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
|
import os
import re
import shutil
import tempfile
import datetime
import zipfile
from . import abstract, parser_factory
class TorrentParser(abstract.AbstractParser):
mimetypes = {'application/x-bittorrent', }
whitelist = {b'announce', b'announce-list', b'info'}
def __init__(self, filename):
super().__init__(filename)
self.__decode_func = {
ord('l'): self.__decode_list,
ord('d'): self.__decode_dict,
ord('i'): self.__decode_int
}
for i in range(0, 10):
self.__decode_func[ord(str(i))] = self.__decode_string
self.__encode_func = {
int: self.__encode_int,
bytes: self.__encode_string,
list: self.__encode_list,
dict: self.__encode_dict,
}
def get_meta(self):
metadata = {}
with open(self.filename, 'rb') as f:
d = self.__bdecode(f.read())
for k,v in d.items():
if k not in self.whitelist:
metadata[k.decode('utf-8')] = v
return metadata
def remove_all(self):
cleaned = dict()
with open(self.filename, 'rb') as f:
d = self.__bdecode(f.read())
for k,v in d.items():
if k in self.whitelist:
cleaned[k] = v
with open(self.output_filename, 'wb') as f:
f.write(self.__bencode(cleaned))
return True
def __decode_int(self, s):
s = s[1:]
next_idx = s.index(b'e')
if s.startswith(b'-0'):
raise ValueError # negative zero doesn't exist
if s.startswith(b'0') and next_idx != 1:
raise ValueError # no leading zero except for zero itself
return int(s[:next_idx]), s[next_idx+1:]
def __decode_string(self, s):
end = s.index(b':')
str_len = int(s[:end])
if s[0] == b'0' and end != 1:
raise ValueError
s = s[1:] # skip terminal `:`
return s[end:end+str_len], s[end+str_len:]
def __decode_list(self, s):
r = list()
s = s[1:] # skip leading `l`
while s[0] != ord('e'):
v, s = self.__decode_func[s[0]](s)
r.append(v)
return r, s[1:]
def __decode_dict(self, s):
r = dict()
s = s[1:]
while s[0] != ord(b'e'):
k, s = self.__decode_string(s)
r[k], s = self.__decode_func[s[0]](s)
return r, s[1:]
def __bdecode(self, s):
try:
r, l = self.__decode_func[s[0]](s)
except (IndexError, KeyError, ValueError) as e:
print("not a valid bencoded string: %s" % e)
return None
if l != b'':
print("invalid bencoded value (data after valid prefix)")
return None
return r
@staticmethod
def __encode_int(x):
return b'i' + bytes(str(x), 'utf-8') + b'e'
@staticmethod
def __encode_string(x:str):
return bytes((str(len(x))), 'utf-8') + b':' + x
def __encode_list(self, x):
ret = b''
for i in x:
ret += self.__encode_func[type(i)](i)
return b'l' + ret + b'e'
def __encode_dict(self, x):
ret = b''
for k, v in sorted(x.items()):
ret += self.__encode_func[type(k)](k)
ret += self.__encode_func[type(v)](v)
return b'd' + ret + b'e'
def __bencode(self, x):
return self.__encode_func[type(x)](x)
|
