Returns the attachment definitions defined by each call to has_attached_file.

[Source]

     # File lib/paperclip.rb, line 201
201:     def attachment_definitions
202:       read_inheritable_attribute(:attachment_definitions)
203:     end

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.
• 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.

[Source]

     # File lib/paperclip.rb, line 113
113:     def has_attached_file name, options = {}
114:       include InstanceMethods
115: 
116:       write_inheritable_attribute(:attachment_definitions, {}) if attachment_definitions.nil?
117:       attachment_definitions[name] = {:validations => []}.merge(options)
118: 
119:       after_save :save_attached_files
120:       before_destroy :destroy_attached_files
121: 
122:       define_method name do |*args|
123:         a = attachment_for(name)
124:         (args.length > 0) ? a.to_s(args.first) : a
125:       end
126: 
127:       define_method "#{name}=" do |file|
128:         attachment_for(name).assign(file)
129:       end
130: 
131:       define_method "#{name}?" do
132:         ! attachment_for(name).original_filename.blank?
133:       end
134: 
135:       validates_each(name) do |record, attr, value|
136:         value.send(:flush_errors)
137:       end
138:     end

Places ActiveRecord-style validations on the content type of the file assigned. The possible options are:

• content_type: Allowed content types. Can be a single content type or an array. Allows all by default.
• message: The message to display when the uploaded file has an invalid content type.

[Source]

     # File lib/paperclip.rb, line 185
185:     def validates_attachment_content_type name, options = {}
186:       attachment_definitions[name][:validations] << lambda do |attachment, instance|
187:         valid_types = [options[:content_type]].flatten
188:         
189:         unless attachment.original_filename.nil?
190:           unless options[:content_type].blank?
191:             content_type = instance["#{name}_content_type""#{name}_content_type"]
192:             unless valid_types.any?{|t| t === content_type }
193:               options[:message] || ActiveRecord::Errors.default_error_messages[:inclusion]
194:             end
195:           end
196:         end
197:       end
198:     end

Places ActiveRecord-style validations on the presence of a file.

[Source]

     # File lib/paperclip.rb, line 173
173:     def validates_attachment_presence name, options = {}
174:       attachment_definitions[name][:validations] << lambda do |attachment, instance|
175:         if attachment.original_filename.blank?
176:           options[:message] || "must be set."
177:         end
178:       end
179:     end

Places ActiveRecord-style validations on the size of the file assigned. The possible options are:

• in: a Range of bytes (i.e. +1..1.megabyte+),
• less_than: equivalent to :in => 0..options[:less_than]
• greater_than: equivalent to :in => options[:greater_than]..Infinity
• message: error message to display, use :min and :max as replacements

[Source]

     # File lib/paperclip.rb, line 146
146:     def validates_attachment_size name, options = {}
147:       attachment_definitions[name][:validations] << lambda do |attachment, instance|
148:         unless options[:greater_than].nil?
149:           options[:in] = (options[:greater_than]..(1/0)) # 1/0 => Infinity
150:         end
151:         unless options[:less_than].nil?
152:           options[:in] = (0..options[:less_than])
153:         end
154:         unless attachment.original_filename.blank? || options[:in].include?(instance["#{name}_file_size""#{name}_file_size"].to_i)
155:           min = options[:in].first
156:           max = options[:in].last
157:           
158:           if options[:message]
159:             options[:message].gsub(/:min/, min.to_s).gsub(/:max/, max.to_s)
160:           else
161:             "file size is not between #{min} and #{max} bytes."
162:           end
163:         end
164:       end
165:     end

Adds errors if thumbnail creation fails. The same as specifying :whiny_thumbnails => true.

[Source]

     # File lib/paperclip.rb, line 168
168:     def validates_attachment_thumbnails name, options = {}
169:       attachment_definitions[name][:whiny_thumbnails] = true
170:     end