Source code for pywb.rewrite.html_rewriter

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import re
import sys

from six.moves.html_parser import HTMLParser
from six.moves.urllib.parse import urljoin, urlsplit, urlunsplit


from pywb.rewrite.url_rewriter import UrlRewriter
from pywb.rewrite.regex_rewriters import JSRewriter, CSSRewriter

from pywb.rewrite.content_rewriter import StreamingRewriter, BaseContentRewriter

from six import text_type

import six.moves.html_parser

try:
    orig_unescape = six.moves.html_parser.unescape
    six.moves.html_parser.unescape = lambda x: x
    BaseContentRewriter.set_unescape(orig_unescape)
except:
    orig_unescape = None

    @staticmethod
    def __unescape(x):
        return HTMLParser().unescape(x)

    BaseContentRewriter.set_unescape(__unescape)


try:
    import _markupbase as markupbase
except:
    import markupbase as markupbase

# ensure invalid cond ending ']-->' closing decl
# is treated same as ']>'
markupbase._msmarkedsectionclose = re.compile(r']\s*-{0,2}>')


#=================================================================
[docs]class HTMLRewriterMixin(StreamingRewriter): """ HTML-Parsing Rewriter for custom rewriting, also delegates to rewriters for script and css """ @staticmethod def _init_rewrite_tags(defmod): rewrite_tags = { 'a': {'href': defmod}, 'applet': {'codebase': 'oe_', 'archive': 'oe_'}, 'area': {'href': defmod}, 'audio': {'src': 'oe_'}, 'base': {'href': defmod}, 'blockquote': {'cite': defmod}, 'body': {'background': 'im_'}, 'button': {'formaction': defmod}, 'command': {'icon': 'im_'}, 'del': {'cite': defmod}, 'embed': {'src': 'oe_'}, 'head': {'': defmod}, # for head rewriting 'iframe': {'src': 'if_'}, 'image': {'src': 'im_', 'xlink:href': 'im_', 'href': 'im_'}, 'img': {'src': 'im_', 'srcset': 'im_'}, 'ins': {'cite': defmod}, 'input': {'src': 'im_', 'formaction': defmod}, 'form': {'action': defmod}, 'frame': {'src': 'fr_'}, 'link': {'href': 'oe_'}, 'meta': {'content': defmod}, 'object': {'codebase': 'oe_', 'data': 'oe_'}, 'param': {'value': 'oe_'}, 'q': {'cite': defmod}, 'ref': {'href': 'oe_'}, 'script': {'src': 'js_', 'xlink:href': 'js_'}, # covers both HTML and SVG script tags 'source': {'src': 'oe_', 'srcset': 'oe_'}, 'video': {'src': 'oe_', 'poster': 'im_'}, } return rewrite_tags BEFORE_HEAD_TAGS = ['html', 'head'] DATA_RW_PROTOCOLS = ('http://', 'https://', '//') PRELOAD_TYPES = { 'script': 'js_', 'worker': 'js_', 'style': 'cs_', 'image': 'im_', 'document': 'if_', 'fetch': 'mp_', 'font': 'oe_', 'audio': 'oe_', 'video': 'oe_', 'embed': 'oe_', 'object': 'oe_', 'track': 'oe_', } #===========================
[docs] class AccumBuff: def __init__(self): self.ls = []
[docs] def write(self, string): self.ls.append(string)
[docs] def getvalue(self): return ''.join(self.ls)
# =========================== def __init__(self, url_rewriter, head_insert=None, js_rewriter_class=None, js_rewriter=None, css_rewriter=None, css_rewriter_class=None, url = '', defmod='', parse_comments=False, charset='utf-8'): super(HTMLRewriterMixin, self).__init__(url_rewriter, False) self.charset = charset self._wb_parse_context = None if js_rewriter: self.js_rewriter = js_rewriter elif js_rewriter_class: self.js_rewriter = js_rewriter_class(url_rewriter) else: self.js_rewriter = JSRewriter(url_rewriter) if css_rewriter: self.css_rewriter = css_rewriter elif css_rewriter_class: self.css_rewriter = css_rewriter_class(url_rewriter) else: self.css_rewriter = CSSRewriter(url_rewriter) self.head_insert = head_insert self.parse_comments = parse_comments self.orig_url = url self.defmod = defmod self.rewrite_tags = self._init_rewrite_tags(defmod) # get opts from urlrewriter self.opts = url_rewriter.rewrite_opts self.force_decl = self.opts.get('force_html_decl', None) self.parsed_any = False self.has_base = False # =========================== META_REFRESH_REGEX = re.compile('^[\\d.]+\\s*;\\s*url\\s*=\\s*(.+?)\\s*$', re.IGNORECASE | re.MULTILINE) ADD_WINDOW = re.compile('(?<![.])(WB_wombat_)') SRCSET_REGEX = re.compile('\s*(\S*\s+[\d\.]+[wx]),|(?:\s*,(?:\s+|(?