Telethon/telethon/requestiter.py
Lonami Exo 36eb1b1009 Create a new RequestIter ABC to deal with iter methods
This should make it easier to maintain these methods, increase
reusability, and get rid of the async_generator dependency.

In the future, people could use this to more easily deal with
raw API themselves.
2019-02-26 20:26:40 +01:00

100 lines
3.2 KiB
Python

import abc
import asyncio
import time
class RequestIter(abc.ABC):
"""
Helper class to deal with requests that need offsets to iterate.
It has some facilities, such as automatically sleeping a desired
amount of time between requests if needed (but not more).
Can be used synchronously if the event loop is not running and
as an asynchronous iterator otherwise.
`limit` is the total amount of items that the iterator should return.
This is handled on this base class, and will be always ``>= 0``.
`left` will be reset every time the iterator is used and will indicate
the amount of items that should be emitted left, so that subclasses can
be more efficient and fetch only as many items as they need.
Iterators may be used with ``reversed``, and their `reverse` flag will
be set to ``True`` if that's the case. Note that if this flag is set,
`buffer` should be filled in reverse too.
"""
def __init__(self, client, limit, *, reverse=False, wait_time=None, **kwargs):
self.client = client
self.reverse = reverse
self.wait_time = wait_time
self.kwargs = kwargs
self.limit = max(float('inf') if limit is None else limit, 0)
self.left = None
self.buffer = None
self.index = None
self.total = None
self.last_load = None
async def _init(self, **kwargs):
"""
Called when asynchronous initialization is necessary. All keyword
arguments passed to `__init__` will be forwarded here, and it's
preferable to use named arguments in the subclasses without defaults
to avoid forgetting or misspelling any of them.
This method may ``raise StopAsyncIteration`` if it cannot continue.
"""
async def __anext__(self):
if self.buffer is ():
await self._init(**self.kwargs)
if self.index == len(self.buffer):
# asyncio will handle times <= 0 to sleep 0 seconds
if self.wait_time:
await asyncio.sleep(
self.wait_time - (time.time() - self.last_load),
loop=self.client.loop
)
self.last_load = time.time()
self.index = 0
self.buffer = await self._load_next_chunk()
if not self.buffer:
raise StopAsyncIteration
result = self.buffer[self.index]
self.left -= 1
self.index += 1
return result
def __aiter__(self):
self.buffer = ()
self.index = 0
self.last_load = 0
self.left = self.limit
return self
def __iter__(self):
if self.client.loop.is_running():
raise RuntimeError(
'You must use "async for" if the event loop '
'is running (i.e. you are inside an "async def")'
)
raise NotImplementedError('lol!')
@abc.abstractmethod
async def _load_next_chunk(self):
"""
Called when the next chunk is necessary.
It should *always* return a `list`.
"""
raise NotImplementedError
def __reversed__(self):
self.reverse = not self.reverse
return self # __aiter__ will be called after, too