add basic functionality of plugin

plugins/article_import/app/overrides/articles/upload/replace_label_with_file_format_option.html.haml.deface

@@ -0,0 +1,5 @@
+/ insert_after 'erb:contains("file_field")'
+- if FoodsoftArticleImport.enabled?
+  %label(for="articles_file")
+    %strong="select the file type you are about to upload"
+  =f.collection_select :type, FoodsoftArticleImport::FORMATS , :to_s, :to_s

plugins/article_import/app/overrides/controllers/articles_controller_override.rb

@@ -0,0 +1,16 @@
+ArticlesController.class_eval do
+  def parse_upload
+    uploaded_file = params[:articles]['file'] or raise I18n.t('articles.controller.parse_upload.no_file')
+    type = params[:articles]['type']
+    options = { filename: uploaded_file.original_filename }
+    options[:outlist_absent] = (params[:articles]['outlist_absent'] == '1')
+    options[:convert_units] = (params[:articles]['convert_units'] == '1')
+    @updated_article_pairs, @outlisted_articles, @new_articles = @supplier.sync_from_file uploaded_file.tempfile, type, options
+    if @updated_article_pairs.empty? && @outlisted_articles.empty? && @new_articles.empty?
+      redirect_to supplier_articles_path(@supplier), :notice => I18n.t('articles.controller.parse_upload.notice')
+    end
+    @ignored_article_count = 0
+  rescue => error
+    redirect_to upload_supplier_articles_path(@supplier), :alert => I18n.t('errors.general_msg', :msg => error.message)
+  end
+end

plugins/article_import/app/overrides/models/supplier_override.rb

@@ -0,0 +1,45 @@
+Supplier.class_eval do
+    # Synchronise articles with spreadsheet.
+  #
+  # @param file [File] Spreadsheet file to parse
+  # @param options [Hash] Options passed to {FoodsoftArticleImport#parse} except when listed here.
+  # @option options [Boolean] :outlist_absent Set to +true+ to remove articles not in spreadsheet.
+  # @option options [Boolean] :convert_units Omit or set to +true+ to keep current units, recomputing unit quantity and price.
+  def sync_from_file(file, type, options = {})
+    all_order_numbers = []
+    updated_article_pairs, outlisted_articles, new_articles = [], [], []
+    custom_codes_path = File.join(Rails.root, "config", "custom_codes.yml")
+    opts = options.except(:convert_units, :outlist_absent)
+    custom_codes_file_path = custom_codes_path if File.exist?(custom_codes_path)
+    FoodsoftArticleImport.parse(file, custom_file_path: custom_codes_file_path, type: type, **opts) do |new_attrs, status, line|
+      article = articles.undeleted.where(order_number: new_attrs[:order_number]).first
+      new_attrs[:article_category] = ArticleCategory.find_match(new_attrs[:article_category])
+      new_attrs[:tax] ||= FoodsoftConfig[:tax_default]
+      new_article = articles.build(new_attrs)
+      if status.nil?
+        if article.nil?
+          new_articles << new_article
+        else
+          unequal_attributes = article.unequal_attributes(new_article, options.slice(:convert_units))
+          unless unequal_attributes.empty?
+            article.attributes = unequal_attributes
+            updated_article_pairs << [article, unequal_attributes]
+          end
+        end
+      elsif status == :outlisted && article.present?
+        outlisted_articles << article
+
+      # stop when there is a parsing error
+      elsif status.is_a? String
+        # @todo move I18n key to model
+        raise I18n.t('articles.model.error_parse', :msg => status, :line => line.to_s)
+      end
+
+      all_order_numbers << article.order_number if article
+    end
+    if options[:outlist_absent]
+      outlisted_articles += articles.undeleted.where.not(order_number: all_order_numbers + [nil])
+    end
+    [updated_article_pairs, outlisted_articles, new_articles]
+  end
+end