Add oidc discovery endpoint

3 files changed, 53 insertions, 1 deletions

diff --git a/VPNAuth.Server/Api/Oidc.cs b/VPNAuth.Server/Api/Oidc.cs
index e8ff3c0..366fabf 100644
--- a/VPNAuth.Server/Api/Oidc.cs
+++ b/VPNAuth.Server/Api/Oidc.cs
@@ -1,4 +1,5 @@
-using VPNAuth.Server.Responses;
+using System.Net;
+using VPNAuth.Server.Responses;
 
 namespace VPNAuth.Server.Api;
 
@@ -73,4 +74,27 @@ public static class Oidc
 
         await context.Response.WriteAsJsonAsync(userInfoResponse);
     }
+
+    public static async Task DiscoveryHandler(HttpContext context)
+    {
+        if (!context.Request.Host.HasValue)
+        {
+            context.Response.StatusCode = StatusCodes.Status400BadRequest;
+            return;
+        }
+
+        var serverAddress = context.Request.IsHttps ? "https://" : "http://" + context.Request.Host.Value;
+
+        await context.Response.WriteAsJsonAsync(new OidcDiscovery
+        {
+            Issuer = serverAddress + "/",
+            AuthorizationEndpoint = $"{serverAddress}/auth",
+            TokenEndpoint = $"{serverAddress}/access-token",
+            UserInfoEndpoint = $"{serverAddress}/user-info",
+            JwksUri = "",
+            ResponseTypesSupported = ["code"],
+            SubjectTypesSupported = [],
+            IdTokenSigningAlgValuesSupported = ["RS256"]
+        });
+    }
 }
diff --git a/VPNAuth.Server/Program.cs b/VPNAuth.Server/Program.cs
index e8e5d4f..067e61b 100644
--- a/VPNAuth.Server/Program.cs
+++ b/VPNAuth.Server/Program.cs
@@ -35,6 +35,7 @@ app.MapGet("/accept-auth/{id}", OAuth2.AcceptAuthHandler);
 app.MapPost("/access-token", OAuth2.AccessTokenHandler);
 app.MapPost("/user-info-settings", UserInterface.UserSettingsHandler);
 app.Map("/user-info", Oidc.UserInfoHandler);
+app.MapGet("/.well-known/openid-configuration", Oidc.DiscoveryHandler);
 
 app.MapStaticAssets();
 app.MapRazorPages()
diff --git a/VPNAuth.Server/Responses/OidcDiscovery.cs b/VPNAuth.Server/Responses/OidcDiscovery.cs
new file mode 100644
index 0000000..e4d66f4
--- /dev/null
+++ b/VPNAuth.Server/Responses/OidcDiscovery.cs
@@ -0,0 +1,27 @@
+using System.Text.Json.Serialization;
+
+namespace VPNAuth.Server.Responses;
+
+public class OidcDiscovery
+{
+    [JsonPropertyName("issuer")] public string Issuer { get; set; }
+
+    [JsonPropertyName("authorization_endpoint")]
+    public string AuthorizationEndpoint { get; set; }
+
+    [JsonPropertyName("token_endpoint")] public string TokenEndpoint { get; set; }
+
+    [JsonPropertyName("userinfo_endpoint")]
+    public string UserInfoEndpoint { get; set; }
+
+    [JsonPropertyName("jwks_uri")] public string JwksUri { get; set; }
+
+    [JsonPropertyName("response_types_supported")]
+    public List<string> ResponseTypesSupported { get; set; }
+
+    [JsonPropertyName("subject_types_supported")]
+    public List<string> SubjectTypesSupported { get; set; }
+
+    [JsonPropertyName("id_token_signing_alg_values_supported")]
+    public List<string> IdTokenSigningAlgValuesSupported { get; set; }
+}