=https?:)))') def _rewrite_srcset(self, value, mod=''): if not value: return '' values = (url.strip() for url in re.split(self.SRCSET_REGEX, value) if url) values = [self._rewrite_url(v.strip()) for v in values] return ', '.join(values) def _rewrite_meta_refresh(self, meta_refresh): if not meta_refresh: return '' m = self.META_REFRESH_REGEX.match(meta_refresh) if not m: return meta_refresh meta_refresh = (meta_refresh[:m.start(1)] + self._rewrite_url(m.group(1)) + meta_refresh[m.end(1):]) return meta_refresh def _rewrite_base(self, url, mod=''): if not url: return '' url = self._ensure_url_has_path(url) base_url = self._rewrite_url(url, mod) self.url_rewriter = self.url_rewriter.rebase_rewriter(url) self.has_base = True if self.opts.get('rewrite_base', True): return base_url else: return url def _write_default_base(self): if not self.orig_url: return base_url = self._ensure_url_has_path(self.orig_url) # write default base only if different from implicit base if self.orig_url != base_url: base_url = self._rewrite_url(base_url) self.out.write('<base href="{0}"/>'.format(base_url)) self.has_base = True def _ensure_url_has_path(self, url): """ ensure the url has a path component eg. http://example.com#abc converted to http://example.com/#abc """ inx = url.find('://') if inx > 0: rest = url[inx + 3:] elif url.startswith('//'): rest = url[2:] else: rest = url if '/' in rest: return url scheme, netloc, path, query, frag = urlsplit(url) if not path: path = '/' url = urlunsplit((scheme, netloc, path, query, frag)) return url def _rewrite_url(self, value, mod=None, force_abs=False): if not value: return '' value = value.strip() if not value: return '' orig_value = value # if not utf-8, then stream was encoded as iso-8859-1, and need to reencode # into correct charset if self.charset != 'utf-8' and self.charset != 'iso-8859-1': try: value = value.encode('iso-8859-1').decode(self.charset) except: pass unesc_value = self.try_unescape(value) rewritten_value = self.url_rewriter.rewrite(unesc_value, mod, force_abs) # if no rewriting has occured, ensure we return original, not reencoded value if rewritten_value == value: return orig_value if unesc_value != value and rewritten_value != unesc_value: rewritten_value = rewritten_value.replace(unesc_value, value) return rewritten_value
[docs] def try_unescape(self, value): if '&#' not in value: return value try: if orig_unescape: new_value = orig_unescape(value) else: new_value = HTMLParser.unescape(self, value) except Exception as e: return value return new_value
def _rewrite_css(self, css_content): if not css_content: return '' unesc_css = self.try_unescape(css_content) rw_css = self.css_rewriter.rewrite_complete(unesc_css) if unesc_css == rw_css: return css_content else: return rw_css def _rewrite_script(self, script_content, inline_attr=False): if not script_content: return '' content = self.js_rewriter.rewrite_complete(script_content, inline_attr=inline_attr) if inline_attr: content = self.ADD_WINDOW.sub('window.\\1', content) return content
[docs] def has_attr(self, tag_attrs, attr): name, value = attr attr_value = self.get_attr(tag_attrs, name) if attr_value is None: return False return attr_value.lower() == value.lower()
[docs] def get_attr(self, tag_attrs, match_name): for attr_name, attr_value in tag_attrs: if attr_name == match_name: return attr_value return None
def _rewrite_tag_attrs(self, tag, tag_attrs, set_parsing_context=True): """Rewrite a tags attributes. If set_parsing_context is false then the parsing context will not set. If the head insert has not been added to the HTML being rewritten, there is no parsing context and the tag is not in BEFORE_HEAD_TAGS then the head_insert will be "inserted" and set to None :param str tag: The name of the tag to be rewritten :param list[tuple[str, str]] tag_attrs: A list of tuples representing the tags attributes :param bool set_parsing_context: Boolean indicating if the parsing context should be set :return: True :rtype: bool """ # special case: head insertion, before-head tags if (self.head_insert and not self._wb_parse_context and (tag not in self.BEFORE_HEAD_TAGS)): self.out.write(self.head_insert) self.head_insert = None if set_parsing_context: self._set_parse_context(tag, tag_attrs) # attr rewriting handler = self.rewrite_tags.get(tag) if not handler: handler = {} self.out.write('<' + tag) for attr_name, attr_value in tag_attrs: empty_attr = False if attr_value is None: attr_value = '' empty_attr = True # special case: inline JS/event handler if ((attr_value and attr_value.startswith('javascript:')) or attr_name.startswith('on') and attr_name[2:3] != '-'): attr_value = self._rewrite_script(attr_value, True) # special case: inline CSS/style attribute elif attr_name == 'style': attr_value = self._rewrite_css(attr_value) # special case: deprecated background attribute elif attr_name == 'background': rw_mod = 'im_' attr_value = self._rewrite_url(attr_value, rw_mod) # special case: srcset list elif attr_name == 'srcset': rw_mod = handler.get(attr_name, '') attr_value = self._rewrite_srcset(attr_value, rw_mod) # special case: disable crossorigin and integrity attr # as they may interfere with rewriting semantics elif attr_name in ('crossorigin', 'integrity'): attr_name = '_' + attr_name # special case: if rewrite_canon not set, # don't rewrite rel=canonical elif tag == 'link' and attr_name == 'href': rw_mod = handler.get(attr_name) attr_value = self._rewrite_link_href(attr_value, tag_attrs, rw_mod) # special case: meta tag elif (tag == 'meta') and (attr_name == 'content'): if self.has_attr(tag_attrs, ('http-equiv', 'refresh')): attr_value = self._rewrite_meta_refresh(attr_value) elif self.has_attr(tag_attrs, ('http-equiv', 'content-security-policy')): attr_name = '_' + attr_name elif self.has_attr(tag_attrs, ('name', 'referrer')): attr_value = 'no-referrer-when-downgrade' elif attr_value.startswith(self.DATA_RW_PROTOCOLS): rw_mod = handler.get(attr_name) attr_value = self._rewrite_url(attr_value, rw_mod) # special case: param value, conditional rewrite elif (tag == 'param'): if attr_value.startswith(self.DATA_RW_PROTOCOLS): rw_mod = handler.get(attr_name) attr_value = self._rewrite_url(attr_value, rw_mod) # special case: base tag elif (tag == 'base') and (attr_name == 'href') and attr_value: rw_mod = handler.get(attr_name) attr_value = self._rewrite_base(attr_value, rw_mod) elif attr_name == 'href': rw_mod = self.defmod attr_value = self._rewrite_url(attr_value, rw_mod) elif tag == 'script' and attr_name == 'src': rw_mod = handler.get(attr_name) ov = attr_value attr_value = self._rewrite_url(attr_value, rw_mod) if attr_value == ov and not ov.startswith(self.url_rewriter.NO_REWRITE_URI_PREFIX): # URL not skipped, likely src='js/....', forcing abs to make sure, cause PHP MIME(JS) === HTML attr_value = self._rewrite_url(attr_value, rw_mod, True) self._write_attr('__wb_orig_src', ov, empty_attr=None) else: # rewrite url using tag handler rw_mod = handler.get(attr_name) if rw_mod is not None: attr_value = self._rewrite_url(attr_value, rw_mod) # write the attr! self._write_attr(attr_name, attr_value, empty_attr) return True def _rewrite_link_href(self, attr_value, tag_attrs, rw_mod): # rel="canonical" rel = self.get_attr(tag_attrs, 'rel') if rel == 'canonical': if self.opts.get('rewrite_rel_canon', True): return self._rewrite_url(attr_value, rw_mod) else: # resolve relative rel=canonical URLs so that they # refer to the same absolute URL as on the original # page (see https://github.com/hypothesis/via/issues/65 # for context) return urljoin(self.orig_url, attr_value) # find proper mod for preload elif rel == 'preload': preload = self.get_attr(tag_attrs, 'as') rw_mod = self.PRELOAD_TYPES.get(preload, rw_mod) # for html imports with an optional as (google exclusive) elif rel == 'import' or rel == 'alternate': rw_mod = 'mp_' elif rel == 'stylesheet': rw_mod = 'cs_' return self._rewrite_url(attr_value, rw_mod) def _set_parse_context(self, tag, tag_attrs): # special case: script or style parse context if not self._wb_parse_context: if tag == 'style': self._wb_parse_context = 'style' elif tag == 'script': if self._allow_js_type(tag_attrs): self._wb_parse_context = 'script' def _allow_js_type(self, tag_attrs): type_value = self.get_attr(tag_attrs, 'type') if not type_value: return True type_value = type_value.lower() if 'javascript' in type_value: return True if 'ecmascript' in type_value: return True return False def _rewrite_head(self, start_end): # special