Provides a macro for defining uploadable fields.

When calling uploadable_field/2, two fields are created:

• a virtual field is created named by the given name prefixed by "uploaded_" and holds the Plug.Upload struct (representing the uploaded file).

• a field with the given name is created holding the casted Plug.Upload struct (typically the struct is casted into a filename).

  The code below

  uploadable_field :image

  will generate

  field :image, :string
  field :uploaded_image, :any, virtual: true

Using this module (use) provides the caller module with the function get_uploadable_fields\0 listing all the uploadable fields and their options.

The following options may be given to uploadable fields:

• :cast: a function that casts a Plug.Upload struct into the value to be stored in the database.
• directory: the base directory containing the file uploads.
• filename: a function that generates the filename based on the given struct.

• on_file_exists: specifies the strategy to apply if the file path already exists. Its value may be:

  • :overwrite: overwrite the file if the file path already exists
  • :compare_hash: do not copy the file if the file path already exists; if the hashes of the files' content are not equal, return an error.
• print: a function that prints the field (typically used be the view).
• type: the field type.