我正在写一个程序来下载一堆文件，程序很长，我通过子进程调用aria2c.exe来下载文件，我遇到了问题。
具体来说，当使用 aria2c + subprocess + QThread 在后台下载文件时，GUI 挂起，并且下载运行时进度条和相关标签不会更新，GUI 保持无响应，直到下载完成。
我使用相同的方法在没有 GUI 的情况下使用 aria2c + subprocess + threading.Thread 在控制台中下载文件。下载成功完成，所有统计信息都正确更新，并且线程完成且没有错误。
这是重现该问题所需的最少代码，尽管它相当长：
import re
import requests
import subprocess
import sys
import time
from PyQt6.QtCore import Qt, QThread, pyqtSignal, pyqtSlot
from PyQt6.QtGui import (
QFont,
QFontMetrics,
)
from PyQt6.QtWidgets import (
QApplication,
QGridLayout,
QGroupBox,
QHBoxLayout,
QLabel,
QProgressBar,
QPushButton,
QSizePolicy,
QVBoxLayout,
QWidget,
)
BASE_COMMAND = [
"aria2c",
"--async-dns=false",
"--connect-timeout=3",
"--disk-cache=256M",
"--disable-ipv6=true",
"--enable-mmap=true",
"--http-no-cache=true",
"--max-connection-per-server=16",
"--min-split-size=1M",
"--piece-length=1M",
"--split=32",
"--timeout=3",
]
url = "http://ipv4.download.thinkbroadband.com/100MB.zip"
UNITS_SIZE = {"B": 1, "KiB": 1 << 10, "MiB": 1 << 20, "GiB": 1 << 30}
DOWNLOAD_PROGRESS = re.compile(
"(?P<downloaded>\d+(\.\d+)?[KMG]iB)/(?P<total>\d+(\.\d+)?[KMG]iB)"
)
UNITS = ("B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB", "RiB", "QiB")
ALIGNMENT = Qt.AlignmentFlag.AlignLeft | Qt.AlignmentFlag.AlignTop
class Font(QFont):
def __init__(self, size: int = 10) -> None:
super().__init__()
self.setFamily("Times New Roman")
self.setStyleHint(QFont.StyleHint.Times)
self.setStyleStrategy(QFont.StyleStrategy.PreferAntialias)
self.setPointSize(size)
self.setBold(True)
self.setHintingPreference(QFont.HintingPreference.PreferFullHinting)
FONT = Font()
FONT_RULER = QFontMetrics(FONT)
class Box(QGroupBox):
def __init__(self) -> None:
super().__init__()
self.setAlignment(ALIGNMENT)
self.setContentsMargins(3, 3, 3, 3)
self.setSizePolicy(QSizePolicy.Policy.Minimum, QSizePolicy.Policy.Minimum)
self.vbox = make_vbox(self)
class Button(QPushButton):
def __init__(self, text: str) -> None:
super().__init__()
self.setFont(FONT)
self.setFixedSize(72, 20)
self.setText(text)
def make_box(
box_type: type[QHBoxLayout] | type[QVBoxLayout] | type[QGridLayout],
parent: QWidget,
margin: int,
) -> QHBoxLayout | QVBoxLayout | QGridLayout:
box = box_type(parent) if parent else box_type()
box.setAlignment(ALIGNMENT)
box.setContentsMargins(*[margin] * 4)
return box
def make_vbox(parent: QWidget = None, margin: int = 0) -> QVBoxLayout:
return make_box(QVBoxLayout, parent, margin)
def make_hbox(parent: QWidget = None, margin: int = 0) -> QHBoxLayout:
return make_box(QHBoxLayout, parent, margin)
class Label(QLabel):
def __init__(self, text: str) -> None:
super().__init__()
self.setFont(FONT)
self.set_text(text)
def autoResize(self) -> None:
self.Height = FONT_RULER.size(0, self.text()).height()
self.Width = FONT_RULER.size(0, self.text()).width()
self.setFixedSize(self.Width + 3, self.Height + 8)
def set_text(self, text: str) -> None:
self.setText(text)
self.autoResize()
class ProgressBar(QProgressBar):
def __init__(self) -> None:
super().__init__()
self.setFont(FONT)
self.setValue(0)
self.setFixedSize(1000, 25)
class DownThread(QThread):
update = pyqtSignal(dict)
def __init__(self, parent: QWidget, url: str, folder: str) -> None:
super().__init__(parent)
self.url = url
self.folder = folder
self.line = ""
self.stats = {}
def run(self) -> None:
self.total = 0
res = requests.head(url)
if res.status_code == 200 and (total := res.headers.get("Content-Length")):
self.total = int(total)
self.process = subprocess.Popen(
BASE_COMMAND + [f"--dir={self.folder}", self.url],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
)
self.monitor()
self.quit()
def monitor(self) -> None:
self.start = self.elapsed = time.time_ns()
self.downloaded = 0
output = self.process.stdout
self.buffer = ""
while self.process.poll() is None:
char = output.read(1)
if char in (b"\n", b"\r"):
self.line = self.buffer
self.buffer = ""
self.update_stats()
else:
self.buffer += char.decode()
self.finish()
def update_stats(self) -> None:
if match := DOWNLOAD_PROGRESS.search(self.line):
current = time.time_ns()
