Question

I have a generic import table that allows the loading of csv files into different columns in my import table. The same import table is used for multiple types of imports, so I don’t process the individual fields until the user is ready and tells me where to process it.

So in this case I have an import table with many cells that I will use to create (or update) donors in my donors table. How do I send my import_table data associated with the import_table model and controller to the create method of my donors_controller?

the create method of my donors_controller:

      def create
        # need to find donor by id if given, else use find_or_create_by_blahblahblah
        unless @donor = Donor.find_by_id(params[:donor][:id])
          @donor = Donor.find_or_initialize_by_company_and_prefix1_and_first_name1_and_last_name1_and_address1(params[:donor])
        end

        if @donor.new_record?   

          respond_to do |format|
            if @donor.save
              format.html { redirect_to @donor, notice: 'Donor was successfully created.' }
              format.json { render json: @donor, status: :created, location: @donor }
            else
              format.html { render action: "new" }
              format.json { render json: @donor.errors, status: :unprocessable_entity }
            end
          end    
        else
          respond_to do |format|
            if @donor.save
              format.html { redirect_to @donor, notice: 'Donor already exists.  Please edit donor if needed.'}
              format.json { render json: @donor, status: :created, location: @donor }
            else
              format.html { render action: "new" }
              format.json { render json: @donor.errors, status: :unprocessable_entity }
            end
          end 
        end   

      end

Then in my import_tables controller I have this method:

def process_import
  @import = ImportTable.find(params[:id])
  if @import.import_type == 'Prospects'
     #do something here....
  elsif @import.import_type == 'Donations'
     #do something here...
  end

end

I am not sure what exactly I should do in the #do something here... parts.

I was thinking I should pick out the right columns from @import and put them in [:donor] array and send them to the create method of my donors_controller, but I am not sure exactly how to do that or if that is the right way to go about this.

Answer 1

The missing link is that you need to get to the Class from it’s name..

There are several ways to do this, e.g. with an “eval’ , but a cleaner and simpler way to do this is to:

# do something:
  class_name = @import.import_type
  klass = ActiveRecord.const_get(class_name)  # now you have a reference to your class

  #... then do whatever you like with your symbolic klass, e.g. create your new entry
  #  klass.find_or_create(...) , klass.find(1), klass.first ,
  #  klass.create( {attributes for new instance of klass} )

this works so conveniently because in your model you do YourClass < ActiveRecord::Base ,
your class is part of the ActiveRecord module, Classes in Ruby are constants which are stored in the context in which they are defined (=in their module), therefore you can query that context, e.g. ActiveRecord, and find your class.

If your class was not derived from ActiveRecord::Base , you could still do a:

 klass = Kernel.const_get( class_name )

see also:
http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/