# coding: utf-8
# frozen_string_literal: true
# This file includes code from the Nokogumbo project, whose license follows.
#
# Copyright 2013-2021 Sam Ruby, Stephen Checkoway
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
require_relative "html5/document"
require_relative "html5/document_fragment"
require_relative "html5/node"
require_relative "html5/builder"
module Nokogiri
# Convenience method for Nokogiri::HTML5::Document.parse
def self.HTML5(...)
Nokogiri::HTML5::Document.parse(...)
end
# == Usage
#
# Parse an HTML5 document:
#
# doc = Nokogiri.HTML5(input)
#
# Parse an HTML5 fragment:
#
# fragment = Nokogiri::HTML5.fragment(input)
#
# ⚠ HTML5 functionality is not available when running JRuby.
#
# == Parsing options
#
# The document and fragment parsing methods support options that are different from
# Nokogiri::HTML4::Document or Nokogiri::XML::Document.
#
# - <tt>Nokogiri.HTML5(input, url:, encoding:, **parse_options)</tt>
# - <tt>Nokogiri::HTML5.parse(input, url:, encoding:, **parse_options)</tt>
# - <tt>Nokogiri::HTML5::Document.parse(input, url:, encoding:, **parse_options)</tt>
# - <tt>Nokogiri::HTML5.fragment(input, encoding:, **parse_options)</tt>
# - <tt>Nokogiri::HTML5::DocumentFragment.parse(input, encoding:, **parse_options)</tt>
#
# The four currently supported parse options are
#
# - +max_errors:+ (Integer, default 0) Maximum number of parse errors to report in HTML5::Document#errors.
# - +max_tree_depth:+ (Integer, default +Nokogiri::Gumbo::DEFAULT_MAX_TREE_DEPTH+) Maximum tree depth to parse.
# - +max_attributes:+ (Integer, default +Nokogiri::Gumbo::DEFAULT_MAX_ATTRIBUTES+) Maximum number of attributes to parse per element.
# - +parse_noscript_content_as_text:+ (Boolean, default false) When enabled, parse +noscript+ tag content as text, mimicking the behavior of web browsers.
