decidim · tramuntanal · Dec 3, 2020 · Dec 1, 2020 · Dec 2, 2020
diff --git a/decidim-core/lib/decidim/core/engine.rb b/decidim-core/lib/decidim/core/engine.rb
@@ -28,6 +28,7 @@
 require "omniauth-google-oauth2"
 require "invisible_captcha"
 require "premailer/rails"
+require "premailer/adapter/decidim"
 require "geocoder"
 require "paper_trail"
 require "cells/rails"
@@ -507,6 +508,10 @@ class Engine < ::Rails::Engine
         NOBSPW.configuration.use_ruby_grep = true
       end
 
+      initializer "decidim.premailer" do
+        Premailer::Adapter.use = :decidim
+      end
+
       config.to_prepare do
         FoundationRailsHelper::FlashHelper.send(:include, Decidim::FlashHelperExtensions)
       end

diff --git a/decidim-core/lib/premailer/adapter/decidim.rb b/decidim-core/lib/premailer/adapter/decidim.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+class Premailer
+  module Adapter
+    # Decidim adapter for Premailer
+    module Decidim
+      include ::Premailer::Adapter::Nokogiri
+
+      # Converts the HTML document to a format suitable for plain-text e-mail.
+      #
+      # If present, uses the <body> element as its base; otherwise uses the whole document.
+      #
+      # Customized for Decidim in order to strip the inline <style> tags away
+      # from the plain text body.
+      #
+      # @return [String] a plain text.
+      def to_plain_text
+        html_src = begin
+                     @doc.at("body").inner_html
+                   rescue StandardError
+                     ""
+                   end
+
+        html_src = @doc.to_html unless html_src && html_src.present?
+
+        # remove style tags and content
+        html_src.gsub!(%r{<style.*?/style>}m, "")
+
+        convert_to_text(html_src, @options[:line_length], @html_encoding)
+      end
+    end
+  end
+end
diff --git a/decidim-core/spec/lib/premailer/adapter/decidim_spec.rb b/decidim-core/spec/lib/premailer/adapter/decidim_spec.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+describe Premailer::Adapter::Decidim do
+  let(:document) { ::Nokogiri::HTML(document_template, nil, "UTF-8", &:recover) }
+  let(:document_template) do
+    <<~HTML
+      <html>
+      <head>
+        <title>Test document</title>
+      </head>
+      <body>
+        <div class="container">
+          #{document_content}
+        </div>
+      </body>
+      </html>
+    HTML
+  end
+  let(:document_content) { "" }
+  let(:utility_class) do
+    adapter = described_class
+
+    Class.new do
+      include HtmlToPlainText
+      include adapter
+
+      def initialize(doc)
+        @doc = doc
+        @options = { line_length: 65 }
+      end
+    end
+  end
+  let(:utility) { utility_class.new(document) }
+
+  describe "#to_plain_text" do
+    let(:document_content) do
+      <<~HTML
+        <style>
+        table.button table td {
+          background: #f0f0f0 !important
+        }
+        </style>
+        <p>This is a document with an inline style tag inside the content node.</p>
+      HTML
+    end
+
+    it "strips out the style tags from the document" do
+      expect(utility.to_plain_text).to eq("This is a document with an inline style tag inside the content\nnode.")
+    end
+
+    context "when the document is not wrapped within HTML body" do
+      let(:document_template) { document_content }
+
+      it "strips out the style tags from the document" do
+        expect(utility.to_plain_text).to eq("This is a document with an inline style tag inside the content\nnode.")
+      end
+    end
+  end
+end