Ensure https for ASP.NET Core apps on Heroku

StartupConfigure.cs

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    if (env.IsProduction())
    {
        app
            .UseForwardedHeaders()
            .UseHttpsRedirection();
    }
    // ...
}

StartupConfigureService.cs

public IServiceProvider ConfigureServices(IServiceCollection services)
{
    // ...
    services.AddHttpsRedirection(options => { options.HttpsPort = 443; });
    services.Configure<ForwardedHeadersOptions>(options =>
    {
        options.KnownNetworks.Clear();
        options.KnownProxies.Clear();
        options.ForwardedHeaders =
            ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto;
    });
    // ...
}