Where is the Rails method that converts data from `datetime_select` into a DateTime object?

This conversion happens within ActiveRecord when you save your model.

You could work around it with something like this:

somedate = DateTime.new(params["date1(1i)"].to_i, 
                        params["date1(2i)"].to_i,
                        params["date1(3i)"].to_i,
                        params["date1(4i)"].to_i,
                        params["date1(5i)"].to_i)

DateTime::new is an alias of DateTime::civil (ruby-doc)

The start of that code path, seems to be right about here:

https://github.com/rails/rails/blob/d90b4e2/activerecord/lib/active_record/base.rb#L1811

That was tricky to find! I hope this helps you find what you need

Hi I have added the following on the ApplicationController, and it does this conversion.

    #extract a datetime object from params, useful for receiving datetime_select attributes
    #out of any activemodel
    def parse_datetime_params params, label, utc_or_local = :local
      begin
        year   = params[(label.to_s + '(1i)').to_sym].to_i
        month  = params[(label.to_s + '(2i)').to_sym].to_i
        mday   = params[(label.to_s + '(3i)').to_sym].to_i
        hour   = (params[(label.to_s + '(4i)').to_sym] || 0).to_i
        minute = (params[(label.to_s + '(5i)').to_sym] || 0).to_i
        second = (params[(label.to_s + '(6i)').to_sym] || 0).to_i

        return DateTime.civil_from_format(utc_or_local,year,month,mday,hour,minute,second)
      rescue => e
        return nil
      end
    end