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# frozen_string_literal: true
module Roadie
# @api private
# Class that improves the markup of a HTML DOM tree
#
# This class will improve the following aspects of the DOM:
# * A HTML5 doctype will be added if missing, other doctypes will be left as-is.
# * Basic HTML elements will be added if missing.
# * `<html>`
# * `<head>`
# * `<body>`
# * `<meta>` declaring charset and content-type (text/html)
class MarkupImprover
# The original HTML must also be passed in in order to handle the doctypes
# since a +Nokogiri::HTML::Document+ will always have a doctype, no matter if
# the original source had it or not. Reading the raw HTML is the only way to
# determine if we want to add a HTML5 doctype or not.
def initialize(dom, original_html)
@dom = dom
@html = original_html
end
# @return [nil] passed DOM will be mutated
def improve
ensure_doctype_present
ensure_html_element_present
head = ensure_head_element_present
ensure_declared_charset head
end
protected
attr_reader :dom
private
def ensure_doctype_present
return if @html.include?("<!DOCTYPE ")
# Nokogiri adds a "default" doctype to the DOM, which we will remove
dom.internal_subset&.remove
dom.create_internal_subset "html", nil, nil
end
def ensure_html_element_present
return if dom.at_xpath("html")
html = Nokogiri::XML::Node.new "html", dom
dom << html
end
def ensure_head_element_present
if (head = dom.at_xpath("html/head"))
head
else
create_head_element dom.at_xpath("html")
end
end
def create_head_element(parent)
head = Nokogiri::XML::Node.new "head", dom
if parent.children.empty?
parent << head
else
# Crashes when no children are present
parent.children.before head
end
head
end
def ensure_declared_charset(parent)
if content_type_meta_element_missing?
parent.add_child make_content_type_element
end
end
def content_type_meta_element_missing?
dom.xpath("html/head/meta").none? do |meta|
meta["http-equiv"].to_s.downcase == "content-type"
end
end
def make_content_type_element
meta = Nokogiri::XML::Node.new("meta", dom)
meta["http-equiv"] = "Content-Type"
meta["content"] = "text/html; charset=UTF-8"
meta
end
end
end
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