = co.DisplayName, DisplayNameShort = co.DisplayName, Name = Helper.ReplaceChars(co.DisplayName), Path = Helper.ReplaceChars(co.DisplayName), CompleteResponse = true}));
return countryList;
}
}
}
Error:
System.AggregateException
HResult=0x80131500
Message=Some services are not able to be constructed (Error while validating the service descriptor 'ServiceType: Author.Query.New.API.GraphQL.Resolvers.ICountriesResolver Lifetime: Scoped ImplementationType: Author.Query.New.API.GraphQL.Resolvers.CountriesResolver':
Unable to resolve service for type 'Author.Query.Persistence.Interfaces.ICountryService' while attempting to activate 'Author.Query.New.API.GraphQL.Resolvers.CountriesResolver'.) (Error while validating the service descriptor 'ServiceType:
Author.Query.New.API.GraphQL.Resolvers.ICountryGroupsResolver Lifetime: Scoped ImplementationType: Author.Query.New.API.GraphQL.Resolvers.CountryGroupsResolver': Unable to resolve service for type 'Author.Query.Persistence.Interfaces.ICountryGroupService' while attempting to activate 'Author.Query.New.API.GraphQL.Resolvers.CountryGroupsResolver'.) (Error while validating the service descriptor 'ServiceType: Author.Query.New.API.GraphQL.Resolvers.IDisclaimerResolver Lifetime: Scoped ImplementationType: Author.Query.New.API.GraphQL.Resolvers.DisclaimerResolver': Unable to resolve service for type 'Author.Query.Persistence.Interfaces.IDisclaimerService' while attempting to activate 'Author.Query.New.API.GraphQL.Resolvers.DisclaimerResolver'.)
Source=Microsoft.Extensions.DependencyInjection
StackTrace:
at Microsoft.Extensions.DependencyInjection.ServiceProvider..ctor(IEnumerable`1 serviceDescriptors, ServiceProviderOptions options)
at Microsoft.Extensions.DependencyInjection.ServiceCollectionContainerBuilderExtensions.BuildServiceProvider(IServiceCollection services, ServiceProviderOptions options)
at Microsoft.Extensions.DependencyInjection.DefaultServiceProviderFactory.CreateServiceProvider(IServiceCollection containerBuilder)
at Microsoft.Extensions.Hosting.Internal.ServiceFactoryAdapter`1.CreateServiceProvider(Object containerBuilder)
at Microsoft.Extensions.Hosting.HostBuilder.CreateServiceProvider()
at Microsoft.Extensions.Hosting.HostBuilder.Build()
at Author.Query.New.API.Program.Main(String[] args) in /src/QueryStack/Author.Query.New.API/Program.cs:line 15
Inner Exception 1:
InvalidOperationException: Error while validating the service descriptor 'ServiceType: Author.Query.New.API.GraphQL.Resolvers.ICountriesResolver Lifetime: Scoped ImplementationType:
Author.Query.New.API.GraphQL.Resolvers.CountriesResolver':
Unable to resolve service for type 'Author.Query.Persistence.Interfaces.ICountryService' while attempting to activate
'Author.Query.New.API.GraphQL.Resolvers.CountriesResolver'.
Inner Exception 2:
InvalidOperationException: Unable to resolve service for type
'Author.Query.Persistence.Interfaces.ICountryService' while attempting to activate
'Author.Query.New.API.GraphQL.Resolvers.CountriesResolver'.
Can anyone help me to know how to fix this issue?
The error says that :
Unable to resolve service for type 'Author.Query.Persistence.Interfaces.ICountryService' while attempting to activate 'Author.Query.New.API.GraphQL.Resolvers.CountriesResolver'
ICountryService
is never registered. AddGraphQLResolvers
registers only ICountriesResolver
, ICountryGroupsResolver
and IDisclaimerResolver
.
The method AddProjectRepositories
only registers classes whose name ends in Persistence
that appear in the same namespace as CommonService
. It never registers CommonService
itself.
The service must be registered, eg with :
services.AddScoped<ICommonService, CommonService>();
Your method AddProjectRepositories()
does not register CountryService
, because the Where
filter in RegisterAssemblyPublicNonGenericClasses()
looks at classes (Type
), not at namespaces.
So perhaps you can change your filter:
services.RegisterAssemblyPublicNonGenericClasses(Assembly.GetAssembly(typeof(CommonService)))
.Where(c => c.Name.EndsWith("Service")) // <-- Change "Persistence" to "Service"
.AsPublicImplementedInterfaces(ServiceLifetime.Scoped);
That should register all classes that end with "Service" in the Assembly that contains CommonService.
For me it was a simple mistake. I had a class with the same name in another namespace and referenced the wrong class/forgot to delete the duplicate class and add the correct one to my startup.
I had a service called UserService in myapp.Utils and another in myapp.Services. I was referencing myapp.Utils when I meant to delete that one and only use myapp.Services. I was incorrectly injecting the one in myapp.Utils when my controllers were set up to use the one in myapp.Services.
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