I am using for GraphQL for .NET package for graphql. But I couldn't understand how can I authentication with JWT in graphql query or mutation.
I read the guide about authorization but I couldn't accomplish.
I need help with GraphQL for .NET authentication.
Any help will be appreciated.
Thanks
The guide is around authorization. The step you're looking for is the authentication and since graphql can be implemented using a ASP.Net API controller, you can implement JWT authentication as you would with any controller.
Here is a sample grapql controller using an Authorize attribute. You could, however, implement this using filter or if you want full control, custom middleware.
[Route("api/[controller]")]
[ApiController]
[Authorize]
public class GraphQLController : ControllerBase
{
private readonly IDocumentExecuter executer;
private readonly ISchema schema;
public GraphQLController(IDocumentExecuter executer, ISchema schema)
{
this.executer = executer;
this.schema = schema;
}
[HttpPost]
public async Task<ActionResult<object>> PostAsync([FromBody]GraphQLQuery query)
{
var inputs = query.Variables.ToInputs();
var queryToExecute = query.Query;
var result = await executer.ExecuteAsync(o => {
o.Schema = schema;
o.Query = queryToExecute;
o.OperationName = query.OperationName;
o.Inputs = inputs;
o.ComplexityConfiguration = new GraphQL.Validation.Complexity.ComplexityConfiguration { MaxDepth = 15};
o.FieldMiddleware.Use<InstrumentFieldsMiddleware>();
}).ConfigureAwait(false);
return this.Ok(result);
}
}
public class GraphQLQuery
{
public string OperationName { get; set; }
public string Query { get; set; }
public Newtonsoft.Json.Linq.JObject Variables { get; set; }
}
In the Startup.cs I have configured JWT bearer token authentication.
Hope this helps.
I myself struggled for two days as well. I'm using https://github.com/graphql-dotnet/authorization now with the setup from this comment (from me): https://github.com/graphql-dotnet/authorization/issues/63#issuecomment-553877731
In a nutshell, you have to set the UserContext for the AuthorizationValidationRule correctly, like so:
public class Startup
{
public virtual void ConfigureServices(IServiceCollection services)
{
...
services.AddGraphQLAuth(_ =>
{
_.AddPolicy("AdminPolicy", p => p.RequireClaim("Role", "Admin"));
});
services.AddScoped<IDependencyResolver>(x => new FuncDependencyResolver(x.GetRequiredService));
services.AddScoped<MySchema>();
services
.AddGraphQL(options => { options.ExposeExceptions = true; })
.AddGraphTypes(ServiceLifetime.Scoped);
...
}
public void Configure(IApplicationBuilder app, IHostingEnvironment env, IServiceProvider serviceProvider)
{
...
app.UseMiddleware<MapRolesForGraphQLMiddleware>(); // optional, only when you don't have a "Role" claim in your token
app.UseGraphQL<MySchema>();
...
}
}
public static class GraphQLAuthExtensions
{
public static void AddGraphQLAuth(this IServiceCollection services, Action<AuthorizationSettings> configure)
{
services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
services.AddSingleton<IAuthorizationEvaluator, AuthorizationEvaluator>();
services.AddTransient<IValidationRule, AuthorizationValidationRule>();
services.AddTransient<IUserContextBuilder>(s => new UserContextBuilder<GraphQLUserContext>(context =>
{
var userContext = new GraphQLUserContext
{
User = context.User
};
return Task.FromResult(userContext);
}));
services.AddSingleton(s =>
{
var authSettings = new AuthorizationSettings();
configure(authSettings);
return authSettings;
});
}
}
public class GraphQLUserContext : IProvideClaimsPrincipal
{
public ClaimsPrincipal User { get; set; }
}
public class MapRolesForGraphQLMiddleware
{
private readonly RequestDelegate _next;
public MapRolesForGraphQLMiddleware(RequestDelegate next)
{
_next = next;
}
public async Task Invoke(HttpContext context)
{
// custom mapping code to end up with a "Role" claim
var metadata = context.User.Claims.SingleOrDefault(x => x.Type.Equals("metadata"));
if (metadata != null)
{
var roleContainer = JsonConvert.DeserializeObject<RoleContainer>(metadata.Value);
(context.User.Identity as ClaimsIdentity).AddClaim(new Claim("Role", string.Join(", ", roleContainer.Roles)));
}
await _next(context);
}
}
public class RoleContainer
{
public String[] Roles { get; set; }
}
Related
The following is working for me, but not sure this is the right way to do use DI in .NET6 blazor.
