Module: CarrierWave::Mount

Included in:
ActiveRecord, DataMapper
Defined in:
lib/carrierwave/mount.rb

Overview

If a Class is extended with this module, it gains the mount_uploader method, which is used for mapping attributes to uploaders and allowing easy assignment.

You can use mount_uploader with pretty much any class, however it is intended to be used with some kind of persistent storage, like an ORM. If you want to persist the uploaded files in a particular Class, it needs to implement a ‘read_uploader` and a `write_uploader` method.

Defined Under Namespace

Modules: Extension

Instance Method Summary collapse

Instance Method Details

#mount_uploader(column, uploader = nil, &block) ⇒ Object

Mounts the given uploader on the given column. This means that assigning and reading from the column will upload and retrieve files. Supposing that a User class has an uploader mounted on image, you can assign and retrieve files like this:

@user.image # => <Uploader>
@user.image = some_file_object

@user.store_image!

@user.image.url # => '/some_url.png'

It is also possible (but not recommended) to ommit the uploader, which will create an anonymous uploader class. Passing a block to this method makes it possible to customize it. This can be convenient for brevity, but if there is any significatnt logic in the uploader, you should do the right thing and have it in its own file.

Examples:

class Song
  mount_uploader :lyrics, LyricsUploader
  mount_uploader :file, SongUploader
end
class Data
  # this will add an anonymous uploader with only
  # the default settings
  mount_uploader :csv
end
class Product
  # this will add an anonymous uploader overriding
  # the store_dir
  mount_uploader :blueprint do
    def store_dir
      'blueprints'
    end
  end
end

Parameters:

  • column (Symbol) —

    the attribute to mount this uploader on

  • uploader (CarrierWave::Uploader) (defaults to: nil) —

    the uploader class to mount

  • &block (Proc) —

    customize anonymous uploaders



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# File 'lib/carrierwave/mount.rb', line 66

def mount_uploader(column, uploader=nil, &block)
  unless uploader
    uploader = Class.new(CarrierWave::Uploader)
    uploader.class_eval(&block)
  end

  uploaders[column.to_sym] = uploader

  include CarrierWave::Mount::Extension

  class_eval <<-EOF, __FILE__, __LINE__+1
    def #{column}                                     # def image
      get_uploader(:#{column})                        #   get_uploader(:image)
    end                                               # end
                                                      #
    def #{column}=(new_file)                          # def image=(new_file)
      set_uploader(:#{column}, new_file)              #   set_uploader(:image, new_file)
    end                                               # end
                                                      #
    def #{column}_cache                               # def image_cache
      get_uploader_cache(:#{column})                  #   get_uploader_cache(:image)
    end                                               # end
                                                      #
    def #{column}_cache=(cache_name)                  # def image_cache=(cache_name)
      set_uploader_cache(:#{column}, cache_name)      #   set_uploader_cache(:image, cache_name)
    end                                               # end
                                                      #
    def store_#{column}!                              # def store_image!
      store_uploader!(:#{column})                     #   store_uploader!(:image)
    end                                               # end
  EOF

  after_mount(column, uploader) if respond_to?(:after_mount)
end

#uploaders ⇒ Hash{Symbol => CarrierWave}

Returns what uploaders are mounted on which columns.

Returns:

  • (Hash{Symbol => CarrierWave}) —

    what uploaders are mounted on which columns



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# File 'lib/carrierwave/mount.rb', line 18

def uploaders
  @uploaders ||= {}
end