How to do Data Scraping in Ruby on Rails by Processing CSV

This article is about How to do simple ruby web scraping by processing CSV.
 

In this article, we will create a Ruby on Rails application to scrap the link uploaded from a CSV file and find the occurrence of the link on a particular page.
 

In the below Ruby on Rails application development, the user needs to pass a CSV file and list of the user’s email to whom the parsed CSV will be sent.
 

In the CSV file, there will be 2 columns
 

referal_link home_link
 

Let’s start creating a Rails Application
 

Run the below command to create a new rails application
 

$ rails new scrape_csv_data
$ cd scrape_csv_data

 

Then, we will generate an Upload CSV module. Run the below command.
 

$ rails g scaffold UploadCsv generated_csv:string csv_file:string
 

This will create all the required models, controllers, and migrations for csv_file. Run the migration using the below command. 
 

$ rails db:migrate
 

Update the app/views/upload_csvs/_form.html.erb with the below code. Then we will add the gem to upload the CSV file. Add the below line to your Gemfile.
 

gem 'carrierwave', '~> 2.0'
 

  Then,
 

$ bundle install
 

Then we will create the uploader in careerwave using the below command.
 

$ rails generate uploader Avatar
 

We will attach the uploader in the model app/models/upload_csv.rb. 
 

class UploadCsv < ApplicationRecord
     mount_uploader :csv_file, AvatarUploader

end

 

Update the routes.

 

Rails.application.routes.draw do
     resources :upload_csvs
     root 'upload_csvs#index'
end

 

Then, we will start the server and check if the application is working successfully or not. 
 

$ rails s
 

Then we will create a job to read the CSV file and scrap the link from it and the generated file will be stored in the generated_csv column of that record for generating the job. Run the below command.
 

$ rails generate job genrate_csv
 

Add the below gem and run bundle install
 

gem 'httparty'
gem 'nokogiri'
 

Then we will replace the below code in the GenerateCsv job. Then we will run the job after_create of upload_csvs and we will add the validation for the csv_file required.  Now update the code of app/models/upload_csv.rb.

After uploading the file check the scrap generated file will be updated. You can check the generated file in /scrape_data/public/result_data.csv
 

Now we will send the generated file through email by using the below instructions.

 

First,  we will generate the mailer by using the below command.
 

$ rails generate mailer NotificationMailer
 

Add this code inside the notification mailer. 
 

Also, we need to add mail configuration inside config/environments/development.rb or production.rb.
 

Also, we need to update the view also app/views/notification_mailer/send_csv.html.erb
 

app/views/notification_mailer/send_csv.html.erb
 

 

Thank you!

 

Source Link: https://www.botreetechnologies.com/blog/web-scraping-with-ruby-by-processing-csv/