mirror of
https://github.com/ihabunek/twitch-dl
synced 2024-08-30 18:32:25 +00:00
134 lines
3.9 KiB
Python
134 lines
3.9 KiB
Python
import asyncio
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import httpx
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import logging
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import os
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import time
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from abc import ABC, abstractmethod
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from typing import List, Optional
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from twitchdl.progress import Progress
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logger = logging.getLogger(__name__)
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KB = 1024
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CHUNK_SIZE = 256 * KB
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"""How much of a VOD to download in each iteration"""
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RETRY_COUNT = 5
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"""Number of times to retry failed downloads before aborting."""
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TIMEOUT = 30
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"""
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Number of seconds to wait before aborting when there is no network activity.
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https://www.python-httpx.org/advanced/#timeout-configuration
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"""
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class TokenBucket(ABC):
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@abstractmethod
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def advance(self, size: int):
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pass
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class LimitingTokenBucket(TokenBucket):
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"""Limit the download speed by strategically inserting sleeps."""
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def __init__(self, rate: int, capacity: Optional[int] = None):
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self.rate: int = rate
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self.capacity: int = capacity or rate * 2
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self.available: int = 0
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self.last_refilled: float = time.time()
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def advance(self, size: int):
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"""Called every time a chunk of data is downloaded."""
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self._refill()
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if self.available < size:
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deficit = size - self.available
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time.sleep(deficit / self.rate)
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self.available -= size
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def _refill(self):
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"""Increase available capacity according to elapsed time since last refill."""
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now = time.time()
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elapsed = now - self.last_refilled
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refill_amount = int(elapsed * self.rate)
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self.available = min(self.available + refill_amount, self.capacity)
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self.last_refilled = now
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class EndlessTokenBucket(TokenBucket):
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"""Used when download speed is not limited."""
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def advance(self, size: int):
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pass
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async def download(
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client: httpx.AsyncClient,
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task_id: int,
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source: str,
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target: str,
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progress: Progress,
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token_bucket: TokenBucket,
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):
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# Download to a temp file first, then copy to target when over to avoid
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# getting saving chunks which may persist if canceled or --keep is used
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tmp_target = f"{target}.tmp"
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with open(tmp_target, "wb") as f:
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async with client.stream("GET", source) as response:
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size = int(response.headers.get("content-length"))
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progress.start(task_id, size)
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async for chunk in response.aiter_bytes(chunk_size=CHUNK_SIZE):
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f.write(chunk)
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size = len(chunk)
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token_bucket.advance(size)
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progress.advance(task_id, size)
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progress.end(task_id)
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os.rename(tmp_target, target)
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async def download_with_retries(
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client: httpx.AsyncClient,
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semaphore: asyncio.Semaphore,
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task_id: int,
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source: str,
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target: str,
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progress: Progress,
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token_bucket: TokenBucket,
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):
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async with semaphore:
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if os.path.exists(target):
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size = os.path.getsize(target)
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progress.already_downloaded(task_id, size)
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return
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for n in range(RETRY_COUNT):
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try:
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return await download(client, task_id, source, target, progress, token_bucket)
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except httpx.RequestError:
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logger.exception("Task {task_id} failed. Retrying. Maybe.")
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progress.abort(task_id)
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if n + 1 >= RETRY_COUNT:
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raise
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raise Exception("Should not happen")
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async def download_all(
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sources: List[str],
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targets: List[str],
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workers: int,
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*,
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rate_limit: Optional[int] = None
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):
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progress = Progress(len(sources))
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token_bucket = LimitingTokenBucket(rate_limit) if rate_limit else EndlessTokenBucket()
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async with httpx.AsyncClient(timeout=TIMEOUT) as client:
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semaphore = asyncio.Semaphore(workers)
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tasks = [download_with_retries(client, semaphore, task_id, source, target, progress, token_bucket)
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for task_id, (source, target) in enumerate(zip(sources, targets))]
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await asyncio.gather(*tasks)
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