Configure OpenApi UI

To configure the OpenApi UI, the spec path along with the name of the spec must be passed in the SwaggerEndpoint() method within the UseSwaggerUI() extension.

  .UseSwagger(c =>
   {
       c.PreSerializeFilters.Add((swagger, httpReq) =>
       {
           swagger.Servers = new List<OpenApiServer> { new OpenApiServer { Url = $"{pathBase}" } };
       });
   })
   .UseSwaggerUI(c =>
   {
       c.DisplayOperationId();
       c.SwaggerEndpoint("all/swagger.json", "Menu (all)");
       c.SwaggerEndpoint("v1/swagger.json", "Menu (version 1)");
       c.SwaggerEndpoint("v2/swagger.json", "Menu (version 2)");

       if (jwtBearerAuthenticationConfiguration.HasOpenApiClient())
       {
           c.OAuthClientId(jwtBearerAuthenticationConfiguration.OpenApi.ClientId);
           c.OAuthUsePkce();
       }
   });

The above snippet registers the v1/swagger.json in the UI. Once the UI is loaded, the documents registered by SwaggerEndpoint() will be loaded.

For registering multiple spec versions, simply register multiple document generations by calling the .AddSwaggerGen(c => ...) multiple times, changing just the document filter from /v1 to the version desired.

// OpenApi multiple doc spec
 services
        .AddSwaggerGen(c =>
        {
            // excluded for brevity 
        });

The OpenAPI UI should be available as below.