type SwaggerDefaultValues () =
    interface IOperationFilter with
        member this.Apply(operation: Operation, context: OperationFilterContext): unit =
            let parameters =
                operation
                |> Option.ofObj
                |> Option.bind (fun operation -> Option.ofObj operation.Parameters)
                |> Option.map (fun parameters -> parameters.OfType<NonBodyParameter>())
                |> Option.defaultValue Seq.empty
            for parameter in parameters do
                let parameterDescription =
                    context.ApiDescription.ParameterDescriptions
                    |> Seq.tryFind (fun x -> x.Name = parameter.Name)
                let description =
                    parameterDescription
                    |> Option.bind (fun description -> Option.ofObj description.ModelMetadata)
                    |> Option.bind (fun modelMetadata -> Option.ofObj modelMetadata.Description)
                if isNull parameter.Description && Option.isSome description
                    then parameter.Description <- description.Value
                let routeInfo = parameterDescription |> Option.map (fun x -> x.RouteInfo)
                if Option.isSome routeInfo then
                    if isNull parameter.Default then parameter.Default <- routeInfo.Value.DefaultValue
                    parameter.Required <- ((parameter.Required) || (not(routeInfo.Value.IsOptional)))
            ()