html5lib-python/html5lib/serializer.py at master · Sid532001/html5lib-python · GitHub

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from __future__ import absolute_import, division, unicode_literals

from six import text_type

import re

from codecs import register_error, xmlcharrefreplace_errors

from .constants import voidElements, booleanAttributes, spaceCharacters

from .constants import rcdataElements, entities, xmlEntities

from . import treewalkers, _utils

from xml.sax.saxutils import escape

_quoteAttributeSpecChars = "".join(spaceCharacters) + "\"'=<>`"

_quoteAttributeSpec = re.compile("[" + _quoteAttributeSpecChars + "]")

_quoteAttributeLegacy = re.compile("[" + _quoteAttributeSpecChars +

"\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n"

"\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15"

"\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"

"\x20\x2f\x60\xa0\u1680\u180e\u180f\u2000"

"\u2001\u2002\u2003\u2004\u2005\u2006\u2007"

"\u2008\u2009\u200a\u2028\u2029\u202f\u205f"

"\u3000]")

_encode_entity_map = {}

_is_ucs4 = len("\U0010FFFF") == 1

for k, v in list(entities.items()):

# skip multi-character entities

if ((_is_ucs4 and len(v) > 1) or

(not _is_ucs4 and len(v) > 2)):

continue

if v != "&":

if len(v) == 2:

v = _utils.surrogatePairToCodepoint(v)

else:

v = ord(v)

if v not in _encode_entity_map or k.islower():

# prefer < over &LT; and similarly for &, >, etc.

_encode_entity_map[v] = k

def htmlentityreplace_errors(exc):

if isinstance(exc, (UnicodeEncodeError, UnicodeTranslateError)):

res = []

codepoints = []

skip = False

for i, c in enumerate(exc.object[exc.start:exc.end]):

if skip:

skip = False

continue

index = i + exc.start

if _utils.isSurrogatePair(exc.object[index:min([exc.end, index + 2])]):

codepoint = _utils.surrogatePairToCodepoint(exc.object[index:index + 2])

skip = True

else:

codepoint = ord(c)

codepoints.append(codepoint)

for cp in codepoints:

e = _encode_entity_map.get(cp)

if e:

res.append("&")

res.append(e)

if not e.endswith(";"):

res.append(";")

else:

res.append("&#x%s;" % (hex(cp)[2:]))

return ("".join(res), exc.end)

else:

return xmlcharrefreplace_errors(exc)

register_error("htmlentityreplace", htmlentityreplace_errors)

def serialize(input, tree="etree", encoding=None, **serializer_opts):

"""Serializes the input token stream using the specified treewalker

:arg input: the token stream to serialize

:arg tree: the treewalker to use

:arg encoding: the encoding to use

:arg serializer_opts: any options to pass to the

:py:class:`html5lib.serializer.HTMLSerializer` that gets created

:returns: the tree serialized as a string

Example:

>>> from html5lib.html5parser import parse

>>> from html5lib.serializer import serialize

>>> token_stream = parse('<html><body><p>Hi!</p></body></html>')

>>> serialize(token_stream, omit_optional_tags=False)

'<html><head></head><body><p>Hi!</p></body></html>'

"""

# XXX: Should we cache this?

walker = treewalkers.getTreeWalker(tree)

s = HTMLSerializer(**serializer_opts)

return s.render(walker(input), encoding)

class HTMLSerializer(object):

# attribute quoting options

quote_attr_values = "legacy" # be secure by default

quote_char = '"'

use_best_quote_char = True

# tag syntax options

omit_optional_tags = True

minimize_boolean_attributes = True

use_trailing_solidus = False

space_before_trailing_solidus = True

# escaping options

escape_lt_in_attrs = False

escape_rcdata = False

resolve_entities = True

# miscellaneous options

alphabetical_attributes = False

inject_meta_charset = True

strip_whitespace = False

sanitize = False

options = ("quote_attr_values", "quote_char", "use_best_quote_char",

"omit_optional_tags", "minimize_boolean_attributes",

"use_trailing_solidus", "space_before_trailing_solidus",

"escape_lt_in_attrs", "escape_rcdata", "resolve_entities",

"alphabetical_attributes", "inject_meta_charset",

"strip_whitespace", "sanitize")

def __init__(self, **kwargs):

"""Initialize HTMLSerializer

:arg inject_meta_charset: Whether or not to inject the meta charset.

