gh-137836: Support more RAWTEXT and PLAINTEXT elements in HTMLParser

Doc/library/html.parser.rst

@@ -15,14 +15,18 @@
 This module defines a class :class:`HTMLParser` which serves as the basis for
 parsing text files formatted in HTML (HyperText Mark-up Language) and XHTML.
 
-.. class:: HTMLParser(*, convert_charrefs=True)
+.. class:: HTMLParser(*, convert_charrefs=True, scripting=False)
 
  Create a parser instance able to parse invalid markup.
 
- If *convert_charrefs* is ``True`` (the default), all character
- references (except the ones in ``script``/``style`` elements) are
+ If *convert_charrefs* is true (the default), all character
+ references (except the ones in elements like ``script`` and ``style``) are
  automatically converted to the corresponding Unicode characters.
 
+ If *scripting* is false (the default), the content of the ``noscript``
+ element is parsed normally; if it's true, it's returned as is without
+ being parsed.
+
  An :class:`.HTMLParser` instance is fed HTML data and calls handler methods
  when start tags, end tags, text, comments, and other markup elements are
  encountered. The user should subclass :class:`.HTMLParser` and override its
@@ -37,6 +41,9 @@ parsing text files formatted in HTML (HyperText Mark-up Language) and XHTML.
  .. versionchanged:: 3.5
  The default value for argument *convert_charrefs* is now ``True``.
 
+ .. versionchanged:: 3.14.1
+ Added the *scripting* parameter.
+
 
 Example HTML Parser Application
 -------------------------------
@@ -161,24 +168,24 @@ implementations do nothing (except for :meth:`~HTMLParser.handle_startendtag`):
 .. method:: HTMLParser.handle_data(data)
 
  This method is called to process arbitrary data (e.g. text nodes and the
- content of ``<script>...</script>`` and ``<style>...</style>``).
+ content of elements like ``script`` and ``style``).
 
 
 .. method:: HTMLParser.handle_entityref(name)
 
  This method is called to process a named character reference of the form
  ``&name;`` (e.g. ``&gt;``), where *name* is a general entity reference
- (e.g. ``'gt'``). This method is never called if *convert_charrefs* is
-``True``.
+ (e.g. ``'gt'``).
+This method is only called if *convert_charrefs* is false.
 
 
 .. method:: HTMLParser.handle_charref(name)
 
  This method is called to process decimal and hexadecimal numeric character
  references of the form :samp:`&#{NNN};` and :samp:`&#x{NNN};`. For example, the decimal
  equivalent for ``&gt;`` is ``&#62;``, whereas the hexadecimal is ``&#x3E;``;
- in this case the method will receive ``'62'`` or ``'x3E'``. This method
- is never called if *convert_charrefs* is ``True``.
+ in this case the method will receive ``'62'`` or ``'x3E'``.
+This method is only called if *convert_charrefs* is false.
 
 
 .. method:: HTMLParser.handle_comment(data)
@@ -292,8 +299,8 @@ Parsing an element with a few attributes and a title:
  Data : Python
  End tag : h1
 
-The content of ``script`` and ``style`` elements is returned as is, without
-further parsing:
+The content of elements like ``script`` and ``style`` is returned as is,
+without further parsing:
 
 .. doctest::
 
@@ -304,10 +311,10 @@ further parsing:
  End tag : style
 
  >>> parser.feed('<script type="text/javascript">'
- ... 'alert("<strong>hello!</strong>");</script>')
+ ... 'alert("<strong>hello! &#9786;</strong>");</script>')
  Start tag: script
  attr: ('type', 'text/javascript')
- Data : alert("<strong>hello!</strong>");
+ Data : alert("<strong>hello! &#9786;</strong>");
  End tag : script
 
 Parsing comments:
@@ -336,7 +343,7 @@ correct char (note: these 3 references are all equivalent to ``'>'``):
 
 Feeding incomplete chunks to :meth:`~HTMLParser.feed` works, but
 :meth:`~HTMLParser.handle_data` might be called more than once
-(unless *convert_charrefs* is set to ``True``):
+if *convert_charrefs* is false:
 
 .. doctest::
 

Lib/html/parser.py

@@ -127,17 +127,25 @@ class HTMLParser(_markupbase.ParserBase):
  argument.
  """
 
- CDATA_CONTENT_ELEMENTS = ("script", "style")
+ # See the HTML5 specs section "13.4 Parsing HTML fragments".
+ # https://html.spec.whatwg.org/multipage/parsing.html#parsing-html-fragments
+ # CDATA_CONTENT_ELEMENTS are parsed in RAWTEXT mode
+ CDATA_CONTENT_ELEMENTS = ("script", "style", "xmp", "iframe", "noembed", "noframes")
  RCDATA_CONTENT_ELEMENTS = ("textarea", "title")
 
- def __init__(self, *, convert_charrefs=True):
+ def __init__(self, *, convert_charrefs=True, scripting=False):
  """Initialize and reset this instance.
 
- If convert_charrefs is True (the default), all character references
+ If convert_charrefs is true (the default), all character references
  are automatically converted to the corresponding Unicode characters.
+
+ If *scripting* is false (the default), the content of the
+ ``noscript`` element is parsed normally; if it's true,
+ it's returned as is without being parsed.
  """
  super().__init__()
  self.convert_charrefs = convert_charrefs
+ self.scripting = scripting
  self.reset()
 
  def reset(self):
@@ -172,7 +180,9 @@ def get_starttag_text(self):
  def set_cdata_mode(self, elem, *, escapable=False):
  self.cdata_elem = elem.lower()
  self._escapable = escapable
- if escapable and not self.convert_charrefs:
+ if self.cdata_elem == 'plaintext':
+ self.interesting = re.compile(r'\z')
+ elif escapable and not self.convert_charrefs:
  self.interesting = re.compile(r'&|</%s(?=[\t\n\r\f />])' % self.cdata_elem,
  re.IGNORECASE|re.ASCII)
  else:
@@ -444,8 +454,10 @@ def parse_starttag(self, i):
  self.handle_startendtag(tag, attrs)
  else:
  self.handle_starttag(tag, attrs)
- if tag in self.CDATA_CONTENT_ELEMENTS:
- self.set_cdata_mode(tag)
+ if (tag in self.CDATA_CONTENT_ELEMENTS or
+ (self.scripting and tag == "noscript") or
+ tag == "plaintext"):
+ self.set_cdata_mode(tag, escapable=False)
  elif tag in self.RCDATA_CONTENT_ELEMENTS:
  self.set_cdata_mode(tag, escapable=True)
  return endpos