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ebook-converter/ebook_converter/ebooks/oeb/polish/parsing.py

96 lines
4.1 KiB
Python

import re
from lxml.etree import Element as LxmlElement
import html5_parser
from ebook_converter import xml_replace_entities
from ebook_converter.utils.xml_parse import safe_xml_fromstring
from ebook_converter.ebooks.chardet import xml_to_unicode, strip_encoding_declarations
from ebook_converter.utils.cleantext import clean_xml_chars
__license__ = 'GPL v3'
__copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
XHTML_NS = 'http://www.w3.org/1999/xhtml'
def parse_html5(raw, decoder=None, log=None, discard_namespaces=False, line_numbers=True, linenumber_attribute=None, replace_entities=True, fix_newlines=True):
if isinstance(raw, bytes):
raw = xml_to_unicode(raw)[0] if decoder is None else decoder(raw)
if replace_entities:
raw = xml_replace_entities(raw)
if fix_newlines:
raw = raw.replace('\r\n', '\n').replace('\r', '\n')
raw = clean_xml_chars(raw)
root = html5_parser.parse(raw, maybe_xhtml=not discard_namespaces, line_number_attr=linenumber_attribute, keep_doctype=False, sanitize_names=True)
if (discard_namespaces and root.tag != 'html') or (
not discard_namespaces and (root.tag != '{%s}%s' % (XHTML_NS, 'html') or root.prefix)):
raise ValueError('Failed to parse correctly, root has tag: %s and prefix: %s' % (root.tag, root.prefix))
return root
def handle_private_entities(data):
# Process private entities
pre = ''
idx = data.find('<html')
if idx == -1:
idx = data.find('<HTML')
if idx > -1:
pre = data[:idx]
num_of_nl_in_pre = pre.count('\n')
if '<!DOCTYPE' in pre: # Handle user defined entities
user_entities = {}
for match in re.finditer(r'<!ENTITY\s+(\S+)\s+([^>]+)', pre):
val = match.group(2)
if val.startswith('"') and val.endswith('"'):
val = val[1:-1]
user_entities[match.group(1)] = val
if user_entities:
data = ('\n' * num_of_nl_in_pre) + data[idx:]
pat = re.compile(r'&(%s);'%('|'.join(user_entities.keys())))
data = pat.sub(lambda m:user_entities[m.group(1)], data)
return data
def parse(raw, decoder=None, log=None, line_numbers=True, linenumber_attribute=None, replace_entities=True, force_html5_parse=False):
if isinstance(raw, bytes):
raw = xml_to_unicode(raw)[0] if decoder is None else decoder(raw)
raw = handle_private_entities(raw)
if replace_entities:
raw = xml_replace_entities(raw).replace('\0', '') # Handle &#0;
raw = raw.replace('\r\n', '\n').replace('\r', '\n')
# Remove any preamble before the opening html tag as it can cause problems,
# especially doctypes, preserve the original linenumbers by inserting
# newlines at the start
pre = raw[:2048]
for match in re.finditer(r'<\s*html', pre, flags=re.I):
newlines = raw.count('\n', 0, match.start())
raw = ('\n' * newlines) + raw[match.start():]
break
raw = strip_encoding_declarations(raw, limit=10*1024, preserve_newlines=True)
if force_html5_parse:
return parse_html5(raw, log=log, line_numbers=line_numbers, linenumber_attribute=linenumber_attribute, replace_entities=False, fix_newlines=False)
try:
ans = safe_xml_fromstring(raw, recover=False)
if ans.tag != '{%s}html' % XHTML_NS:
raise ValueError('Root tag is not <html> in the XHTML namespace')
if linenumber_attribute:
for elem in ans.iter(LxmlElement):
if elem.sourceline is not None:
elem.set(linenumber_attribute, str(elem.sourceline))
return ans
except Exception:
if log is not None:
log.exception('Failed to parse as XML, parsing as tag soup')
return parse_html5(raw, log=log, line_numbers=line_numbers, linenumber_attribute=linenumber_attribute, replace_entities=False, fix_newlines=False)
if __name__ == '__main__':
from lxml import etree
root = parse_html5('\n<html><head><title>a\n</title><p b=1 c=2 a=0>&nbsp;\n<b>b<svg ass="wipe" viewbox="0">', discard_namespaces=False)
print(etree.tostring(root, encoding='utf-8'))
print()