I have the following class
public class Authentication
{
private IConfiguration _configuration;
private AppState _appState;
public Authentication(IConfiguration Configuration, AppState appState)
{
_configuration = Configuration;
_appState = appState; ;
}
public async Task<AccessToken?> getAccessToken()
{
var tokenServer = _configuration.GetValue<string>("tokenUrl");
var clientID = _configuration.GetValue<string>("ABC:ClientID");
var clientSecret = _configuration.GetValue<string>("ABC:ClientSecret");
var grantType = _configuration.GetValue<string>("ABC:GrantType");
AccessToken? accessToken = null;
.............
............
return accessToken;
}
}
in my code behind of razor page
namespace XXXXXXXXXXX.Pages
{
public partial class Index
{
[Inject]
public ILogger<Index> _Logger { get; set; }
[Inject]
public IConfiguration Configuration { get; set; }
[Inject]
public AppState _appState { get; set; }
**Authentication auth;**
protected override void OnInitialized()
{
**auth = new Authentication(Configuration, _appState);**
base.OnInitialized();
}
private async Task HandleValidSubmit()
{
_Logger.LogInformation("HandleValidSubmit called");
auth.getAccessToken();
// Process the valid form
}
}
}
My Question is I was Expecting the DI to do its magic and Insert the Dependency in my class.
but to get this working i had to write
auth = new Authentication(Configuration, _appState);
I was expecting to instantiate
using auth = new Authentication() , but this one throws compiler error.
I have a NLayers application:
asp.net core mvc
asp.net web api
and some of my class libraries:
DataLayer
DomainClasses
Models
Services
here is my BaseService in ServicesLayer:
public abstract partial class BaseService
{
protected BaseService(AppDbContext dbContext
, UserManager<MyApplicationUser> userManager
, int authenticatedUserId)
{
DbContext = dbContext;
AuthenticatedUserId = authenticatedUserId;
MyUserManager = userManager;
Init();
}
public AppDbContext DbContext { get; }
protected UserManager<MyApplicationUser> MyUserManager;
public string AuthenticatedUserId { get; }
protected virtual void Init()
{
//
}
...
}
and one of my child service classes:
public class BookService :BaseService
{
public BookService(AppDbContext dbContext
, UserManager<MyApplicationUser> userManager
, int authenticatedUserId)
:base(dbContext,userManager, authenticatedUserId)
{
}
}
I want to access the authenticated user id (from Asp net core) in my services (class library). How can I pass it via DI or something else?
Updated based on #Frank's suggestion:
public class CommonServicesContainer
{
public AppDbContext DbContext { get; set; }
public AppUserManager UserManager { get; set; }
public int AuthenticatedUserId{ get; set; }
public CommonServicesContainer(AppDbContext appDbContext, AppUserManager userManager, string authenticatedUserId)
{
DbContext = dbContext;
UserManager = userManager;
AuthenticatedUserId = autheticatedUserId;
}
}
my startup:
services.AddScoped<AppDbContext>();
services.AddScoped<AppUserManager>();
services.AddScoped(x =>
{
var authenticatedUserId = x.GetRequiredService<IHttpContextAccessor>().HttpContext.User.Identity.Name;
return new CommonServicesContainer(x.GetRequiredService<AppDbContext>()
, x.GetRequiredService<AppUserManager>()
, authenticatedUserId);
});
AccountController :
private readonly CommonServicesContainer _commonServicesContainer;
public AccountController(CommonServicesContainer commonServicesContainer)
{
_commonServicesContainer = commonServicesContainer;
// ...
}
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Login(LoginInputModel model)
{
// ...
if(ModelState.IsValid)
{
var isValid = await _usersService.AreCredentialsValidAsync(model.Username, model.Password);
if(isValid)
{
var foundUser = await _usersService.GetByUserNameAsync(model.Username);
await HttpContext.SignInAsync(
foundUser.SubjectId,
foundUser.UserName);
//_commonServicesContainer.AuthenticatedUserId = foundUser.Id;
// ...
