I want to try the new OpenApi feature in my .NET Core Web Application already running with SwaggerFeature plugin : Swagger UI link is visible from /metadata page, and is working as excepted.
So I have replaced the Plugins.Add(new SwaggerFeature()); in my AppHost with Plugins.Add(new OpenApiFeature()); after installing the ServiceStack.Api.OpenApi.Core nuget package.
Compilation is ok ; Swagger UI link is still visible from /metadata page, but when I try to access it I have an HTTP 404 error.
You made all correctly. Unfortunately current ServiceStack.Api.OpenApi.Core package on nuget does not include some of swagger UI resource files. This is already fixed but new version package is not published on nuget yet. As a workaround, while package with fix is not being published you can download swagger-ui files from here and place it into /swagger-ui directory under root web folder. More detailed description you can find in ServiceStack.Api.OpenAPI documentation