Method: CarrierWave::Mount#mount_uploader

Defined in:: lib/carrierwave/mount.rb

#mount_uploader(column, uploader = nil, options = {}, &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.store!(some_file_object)

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

It is also possible (but not recommended) to omit the uploader, which will create an anonymous uploader class.

Passing a block makes it possible to customize the uploader. This can be convenient for brevity, but if there is any significant logic in the uploader, you should do the right thing and have it in its own file.

Added instance methods

Supposing a class has used mount_uploader to mount an uploader on a column named image, in that case the following methods will be added to the class:

image: Returns an instance of the uploader only if anything has been uploaded
image=: Caches the given file
image_url: Returns the url to the uploaded file
image_cache: Returns a string that identifies the cache location of the file
image_cache=: Retrieves the file from the cache based on the given cache name
remote_image_url: Returns previously cached remote url
remote_image_url=: Retrieve the file from the remote url
remove_image: An attribute reader that can be used with a checkbox to mark a file for removal
remove_image=: An attribute writer that can be used with a checkbox to mark a file for removal
remove_image?: Whether the file should be removed when store_image! is called.
store_image!: Stores a file that has been assigned with image=
remove_image!: Removes the uploaded file from the filesystem.
image_integrity_error: Returns an error object if the last file to be assigned caused an integrity error
image_processing_error: Returns an error object if the last file to be assigned caused a processing error
image_download_error: Returns an error object if the last file to be remotely assigned caused a download error
image_identifier: Reads out the identifier of the file

Parameters

column (Symbol): the attribute to mount this uploader on
uploader (CarrierWave::Uploader): the uploader class to mount
options (Hash=> Object): a set of options
&block (Proc): customize anonymous uploaders

Options

:mount_on => Symbol: if the name of the column to be serialized to differs you can override it using this option
:ignore_integrity_errors => Boolean: if set to true, integrity errors will result in caching failing silently
:ignore_processing_errors => Boolean: if set to true, processing errors will result in caching failing silently

Examples

Mounting uploaders on different columns.

class Song
  mount_uploader :lyrics, LyricsUploader
  mount_uploader :alternative_lyrics, LyricsUploader
  mount_uploader :file, SongUploader
end

This will add an anonymous uploader with only the default settings:

class Data
  mount_uploader :csv
end

this will add an anonymous uploader overriding the store_dir:

class Product
  mount_uploader :blueprint do
    def store_dir
      'blueprints'
    end
  end
end