new, total = map(self.parse_size, match.groupdict().values())
delta = (current - self.elapsed) / 1e9
speed = (new - self.downloaded) / delta
self.stats = {
"downloaded": new,
"total": total,
"speed": speed,
"elapsed": (current - self.start) / 1e9,
"eta": ((total - new) / speed) if speed != 0 else 1e309,
}
self.elapsed = current
self.downloaded = new
self.update.emit(self.stats)
@staticmethod
def parse_size(size: str) -> int:
unit = size[-3:]
size = size.replace(unit, "")
return (float if "." in size else int)(size) * UNITS_SIZE[unit]
def finish(self):
self.elapsed = (time.time_ns() - self.start) // 1e9
total = self.total or self.stats["total"]
self.stats["downloaded"] = total
self.stats["total"] = total
self.stats["elapsed"] = self.elapsed
self.stats["eta"] = 0
self.stats["speed"] = total / self.elapsed
self.update.emit(self.stats)
class Underbar(Box):
def __init__(self):
super().__init__()
self.setFixedHeight(256)
self.progressbar = ProgressBar()
self.hbox = make_hbox()
self.hbox.addWidget(self.progressbar)
self.displays = {}
for name in ("Downloaded", "Total", "Speed", "Elapsed", "ETA"):
self.hbox.addWidget(Label(name))
widget = Label("0")
self.hbox.addWidget(widget)
self.displays[name] = widget
self.vbox.addLayout(self.hbox)
self.button = Button("Test")
self.vbox.addWidget(self.button)
self.button.clicked.connect(self.test)
def test(self):
self.progressbar.setValue(0)
down = DownThread(self, url, "D:/downloads")
down.update.connect(self.update_displays)
down.run()
def update_displays(self, stats):
self.progressbar.setValue(100 * int(stats["downloaded"] / stats["total"] + 0.5))
for name, suffix in (("Downloaded", ""), ("Total", ""), ("Speed", "/s")):
self.displays[name].setText(
f"{round(stats[name.lower()] / 1048576, 2)}MiB{suffix}"
)
self.displays["Elapsed"].setText(f'{round(stats["elapsed"], 2)}s')
self.displays["ETA"].setText(f'{round(stats["eta"], 2)}s')
for label in self.displays.values():
label.autoResize()
if __name__ == "__main__":
app = QApplication([])
app.setStyle("Fusion")
window = Underbar()
window.show()
sys.exit(app.exec())
如何解决这个问题？
我已经解决了这个问题。我放弃了使用子进程调用 aria2c 的想法，而是使用 aiohttp + aiofiles 使用 HTTP Range 标头分多个部分下载文件。
然后我使用 qasync 中的 QEventLoop 使 asyncio 与 QThread 一起工作，并且它可以正常工作。
import aiofiles
import asyncio
import sys
from aiohttp import ClientSession
from bisect import bisect
from PyQt6.QtCore import Qt, QThread, pyqtSignal, pyqtSlot
from PyQt6.QtGui import (
QFont,
QFontMetrics,
)
from PyQt6.QtWidgets import (
QApplication,
QGridLayout,
QGroupBox,
QHBoxLayout,
QLabel,
QProgressBar,
QPushButton,
QSizePolicy,
QVBoxLayout,
QWidget,
)
from qasync import QEventLoop
from tqdm import tqdm
CHUNK = 524288
url = "http://ipv4.download.thinkbroadband.com/100MB.zip"
UNITS = ("B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB", "RiB", "QiB")
UNIT_SIZES = [1 << (i * 10) for i in range(11)]
ALIGNMENT = Qt.AlignmentFlag.AlignLeft | Qt.AlignmentFlag.AlignTop
def to_time(n: float) -> str:
n = int(n + 0.5)
segments = []
for _ in (0, 1):
n, d = divmod(n, 60)
segments.insert(0, d)
if n:
segments.insert(0, n)
return ":".join(map(str, segments))
def format_size(size: int) -> str:
i = bisect(UNIT_SIZES, size) - 1
return f"{round(size/UNIT_SIZES[i], 3)}{UNITS[i]}"
class Downloader(QThread):
update = pyqtSignal()
refresh = pyqtSignal()
def __init__(self, url: str, filepath: str, links: int = 16) -> None:
super().__init__()
self.url = url
self.filepath = filepath
self.links = links
self.update.connect(self.update_values)
async def preprocess(self, session: ClientSession) -> None:
resp = await session.head(self.url)
self.total = int(resp.headers["Content-Length"])
self.progress = tqdm(
total=self.total, unit_scale=True, unit_divisor=1024, unit="B"
)
async def start_download(self) -> None:
async with ClientSession(
headers={
"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:123.0) Gecko/20100101 Firefox/123.0"
}
) as session:
await self.preprocess(session)
self.chunk = self.total // self.links
ends = range(0, self.total, self.chunk)[: self.links]
self.ranges = [
