1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
|
# Copyright (C) 2001-2014 Bastian Kleineidam
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
"""
Find link tags in HTML text.
"""
import re
from .srcsetparse import parse_srcset
from .. import strformat, log, LOG_CHECK, url as urlutil
unquote = strformat.unquote
# HTML4/5 link tags
# ripped mainly from HTML::Tagset.pm with HTML5 added
LinkTags = {
'a': ['href'],
'applet': ['archive', 'src'],
'area': ['href'],
'audio': ['src'], # HTML5
'bgsound': ['src'],
'blockquote': ['cite'],
'body': ['background'],
'button': ['formaction'], # HTML5
'del': ['cite'],
'embed': ['pluginspage', 'src'],
'form': ['action'],
'frame': ['src', 'longdesc'],
'head': ['profile'],
'html': ['manifest'], # HTML5
'iframe': ['src', 'longdesc'],
'ilayer': ['background'],
'img': ['src', 'lowsrc', 'longdesc', 'usemap', 'srcset'],
'input': ['src', 'usemap', 'formaction'],
'ins': ['cite'],
'isindex': ['action'],
'layer': ['background', 'src'],
'link': ['href'],
'meta': ['content', 'href'],
'object': ['classid', 'data', 'archive', 'usemap', 'codebase'],
'q': ['cite'],
'script': ['src'],
'source': ['src'], # HTML5
'table': ['background'],
'td': ['background'],
'th': ['background'],
'tr': ['background'],
'track': ['src'], # HTML5
'video': ['src'], # HTML5
'xmp': ['href'],
None: ['style', 'itemtype'],
}
# HTML anchor tags
AnchorTags = {
'a': ['name'],
None: ['id'],
}
# WML tags
WmlTags = {
'a': ['href'],
'go': ['href'],
'img': ['src'],
}
# matcher for <meta http-equiv=refresh> tags
refresh_re = re.compile(r"(?i)^\d+;\s*url=(?P<url>.+)$")
_quoted_pat = r"('[^']+'|\"[^\"]+\"|[^\)\s]+)"
css_url_re = re.compile(r"url\(\s*(?P<url>%s)\s*\)" % _quoted_pat)
# Note that swf_url_re, unlike all other regular expressions here, is meant
# to match byte strings. Yes, we're scraping binary SWF data for anything
# that looks like a URL. What did you expect, a full SWF format decoder?
swf_url_re = re.compile(b"(?i)%s" % urlutil.safe_url_pattern.encode('ascii'))
c_comment_re = re.compile(r"/\*.*?\*/", re.DOTALL)
def strip_c_comments(text):
"""Remove C/CSS-style comments from text. Note that this method also
deliberately removes comments inside of strings."""
return c_comment_re.sub('', text)
def is_meta_url(attr, attrs):
"""Check if the meta attributes contain a URL."""
res = False
if attr == "content":
equiv = attrs.get('http-equiv', '').lower()
scheme = attrs.get('scheme', '').lower()
res = equiv in ('refresh',) or scheme in ('dcterms.uri',)
if attr == "href":
rel = attrs.get('rel', '').lower()
res = rel in ('shortcut icon', 'icon')
return res
def is_form_get(attr, attrs):
"""Check if this is a GET form action URL."""
res = False
if attr == "action":
method = attrs.get('method', '').lower()
res = method != 'post'
return res
class LinkFinder:
"""Find HTML links, and apply them to the callback function with the
format (url, lineno, column, name, codebase)."""
def __init__(self, callback, tags):
"""Store content in buffer and initialize URL list."""
self.callback = callback
# set universal tag attributes using tagname None
self.universal_attrs = set(tags.get(None, []))
self.tags = dict()
for tag, attrs in tags.items():
self.tags[tag] = set(attrs)
# add universal tag attributes
self.tags[tag].update(self.universal_attrs)
self.base_ref = ''
def html_element(self, tag, attrs, element_text, lineno, column):
"""Search for links and store found URLs in a list."""
log.debug(LOG_CHECK, "LinkFinder tag %s attrs %s", tag, attrs)
log.debug(LOG_CHECK, "line %d col %d", lineno, column)
if tag == "base" and not self.base_ref:
self.base_ref = attrs.get("href", '')
tagattrs = self.tags.get(tag, self.universal_attrs)
# parse URLs in tag (possibly multiple URLs in CSS styles)
for attr in sorted(tagattrs.intersection(attrs)):
if tag == "meta" and not is_meta_url(attr, attrs):
continue
if tag == "form" and not is_form_get(attr, attrs):
continue
# name of this link
name = self.get_link_name(tag, attrs, attr, element_text)
# possible codebase
base = ''
if tag == 'applet':
base = attrs.get('codebase', '')
if not base:
base = self.base_ref
# note: value can be None
value = attrs.get(attr)
if tag == 'link' and (rel := attrs.get('rel', '').lower()) \
and ('dns-prefetch' in rel or 'preconnect' in rel):
if ':' in value:
value = value.split(':', 1)[1]
value = 'dns:' + value.rstrip('/')
# parse tag for URLs
self.parse_tag(tag, attr, value, name, base, lineno, column)
log.debug(LOG_CHECK, "LinkFinder finished tag %s", tag)
def get_link_name(self, tag, attrs, attr, name=None):
"""Parse attrs for link name. Return name of link."""
if tag == 'a' and attr == 'href':
if not name:
name = attrs.get('title', '')
elif tag == 'img':
name = attrs.get('alt', '')
if not name:
name = attrs.get('title', '')
else:
name = ""
return name
def parse_tag(self, tag, attr, value, name, base, lineno, column):
"""Add given url data to url list."""
assert isinstance(tag, str), repr(tag)
assert isinstance(attr, str), repr(attr)
assert isinstance(name, str), repr(name)
assert isinstance(base, str), repr(base)
assert isinstance(value, str) or value is None, repr(value)
# look for meta refresh
if tag == 'meta' and value:
mo = refresh_re.match(value)
if mo:
self.found_url(mo.group("url"), name, base, lineno, column)
elif attr != 'content':
self.found_url(value, name, base, lineno, column)
elif attr == 'style' and value:
for mo in css_url_re.finditer(value):
url = unquote(mo.group("url"), matching=True)
self.found_url(url, name, base, lineno, column)
elif attr == 'archive':
for url in value.split(','):
self.found_url(url, name, base, lineno, column)
elif attr == 'srcset':
for url in parse_srcset(value):
self.found_url(url, name, base, lineno, column)
else:
self.found_url(value, name, base, lineno, column)
def found_url(self, url, name, base, lineno, column):
"""Add newly found URL to queue."""
assert isinstance(url, str) or url is None, repr(url)
self.callback(url, line=lineno, column=column, name=name, base=base)
def find_links(soup, callback, tags):
"""Parse into content and search for URLs to check.
When a URL is found it is passed to the supplied callback.
"""
lf = LinkFinder(callback, tags)
for element in soup.find_all(True):
lf.html_element(
element.name,
element.attrs,
element.text.strip(),
element.sourceline,
None if element.sourcepos is None else element.sourcepos + 1,
)
|
