Image resizing by using Cloudinary[Ruby]

Cloudinary is one of services providing useful image-based API and CDN. In this article, I would like to introduce Ruby the sample code to resize a image by using the service.

🚌 Installation

Install RubyGem cloudinary. Please add the following RubyGem name and execute bundle install in terminal.

gem 'cloudinary'

🏈 Ge API Key

Free member registration from https://cloudinary.com/ and you can get your API key.

🎂 Sample code for resizing image

You can get resized image by the following code:

require 'faraday'

def thumbnail_image(image_url)
  tmp_path = _save_image_to_tmp(image_url)
  output = ::Cloudinary::Uploader.upload(tmp_path, _cloudinary_auth)
  raise "Invalid output! #{output}" if output['public_id'].blank?

  _optimized_url(output['public_id'])
end

# @return [String] S3 URL for lambda
private def _save_image_to_tmp(image_url)
  content = get_content(image_url)

  temp = Tempfile.new.tap do |t|
    t.binmode
    t.write(_gzip(content))
    t.close
  end
  temp.path
end

private def _get_content(url)
  connection = Faraday.new do |conn|
    conn.use FaradayMiddleware::FollowRedirects, limit: 5
    conn.adapter Faraday.default_adapter
    conn.response :encoding
  end

  response = connection.get url.force_encoding(Encoding::BINARY)
  raise NotFoundError, "404 Not Found: #{response.body}" if response.status == 404
  raise "Invalid response: #{response.body}" unless response.success?

  response.body
end

private def _optimized_url(_public_id)
  "http://res.cloudinary.com/USER_NAME/image/upload/w_300,h_300,c_fill,q_auto:eco/#{public_id}.jpg"
end

private def _cloudinary_auth
  {
      cloud_name: 'xxx',
      api_key: 'xxxx',
      api_secret: 'xxxx'
  }
end

private def _gzip(data)
  sio = StringIO.new
  gz = Zlib::GzipWriter.new(sio)
  gz.write(data)
  gz.close
  sio.string
end

🎃 References

• https://www.rubydoc.info/github/cloudinary/cloudinary_gem/index
• https://cloudinary.com/documentation/image_transformations
• https://cloudinary.com/documentation/image_transformation_reference

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