}
// ...
}
You can do that by register a AuthenticatedUser type as a AddScoped.
class AuthenticatedUser {
public int? UserId {get;set;}
public bool IsAuthenticated => int.HasValue;
}
in Startup.cs of your AspNetCore project:
public IServiceProvider ConfigureServices(IServiceCollection services) {
...
services.AddScoped<AuthenticatedUser>();
...
}
Somewhere you do the authentication, you get the AuthenticatedUser and set the UserId.
Since AuthenticatedUser is added as scoped it acts as global (same instance) for the particular httprequest scope. So all .GetService<AuthenticatedUser> / .GetRequiredService<AuthenticatedUser> will have the same instance - within the same scope.
Each http-request has it is own scope, and thereby also their own AuthenticatedUser.
When the user is Authenticated, using AspNetCore Identity, you can find the AspNetUsers Id by:
if( httpContext.User.Identity.IsAuthenticated ) {
var userIdClaim = httpContext.User.Claims.SingleOrDefault(c => c.Type == "http://schemas.xmlsoap.org/ws/2005/05/identity/claims/nameidentifier");
var aspNetUsersId = userIdClaim?.Value ?? 0;
}
This can be done as Middleware, then setting AuthenticatedUser.UserId.
I've got an asp.net core 2.2 project with a startup.cs service that does an async REST GET call back to my current site and then returns the result (View Component using DI) back to the razor view.
In the service, I want to call "/api/sessions" and not "http://localhost:3433/api/sessions". I know I could use the ~ ta helper if I were inside my razor page to get the base path to the web server, but how can I get that from a service?
Here is my service and relevant code.
From: SessionsService.cs (this is where I don't want http://localhost but just ~/
public class Session
{
public int Id { get; set; }
public string Title { get; set; }
public string Description { get; set; }
}
public class SessionsService : ISessionsService
{
public async Task<List<Session>> GetSessions(int speakerId)
{
var uri = new Uri("http://localhost:50463/api/sessions");
var httpClient = new HttpClient();
var result = await httpClient.GetStringAsync(uri);
var sessions = JsonConvert.DeserializeObject<List<Session>>(result);
return sessions;
}
}
From: startup.cs
public void ConfigureServices(IServiceCollection services)
{
services.AddTransient<ISessionsService, SessionsService>();
From: index.cshtml
<vc:speaker-card speaker="#speaker" ></vc:speaker-card>
From: SpeakerCardViewComponent.cs
{
private ISessionsService _sessionsService;
public SpeakerCardViewComponent(ISessionsService sessionsService)
{
_sessionsService = sessionsService;
}
public async Task<IViewComponentResult> InvokeAsync(
Speaker speaker)
{
var sessions = await _sessionsService.GetSessions(101);
speaker.Sessions = sessions;
return View(speaker);
}
}
ANSWER AS SUGGESTED BY KIRK LARKIN FOLLOWS:
public async Task<List<Session>> GetSessions(int speakerId,string baseUrl)
{
var uri = new Uri($"{baseUrl}api/sessions");
var httpClient = new HttpClient();
var result = await httpClient.GetStringAsync(uri);
var sessions = JsonConvert.DeserializeObject<List<Session>>(result);
return sessions;
}
public void ConfigureServices(IServiceCollection services)
{
services.AddTransient<ISessionsService, SessionsService>();
services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
public class SpeakerCardViewComponent : ViewComponent
{
private ISessionsService _sessionsService;
private IHttpContextAccessor _httpContextAccessor;
public SpeakerCardViewComponent(ISessionsService sessionsService, IHttpContextAccessor httpContextAccessor)
{
_sessionsService = sessionsService;
_httpContextAccessor = httpContextAccessor;
}
public async Task<IViewComponentResult> InvokeAsync(
Speaker speaker)
{
var isHttps = _httpContextAccessor.HttpContext.Request.IsHttps;
var baseUrl = isHttps ? "https://" : "http://"
+ _httpContextAccessor.HttpContext.Request.Host.Value
+ "/";
var sessions = await _sessionsService.GetSessions(speaker.SpeakerId, baseUrl);
speaker.Sessions = sessions;
return View(speaker);
}
}
I am wondering if someone could point me a direction or an example which have the completed code for me to get an overall idea?