#
# These options are explained in the following sections.
#
# === Error reporting: +max_errors:+
#
# Nokogiri contains an experimental HTML5 parse error reporting facility. By default, no parse
# errors are reported but this can be configured by passing the +:max_errors+ option to
# HTML5.parse or HTML5.fragment.
#
# For example, this script:
#
# doc = Nokogiri::HTML5.parse('<span/>Hi there!</span foo=bar />', max_errors: 10)
# doc.errors.each do |err|
# puts(err)
# end
#
# Emits:
#
# 1:1: ERROR: Expected a doctype token
# <span/>Hi there!</span foo=bar />
# ^
# 1:1: ERROR: Start tag of nonvoid HTML element ends with '/>', use '>'.
# <span/>Hi there!</span foo=bar />
# ^
# 1:17: ERROR: End tag ends with '/>', use '>'.
# <span/>Hi there!</span foo=bar />
# ^
# 1:17: ERROR: End tag contains attributes.
# <span/>Hi there!</span foo=bar />
# ^
#
# Using <tt>max_errors: -1</tt> results in an unlimited number of errors being returned.
#
# The errors returned by HTML5::Document#errors are instances of Nokogiri::XML::SyntaxError.
#
# The {HTML standard}[https://html.spec.whatwg.org/multipage/parsing.html#parse-errors] defines a
# number of standard parse error codes. These error codes only cover the "tokenization" stage of
# parsing HTML. The parse errors in the "tree construction" stage do not have standardized error
# codes (yet).
#
# As a convenience to Nokogiri users, the defined error codes are available
# via Nokogiri::XML::SyntaxError#str1 method.
#
# doc = Nokogiri::HTML5.parse('<span/>Hi there!</span foo=bar />', max_errors: 10)
# doc.errors.each do |err|
# puts("#{err.line}:#{err.column}: #{err.str1}")
# end
# doc = Nokogiri::HTML5.parse('<span/>Hi there!</span foo=bar />',
# # => 1:1: generic-parser
# # 1:1: non-void-html-element-start-tag-with-trailing-solidus
# # 1:17: end-tag-with-trailing-solidus
# # 1:17: end-tag-with-attributes
#
# Note that the first error is +generic-parser+ because it's an error from the tree construction
# stage and doesn't have a standardized error code.
#
# For the purposes of semantic versioning, the error messages, error locations, and error codes
# are not part of Nokogiri's public API. That is, these are subject to change without Nokogiri's
# major version number changing. These may be stabilized in the future.
#
# === Maximum tree depth: +max_tree_depth:+
#
# The maximum depth of the DOM tree parsed by the various parsing methods is configurable by the
# +:max_tree_depth+ option. If the depth of the tree would exceed this limit, then an
# +ArgumentError+ is thrown.
#
# This limit (which defaults to +Nokogiri::Gumbo::DEFAULT_MAX_TREE_DEPTH+) can be removed by
# giving the option <tt>max_tree_depth: -1</tt>.
#
# html = '<!DOCTYPE html>' + '<div>' * 1000
# doc = Nokogiri.HTML5(html)
# # raises ArgumentError: Document tree depth limit exceeded
# doc = Nokogiri.HTML5(html, max_tree_depth: -1)
#
# === Attribute limit per element: +max_attributes:+
#
# The maximum number of attributes per DOM element is configurable by the +:max_attributes+
# option. If a given element would exceed this limit, then an +ArgumentError+ is thrown.
#
# This limit (which defaults to +Nokogiri::Gumbo::DEFAULT_MAX_ATTRIBUTES+) can be removed by
# giving the option <tt>max_attributes: -1</tt>.
#
# html = '<!DOCTYPE html><div ' + (1..1000).map { |x| "attr-#{x}" }.join(' # ') + '>'
# # "<!DOCTYPE html><div attr-1 attr-2 attr-3 ... attr-1000>"
# doc = Nokogiri.HTML5(html)
# # raises ArgumentError: Attributes per element limit exceeded
#
# doc = Nokogiri.HTML5(html, max_attributes: -1)
# # parses successfully
#
# === Parse +noscript+ elements' content as text: +parse_noscript_content_as_text:+
#
# By default, the content of +noscript+ elements is parsed as HTML elements. Browsers that
# support scripting parse the content of +noscript+ elements as raw text.
#
# The +:parse_noscript_content_as_text+ option causes Nokogiri to parse the content of +noscript+
# elements as a single text node.
#
# html = "<!DOCTYPE html><noscript><meta charset='UTF-8'><link rel=stylesheet href=!></noscript>"
# doc = Nokogiri::HTML5.parse(html, parse_noscript_content_as_text: true)
# pp doc.at_xpath("/html/head/noscript")
# # => #(Element:0x878c {
# # name = "noscript",
# # children = [ #(Text "<meta charset='UTF-8'><link rel=stylesheet href=!>")]
# # })
#
# In contrast, <tt>parse_noscript_content_as_text: false</tt> (the default) causes the +noscript+
# element in the previous example to have two children, a +meta+ element and a +link+ element.
#
# doc = Nokogiri::HTML5.parse(html)
# puts doc.at_xpath("/html/head/noscript")
# # => #(Element:0x96b4 {
# # name = "noscript",
# # children = [
# # #(Element:0x97e0 { name = "meta", attribute_nodes = [ #(Attr:0x990c { name = "charset", value = "UTF-8" })] }),
# # #(Element:0x9b00 {
# # name = "link",
# # attribute_nodes = [
# # #(Attr:0x9c2c { name = "rel", value = "stylesheet" }),
# # #(Attr:0x9dd0 { name = "href", value = "!" })]
# # })]
# # })
#
# == HTML Serialization
#
# After parsing HTML, it may be serialized using any of the Nokogiri::XML::Node serialization
# methods. In particular, XML::Node#serialize, XML::Node#to_html, and XML::Node#to_s will
# serialize a given node and its children. (This is the equivalent of JavaScript's
# +Element.outerHTML+.) Similarly, XML::Node#inner_html will serialize the children of a given
# node. (This is the equivalent of JavaScript's +Element.innerHTML+.)
#
# doc = Nokogiri::HTML5("<!DOCTYPE html><span>Hello world!</span>")
# puts doc.serialize
# # => <!DOCTYPE html><html><head></head><body><span>Hello world!