Telethon/telethon/helpers.py
Rongrong 046e2cb605
Fix HTML/MD parser producing empty MessageEntity (#3885)
Closes #3884. The implementation is also simplified.
2022-07-25 11:11:26 +02:00

426 lines
14 KiB
Python

"""Various helpers not related to the Telegram API itself"""
import asyncio
import io
import enum
import os
import struct
import inspect
import logging
import functools
from pathlib import Path
from hashlib import sha1
class _EntityType(enum.Enum):
USER = 0
CHAT = 1
CHANNEL = 2
_log = logging.getLogger(__name__)
# region Multiple utilities
def generate_random_long(signed=True):
"""Generates a random long integer (8 bytes), which is optionally signed"""
return int.from_bytes(os.urandom(8), signed=signed, byteorder='little')
def ensure_parent_dir_exists(file_path):
"""Ensures that the parent directory exists"""
parent = os.path.dirname(file_path)
if parent:
os.makedirs(parent, exist_ok=True)
def add_surrogate(text):
return ''.join(
# SMP -> Surrogate Pairs (Telegram offsets are calculated with these).
# See https://en.wikipedia.org/wiki/Plane_(Unicode)#Overview for more.
''.join(chr(y) for y in struct.unpack('<HH', x.encode('utf-16le')))
if (0x10000 <= ord(x) <= 0x10FFFF) else x for x in text
)
def del_surrogate(text):
return text.encode('utf-16', 'surrogatepass').decode('utf-16')
def within_surrogate(text, index, *, length=None):
"""
`True` if ``index`` is within a surrogate (before and after it, not at!).
"""
if length is None:
length = len(text)
return (
1 < index < len(text) and # in bounds
'\ud800' <= text[index - 1] <= '\udfff' and # previous is
'\ud800' <= text[index] <= '\udfff' # current is
)
def strip_text(text, entities):
"""
Strips whitespace from the given surrogated text modifying the provided
entities, also removing any empty (0-length) entities.
This assumes that the length of entities is greater or equal to 0, and
that no entity is out of bounds.
"""
if not entities:
return text.strip()
len_ori = len(text)
text = text.lstrip()
left_offset = len_ori - len(text)
text = text.rstrip()
len_final = len(text)
for i in reversed(range(len(entities))):
e = entities[i]
if e.length == 0:
del entities[i]
continue
if e.offset + e.length > left_offset:
if e.offset >= left_offset:
# 0 1|2 3 4 5 | 0 1|2 3 4 5
# ^ ^ | ^
# lo(2) o(5) | o(2)/lo(2)
e.offset -= left_offset
# |0 1 2 3 | |0 1 2 3
# ^ | ^
# o=o-lo(3=5-2) | o=o-lo(0=2-2)
else:
# e.offset < left_offset and e.offset + e.length > left_offset
# 0 1 2 3|4 5 6 7 8 9 10
# ^ ^ ^
# o(1) lo(4) o+l(1+9)
e.length = e.offset + e.length - left_offset
e.offset = 0
# |0 1 2 3 4 5 6
# ^ ^
# o(0) o+l=0+o+l-lo(6=0+6=0+1+9-4)
else:
# e.offset + e.length <= left_offset
# 0 1 2 3|4 5
# ^ ^
# o(0) o+l(4)
# lo(4)
del entities[i]
continue
if e.offset + e.length <= len_final:
# |0 1 2 3 4 5 6 7 8 9
# ^ ^
# o(1) o+l(1+9)/lf(10)
continue
if e.offset >= len_final:
# |0 1 2 3 4
# ^
# o(5)/lf(5)
del entities[i]
else:
# e.offset < len_final and e.offset + e.length > len_final
# |0 1 2 3 4 5 (6) (7) (8) (9)
# ^ ^ ^
# o(1) lf(6) o+l(1+8)
e.length = len_final - e.offset
# |0 1 2 3 4 5
# ^ ^
# o(1) o+l=o+lf-o=lf(6=1+5=1+6-1)
return text
def retry_range(retries, force_retry=True):
"""
Generates an integer sequence starting from 1. If `retries` is
not a zero or a positive integer value, the sequence will be
infinite, otherwise it will end at `retries + 1`.