case: head tag # if no insert or in context, no rewrite if not self.head_insert or self._wb_parse_context: return False self.out.write('>') self.out.write(self.head_insert) self.head_insert = None if start_end: if not self.has_base: self._write_default_base() self.out.write('</head>') return True def _write_attr(self, name, value, empty_attr): # if empty_attr is set, just write 'attr'! if empty_attr: self.out.write(' ' + name) # write with value, if set elif value: self.out.write(' ' + name + '="' + value.replace('"', '&quot;') + '"') # otherwise, 'attr=""' is more common, so use that form else: self.out.write(' ' + name + '=""')
[docs] def parse_data(self, data): if self._wb_parse_context == 'script': data = self._rewrite_script(data) elif self._wb_parse_context == 'style': data = self._rewrite_css(data) self.out.write(data)
[docs] def rewrite(self, string): self.out = self.AccumBuff() self.feed(string) result = self.out.getvalue() # track that something was parsed self.parsed_any = self.parsed_any or bool(string) # Clear buffer to create new one for next rewrite() self.out = None if self.force_decl: result = self.force_decl + '\n' + result self.force_decl = None return result
[docs] def final_read(self): self.out = self.AccumBuff() self._internal_close() result = self.out.getvalue() # Clear buffer to create new one for next rewrite() self.out = None return result
[docs] def close(self): return self.final_read()
def _internal_close(self): # pragma: no cover raise NotImplementedError('Base method')
#=================================================================
[docs]class HTMLRewriter(HTMLRewriterMixin, HTMLParser): PARSETAG = re.compile('[<]') def __init__(self, *args, **kwargs): if sys.version_info > (3,4): #pragma: no cover HTMLParser.__init__(self, convert_charrefs=False) else: #pragma: no cover HTMLParser.__init__(self) super(HTMLRewriter, self).__init__(*args, **kwargs)
[docs] def reset(self): HTMLParser.reset(self) self.interesting = self.PARSETAG
[docs] def clear_cdata_mode(self): HTMLParser.clear_cdata_mode(self) self.interesting = self.PARSETAG
[docs] def feed(self, string): try: HTMLParser.feed(self, string) except Exception as e: # pragma: no cover import traceback traceback.print_exc() self.out.write(string)
def _internal_close(self): if (self._wb_parse_context): end_tag = '</' + self._wb_parse_context + '>' self.feed(end_tag) self._wb_parse_context = None # if haven't insert head_insert, but wrote some content # out, then insert head_insert now if self.head_insert and self.parsed_any: self.out.write(self.head_insert) self.head_insert = None try: HTMLParser.close(self) except Exception: # pragma: no cover # only raised in 2.6 pass # called to unescape attrs -- do not unescape!
[docs] def unescape(self, s): return s
[docs] def handle_starttag(self, tag, attrs): self._rewrite_tag_attrs(tag, attrs) if tag != 'head' or not self._rewrite_head(False): self.out.write('>')
[docs] def handle_startendtag(self, tag, attrs): self._rewrite_tag_attrs(tag, attrs, False) if tag != 'head' or not self._rewrite_head(True): self.out.write('/>')
[docs] def handle_endtag(self, tag): if (tag == self._wb_parse_context): self._wb_parse_context = None if tag == 'head' and not self.has_base: self._write_default_base() self.out.write('</' + tag + '>')
[docs] def handle_data(self, data): self.parse_data(data)
# overriding regex so that these are no longer called #def handle_entityref(self, data): # self.out.write('&' + data + ';') #def handle_charref(self, data): # self.out.write('&#' + data + ';')
[docs] def handle_comment(self, data): self.out.write('<!--') if self.parse_comments: #data = self._rewrite_script(data) # Rewrite with seperate HTMLRewriter comment_rewriter = HTMLRewriter(self.url_rewriter, defmod=self.defmod) data = comment_rewriter.rewrite_complete(data) self.out.write(data) else: self.parse_data(data) self.out.write('-->')
[docs] def handle_decl(self, data): self.out.write('<!' + data + '>') self.force_decl = None
[docs] def handle_pi(self, data): self.out.write('<?' + data + '>')
[docs] def unknown_decl(self, data): self.out.write('<![') self.parse_data(data) self.out.write(']>')