"""
An interface to html5lib that mimics the lxml.html interface.
"""
import sys
import string
from html5lib import HTMLParser as _HTMLParser
from html5lib.treebuilders.etree_lxml import TreeBuilder
from lxml import etree
from lxml.html import Element, XHTML_NAMESPACE, _contains_block_level_tag
# python3 compatibility
try:
_strings = basestring
except NameError:
_strings = (bytes, str)
try:
from urllib2 import urlopen
except ImportError:
from urllib.request import urlopen
try:
from urlparse import urlparse
except ImportError:
from urllib.parse import urlparse
class HTMLParser(_HTMLParser):
"""An html5lib HTML parser with lxml as tree."""
def __init__(self, strict=False, **kwargs):
_HTMLParser.__init__(self, strict=strict, tree=TreeBuilder, **kwargs)
try:
from html5lib import XHTMLParser as _XHTMLParser
except ImportError:
pass
else:
class XHTMLParser(_XHTMLParser):
"""An html5lib XHTML Parser with lxml as tree."""
def __init__(self, strict=False, **kwargs):
_XHTMLParser.__init__(self, strict=strict, tree=TreeBuilder, **kwargs)
xhtml_parser = XHTMLParser()
def _find_tag(tree, tag):
elem = tree.find(tag)
if elem is not None:
return elem
return tree.find('{%s}%s' % (XHTML_NAMESPACE, tag))
def document_fromstring(html, guess_charset=None, parser=None):
"""
Parse a whole document into a string.
If `guess_charset` is true, or if the input is not Unicode but a
byte string, the `chardet` library will perform charset guessing
on the string.
"""
if not isinstance(html, _strings):
raise TypeError('string required')
if parser is None:
parser = html_parser
options = {}
if guess_charset is None and isinstance(html, bytes):
# html5lib does not accept useChardet as an argument, if it
# detected the html argument would produce unicode objects.
guess_charset = True
if guess_charset is not None:
options['useChardet'] = guess_charset
return parser.parse(html, **options).getroot()
def fragments_fromstring(html, no_leading_text=False,
guess_charset=None, parser=None):
"""Parses several HTML elements, returning a list of elements.
The first item in the list may be a string. If no_leading_text is true,
then it will be an error if there is leading text, and it will always be
a list of only elements.
If `guess_charset` is true, the `chardet` library will perform charset
guessing on the string.
"""
if not isinstance(html, _strings):
raise TypeError('string required')
if parser is None:
parser = html_parser
options = {}
if guess_charset is None and isinstance(html, bytes):
# html5lib does not accept useChardet as an argument, if it
# detected the html argument would produce unicode objects.
guess_charset = False
if guess_charset is not None:
options['useChardet'] = guess_charset
children = parser.parseFragment(html, 'div', **options)
if children and isinstance(children[0], _strings):
if no_leading_text:
if children[0].strip():
raise etree.ParserError('There is leading text: %r' %
children[0])
del children[0]
return children
def fragment_fromstring(html, create_parent=False,
guess_charset=None, parser=None):
"""Parses a single HTML element; it is an error if there is more than
one element, or if anything but whitespace precedes or follows the
element.
If 'create_parent' is true (or is a tag name) then a parent node
will be created to encapsulate the HTML in a single element. In
this case, leading or trailing text is allowed.
If `guess_charset` is true, the `chardet` library will perform charset
guessing on the string.
"""
if not isinstance(html, _strings):
raise TypeError('string required')
accept_leading_text = bool(create_parent)
elements = fragments_fromstring(
html, guess_charset=guess_charset, parser=parser,
no_leading_text=not accept_leading_text)
if create_parent:
if not isinstance(create_parent, _strings):
create_parent = 'div'
new_root = Element(create_parent)
if elements:
if isinstance(elements[0], _strings):
new_root.text = elements[0]
del elements[0]
new_root.extend(elements)
return new_root
if not elements:
raise etree.ParserError('No elements found')
if len(elements) > 1:
raise etree.ParserError('Multiple elements found')
result = elements[0]
if result.tail and result.tail.strip():
raise etree.ParserError('Element followed by text: %r' % result.tail)
result.tail = None
return result
def fromstring(html, guess_charset=None, parser=None):
"""Parse the html, returning a single element/document.
This tries to minimally parse the chunk of text, without knowing if it
is a fragment or a document.
'base_url' will set the document's base_url attribute (and the tree's
docinfo.URL)
If `guess_charset` is true, or if the input is not Unicode but a
byte string, the `chardet` library will perform charset guessing
on the string.
"""
if not isinstance(html, _strings):
raise TypeError('string required')
doc = document_fromstring(html, parser=parser,
guess_charset=guess_charset)
# document starts with doctype or <html>, full document!
start = html[:50]
if isinstance(start, bytes):
# Allow text comparison in python3.
# Decode as ascii, that also covers latin-1 and utf-8 for the
# characters we need.
start = start.decode('ascii', 'replace')
start = start.lstrip().lower()
if start.startswith('<html') or start.startswith('<!doctype'):
return doc
head = _find_tag(doc, 'head')
# if the head is not empty we have a full document
if len(head):
return doc
body = _find_tag(doc, 'body')
# The body has just one element, so it was probably a single
# element passed in
if (len(body) == 1 and (not body.text or not body.text.strip())
and (not body[-1].tail or not body[-1].tail.strip())):
return body[0]
# Now we have a body which represents a bunch of tags which have the
# content that was passed in. We will create a fake container, which
# is the body tag, except <body> implies too much structure.
if _contains_block_level_tag(body):
body.tag = 'div'
else:
body.tag = 'span'
return body
def parse(filename_url_or_file, guess_charset=None, parser=None):
"""Parse a filename, URL, or file-like object into an HTML document
tree. Note: this returns a tree, not an element. Use
``parse(...).getroot()`` to get the document root.
If ``guess_charset`` is true, the ``useChardet`` option is passed into
html5lib to enable character detection. This option is on by default
when parsing from URLs, off by default when parsing from file(-like)
objects (which tend to return Unicode more often than not), and on by
default when parsing from a file path (which is read in binary mode).
"""
if parser is None:
parser = html_parser
if not isinstance(filename_url_or_file, _strings):
fp = filename_url_or_file
if guess_charset is None:
# assume that file-like objects return Unicode more often than bytes
guess_charset = False
elif _looks_like_url(filename_url_or_file):
fp = urlopen(filename_url_or_file)
if guess_charset is None:
# assume that URLs return bytes
guess_charset = True
else:
fp = open(filename_url_or_file, 'rb')
if guess_charset is None:
guess_charset = True
options = {}
# html5lib does not accept useChardet as an argument, if it
# detected the html argument would produce unicode objects.
if guess_charset:
options['useChardet'] = guess_charset
return parser.parse(fp, **options)
def _looks_like_url(str):
scheme = urlparse(str)[0]
if not scheme:
return False
elif (sys.platform == 'win32' and
scheme in string.ascii_letters
and len(scheme) == 1):
# looks like a 'normal' absolute path
return False
else:
return True
html_parser = HTMLParser()