How to set base path property in swagger for .Net Core Web API

in the end i used this to fix it:

you can set the PreSerializeFilters to add both the BasePath and edit the Paths. Thought there would be a more elegant way but this works.

var basepath = "/api/AppStatus";
c.PreSerializeFilters.Add((swaggerDoc, httpReq) => swaggerDoc.BasePath = basepath);


c.PreSerializeFilters.Add((swaggerDoc, httpReq) => {
    IDictionary<string, PathItem> paths = new Dictionary<string, PathItem>();
    foreach (var path in swaggerDoc.Paths)
    {
        paths.Add(path.Key.Replace(basepath, "/"), path.Value);
    }
    swaggerDoc.Paths = paths;
});

BasePath was used in Swagger v2.0 It has been replaced by the servers array in OpenApi v3.0

In v5 you have to do this for using OpenApi v3.0:

var basePath = "/v1";
app.UseSwagger(c =>
    {
        c.RouteTemplate = "swagger/{documentName}/swagger.json";
        c.PreSerializeFilters.Add((swaggerDoc, httpReq) =>
        {
            swaggerDoc.Servers = new List<OpenApiServer> { new OpenApiServer { Url = $"{httpReq.Scheme}://{httpReq.Host.Value}{basePath}" } };
        });
    });