Thanks.
Update:
I only have following piece of code in Startup.cs and make sure windowsAutication is true in launchSettings.json.
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc();
services.AddMvc(config =>
{
var policy = new AuthorizationPolicyBuilder()
.RequireAuthenticatedUser()
//.RequireRole(#"Departmental - Information Technology - Development") // Works
.RequireRole(#"*IT.Center of Excellence.Digital Workplace") // Error
.Build();
config.Filters.Add(new AuthorizeFilter(policy));
});
}
I guess I have enabled Authentication and tries to authorize users who are within the specified AD group to have access to the application at global level.
If I use the commented RequireRole it works, but use the uncommented RequireRole it gives me this error:
Win32Exception: The trust relationship between the primary domain and the trusted domain failed.
The top line in the stack shows:
System.Security.Principal.NTAccount.TranslateToSids(IdentityReferenceCollection sourceAccounts, out bool someFailed)
Any idea why?
My understanding from update above
It seems the group name specified in RequireRole is an email distribution list not security group. If I use some other AD group it works but with this new error:
InvalidOperationException: No authenticationScheme was specified, and there was no DefaultForbidScheme found.
If I add IIS default authenticationScheme in ConfigureServices within Startup.cs
services.AddAuthentication(IISDefaults.AuthenticationScheme);
it gives me an HTTP 403 page: The website declined to show this webpage
So this is the final code:
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc();
services.AddAuthentication(IISDefaults.AuthenticationScheme);
services.AddMvc(config =>
{
var policy = new AuthorizationPolicyBuilder()
.RequireAuthenticatedUser()
.RequireRole(#"Departmental - Information Technology - Development") // AD security group
.Build();
config.Filters.Add(new AuthorizeFilter(policy));
});
}
Correct me if I understand wrongly. Thank you.
Option 1: Windows Authentication
You can turn on Windows Authentication for intranet applications. Read the docs here. You can check whether a user is in a role/group by doing something like this.
Before you do, you can check the groups information your computer joined by doing gpresult /R in the command prompt. See this post for more information.
User.IsInRole("xxxx") // this should return True for any group listed up there
You don't need to convert current principal to Windows principal if you don't need to get any information related to Windows.
If you want to get a list of all groups, you still need to query your AD.
warning:
Sometimes I see some groups are not showing up in the result using gpresult /R on the computer, comparing to the option 2 method. That's why sometimes when you do User.IsInRole() and it returns false. I still don't know why this happens.
Option 2: Form Authentication with AD lookup
The Windows Authentication offers just a little information about the user and the AD groups. Sometimes that's enough but most of the time it's not.
You can also use regular Form Authentication and talk to the AD underneath and issue a cookie. That way although the user needs to login to your app using their windows credential and password, you have full control on the AD information.
You don't want to write everything by hand. Luckily there is a library Novell.Directory.Ldap.NETStandard to help. You can find it in NuGet.
Interfaces to define what you need from the AD, as well as the login protocol:
namespace DL.SO.Services.Core
{
public interface IAppUser
{
string Username { get; }
string DisplayName { get; }
string Email { get; }
string[] Roles { get; }
}
public interface IAuthenticationService
{
IAppUser Login(string username, string password);
}
}
AppUser implementation:
using DL.SO.Services.Core;
namespace DL.SO.Services.Security.Ldap.Entities
{
public class AppUser : IAppUser
{
public string Username { get; set; }
public string DisplayName { get; set; }
public string Email { get; set; }
public string[] Roles { get; set; }
}
}
Ldap configuration object for mapping values from appsettings.json:
namespace DL.SO.Services.Security.Ldap
{
public class LdapConfig
{
public string Url { get; set; }
public string BindDn { get; set; }
public string Username { get; set; }
public string Password { get; set; }
public string SearchBase { get; set; }
public string SearchFilter { get; set; }
}
}
