Module: Paperclip::ClassMethods

Defined in:
lib/dm-paperclip.rb

Instance Method Summary collapse

Instance Method Details

#attachment_definitions ⇒ Object

Returns the attachment definitions defined by each call to has_attached_file.



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# File 'lib/dm-paperclip.rb', line 335

def attachment_definitions
  read_inheritable_attribute(:attachment_definitions)
end

#has_attached_file(name, options = {}) ⇒ Object

has_attached_file gives the class it is called on an attribute that maps to a file. This is typically a file stored somewhere on the filesystem and has been uploaded by a user. The attribute returns a Paperclip::Attachment object which handles the management of that file. The intent is to make the attachment as much like a normal attribute. The thumbnails will be created when the new file is assigned, but they will not be saved until save is called on the record. Likewise, if the attribute is set to nil is called on it, the attachment will not be deleted until save is called. See the Paperclip::Attachment documentation for more specifics. There are a number of options you can set to change the behavior of a Paperclip attachment:

  • url: The full URL of where the attachment is publically accessible. This can just as easily point to a directory served directly through Apache as it can to an action that can control permissions. You can specify the full domain and path, but usually just an absolute path is sufficient. The leading slash must be included manually for absolute paths. The default value is “/:class/:attachment/:id/:style_:filename”. See Paperclip::Attachment#interpolate for more information on variable interpolaton.

    :url => "/:attachment/:id/:style_:basename:extension"
:url => "http://some.other.host/stuff/:class/:id_:extension"

  • default_url: The URL that will be returned if there is no attachment assigned. This field is interpolated just as the url is. The default value is “/:class/:attachment/missing_:style.png”

    has_attached_file :avatar, :default_url => "/images/default_:style_avatar.png"
User.new.avatar_url(:small) # => "/images/default_small_avatar.png"

  • styles: A hash of thumbnail styles and their geometries. You can find more about geometry strings at the ImageMagick website (www.imagemagick.org/script/command-line-options.php#resize). Paperclip also adds the “#” option (e.g. “50x50#”), which will resize the image to fit maximally inside the dimensions and then crop the rest off (weighted at the center). The default value is to generate no thumbnails.

  • default_style: The thumbnail style that will be used by default URLs. Defaults to original.

    has_attached_file :avatar, :styles => { :normal => "100x100#" },
                  :default_style => :normal
user.avatar.url # => "/avatars/23/normal_me.png"

  • whiny_thumbnails: Will raise an error if Paperclip cannot process thumbnails of an uploaded image. This will ovrride the global setting for this attachment. Defaults to true.

  • convert_options: When creating thumbnails, use this free-form options field to pass in various convert command options. Typical options are “-strip” to remove all Exif data from the image (save space for thumbnails and avatars) or “-depth 8” to specify the bit depth of the resulting conversion. See ImageMagick convert documentation for more options: (www.imagemagick.org/script/convert.php) Note that this option takes a hash of options, each of which correspond to the style of thumbnail being generated. You can also specify :all as a key, which will apply to all of the thumbnails being generated. If you specify options for the :original, it would be best if you did not specify destructive options, as the intent of keeping the original around is to regenerate all the thumbnails then requirements change.

    has_attached_file :avatar, :styles => { :large => "300x300", :negative => "100x100" }
                           :convert_options => {
                             :all => "-strip",
                             :negative => "-negate"
                           }

  • storage: Chooses the storage backend where the files will be stored. The current choices are :filesystem and :s3. The default is :filesystem. Make sure you read the documentation for Paperclip::Storage::Filesystem and Paperclip::Storage::S3 for backend-specific options.



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# File 'lib/dm-paperclip.rb', line 294

def has_attached_file name, options = {}
  include InstanceMethods

  self.attachment_definitions = {} if self.attachment_definitions.nil?
  self.attachment_definitions[name] = {:validations => []}.merge(options)
  
  property_options = options.delete_if { |k,v| ![ :public, :protected, :private, :accessor, :reader, :writer ].include?(key) }

  property :"#{name}_file_name",    String,   property_options.merge(:length => 255)
  property :"#{name}_content_type", String,   property_options.merge(:length => 255)
  property :"#{name}_file_size",    Integer,  property_options
  property :"#{name}_updated_at",   DateTime, property_options

  after :save, :save_attached_files
  before :destroy, :destroy_attached_files
  
  # not needed with extlib just do before :post_process, or after :post_process
  # define_callbacks :before_post_process, :after_post_process
  # define_callbacks :"before_#{name}_post_process", :"after_#{name}_post_process"

  define_method name do |*args|
    a = attachment_for(name)
    (args.length > 0) ? a.to_s(args.first) : a
  end

  define_method "#{name}=" do |file|
    attachment_for(name).assign(file)
  end

  define_method "#{name}?" do
    ! attachment_for(name).original_filename.blank?
  end

  if Paperclip.config.use_dm_validations
    add_validator_to_context(opts_from_validator_args([name]), [name], Paperclip::Validate::CopyAttachmentErrors)
  end

end