"""
# We need at least one iteration even if the retries are 0
# when force_retry is True.
if force_retry and not (retries is None or retries < 0):
retries += 1
attempt = 0
while attempt != retries:
attempt += 1
yield attempt
async def _maybe_await(value):
if inspect.isawaitable(value):
return await value
else:
return value
async def _cancel(log, **tasks):
"""
Helper to cancel one or more tasks gracefully, logging exceptions.
"""
for name, task in tasks.items():
if not task:
continue
task.cancel()
try:
await task
except asyncio.CancelledError:
pass
except RuntimeError:
# Probably: RuntimeError: await wasn't used with future
#
# See: https://github.com/python/cpython/blob/12d3061c7819a73d891dcce44327410eaf0e1bc2/Lib/asyncio/futures.py#L265
#
# Happens with _asyncio.Task instances (in "Task cancelling" state)
# trying to SIGINT the program right during initial connection, on
# _recv_loop coroutine (but we're creating its task explicitly with
# a loop, so how can it bug out like this?).
#
# Since we're aware of this error there's no point in logging it.
# *May* be https://bugs.python.org/issue37172
pass
except AssertionError as e:
# In Python 3.6, the above RuntimeError is an AssertionError
# See https://github.com/python/cpython/blob/7df32f844efed33ca781a016017eab7050263b90/Lib/asyncio/futures.py#L328
if e.args != ("yield from wasn't used with future",):
log.exception('Unhandled exception from %s after cancelling '
'%s (%s)', name, type(task), task)
except Exception:
log.exception('Unhandled exception from %s after cancelling '
'%s (%s)', name, type(task), task)
def _sync_enter(self):
"""
Helps to cut boilerplate on async context
managers that offer synchronous variants.
"""
if hasattr(self, 'loop'):
loop = self.loop
else:
loop = self._client.loop
if loop.is_running():
raise RuntimeError(
'You must use "async with" if the event loop '
'is running (i.e. you are inside an "async def")'
)
return loop.run_until_complete(self.__aenter__())
def _sync_exit(self, *args):
if hasattr(self, 'loop'):
loop = self.loop
else:
loop = self._client.loop
return loop.run_until_complete(self.__aexit__(*args))
def _entity_type(entity):
# This could be a `utils` method that just ran a few `isinstance` on
# `utils.get_peer(...)`'s result. However, there are *a lot* of auto
# casts going on, plenty of calls and temporary short-lived objects.
#
# So we just check if a string is in the class name.
# Still, assert that it's the right type to not return false results.
try:
if entity.SUBCLASS_OF_ID not in (
0x2d45687, # crc32(b'Peer')
0xc91c90b6, # crc32(b'InputPeer')
0xe669bf46, # crc32(b'InputUser')
0x40f202fd, # crc32(b'InputChannel')
0x2da17977, # crc32(b'User')
0xc5af5d94, # crc32(b'Chat')
0x1f4661b9, # crc32(b'UserFull')
0xd49a2697, # crc32(b'ChatFull')
):
raise TypeError('{} does not have any entity type'.format(entity))
except AttributeError:
raise TypeError('{} is not a TLObject, cannot determine entity type'.format(entity))
name = entity.__class__.__name__
if 'User' in name:
return _EntityType.USER
elif 'Chat' in name:
return _EntityType.CHAT
elif 'Channel' in name:
return _EntityType.CHANNEL
elif 'Self' in name:
return _EntityType.USER
# 'Empty' in name or not found, we don't care, not a valid entity.
raise TypeError('{} does not have any entity type'.format(entity))
# endregion
# region Cryptographic related utils
def generate_key_data_from_nonce(server_nonce, new_nonce):
"""Generates the key data corresponding to the given nonce"""
server_nonce = server_nonce.to_bytes(16, 'little', signed=True)
new_nonce = new_nonce.to_bytes(32, 'little', signed=True)
hash1 = sha1(new_nonce + server_nonce).digest()
hash2 = sha1(server_nonce + new_nonce).digest()
hash3 = sha1(new_nonce + new_nonce).digest()
key = hash1 + hash2[:12]
iv = hash2[12:20] + hash3 + new_nonce[:4]
return key, iv
# endregion
# region Custom Classes
class TotalList(list):
"""
A list with an extra `total` property, which may not match its `len`
since the total represents the total amount of items *available*
somewhere else, not the items *in this list*.
