"""External interface to the BeautifulSoup HTML parser.
"""
__all__ = ["fromstring", "parse", "convert_tree"]
import re
from lxml import etree, html
try:
from bs4 import (
BeautifulSoup, Tag, Comment, ProcessingInstruction, NavigableString,
Declaration, Doctype)
_DECLARATION_OR_DOCTYPE = (Declaration, Doctype)
except ImportError:
from BeautifulSoup import (
BeautifulSoup, Tag, Comment, ProcessingInstruction, NavigableString,
Declaration)
_DECLARATION_OR_DOCTYPE = Declaration
def fromstring(data, beautifulsoup=None, makeelement=None, **bsargs):
"""Parse a string of HTML data into an Element tree using the
BeautifulSoup parser.
Returns the root ``<html>`` Element of the tree.
You can pass a different BeautifulSoup parser through the
`beautifulsoup` keyword, and a diffent Element factory function
through the `makeelement` keyword. By default, the standard
``BeautifulSoup`` class and the default factory of `lxml.html` are
used.
"""
return _parse(data, beautifulsoup, makeelement, **bsargs)
def parse(file, beautifulsoup=None, makeelement=None, **bsargs):
"""Parse a file into an ElemenTree using the BeautifulSoup parser.
You can pass a different BeautifulSoup parser through the
`beautifulsoup` keyword, and a diffent Element factory function
through the `makeelement` keyword. By default, the standard
``BeautifulSoup`` class and the default factory of `lxml.html` are
used.
"""
if not hasattr(file, 'read'):
file = open(file)
root = _parse(file, beautifulsoup, makeelement, **bsargs)
return etree.ElementTree(root)
def convert_tree(beautiful_soup_tree, makeelement=None):
"""Convert a BeautifulSoup tree to a list of Element trees.
Returns a list instead of a single root Element to support
HTML-like soup with more than one root element.
You can pass a different Element factory through the `makeelement`
keyword.
"""
root = _convert_tree(beautiful_soup_tree, makeelement)
children = root.getchildren()
for child in children:
root.remove(child)
return children
# helpers
def _parse(source, beautifulsoup, makeelement, **bsargs):
if beautifulsoup is None:
beautifulsoup = BeautifulSoup
if hasattr(beautifulsoup, "HTML_ENTITIES"): # bs3
if 'convertEntities' not in bsargs:
bsargs['convertEntities'] = 'html'
if hasattr(beautifulsoup, "DEFAULT_BUILDER_FEATURES"): # bs4
if 'features' not in bsargs:
bsargs['features'] = 'html.parser' # use Python html parser
tree = beautifulsoup(source, **bsargs)
root = _convert_tree(tree, makeelement)
# from ET: wrap the document in a html root element, if necessary
if len(root) == 1 and root[0].tag == "html":
return root[0]
root.tag = "html"
return root
_parse_doctype_declaration = re.compile(
r'(?:\s|[<!])*DOCTYPE\s*HTML'
r'(?:\s+PUBLIC)?(?:\s+(\'[^\']*\'|"[^"]*"))?'
r'(?:\s+(\'[^\']*\'|"[^"]*"))?',
re.IGNORECASE).match
class _PseudoTag:
# Minimal imitation of BeautifulSoup.Tag
def __init__(self, contents):
self.name = 'html'
self.attrs = []
self.contents = contents
def __iter__(self):
return self.contents.__iter__()
def _convert_tree(beautiful_soup_tree, makeelement):
if makeelement is None:
makeelement = html.html_parser.makeelement
# Split the tree into three parts:
# i) everything before the root element: document type
# declaration, comments, processing instructions, whitespace
# ii) the root(s),
# iii) everything after the root: comments, processing
# instructions, whitespace
first_element_idx = last_element_idx = None
html_root = declaration = None
for i, e in enumerate(beautiful_soup_tree):
if isinstance(e, Tag):
if first_element_idx is None:
first_element_idx = i
last_element_idx = i
if html_root is None and e.name and e.name.lower() == 'html':
html_root = e
elif declaration is None and isinstance(e, _DECLARATION_OR_DOCTYPE):
