Struggling to get a CSV Report to load when requested - ruby-on-rails

Question

I'm trying to make it possible to view a report from a webpage and I am struggling. This task uses Sidekiq.
When I click on the link that should take me there I get the error: "The action 'churn_risk_report' could not be found for Admin::ReportsController."
In a show.html.erb file, in the Reports view, I've added <li><%= link_to 'Churn Risk Report', churn_risk_report_admin_reports_path %></li> beneath a number of similar lines with links to other reports.
I've added get 'churn_risk_report' in the correct place in my Routes file.
In my Workers directory, which I believe is my system's version of a Scripts directory used for Sidekiq jobs, I have a file called churn_risk_report.rb and in this file I have the following code:
class ChurnRiskReport
include Sidekiq::Worker
def perform
csv_temp = Tempfile.new
puts csv_temp.path
CSV.open(csv_temp.path, 'wb') do |csv|
csv << ["AAA", "BBB", "CCC", "DDD", "EEE", "FFF"]
AccountChurnRisk.all.each do |acr|
report_data = [acr.aaa,
acr.bbb,
"#{acr.ccc} #{acr.ccc}",
acr.ddd,
acr.eee,
acr.fff]
csv << report_data
end
end
report_name = "churn_risk_report"
file_name = "gggggggggg-#{report_name}-#{DateTime.now.to_date.strftime("%b-%Y")}.csv".downcase
bucket_name = 'hhh-reports'
s3 = AWS::S3.new
key = "reports/churn_reports/" + File.basename(file_name)
x = s3.buckets[bucket_name].objects[key].write(:file => csv_temp.path)
end
end
Consecutive letters = code that I think should be kept private. This code worked in a rails console when I ran it, so I know the code works.
I'm struggling with the final part of the task. In the Reports controller I've defined churn_risk_report and just copied in the same code as is in the Worker file. I know this is incorrect but I'm not sure what should go in there. I think there should be some code in here that temporarily creates a churn_risk_report file in the Workers directory, however this might not be the case. I also think that 'async' should be involved somewhere.
Thanks in advance for any help!

Answer 1

At the bottom of this answer, is the gist I keep specifically for basic CSV export logic handling works for most cases that don't require high performance. Typically I use it as a way for the user to download a CSV copy of the data they are currently looking at (so caching in S3 isn't overly practical): https://gist.github.com/MyklClason/f6ac68ca4ce1faa5d655abfb0abe788b
Depending on how large the report is, saving it in S3 may be excessive, but could work as a way to cache it (or store it for long term). In which case before rendering the download link (to the S3 file itself), you check to see if the report already exists, if it does, render a link directly to AWS, if it doesn't, render a "generate report" link, then once the report is generated, render a "Download report" link.
Even better if you can auto-generate the reports, which seems to be what you are doing in the original code. Though I think a "Generate report" button could queue up the job to run the code you have though likely the reports are monthly or something so you know exactly when you need to create them, in which case the "Generate report" button probably isn't needed and you can just provide an S3 download link, if the report has been generated.
Gist content:
# Good solution for exporting to CSV in rails.
# Source: https://www.codementor.io/victorhazbun/export-records-to-csv-files-ruby-on-rails-vda8323q0
class UsersController < ApplicationController
def index
#users = User.all
respond_to do |format|
format.html
format.csv { send_data #users.to_csv, filename: "users-#{Date.today}.csv" }
end
end
end
class User < ActiveRecord::Base
def self.to_csv
attributes = %w{id email name}
CSV.generate(headers: true) do |csv|
csv << attributes
all.each do |user|
csv << attributes.map{ |attr| user.send(attr) }
end
end
end
end
<%= link_to 'Export CSV', user_path(format: :csv) %>