Migrating Owin Openid Connect

OWIN OpenID Connect Authentication Migration

Overview

Migrate OWIN-based OpenID Connect authentication to ASP.NET Core. The main change is replacing OWIN middleware registration and notification callbacks with the ASP.NET Core AddOpenIdConnect() builder pattern and strongly-typed events. Cookie authentication must be explicitly paired because ASP.NET Core does not implicitly manage session cookies for OpenID Connect.

Package Reference Changes

Old References (Remove)

<PackageReference Include="Microsoft.Owin.Security.OpenIdConnect" Version="{old-version}" />
<PackageReference Include="Microsoft.Owin.Security.Cookies" Version="{old-version}" />
<PackageReference Include="Microsoft.Owin" Version="{old-version}" />

New References (Add)

<PackageReference Include="Microsoft.AspNetCore.Authentication.OpenIdConnect" Version="{version}" />

The cookie authentication middleware is included in the ASP.NET Core shared framework and does not require a separate package reference.

Workflow

Migration Progress:
- [ ] Step 1: Detect OWIN OpenID Connect usage
- [ ] Step 2: Update project file references
- [ ] Step 3: Replace middleware registration
- [ ] Step 4: Migrate options and notification callbacks
- [ ] Step 5: Build and verify

Step 1: Detect OWIN OpenID Connect Usage

Scan the project for:

• using Microsoft.Owin.Security.OpenIdConnect; statements
• app.UseOpenIdConnectAuthentication(...) calls
• OpenIdConnectAuthenticationOptions configuration
• Notifications property assignments (SecurityTokenValidated, AuthorizationCodeReceived, etc.)

Step 2: Update Project File References

Remove old OWIN packages and add the ASP.NET Core package (see "Package Reference Changes" above).

Step 3: Replace Middleware Registration

Replace the OWIN middleware setup with ASP.NET Core service registration:

// Old: OWIN Startup.Auth.cs
app.UseOpenIdConnectAuthentication(new OpenIdConnectAuthenticationOptions { ... });

// New: ASP.NET Core Program.cs / Startup.cs
builder.Services.AddAuthentication(options =>
{
    options.DefaultScheme = CookieAuthenticationDefaults.AuthenticationScheme;
    options.DefaultChallengeScheme = OpenIdConnectDefaults.AuthenticationScheme;
})
.AddCookie()
.AddOpenIdConnect(options => { /* see Step 4 */ });

Pair AddOpenIdConnect() with AddCookie() — ASP.NET Core requires explicit cookie auth for session management after the OpenID Connect handshake.

Step 4: Migrate Options and Notification Callbacks

| OWIN (Old) | ASP.NET Core (New) |

|------------|-------------------|

| OpenIdConnectAuthenticationOptions | OpenIdConnectOptions |

| options.ClientId | options.ClientId (same) |

| options.Authority | options.Authority (same) |

| options.RedirectUri | options.CallbackPath (relative path, not absolute URI) |

| options.PostLogoutRedirectUri | options.SignedOutCallbackPath |

| options.Notifications | options.Events |

| Notifications.SecurityTokenValidated | Events.OnTokenValidated |

| Notifications.AuthorizationCodeReceived | Events.OnAuthorizationCodeReceived |

| Notifications.RedirectToIdentityProvider | Events.OnRedirectToIdentityProvider |

| Notifications.AuthenticationFailed | Events.OnAuthenticationFailed |

Callback context types also change — update parameter types in event handlers:

// Old
Notifications = new OpenIdConnectAuthenticationNotifications
{
    SecurityTokenValidated = context => { /* SecurityTokenValidatedNotification */ }
};

// New
Events = new OpenIdConnectEvents
{
    OnTokenValidated = context => { /* TokenValidatedContext */ }
};

Step 5: Build and Verify

• Build the project:

   dotnet build

• Verify the authentication flow end-to-end: sign-in redirect, callback handling, token validation, and sign-out
• Confirm cookie-based session persistence works after the OpenID Connect handshake

Troubleshooting

Redirect URI Mismatch

ASP.NET Core uses CallbackPath (a relative path like /signin-oidc) rather than a full redirect URI. Update the identity provider's registered redirect URI to match the application's base URL plus the callback path.

Missing Cookie Authentication

If users are redirected in a loop after authentication, AddCookie() is likely missing. ASP.NET Core requires explicit cookie auth to persist the session after the OpenID Connect handshake.

Notification Context Type Errors

The event context types changed between OWIN and ASP.NET Core. Replace OWIN notification parameter types with the corresponding ASP.NET Core context types (e.g., TokenValidatedContext instead of SecurityTokenValidatedNotification).