= carrierwave-meta

= Installation

Add the following line to your Gemfile:
  gem 'carrierwave-meta'

= Usage example

  class TestUploader < CarrierWave::Uploader::Base
    include CarrierWave::RMagick
    include CarrierWave::Meta
  
    def store_dir
      "tmp/store"
    end

    def cache_dir
      "tmp/cache"
    end

    storage :file

    process :store_meta
    version :version do
      process :resize_to_fill => [200, 200]
      process :store_meta
    end
  end
  
  file = File.open('test.jpg') # JPEG 500x300, 20000 bytes
  uploader = TestUploader.new
  uploader.store!(file)
  
  uploader.width        # 500
  uploader.height       # 300
  uploader.image_size   # [500, 300]
  uploader.file_zie     # 20000
  uploader.content_type # "image/jpeg"
  
  uploader.version.width        # 200
  uploader.version.height       # 200  
  uploader.version.image_size   # [200, 200]  
  uploader.version.file_zie     # less than 20000
  uploader.version.content_type # "image/jpeg"

= Saving values to database

  class TestModel
    attr_accessor :image_width  
    attr_accessor :image_height
    attr_accessor :image_image_size  
    attr_accessor :image_content_type
    attr_accessor :image_file_size

    attr_accessor :image_version_width  
    attr_accessor :image_version_height
    attr_accessor :image_version_image_size
    attr_accessor :image_version_content_type
    attr_accessor :image_version_file_size  
  end

  file = File.open('test.jpg')
  model = TestModel.new
  uploader = TestUploader.new(model, :image)
  uploader.store!(file)
  
  uploader.width      # 500
  model.image_width   # 500
  model.image_height  # 300
  ...

When columns are available in the model instance, metadata is stored in that columns.

= Behind the scenes

After the file is retrieved from store metadata is recalculated for it unless uploader has
attached model instance.

  uploader = TestUploader.new
  uploader.retrieve_from_store!('test.jpg')

  uploader.version.width # 200

So, if you are storing width and height in database column and then you decided to store 
content type.

Uploader tries to retrieve metadata from a model's column first.

= Integrating CarrierWave & JCrop using carrierwave-meta


= TODO

1. I do not know how it would work with S3 and other remote storages. Should be tested.
2. Write integration guide for JCrop.
3. A notice about content-type.
4. It works now only with RMagick. Add support for other image libraries. It's easy.