Defaults to ``True``.

:arg quote_attr_values: Whether to quote attribute values that don't

require quoting per legacy browser behavior (``"legacy"``), when

required by the standard (``"spec"``), or always (``"always"``).

Defaults to ``"legacy"``.

:arg quote_char: Use given quote character for attribute quoting.

Defaults to ``"`` which will use double quotes unless attribute

value contains a double quote, in which case single quotes are

used.

:arg escape_lt_in_attrs: Whether or not to escape ``<`` in attribute

values.

Defaults to ``False``.

:arg escape_rcdata: Whether to escape characters that need to be

escaped within normal elements within rcdata elements such as

style.

Defaults to ``False``.

:arg resolve_entities: Whether to resolve named character entities that

appear in the source tree. The XML predefined entities < >

& " ' are unaffected by this setting.

Defaults to ``True``.

:arg strip_whitespace: Whether to remove semantically meaningless

whitespace. (This compresses all whitespace to a single space

except within ``pre``.)

Defaults to ``False``.

:arg minimize_boolean_attributes: Shortens boolean attributes to give

just the attribute value, for example::

becomes::

Defaults to ``True``.

:arg use_trailing_solidus: Includes a close-tag slash at the end of the

start tag of void elements (empty elements whose end tag is

forbidden). E.g. ``<hr/>``.

Defaults to ``False``.

:arg space_before_trailing_solidus: Places a space immediately before

the closing slash in a tag using a trailing solidus. E.g.

``<hr />``. Requires ``use_trailing_solidus=True``.

Defaults to ``True``.

:arg sanitize: Strip all unsafe or unknown constructs from output.

See :py:class:`html5lib.filters.sanitizer.Filter`.

Defaults to ``False``.

:arg omit_optional_tags: Omit start/end tags that are optional.

Defaults to ``True``.

:arg alphabetical_attributes: Reorder attributes to be in alphabetical order.

Defaults to ``False``.

"""

unexpected_args = frozenset(kwargs) - frozenset(self.options)

if len(unexpected_args) > 0:

raise TypeError("__init__() got an unexpected keyword argument '%s'" % next(iter(unexpected_args)))

if 'quote_char' in kwargs:

self.use_best_quote_char = False

for attr in self.options:

setattr(self, attr, kwargs.get(attr, getattr(self, attr)))

self.errors = []

self.strict = False

def encode(self, string):

assert(isinstance(string, text_type))

if self.encoding:

return string.encode(self.encoding, "htmlentityreplace")

else:

return string

def encodeStrict(self, string):

assert(isinstance(string, text_type))

if self.encoding:

return string.encode(self.encoding, "strict")

else:

return string

def serialize(self, treewalker, encoding=None):

# pylint:disable=too-many-nested-blocks

self.encoding = encoding

in_cdata = False

self.errors = []

if encoding and self.inject_meta_charset:

from .filters.inject_meta_charset import Filter

treewalker = Filter(treewalker, encoding)

# Alphabetical attributes is here under the assumption that none of

# the later filters add or change order of attributes; it needs to be

# before the sanitizer so escaped elements come out correctly

if self.alphabetical_attributes:

from .filters.alphabeticalattributes import Filter

treewalker = Filter(treewalker)

# WhitespaceFilter should be used before OptionalTagFilter

# for maximum efficiently of this latter filter

if self.strip_whitespace:

from .filters.whitespace import Filter

treewalker = Filter(treewalker)

if self.sanitize:

from .filters.sanitizer import Filter

treewalker = Filter(treewalker)

if self.omit_optional_tags:

from .filters.optionaltags import Filter

treewalker = Filter(treewalker)

for token in treewalker:

type = token["type"]

if type == "Doctype":

doctype = "<!DOCTYPE %s" % token["name"]

if token["publicId"]:

doctype += ' PUBLIC "%s"' % token["publicId"]

elif token["systemId"]:

doctype += " SYSTEM"

if token["systemId"]:

if token["systemId"].find('"') >= 0:

if token["systemId"].find("'") >= 0:

