在 QMainWindow 中显示来自回调的进度条，boto3.s3

Question

我正在创建一个将文件夹上传到存储桶的程序。现在我已经设置了程序和UI，我只想添加一个进度条，显示正在上传的文件。

我想知道是否有办法使用s3.upload_file(fileName, bucketName, objectName, Callback=ProgressPercentage(path.text()))在我的QMainWindow上获取进度条。或者如果我需要以不同的方式解决这个问题。

class ProgressPercentage(object):
def __init__(self, filename):
self._filename = filename
self._size = float(os.path.getsize(filename))
self._seen_so_far = 0
self._lock = threading.Lock()
def __call__(self, bytes_amount):
# To simplify, assume this is hooked up to a single filename
with self._lock:
self._seen_so_far += bytes_amount
percentage = (self._seen_so_far / self._size) * 100
sys.stdout.write(
"r%s  %s / %s  (%.2f%%)" % (
self._filename, self._seen_so_far, self._size,
percentage))
sys.stdout.flush()

Answer 1

在这种情况下，逻辑是创建一个具有指示进度的信号的 QObject，此外，上传任务必须在辅助线程中执行，以便 GUI 不会冻结：

import math
import os
import sys
import threading
import boto3
from PyQt5 import QtCore, QtWidgets

class S3Worker(QtCore.QObject):
started = QtCore.pyqtSignal()
finished = QtCore.pyqtSignal()
percentageChanged = QtCore.pyqtSignal(int)
def __init__(self, parent=None):
super().__init__(parent)
self._s3 = boto3.client("s3")
@property
def s3(self):
return self._s3
def upload(self, filename, bucketname, objectname):
self._size = float(os.path.getsize(filename))
self._seen_so_far = 0
threading.Thread(
target=self._execute, args=(filename, bucketname, objectname), daemon=True
).start()
def _execute(self, fileName, bucketName, objectName):
self.started.emit()
self.s3.upload_file(fileName, bucketName, objectName, Callback=self._callback)
self.finished.emit()
def _callback(self, bytes_amount):
self._seen_so_far += bytes_amount
percentage = (self._seen_so_far / self._size) * 100
self.percentageChanged.emit(math.floor(percentage))

class Widget(QtWidgets.QWidget):
def __init__(self, parent=None):
super().__init__(parent)
self.filename_le = QtWidgets.QLineEdit()
self.upload_btn = QtWidgets.QPushButton("Upload")
self.percentage_pb = QtWidgets.QProgressBar()
lay = QtWidgets.QGridLayout(self)
lay.addWidget(QtWidgets.QLabel("filename:"))
lay.addWidget(self.filename_le, 0, 1)
lay.addWidget(self.upload_btn, 0, 2)
lay.addWidget(self.percentage_pb, 1, 0, 1, 3)
self.qs3 = S3Worker()
self.upload_btn.clicked.connect(self.start_upload)
self.qs3.started.connect(lambda: self.upload_btn.setEnabled(False))
self.qs3.finished.connect(lambda: self.upload_btn.setEnabled(True))
self.qs3.percentageChanged.connect(self.percentage_pb.setValue)
def start_upload(self):
filename = self.filename_le.text()
if os.path.exists(filename):
self.qs3.upload(filename, "mybucket", "foobject")

def main():
app = QtWidgets.QApplication(sys.argv)
w = Widget()
w.show()
sys.exit(app.exec_())
if __name__ == "__main__":
main()