LdapAuthenticationService implementation:
using Microsoft.Extensions.Options;
using Novell.Directory.Ldap;
using System;
using System.Linq;
using System.Text.RegularExpressions;
using DL.SO.Services.Core;
using DL.SO.Services.Security.Ldap.Entities;
namespace DL.SO.Services.Security.Ldap
{
public class LdapAuthenticationService : IAuthenticationService
{
private const string MemberOfAttribute = "memberOf";
private const string DisplayNameAttribute = "displayName";
private const string SAMAccountNameAttribute = "sAMAccountName";
private const string MailAttribute = "mail";
private readonly LdapConfig _config;
private readonly LdapConnection _connection;
public LdapAuthenticationService(IOptions<LdapConfig> configAccessor)
{
_config = configAccessor.Value;
_connection = new LdapConnection();
}
public IAppUser Login(string username, string password)
{
_connection.Connect(_config.Url, LdapConnection.DEFAULT_PORT);
_connection.Bind(_config.Username, _config.Password);
var searchFilter = String.Format(_config.SearchFilter, username);
var result = _connection.Search(
_config.SearchBase,
LdapConnection.SCOPE_SUB,
searchFilter,
new[] {
MemberOfAttribute,
DisplayNameAttribute,
SAMAccountNameAttribute,
MailAttribute
},
false
);
try
{
var user = result.next();
if (user != null)
{
_connection.Bind(user.DN, password);
if (_connection.Bound)
{
var accountNameAttr = user.getAttribute(SAMAccountNameAttribute);
if (accountNameAttr == null)
{
throw new Exception("Your account is missing the account name.");
}
var displayNameAttr = user.getAttribute(DisplayNameAttribute);
if (displayNameAttr == null)
{
throw new Exception("Your account is missing the display name.");
}
var emailAttr = user.getAttribute(MailAttribute);
if (emailAttr == null)
{
throw new Exception("Your account is missing an email.");
}
var memberAttr = user.getAttribute(MemberOfAttribute);
if (memberAttr == null)
{
throw new Exception("Your account is missing roles.");
}
return new AppUser
{
DisplayName = displayNameAttr.StringValue,
Username = accountNameAttr.StringValue,
Email = emailAttr.StringValue,
Roles = memberAttr.StringValueArray
.Select(x => GetGroup(x))
.Where(x => x != null)
.Distinct()
.ToArray()
};
}
}
}
finally
{
_connection.Disconnect();
}
return null;
}
private string GetGroup(string value)
{
Match match = Regex.Match(value, "^CN=([^,]*)");
if (!match.Success)
{
return null;
}
return match.Groups[1].Value;
}
}
}
Configuration in appsettings.json (just an example):
{
"ldap": {
"url": "[YOUR_COMPANY].loc",
"bindDn": "CN=Users,DC=[YOUR_COMPANY],DC=loc",
"username": "[YOUR_COMPANY_ADMIN]",
"password": "xxx",
"searchBase": "DC=[YOUR_COMPANY],DC=loc",
"searchFilter": "(&(objectClass=user)(objectClass=person)(sAMAccountName={0}))"
},
"cookies": {
"cookieName": "cookie-name-you-want-for-your-app",
"loginPath": "/account/login",
"logoutPath": "/account/logout",
"accessDeniedPath": "/account/accessDenied",
"returnUrlParameter": "returnUrl"
}
}
Setup Authentication (maybe Authorization as well) for the app:
namespace DL.SO.Web.UI
{
public class Startup
{
private readonly IHostingEnvironment _currentEnvironment;
public IConfiguration Configuration { get; private set; }
public Startup(IConfiguration configuration, IHostingEnvironment env)
{
_currentEnvironment = env;
Configuration = configuration;
}
public void ConfigureServices(IServiceCollection services)
{
// Authentication service
services.Configure<LdapConfig>(this.Configuration.GetSection("ldap"));
services.AddScoped<IAuthenticationService, LdapAuthenticationService>();
// MVC
services.AddMvc(config =>
{
// Requiring authenticated users on the site globally
var policy = new AuthorizationPolicyBuilder()
.RequireAuthenticatedUser()
// You can chain more requirements here
// .RequireRole(...) OR
// .RequireClaim(...) OR
// .Requirements.Add(...)
.Build();
config.Filters.Add(new AuthorizeFilter(policy));
});
services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
// Authentication
var cookiesConfig = this.Configuration.GetSection("cookies")
.Get<CookiesConfig>();
services.AddAuthentication(
CookieAuthenticationDefaults.AuthenticationScheme)
.AddCookie(options =>
{
options.Cookie.Name = cookiesConfig.CookieName;
options.LoginPath = cookiesConfig.LoginPath;
options.LogoutPath = cookiesConfig.LogoutPath;
options.AccessDeniedPath = cookiesConfig.AccessDeniedPath;
options.ReturnUrlParameter = cookiesConfig.ReturnUrlParameter;
});
// Setup more authorization policies as an example.
