How to solve when parsing CSV file return empty values?

Question

I am using ruby 1.9.2 and Rails 3.0.7. I have written ruby back-end script that will create one CSV file on every 15 min interval using cron job.

Back-end ruby script:

 CSV.open("count.csv", 'wb',:col_sep=>',') do |csv|
 # header row
   csv << ['id', 'count']
   models = Model.all
   models.each do |obj|
      csv << [ obj.id, obj.get_count]
   end
 end

From above script CSV file(count.csv) created successfully. In Rails app,

 CSV.foreach("count.csv", :quote_char => '"', :col_sep =>',', :row_sep =>:auto, :headers => true) do |row|
   count =  row["count"].to_i if row["id"].to_i == @id
 end

I need to parse count value from that CSV file. but problem is when the time of cron execution, I unable to get count value from that CSV file return zero for all record and after execution finish I can get value of count. But I need count value always whether the cron execution stop or start, Can any one help me to resolve or any suggestion ? Thanks in advance.

Your code looks fine to me. Are you sure @id is initialized? — Daniel Rikowski
– Daniel Rikowski, Commented Nov 15, 2011 at 10:43
@daniel - Yes i have initialized. The problem occur during the time of ruby script execution. In Rails reporting side I got zero value for all data. I don't how its happen? any guess? — prabu
– prabu, Commented Nov 15, 2011 at 10:50
Why are you doing all this as opposed to simply calling obj.get_count in Rails? — Mark Thomas
– Mark Thomas, Commented Nov 15, 2011 at 12:06
Have you checked the permissions on count.csv? How about the location? Can you open and read it using File.open? — mu is too short
– mu is too short, Commented Nov 15, 2011 at 17:19
Not on Heroku you don't. Why bother with a CSV at all? Why not just add an extra table to your database? — mu is too short
– mu is too short, Commented Nov 17, 2011 at 7:18

Pasted · Accepted Answer · 2011-11-16 17:31:30Z

1

models = Model.all
models.each do |obj|
  csv_string << [ obj.id, obj.get_count]
end

CSV.open("count.csv", 'wb',:col_sep=>',') do |csv|
# header row
 csv << ['id', 'count']
 csv << csv_string
end

answered Nov 16, 2011 at 17:31

Pasted

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