HangfireIO/Hangfire · error · ArgumentNullException

storage

Error message

storage

What it means

Thrown by the obsolete DashboardMiddleware constructor (OWIN-based) when the storage parameter is null. The middleware needs a JobStorage instance to serve dashboard pages and fetch monitoring data; a null storage makes all dashboard requests fail.

Source

Thrown at src/Hangfire.Core/Obsolete/DashboardMiddleware.cs:45

{
    internal sealed class DashboardMiddleware : OwinMiddleware
    {
        private readonly string _appPath;
        private readonly int _statsPollingInterval;
        private readonly JobStorage _storage;
        private readonly RouteCollection _routes;
        private readonly IEnumerable<IAuthorizationFilter> _authorizationFilters;

        public DashboardMiddleware(
            OwinMiddleware next,
            string appPath,
            int statsPollingInterval,
            [NotNull] JobStorage storage,
            [NotNull] RouteCollection routes, 
            [NotNull] IEnumerable<IAuthorizationFilter> authorizationFilters)
            : base(next)
        {
            if (storage == null) throw new ArgumentNullException(nameof(storage));
            if (routes == null) throw new ArgumentNullException(nameof(routes));
            if (authorizationFilters == null) throw new ArgumentNullException(nameof(authorizationFilters));

            _appPath = appPath;
            _statsPollingInterval = statsPollingInterval;
            _storage = storage;
            _routes = routes;
            _authorizationFilters = authorizationFilters;
        }

        public override Task Invoke(IOwinContext owinContext)
        {
            var dispatcher = _routes.FindDispatcher(owinContext.Request.Path.Value);
            
            if (dispatcher == null)
            {
                return Next.Invoke(owinContext);
            }

View on GitHub (pinned to c236dd0f93)

Solutions

1. Use the modern app.UseHangfireDashboard() extension method instead of constructing DashboardMiddleware directly
2. If constructing manually, pass JobStorage.Current (ensure it is set first via UseStorage)
3. Ensure the OWIN startup class runs after storage configuration

Example fix

// before
app.Use(typeof(DashboardMiddleware), next, "/app", 2000, null, routes, filters);

// after
// Register storage first
GlobalConfiguration.Configuration.UseSqlServerStorage(connStr);
// Use the extension method
app.UseHangfireDashboard("/hangfire");

var storage = JobStorage.Current; // ensure initialized first
if (storage == null) throw new InvalidOperationException("JobStorage not configured.");
var middleware = new DashboardMiddleware(next, appPath, interval, storage, routes, authFilters);

storage != null && storage is JobStorage

When it happens

Trigger: Constructing new DashboardMiddleware(next, appPath, interval, null, routes, authFilters) or an OWIN pipeline registration that passes null for the JobStorage.

Common situations: Using the obsolete OWIN middleware directly (instead of the recommended app.UseHangfireDashboard extension), where JobStorage.Current has not been set yet at pipeline construction time, or a misconfigured OWIN startup class.

Related errors

• owinEnvironment
• app
• owinEnvironment
• context must be of type 'OwinDashboardContext'
• routes

AI-assisted analysis of HangfireIO/Hangfire@c236dd0f93 (2026-08-13). Data as JSON: /api/errors/23a9cdc12e33482b. Report an issue: GitHub.