self.serializeError("System identifier contains both single and double quote characters")

quote_char = "'"

else:

quote_char = '"'

doctype += " %s%s%s" % (quote_char, token["systemId"], quote_char)

doctype += ">"

yield self.encodeStrict(doctype)

elif type in ("Characters", "SpaceCharacters"):

if type == "SpaceCharacters" or in_cdata:

if in_cdata and token["data"].find("</") >= 0:

self.serializeError("Unexpected </ in CDATA")

yield self.encode(token["data"])

else:

yield self.encode(escape(token["data"]))

elif type in ("StartTag", "EmptyTag"):

name = token["name"]

yield self.encodeStrict("<%s" % name)

if name in rcdataElements and not self.escape_rcdata:

in_cdata = True

elif in_cdata:

self.serializeError("Unexpected child element of a CDATA element")

for (_, attr_name), attr_value in token["data"].items():

# TODO: Add namespace support here

k = attr_name

v = attr_value

yield self.encodeStrict(' ')

yield self.encodeStrict(k)

if not self.minimize_boolean_attributes or \

(k not in booleanAttributes.get(name, tuple()) and

k not in booleanAttributes.get("", tuple())):

yield self.encodeStrict("=")

if self.quote_attr_values == "always" or len(v) == 0:

quote_attr = True

elif self.quote_attr_values == "spec":

quote_attr = _quoteAttributeSpec.search(v) is not None

elif self.quote_attr_values == "legacy":

quote_attr = _quoteAttributeLegacy.search(v) is not None

else:

raise ValueError("quote_attr_values must be one of: "

"'always', 'spec', or 'legacy'")

v = v.replace("&", "&")

if self.escape_lt_in_attrs:

v = v.replace("<", "<")

if quote_attr:

quote_char = self.quote_char

if self.use_best_quote_char:

if "'" in v and '"' not in v:

quote_char = '"'

elif '"' in v and "'" not in v:

quote_char = "'"

if quote_char == "'":

v = v.replace("'", "'")

else:

v = v.replace('"', """)

yield self.encodeStrict(quote_char)

yield self.encode(v)

yield self.encodeStrict(quote_char)

else:

yield self.encode(v)

if name in voidElements and self.use_trailing_solidus:

if self.space_before_trailing_solidus:

yield self.encodeStrict(" /")

else:

yield self.encodeStrict("/")

yield self.encode(">")

elif type == "EndTag":

name = token["name"]

if name in rcdataElements:

in_cdata = False

elif in_cdata:

self.serializeError("Unexpected child element of a CDATA element")

yield self.encodeStrict("</%s>" % name)

elif type == "Comment":

data = token["data"]

if data.find("--") >= 0:

self.serializeError("Comment contains --")

yield self.encodeStrict("" % token["data"])

elif type == "Entity":

name = token["name"]

key = name + ";"

if key not in entities:

self.serializeError("Entity %s not recognized" % name)

if self.resolve_entities and key not in xmlEntities:

data = entities[key]

else:

data = "&%s;" % name

yield self.encodeStrict(data)

else:

self.serializeError(token["data"])

def render(self, treewalker, encoding=None):

"""Serializes the stream from the treewalker into a string

:arg treewalker: the treewalker to serialize

:arg encoding: the string encoding to use

:returns: the serialized tree

Example:

>>> from html5lib import parse, getTreeWalker

>>> from html5lib.serializer import HTMLSerializer

>>> token_stream = parse('<html><body>Hi!</body></html>')

>>> walker = getTreeWalker('etree')

>>> serializer = HTMLSerializer(omit_optional_tags=False)

>>> serializer.render(walker(token_stream))

'<html><head></head><body>Hi!</body></html>'

"""

if encoding:

return b"".join(list(self.serialize(treewalker, encoding)))

else:

return "".join(list(self.serialize(treewalker)))

def serializeError(self, data="XXX ERROR MESSAGE NEEDED"):

# XXX The idea is to make data mandatory.

self.errors.append(data)

if self.strict:

raise SerializeError

class SerializeError(Exception):

"""Error in serialized tree"""

pass

html5lib-python/html5lib/serializer.py at master · Sid532001/html5lib-python · GitHub

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