Clean up the torrent implementation
This commit is contained in:
jvoisin
parent
57bf89e035
commit
9e485c0dad
141
src/torrent.py
141
src/torrent.py
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@ -1,75 +1,78 @@
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import os
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import re
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import shutil
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import tempfile
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import datetime
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import zipfile
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from . import abstract, parser_factory
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from . import abstract
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class TorrentParser(abstract.AbstractParser):
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mimetypes = {'application/x-bittorrent', }
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whitelist = {b'announce', b'announce-list', b'info'}
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def __init__(self, filename):
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super().__init__(filename)
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self.__decode_func = {
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ord('l'): self.__decode_list,
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ord('d'): self.__decode_dict,
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ord('i'): self.__decode_int
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}
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for i in range(0, 10):
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self.__decode_func[ord(str(i))] = self.__decode_string
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self.__encode_func = {
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int: self.__encode_int,
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bytes: self.__encode_string,
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list: self.__encode_list,
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dict: self.__encode_dict,
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}
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def get_meta(self):
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def get_meta(self) -> dict:
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metadata = {}
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with open(self.filename, 'rb') as f:
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d = self.__bdecode(f.read())
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d = _BencodeHandler().bdecode(f.read())
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if d is None:
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return {'Unknown meta': 'Unable to parse torrent file "%s".' % self.filename}
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for k,v in d.items():
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if k not in self.whitelist:
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metadata[k.decode('utf-8')] = v
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return metadata
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def remove_all(self):
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def remove_all(self) -> bool:
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cleaned = dict()
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with open(self.filename, 'rb') as f:
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d = self.__bdecode(f.read())
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d = _BencodeHandler().bdecode(f.read())
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if d is None:
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return False
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for k,v in d.items():
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if k in self.whitelist:
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cleaned[k] = v
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with open(self.output_filename, 'wb') as f:
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f.write(self.__bencode(cleaned))
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f.write(_BencodeHandler().bencode(cleaned))
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return True
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def __decode_int(self, s):
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class _BencodeHandler(object):
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"""
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Since bencode isn't that hard to parse,
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MAT2 comes with its own parser, based on the spec
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https://wiki.theory.org/index.php/BitTorrentSpecification#Bencoding
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"""
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def __init__(self):
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self.__decode_func = {
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ord('d'): self.__decode_dict,
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ord('i'): self.__decode_int,
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ord('l'): self.__decode_list,
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}
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for i in range(0, 10):
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self.__decode_func[ord(str(i))] = self.__decode_string
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self.__encode_func = {
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bytes: self.__encode_string,
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dict: self.__encode_dict,
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int: self.__encode_int,
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list: self.__encode_list,
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}
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def __decode_int(self, s:str) -> (int, str):
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s = s[1:]
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next_idx = s.index(b'e')
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if s.startswith(b'-0'):
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raise ValueError # negative zero doesn't exist
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if s.startswith(b'0') and next_idx != 1:
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elif s.startswith(b'0') and next_idx != 1:
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raise ValueError # no leading zero except for zero itself
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return int(s[:next_idx]), s[next_idx+1:]
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def __decode_string(self, s):
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end = s.index(b':')
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str_len = int(s[:end])
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if s[0] == b'0' and end != 1:
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def __decode_string(self, s:str) -> (str, str):
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sep = s.index(b':')
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str_len = int(s[:sep])
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if str_len < 0:
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raise ValueError
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s = s[1:] # skip terminal `:`
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return s[end:end+str_len], s[end+str_len:]
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elif s[0] == b'0' and sep != 1:
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raise ValueError
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s = s[1:]
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return s[sep:sep+str_len], s[sep+str_len:]
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def __decode_list(self, s):
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def __decode_list(self, s:str) -> (list, str):
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r = list()
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s = s[1:] # skip leading `l`
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while s[0] != ord('e'):
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@ -77,15 +80,39 @@ class TorrentParser(abstract.AbstractParser):
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r.append(v)
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return r, s[1:]
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def __decode_dict(self, s):
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def __decode_dict(self, s:str) -> (dict, str):
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r = dict()
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s = s[1:]
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s = s[1:] # skip leading `d`
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while s[0] != ord(b'e'):
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k, s = self.__decode_string(s)
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r[k], s = self.__decode_func[s[0]](s)
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return r, s[1:]
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def __bdecode(self, s):
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@staticmethod
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def __encode_int(x:str) -> bytes:
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return b'i' + bytes(str(x), 'utf-8') + b'e'
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@staticmethod
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def __encode_string(x:str) -> bytes:
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return bytes((str(len(x))), 'utf-8') + b':' + x
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def __encode_list(self, x:str) -> bytes:
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ret = b''
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for i in x:
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ret += self.__encode_func[type(i)](i)
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return b'l' + ret + b'e'
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def __encode_dict(self, x:str) -> bytes:
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ret = b''
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for k, v in sorted(x.items()):
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ret += self.__encode_func[type(k)](k)
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ret += self.__encode_func[type(v)](v)
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return b'd' + ret + b'e'
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def bencode(self, s:str) -> bytes:
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return self.__encode_func[type(s)](s)
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def bdecode(self, s:str):
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try:
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r, l = self.__decode_func[s[0]](s)
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except (IndexError, KeyError, ValueError) as e:
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@ -95,29 +122,3 @@ class TorrentParser(abstract.AbstractParser):
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print("invalid bencoded value (data after valid prefix)")
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return None
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return r
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@staticmethod
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def __encode_int(x):
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return b'i' + bytes(str(x), 'utf-8') + b'e'
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@staticmethod
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def __encode_string(x:str):
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return bytes((str(len(x))), 'utf-8') + b':' + x
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def __encode_list(self, x):
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ret = b''
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for i in x:
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ret += self.__encode_func[type(i)](i)
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return b'l' + ret + b'e'
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def __encode_dict(self, x):
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ret = b''
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for k, v in sorted(x.items()):
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ret += self.__encode_func[type(k)](k)
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ret += self.__encode_func[type(v)](v)
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return b'd' + ret + b'e'
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def __bencode(self, x):
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return self.__encode_func[type(x)](x)
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