</span></body></html>
#
# Due to quirks in how HTML is parsed and serialized, it's possible for a DOM tree to be
# serialized and then re-parsed, resulting in a different DOM. Mostly, this happens with DOMs
# produced from invalid HTML. Unfortunately, even valid HTML may not survive serialization and
# re-parsing.
#
# In particular, a newline at the start of +pre+, +listing+, and +textarea+
# elements is ignored by the parser.
#
# doc = Nokogiri::HTML5(<<-EOF)
# <!DOCTYPE html>
# <pre>
# Content</pre>
# EOF
# puts doc.at('/html/body/pre').serialize
# # => <pre>Content</pre>
#
# In this case, the original HTML is semantically equivalent to the serialized version. If the
# +pre+, +listing+, or +textarea+ content starts with two newlines, the first newline will be
# stripped on the first parse and the second newline will be stripped on the second, leading to
# semantically different DOMs. Passing the parameter <tt>preserve_newline: true</tt> will cause
# two or more newlines to be preserved. (A single leading newline will still be removed.)
#
# doc = Nokogiri::HTML5(<<-EOF)
# <!DOCTYPE html>
# <listing>
#
# Content</listing>
# EOF
# puts doc.at('/html/body/listing').serialize(preserve_newline: true)
# # => <listing>
# #
# # Content</listing>
#
# == Encodings
#
# Nokogiri always parses HTML5 using {UTF-8}[https://en.wikipedia.org/wiki/UTF-8]; however, the
# encoding of the input can be explicitly selected via the optional +encoding+ parameter. This is
# most useful when the input comes not from a string but from an IO object.
#
# When serializing a document or node, the encoding of the output string can be specified via the
# +:encoding+ options. Characters that cannot be encoded in the selected encoding will be encoded
# as {HTML numeric
# entities}[https://en.wikipedia.org/wiki/List_of_XML_and_HTML_character_entity_references].
#
# frag = Nokogiri::HTML5.fragment('<span>아는 길도 물어가라</span>')
# html = frag.serialize(encoding: 'US-ASCII')
# puts html
# # => <span>아는 길도 물어가라</span>
#
# frag = Nokogiri::HTML5.fragment(html)
# puts frag.serialize
# # => <span>아는 길도 물어가라</span>
#
# (There's a {bug}[https://bugs.ruby-lang.org/issues/15033] in all current versions of Ruby that
# can cause the entity encoding to fail. Of the mandated supported encodings for HTML, the only
# encoding I'm aware of that has this bug is <tt>'ISO-2022-JP'</tt>. We recommend avoiding this
# encoding.)
#
# == Notes
#
# * The Nokogiri::HTML5.fragment function takes a String or IO and parses it as a HTML5 document
# in a +body+ context. As a result, the +html+, +head+, and +body+ elements are removed from
# this document, and any children of these elements that remain are returned as a
# Nokogiri::HTML5::DocumentFragment; but you can pass in a different context (e.g., "html" to
# get +head+ and +body+ tags in the result).
#
# * The Nokogiri::HTML5.parse function takes a String or IO and passes it to the
# <code>gumbo_parse_with_options</code> method, using the default options. The resulting Gumbo
# parse tree is then walked.
#
# * Instead of uppercase element names, lowercase element names are produced.
#
# * Instead of returning +unknown+ as the element name for unknown tags, the original tag name is
# returned verbatim.
#
# Since v1.12.0
module HTML5
class << self
# Convenience method for Nokogiri::HTML5::Document.parse
def parse(...)
Document.parse(...)
end
# Convenience method for Nokogiri::HTML5::DocumentFragment.parse
def fragment(...)
DocumentFragment.parse(...)
end
# :nodoc:
def read_and_encode(string, encoding)
# Read the string with the given encoding.
if string.respond_to?(:read)
string = if encoding.nil?
string.read
else
string.read(encoding: encoding)
end
else
# Otherwise the string has the given encoding.
string = string.to_s
if encoding
string = string.dup
string.force_encoding(encoding)
end
end
# convert to UTF-8
if string.encoding != Encoding::UTF_8
string = reencode(string)
end
string
end
private
# Charset sniffing is a complex and controversial topic that understandably isn't done _by
# default_ by the Ruby Net::HTTP library. This being said, it is a very real problem for
# consumers of HTML as the default for HTML is iso-8859-1, most "good" producers use utf-8, and
# the Gumbo parser *only* supports utf-8.
#
# Accordingly, Nokogiri::HTML4::Document.parse provides limited encoding detection. Following
# this lead, Nokogiri::HTML5 attempts to do likewise, while attempting to more closely follow
# the HTML5 standard.
#
# http://bugs.ruby-lang.org/issues/2567
# http://www.w3.org/TR/html5/syntax.html#determining-the-character-encoding
#
def reencode(body, content_type = nil)
if body.encoding == Encoding::ASCII_8BIT
encoding = nil
# look for a Byte Order Mark (BOM)
initial_bytes = body[0..2].bytes
if initial_bytes[0..2] == [0xEF, 0xBB, 0xBF]
encoding = Encoding::UTF_8
elsif initial_bytes[0..1] == [0xFE, 0xFF]
encoding = Encoding::UTF_16BE
elsif initial_bytes[0..1] == [0xFF, 0xFE]
encoding = Encoding::UTF_16LE
end
# look for a charset in a content-encoding header
if content_type
encoding ||= content_type[/charset=["']?(.*?)($|["';\s])/i, 1]
end
# look for a charset in a meta tag in the first 1024 bytes
unless encoding
data = body[0..1023].gsub(/<!--.*?(-->|\Z)/m, "")
data.scan(/<meta.*?>/im).each do |meta|
encoding ||= meta[/charset=["']?([^>]*?)($|["'\s>])/im, 1]
end
end
# if all else fails, default to the official default encoding for HTML
encoding ||= Encoding::ISO_8859_1
# change the encoding to match the detected or inferred encoding
body = body.dup
begin
body.force_encoding(encoding)
rescue ArgumentError
body.force_encoding(Encoding::ISO_8859_1)
end
end
body.encode(Encoding::UTF_8)
end
end
end
end
require_relative "gumbo"