gitlabhq/app/controllers/blob_controller.rb

# Controller for viewing a file's blame
class BlobController < ProjectResourceController
  include ExtractsPath
  include Gitlab::Encode

  # Authorize
  before_filter :authorize_read_project!
  before_filter :authorize_code_access!
  before_filter :require_non_empty_project

  before_filter :assign_ref_vars

  def show
    if @tree.is_blob?
      if @tree.text?
        encoding = detect_encoding(@tree.data)
        mime_type = encoding ? "text/plain; charset=#{encoding}" : "text/plain"
      else
        mime_type = @tree.mime_type
      end

      send_data(
        @tree.data,
        type: mime_type,
        disposition: 'inline',
        filename: @tree.name
      )
    else
      not_found!
    end
  end
end