*((start, end - 1) for start, end in zip(ends, ends[1:])),
(ends[-1], self.total - 1),
]
await asyncio.gather(
*(self.download_worker(i, session) for i in range(self.links))
)
async def download_worker(self, index: int, session: ClientSession) -> None:
async with aiofiles.open(self.filepath, "wb") as file:
start, end = self.ranges[index]
await file.seek(start)
async with session.get(
url=self.url,
headers={"Range": f"bytes={start}-{end}"},
) as resp:
async for chunk in resp.content.iter_chunked(CHUNK):
self.progress.update(len(chunk))
self.update.emit()
await file.write(chunk)
def update_values(self) -> None:
d = self.progress.format_dict
self.stats = {
"Downloaded": d["n"],
"Total": d["total"],
"Elapsed": d["elapsed"],
"Speed": d["rate"],
"ETA": (d["total"] - d["n"]) / d["rate"],
}
self.refresh.emit()
def run(self) -> None:
loop = QEventLoop(self)
asyncio.set_event_loop(loop)
loop.run_until_complete(self.start_download())
class Font(QFont):
def __init__(self, size: int = 10) -> None:
super().__init__()
self.setFamily("Times New Roman")
self.setStyleHint(QFont.StyleHint.Times)
self.setStyleStrategy(QFont.StyleStrategy.PreferAntialias)
self.setPointSize(size)
self.setBold(True)
self.setHintingPreference(QFont.HintingPreference.PreferFullHinting)
FONT = Font()
FONT_RULER = QFontMetrics(FONT)
class Box(QGroupBox):
def __init__(self) -> None:
super().__init__()
self.setAlignment(ALIGNMENT)
self.setContentsMargins(3, 3, 3, 3)
self.setSizePolicy(QSizePolicy.Policy.Minimum, QSizePolicy.Policy.Minimum)
self.vbox = make_vbox(self)
class Button(QPushButton):
def __init__(self, text: str) -> None:
super().__init__()
self.setFont(FONT)
self.setFixedSize(72, 20)
self.setText(text)
def make_box(
box_type: type[QHBoxLayout] | type[QVBoxLayout] | type[QGridLayout],
parent: QWidget,
margin: int,
) -> QHBoxLayout | QVBoxLayout | QGridLayout:
box = box_type(parent) if parent else box_type()
box.setAlignment(ALIGNMENT)
box.setContentsMargins(*[margin] * 4)
return box
def make_vbox(parent: QWidget = None, margin: int = 0) -> QVBoxLayout:
return make_box(QVBoxLayout, parent, margin)
def make_hbox(parent: QWidget = None, margin: int = 0) -> QHBoxLayout:
return make_box(QHBoxLayout, parent, margin)
class Label(QLabel):
def __init__(self, text: str) -> None:
super().__init__()
self.setFont(FONT)
self.set_text(text)
def autoResize(self) -> None:
self.Height = FONT_RULER.size(0, self.text()).height()
self.Width = FONT_RULER.size(0, self.text()).width()
self.setFixedSize(self.Width + 3, self.Height + 8)
def set_text(self, text: str) -> None:
self.setText(text)
self.autoResize()
class ProgressBar(QProgressBar):
def __init__(self) -> None:
super().__init__()
self.setFont(FONT)
self.setValue(0)
self.setFixedSize(1000, 25)
class Underbar(Box):
def __init__(self):
super().__init__()
self.setFixedHeight(256)
self.progressbar = ProgressBar()
self.hbox = make_hbox()
self.hbox.addWidget(self.progressbar)
self.displays = {}
for name in ("Downloaded", "Total", "Speed", "Elapsed", "ETA"):
self.hbox.addWidget(Label(name))
widget = Label("0")
self.hbox.addWidget(widget)
self.displays[name] = widget
self.vbox.addLayout(self.hbox)
self.button = Button("Test")
self.vbox.addWidget(self.button)
self.button.clicked.connect(self.test)
def test(self):
self.progressbar.setValue(0)
self.down = Downloader(url, "D:/speedtest/100MB.zip")
self.down.refresh.connect(self.update_values)
self.down.run()
def update_values(self):
stats = self.down.stats
self.displays["Downloaded"].setText(format_size(stats["Downloaded"]))
self.displays["Total"].setText(format_size(stats["Total"]))
self.displays["Speed"].setText(format_size(stats["Speed"]) + "/s")
self.displays["Elapsed"].setText(to_time(stats["Elapsed"]))
self.displays["ETA"].setText(to_time(stats["ETA"]))
self.progressbar.setValue(int(stats["Downloaded"] / stats["Total"] * 100 + 0.5))
for label in self.displays.values():
label.autoResize()
if __name__ == "__main__":
app = QApplication([])
app.setStyle("Fusion")
window = Underbar()
window.show()
sys.exit(app.exec())