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
|
# -*- coding: utf-8 -*-
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
"""Generic information extractor"""
from .common import Extractor, Message
from .. import config, text, util
import os.path
class GenericExtractor(Extractor):
"""Extractor for images in a generic web page."""
category = "generic"
directory_fmt = ("{category}", "{subcategory}", "{path}")
archive_fmt = "{imageurl}"
# By default, the generic extractor is disabled
# and the "g(eneric):" prefix in url is required.
# If the extractor is enabled, make the prefix optional
pattern = r"(?i)(?P<generic>g(?:eneric)?:)"
if config.get(("extractor", "generic"), "enabled"):
pattern += r"?"
# The generic extractor pattern should match (almost) any valid url
# Based on: https://tools.ietf.org/html/rfc3986#appendix-B
pattern += (
r"(?P<scheme>https?://)?" # optional http(s) scheme
r"(?P<domain>[-\w\.]+)" # required domain
r"(?P<path>/[^?#]*)?" # optional path
r"(?:\?(?P<query>[^#]*))?" # optional query
r"(?:\#(?P<fragment>.*))?" # optional fragment
)
example = "generic:https://www.nongnu.org/lzip/"
def __init__(self, match):
self.subcategory = match['domain']
Extractor.__init__(self, match)
# Strip the "g(eneric):" prefix
# and inform about "forced" or "fallback" mode
if match['generic']:
self.url = match[0].partition(":")[2]
else:
self.log.info("Falling back on generic information extractor.")
self.url = match[0]
# Make sure we have a scheme, or use https
if match['scheme']:
self.scheme = match['scheme']
else:
self.scheme = 'https://'
self.url = text.ensure_http_scheme(self.url, self.scheme)
self.path = match['path']
# Used to resolve relative image urls
self.root = self.scheme + match['domain']
def items(self):
"""Get page, extract metadata & images, yield them in suitable messages
Adapted from common.GalleryExtractor.items()
"""
page = self.request(self.url).text
data = self.metadata(page)
imgs = self.images(page)
try:
data["count"] = len(imgs)
except TypeError:
pass
images = enumerate(imgs, 1)
yield Message.Directory, data
for data["num"], (url, imgdata) in images:
if imgdata:
data.update(imgdata)
if "extension" not in imgdata:
text.nameext_from_url(url, data)
else:
text.nameext_from_url(url, data)
yield Message.Url, url, data
def metadata(self, page):
"""Extract generic webpage metadata, return them in a dict."""
data = {
"title" : text.extr(
page, "<title>", "</title>"),
"description" : text.extr(
page, '<meta name="description" content="', '"'),
"keywords" : text.extr(
page, '<meta name="keywords" content="', '"'),
"language" : text.extr(
page, '<meta name="language" content="', '"'),
"name" : text.extr(
page, '<meta itemprop="name" content="', '"'),
"copyright" : text.extr(
page, '<meta name="copyright" content="', '"'),
"og_site" : text.extr(
page, '<meta property="og:site" content="', '"'),
"og_site_name" : text.extr(
page, '<meta property="og:site_name" content="', '"'),
"og_title" : text.extr(
page, '<meta property="og:title" content="', '"'),
"og_description": text.extr(
page, '<meta property="og:description" content="', '"'),
}
data = {k: text.unescape(v) for k, v in data.items() if v}
data["path"] = self.path.replace("/", "")
data["pageurl"] = self.url
return data
def images(self, page):
"""Extract image urls, return a list of (image url, metadata) tuples.
The extractor aims at finding as many _likely_ image urls as possible,
using two strategies (see below); since these often overlap, any
duplicate urls will be removed at the end of the process.
Note: since we are using re.findall() (see below), it's essential that
the following patterns contain 0 or at most 1 capturing group, so that
re.findall() return a list of urls (instead of a list of tuples of
matching groups). All other groups used in the pattern should be
non-capturing (?:...).
1: Look in src/srcset attributes of img/video/source elements
See:
https://www.w3schools.com/tags/att_src.asp
https://www.w3schools.com/tags/att_source_srcset.asp
We allow both absolute and relative urls here.
Note that srcset attributes often contain multiple space separated
image urls; this pattern matches only the first url; remaining urls
will be matched by the "imageurl_pattern_ext" pattern below.
"""
imageurl_pattern_src = (
r"(?i)"
r"<(?:img|video|source)\s[^>]*" # <img>, <video> or <source>
r"src(?:set)?=[\"']?" # src or srcset attributes
r"(?P<URL>[^\"'\s>]+)" # url
)
"""
2: Look anywhere for urls containing common image/video extensions
The list of allowed extensions is borrowed from the directlink.py
extractor; other could be added, see
https://en.wikipedia.org/wiki/List_of_file_formats
Compared to the "pattern" class variable, here we must exclude also
other special characters (space, ", ', <, >), since we are looking for
urls in html tags.
"""
imageurl_pattern_ext = (
r"(?i)"
r"(?:[^?&#\"'>\s]+)" # anything until dot+extension
# dot + image/video extensions
r"\.(?:jpe?g|jpe|png|gif|web[mp]|mp4|mkv|og[gmv]|opus)"
r"(?:[^\"'<>\s]*)?" # optional query and fragment
)
imageurls_src = util.re(imageurl_pattern_src).findall(page)
imageurls_ext = util.re(imageurl_pattern_ext).findall(page)
imageurls = imageurls_src + imageurls_ext
# Resolve relative urls
#
# Image urls catched so far may be relative, so we must resolve them
# by prepending a suitable base url.
#
# If the page contains a <base> element, use it as base url
basematch = util.re(
r"(?i)(?:<base\s.*?href=[\"']?)(?P<url>[^\"' >]+)").search(page)
if basematch:
self.baseurl = basematch['url'].rstrip('/')
# Otherwise, extract the base url from self.url
else:
if self.url.endswith("/"):
self.baseurl = self.url.rstrip('/')
else:
self.baseurl = os.path.dirname(self.url)
# Build the list of absolute image urls
absimageurls = []
for u in imageurls:
# Absolute urls are taken as-is
if u.startswith('http'):
absimageurls.append(u)
# // relative urls are prefixed with current scheme
elif u.startswith('//'):
absimageurls.append(self.scheme + u.lstrip('/'))
# / relative urls are prefixed with current scheme+domain
elif u.startswith('/'):
absimageurls.append(self.root + u)
# other relative urls are prefixed with baseurl
else:
absimageurls.append(self.baseurl + '/' + u)
# Remove duplicates
absimageurls = dict.fromkeys(absimageurls)
# Create the image metadata dict and add imageurl to it
# (image filename and extension are added by items())
images = [(u, {'imageurl': u}) for u in absimageurls]
return images
|