declaration = e
# For a nice, well-formatted document, the variable roots below is
# a list consisting of a single <html> element. However, the document
# may be a soup like '<meta><head><title>Hello</head><body>Hi
# all<\p>'. In this example roots is a list containing meta, head
# and body elements.
if first_element_idx is None:
pre_root = post_root = []
roots = beautiful_soup_tree.contents
else:
pre_root = beautiful_soup_tree.contents[:first_element_idx]
roots = beautiful_soup_tree.contents[first_element_idx:last_element_idx+1]
post_root = beautiful_soup_tree.contents[last_element_idx+1:]
# Reorganize so that there is one <html> root...
if html_root is not None:
# ... use existing one if possible, ...
i = roots.index(html_root)
html_root.contents = roots[:i] + html_root.contents + roots[i+1:]
else:
# ... otherwise create a new one.
html_root = _PseudoTag(roots)
convert_node = _init_node_converters(makeelement)
# Process pre_root
res_root = convert_node(html_root)
prev = res_root
for e in reversed(pre_root):
converted = convert_node(e)
if converted is not None:
prev.addprevious(converted)
prev = converted
# ditto for post_root
prev = res_root
for e in post_root:
converted = convert_node(e)
if converted is not None:
prev.addnext(converted)
prev = converted
if declaration is not None:
try:
# bs4 provides full Doctype string
doctype_string = declaration.output_ready()
except AttributeError:
doctype_string = declaration.string
match = _parse_doctype_declaration(doctype_string)
if not match:
# Something is wrong if we end up in here. Since soupparser should
# tolerate errors, do not raise Exception, just let it pass.
pass
else:
external_id, sys_uri = match.groups()
docinfo = res_root.getroottree().docinfo
# strip quotes and update DOCTYPE values (any of None, '', '...')
docinfo.public_id = external_id and external_id[1:-1]
docinfo.system_url = sys_uri and sys_uri[1:-1]
return res_root
def _init_node_converters(makeelement):
converters = {}
ordered_node_types = []
def converter(*types):
def add(handler):
for t in types:
converters[t] = handler
ordered_node_types.append(t)
return handler
return add
def find_best_converter(node):
for t in ordered_node_types:
if isinstance(node, t):
return converters[t]
return None
def convert_node(bs_node, parent=None):
# duplicated in convert_tag() below
try:
handler = converters[type(bs_node)]
except KeyError:
handler = converters[type(bs_node)] = find_best_converter(bs_node)
if handler is None:
return None
return handler(bs_node, parent)
def map_attrs(bs_attrs):
if isinstance(bs_attrs, dict): # bs4
attribs = {}
for k, v in bs_attrs.items():
if isinstance(v, list):
v = " ".join(v)
attribs[k] = unescape(v)
else:
attribs = dict((k, unescape(v)) for k, v in bs_attrs)
return attribs
def append_text(parent, text):
if len(parent) == 0:
parent.text = (parent.text or '') + text
else:
parent[-1].tail = (parent[-1].tail or '') + text
# converters are tried in order of their definition
@converter(Tag, _PseudoTag)
def convert_tag(bs_node, parent):
attrs = bs_node.attrs
if parent is not None:
attribs = map_attrs(attrs) if attrs else None
res = etree.SubElement(parent, bs_node.name, attrib=attribs)
else:
attribs = map_attrs(attrs) if attrs else {}
res = makeelement(bs_node.name, attrib=attribs)
for child in bs_node:
# avoid double recursion by inlining convert_node(), see above
try:
handler = converters[type(child)]
except KeyError:
pass
else:
if handler is not None:
handler(child, res)
continue
convert_node(child, res)
return res
@converter(Comment)
def convert_comment(bs_node, parent):
res = html.HtmlComment(bs_node)
if parent is not None:
parent.append(res)
return res
@converter(ProcessingInstruction)
def convert_pi(bs_node, parent):
if bs_node.endswith('?'):
# The PI is of XML style (<?as df?>) but BeautifulSoup
# interpreted it as being SGML style (<?as df>). Fix.
bs_node = bs_node[:-1]
res = etree.ProcessingInstruction(*bs_node.split(' ', 1))
if parent is not None:
parent.append(res)
return res
@converter(NavigableString)
def convert_text(bs_node, parent):
if parent is not None:
append_text(parent, unescape(bs_node))
return None
return convert_node
# copied from ET's ElementSoup
try:
from html.entities import name2codepoint # Python 3
except ImportError:
from htmlentitydefs import name2codepoint
handle_entities = re.compile(r"&(\w+);").sub
try:
unichr
except NameError:
# Python 3
unichr = chr
def unescape(string):
if not string:
return ''
# work around oddities in BeautifulSoup's entity handling
def unescape_entity(m):
try:
return unichr(name2codepoint[m.group(1)])
except KeyError:
return m.group(0) # use as is
return handle_entities(unescape_entity, string)