Undefined method 'column_names' when generating CSV in after_save_filter

Question

I want to generate CSV file after user creates his account, so I created after_save filter in User Model, but I'm getting errors.

Here is my code:

    after_save :to_csv

    def to_csv(options = {})
    require 'csv'
    CSV.generate(options) do |csv|
        csv << self.column_names//also tried User.column_names
        csv << self.attributes.values_at(*column_names)
    end
    end

but when User is created I get error:

     undefined local variable or method `column_names' for #<User:0x326f778>       
     app/models/user.rb:52:in `block in to_csv'
     app/models/user.rb:50:in `to_csv'
     app/controllers/users_controller.rb:27:in `create'

Why I'm getting this ? I'm using this railscast - http://railscasts.com/episodes/362-exporting-csv-and-excel.

score 4 · Accepted Answer · answered Sep 03 '12 at 07:38

4

column_names is a method on the class. You're calling it on the instance. If you really want column_names then use self.class.column_names.

answered Sep 03 '12 at 07:38

Ryan Bigg

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can you suggest where is my generated file ? Also tried to generated by calling `CSV.open("myfile.csv", "w") do |csv| ` – MID Sep 03 '12 at 07:47

score 3 · Answer 2 · answered Sep 03 '12 at 07:37

3

Try self.attributes.keys which return columns

answered Sep 03 '12 at 07:37

Amar

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no more errors, thanks. But where is the file ? Or I didn't generate it yet ? – MID Sep 03 '12 at 07:41

score 0 · Answer 3 · answered Aug 26 '16 at 12:20

0

Am bit late int he game but here it is

self.attribute_names

does the job for me.

answered Aug 26 '16 at 12:20

Bart C

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Undefined method 'column_names' when generating CSV in after_save_filter

3 Answers3