attach_file.md

Attach file

gem 'quiet_assets'
gem 'carrierwave'

bundle
rails g uploader Image

• a file called image_uploader.rb will be created:

# encoding: utf-8

class ImageUploader < CarrierWave::Uploader::Base

  # Include RMagick or MiniMagick support:
  # include CarrierWave::RMagick
  # include CarrierWave::MiniMagick

  # Choose what kind of storage to use for this uploader:
  storage :file
  # storage :fog

  # Override the directory where uploaded files will be stored.
  # This is a sensible default for uploaders that are meant to be mounted:
  def store_dir
    "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end

  # Provide a default URL as a default if there hasn't been a file uploaded:
  # def default_url
  #   # For Rails 3.1+ asset pipeline compatibility:
  #   # ActionController::Base.helpers.asset_path("fallback/" + [version_name, "default.png"].compact.join('_'))
  #
  #   "/images/fallback/" + [version_name, "default.png"].compact.join('_')
  # end

  # Process files as they are uploaded:
  # process :scale => [200, 300]
  #
  # def scale(width, height)
  #   # do something
  # end

  # Create different versions of your uploaded files:
  # version :thumb do
  #   process :resize_to_fit => [50, 50]
  # end

  # Add a white list of extensions which are allowed to be uploaded.
  # For images you might use something like this:
  # def extension_white_list
  #   %w(jpg jpeg gif png)
  # end

  # Override the filename of the uploaded files:
  # Avoid using model.id or version_name here, see uploader/store.rb for details.
  # def filename
  #   "something.jpg" if original_filename
  # end

end

• create a migration

rails g migration add_images_to_campaigns image
rake db:migrate

• in campaign model

  # This is CarrierWave config:
  # :image is the field in the database that will store the image name
  # ImageUploader is the uplaoder class we created in /app/uploaders/image_uploader.rb
  mount_uploader :image, ImageUploader

• now modify the form

<%= f.file_field :image  %>

image resizing

brew install imagemagick

• uncomment out the miniMagic in image_uploader.rb

  # Include RMagick or MiniMagick support:
  # include CarrierWave::RMagick
  include CarrierWave::MiniMagick
  
  ...

• and uncomment the following thumb config in image_uploader.rb

  # Create different versions of your uploaded files:
  version :thumb do
    process :resize_to_fit => [50, 50]
  end

• optionally you can also add the following in addition to :thumb version

version :medium do
    process :resize_to_fit => [200, 200]
  end
  version :large do
    process :resize_to_fit => [400, 400]
  end
  version :square do
    process :resize_to_fill => [200, 200]
  end

• install gem

gem 'mini_magick'

• show page:

<%= image_tag @campaign.image.url %>
<!-- or  -->
<%= image_tag @campaign.image.url(:large) %>

Upload to cloud

gem 'fog'

http://aws.amazon.com/