// You can use them to protected more strict areas. Otherwise
// you don't need them.
services.AddAuthorization(options =>
{
options.AddPolicy("AdminOnly",
policy => policy.RequireClaim(ClaimTypes.Role, "[ADMIN_ROLE_OF_YOUR_COMPANY]"));
// More on Microsoft documentation
// https://learn.microsoft.com/en-us/aspnet/core/security/authorization/policies?view=aspnetcore-2.1
});
}
public void Configure(IApplicationBuilder app)
{
app.UseAuthentication();
app.UseMvc(...);
}
}
}
How to authenticate users using the authentication service:
namespace DL.SO.Web.UI.Controllers
{
public class AccountController : Controller
{
private readonly IAuthenticationService _authService;
public AccountController(IAuthenticationService authService)
{
_authService = authService;
}
[AllowAnonymous]
[HttpPost]
public async Task<IActionResult> Login(LoginViewModel model)
{
if (ModelState.IsValid)
{
try
{
var user = _authService.Login(model.Username, model.Password);
// If the user is authenticated, store its claims to cookie
if (user != null)
{
var userClaims = new List<Claim>
{
new Claim(ClaimTypes.Name, user.Username),
new Claim(CustomClaimTypes.DisplayName, user.DisplayName),
new Claim(ClaimTypes.Email, user.Email)
};
// Roles
foreach (var role in user.Roles)
{
userClaims.Add(new Claim(ClaimTypes.Role, role));
}
var principal = new ClaimsPrincipal(
new ClaimsIdentity(userClaims, _authService.GetType().Name)
);
await HttpContext.SignInAsync(
CookieAuthenticationDefaults.AuthenticationScheme,
principal,
new AuthenticationProperties
{
IsPersistent = model.RememberMe
}
);
return Redirect(Url.IsLocalUrl(model.ReturnUrl)
? model.ReturnUrl
: "/");
}
ModelState.AddModelError("", #"Your username or password
is incorrect. Please try again.");
}
catch (Exception ex)
{
ModelState.AddModelError("", ex.Message);
}
}
return View(model);
}
}
}
How to read the information stored in the claims:
public class TopNavbarViewComponent : ViewComponent
{
private readonly IHttpContextAccessor _httpContextAccessor;
public TopNavbarViewComponent(IHttpContextAccessor httpContextAccessor)
{
_httpContextAccessor = httpContextAccessor;
}
public async Task<IViewComponentResult> InvokeAsync()
{
string loggedInUsername = _httpContextAccessor.HttpContext.User.Identity.Name;
string loggedInUserDisplayName = _httpContextAccessor.HttpContext.User.GetDisplayName();
...
return View(vm);
}
}
Extension method for ClaimsPrincipal:
namespace DL.SO.Framework.Mvc.Extensions
{
public static class ClaimsPrincipalExtensions
{
public static Claim GetClaim(this ClaimsPrincipal user, string claimType)
{
return user.Claims
.SingleOrDefault(c => c.Type == claimType);
}
public static string GetDisplayName(this ClaimsPrincipal user)
{
var claim = GetClaim(user, CustomClaimTypes.DisplayName);
return claim?.Value;
}
public static string GetEmail(this ClaimsPrincipal user)
{
var claim = GetClaim(user, ClaimTypes.Email);
return claim?.Value;
}
}
}
How to use policy authorization:
namespace DL.SO.Web.UI.Areas.Admin.Controllers
{
[Area("admin")]
[Authorize(Policy = "AdminOnly")]
public abstract class AdminControllerBase : Controller {}
}
Bonus
You can download the AD Explorer from Microsoft so that you can visualize your company AD.
Opps. I was planning to just give out something for head start but I ended up writing a very long post.
I've just started to use MediatR in an asp.net core project and am struggling to wire up validation ...