Examples:
.. code-block:: python
# Telethon returns these lists in some cases (for example,
# only when a chunk is returned, but the "total" count
# is available).
result = await client.get_messages(chat, limit=10)
print(result.total) # large number
print(len(result)) # 10
print(result[0]) # latest message
for x in result: # show the 10 messages
print(x.text)
"""
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.total = 0
def __str__(self):
return '[{}, total={}]'.format(
', '.join(str(x) for x in self), self.total)
def __repr__(self):
return '[{}, total={}]'.format(
', '.join(repr(x) for x in self), self.total)
class _FileStream(io.IOBase):
"""
Proxy around things that represent a file and need to be used as streams
which may or not need to be closed.
This will handle `pathlib.Path`, `str` paths, in-memory `bytes`, and
anything IO-like (including `aiofiles`).
It also provides access to the name and file size (also necessary).
"""
def __init__(self, file, *, file_size=None):
if isinstance(file, Path):
file = str(file.absolute())
self._file = file
self._name = None
self._size = file_size
self._stream = None
self._close_stream = None
async def __aenter__(self):
if isinstance(self._file, str):
self._name = os.path.basename(self._file)
self._size = os.path.getsize(self._file)
self._stream = open(self._file, 'rb')
self._close_stream = True
elif isinstance(self._file, bytes):
self._size = len(self._file)
self._stream = io.BytesIO(self._file)
self._close_stream = True
elif not callable(getattr(self._file, 'read', None)):
raise TypeError('file description should have a `read` method')
elif self._size is not None:
self._name = getattr(self._file, 'name', None)
self._stream = self._file
self._close_stream = False
else:
if callable(getattr(self._file, 'seekable', None)):
seekable = await _maybe_await(self._file.seekable())
else:
seekable = False
if seekable:
pos = await _maybe_await(self._file.tell())
await _maybe_await(self._file.seek(0, os.SEEK_END))
self._size = await _maybe_await(self._file.tell())
await _maybe_await(self._file.seek(pos, os.SEEK_SET))
self._stream = self._file
self._close_stream = False
else:
_log.warning(
'Could not determine file size beforehand so the entire '
'file will be read in-memory')
data = await _maybe_await(self._file.read())
self._size = len(data)
self._stream = io.BytesIO(data)
self._close_stream = True
return self
async def __aexit__(self, exc_type, exc_val, exc_tb):
if self._close_stream and self._stream:
await _maybe_await(self._stream.close())
@property
def file_size(self):
return self._size
@property
def name(self):
return self._name
# Proxy all the methods. Doesn't need to be readable (makes multiline edits easier)
def read(self, *args, **kwargs): return self._stream.read(*args, **kwargs)
def readinto(self, *args, **kwargs): return self._stream.readinto(*args, **kwargs)
def write(self, *args, **kwargs): return self._stream.write(*args, **kwargs)
def fileno(self, *args, **kwargs): return self._stream.fileno(*args, **kwargs)
def flush(self, *args, **kwargs): return self._stream.flush(*args, **kwargs)
def isatty(self, *args, **kwargs): return self._stream.isatty(*args, **kwargs)
def readable(self, *args, **kwargs): return self._stream.readable(*args, **kwargs)
def readline(self, *args, **kwargs): return self._stream.readline(*args, **kwargs)
def readlines(self, *args, **kwargs): return self._stream.readlines(*args, **kwargs)
def seek(self, *args, **kwargs): return self._stream.seek(*args, **kwargs)
def seekable(self, *args, **kwargs): return self._stream.seekable(*args, **kwargs)
def tell(self, *args, **kwargs): return self._stream.tell(*args, **kwargs)
def truncate(self, *args, **kwargs): return self._stream.truncate(*args, **kwargs)
def writable(self, *args, **kwargs): return self._stream.writable(*args, **kwargs)
def writelines(self, *args, **kwargs): return self._stream.writelines(*args, **kwargs)
# close is special because it will be called by __del__ but we do NOT
# want to close the file unless we have to (we're just a wrapper).
# Instead, we do nothing (we should be used through the decorator which
# has its own mechanism to close the file correctly).
def close(self, *args, **kwargs):
pass
# endregion