suave redirect to https webpart

gistfile1.fs

let redirectToSsl : WebPart =
  context(fun c ->
    if not c.runtime.matchedBinding.scheme.secure 
    then
      let uriBuilder = new UriBuilder(c.request.url)
      uriBuilder.Scheme <- Uri.UriSchemeHttps
      Redirection.redirect (uriBuilder.Uri.ToString()) 
    else never)

To make this work on heroku you can use:

    let redirectToSsl : WebPart =
          context(fun c ->
           match c.request.header "x-forwarded-proto" with
            | Choice1Of2 "http" ->
                  let uriBuilder = new UriBuilder(
                                          Scheme = Uri.UriSchemeHttps,
                                          Path = c.request.path,
                                          Host = c.request.host)
                  Redirection.redirect (uriBuilder.Uri.ToString())
            | _ -> fun _ ->async { return None })