Here's my controller:
public class PersonController : Controller
{
IMediator mediator;
public PersonController(IMediator mediator)
{
this.mediator = mediator;
}
[HttpPost]
public async Task<ActionResult> Post([FromBody]CreatePerson model)
{
var success = await mediator.Send(model);
if (success)
{
return Ok();
}
else
{
return BadRequest();
}
}
}
... and the CreatePerson command, validation (via FluentValidation) and request handler:
public class CreatePerson : IRequest<bool>
{
public string Title { get; set; }
public string FirstName { get; set; }
public string Surname { get; set; }
}
public class CreatePersonValidator : AbstractValidator<CreatePerson>
{
public CreatePersonValidator()
{
RuleFor(m => m.FirstName).NotEmpty().Length(1, 50);
RuleFor(m => m.Surname).NotEmpty().Length(3, 50);
}
}
public class CreatePersonHandler : IRequestHandler<CreatePerson, bool>
{
public CreatePersonHandler()
{
}
public bool Handle(CreatePerson message)
{
// do some stuff
return true;
}
}
I have this generic validation handler:
public class ValidatorHandler<TRequest, TResponse> : IRequestHandler<TRequest, TResponse> where TRequest : IRequest<TResponse>
{
private readonly IRequestHandler<TRequest, TResponse> inner;
private readonly IValidator<TRequest>[] validators;
public ValidatorHandler(IRequestHandler<TRequest, TResponse> inner, IValidator<TRequest>[] validators)
{
this.inner = inner;
this.validators = validators;
}
public TResponse Handle(TRequest message)
{
var context = new ValidationContext(message);
var failures = validators
.Select(v => v.Validate(context))
.SelectMany(result => result.Errors)
.Where(f => f != null)
.ToList();
if (failures.Any())
throw new ValidationException(failures);
return inner.Handle(message);
}
}
... but I'm struggling to wire the validation up correctly in Startup.ConfigureServices using autofac:
public IServiceProvider ConfigureServices(IServiceCollection services)
{
// Add framework services.
services.AddMvc();
var builder = new ContainerBuilder();
builder.Register<SingleInstanceFactory>(ctx =>
{
var c = ctx.Resolve<IComponentContext>();
return t => c.Resolve(t);
});
builder.Register<MultiInstanceFactory>(ctx =>
{
var c = ctx.Resolve<IComponentContext>();
return t => (IEnumerable<object>)c.Resolve(typeof(IEnumerable<>).MakeGenericType(t));
});
builder.RegisterAssemblyTypes(typeof(IMediator).GetTypeInfo().Assembly).AsImplementedInterfaces();
builder.RegisterAssemblyTypes(typeof(CreatePersonHandler).GetTypeInfo().Assembly).AsClosedTypesOf(typeof(IRequestHandler<,>));
builder.RegisterGenericDecorator(typeof(ValidatorHandler<,>), typeof(IRequestHandler<,>), "Validator").InstancePerLifetimeScope();
builder.Populate(services);
var container = builder.Build();
return container.Resolve<IServiceProvider>();
}
When I run the app and POST /api/person
{
"title": "Mr",
"firstName": "Paul",
"surname": ""
}
I get a 200.
CreatePersonHandler.Handle() was called but CreatePersonValidator() is never called.
Am i missing something in Startup.ConfigureServices()?
I suggest that you read the official documentation on how to wire up decorators in Autofac.
Decorators use named services to resolve the decorated services.
For example, in your piece of code:
builder.RegisterGenericDecorator(
typeof(ValidatorHandler<,>),
typeof(IRequestHandler<,>),
"Validator").InstancePerLifetimeScope();
you're instructing Autofac to use ValidationHandler<,> as a decorator to IRequestHandler<,> services that have been registered with the Validator name, which is probably not what you want.
Here's how you could get it working:
// Register the request handlers as named services
builder
.RegisterAssemblyTypes(typeof(CreatePersonHandler).GetTypeInfo().Assembly)
.AsClosedTypesOf(typeof(IRequestHandler<,>))
.Named("BaseImplementation");
// Register the decorators on top of your request handlers
builder.RegisterGenericDecorator(
typeof(ValidatorHandler<,>),
typeof(IRequestHandler<,>),
fromKey: "BaseImplementation").InstancePerLifetimeScope();
I find specifying the name of the fromKey parameter helps in understanding how decorators work with Autofac.