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Unzip an archive and attach images to Active Record model objects

masroorhussainv profile image Masroor Hussain Updated on ・2 min read

Recently I worked on a project where I had to upload a zip archive of images and then attach those images to Active Record model objects on the Rails server.

  • Note: This example uses Active Storage to attach images to Active Record objects.

Here is how I got it all working

Install Gem

Include this gem

gem 'rubyzip'
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then do

bundle install
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Unzipping and file attachment

We suppose an Active Record model named Product, which has an Active Storage attribute called product_image

class OrderItem < ApplicationRecord
  has_one_attached :product_image
end
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The controller which renders a zip upload form in the action zip_upload_form (view template code is not provided here) and the form gets posted to the zip_file action, which then processes the zip file by calling the process_zip_file method.

require 'zip'

class UnzipController < ApplicationController

  # GET
  def zip_upload_form
    # this action renders form for zip file upload
  end

  # POST
  def zip_file
    # the form is posted to this action
    # this action processes the uploaded zip file

    # params[:zip] is the uploaded zip file
    zip = params[:zip]

    if zip
      process_zip_file(zip)
    else
      redirect_to zip_upload_form_path
    end
  end

  private

  def process_zip_file(tmpfile_zip)
    Zip::File.open(tmpfile_zip.path) do |zipfile|

      # iterating through all the entries found in the zip file
      zipfile.each do |entry|
        if entry.file?
          puts "#{entry.name} is a file!"
          attach_file_to_model_obj(entry)

        elsif entry.directory?
          puts "#{entry.name} is a directory!"

        elsif entry.symlink?
          puts "#{entry.name} is a symlink!"
        end

      end
    end
  end

  def attach_file_to_model_obj(entry)
    # first we create a temp file from the file found in the zip archive
    # then attach the temp file to model obj

    Tempfile.open(["my-filename", ".#{put_extension_here}"]) do |tmp|
      # this line creates the temp file
      entry.extract(tmp.path) { true }

      # attaching the temp image file to active record object
      Product.first
             .product_image
             .attach(io: File.open(tmp.path), filename: "my-filename.#{put_extension_here}")
    end
  end

end
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Cover Image by JOHN TOWNER on Unsplash

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