If I try to rename a file via a form_for

1 file = session.file_by_title(@specification.title)
2 if file
3 file.rename(params[:specification][:title])
4 end

On line 1 file is

<GoogleDrive::File document_feed_url="https://docs.google.com/feeds/default/private/full/document%3A12IlSBUz0kwCC2g53PGhikcwQHSQysB1U9vpOuDwy_ts", title="Test">

On line 3

Response code 400 for get https://docs.google.com/feeds/default/private ... : : Invalid request URI

I also tried

file.title = params[:specifications][:title]

What exactly goes wrong?