YouTube视频下载器

Question

我做了一个youtube视频下载管理器。它下载视频，但我面临一个问题，当我下载相同的视频时，它不会再次下载。我怎样才能像pic.png一样用同样的标题再次下载它并发送pic1.png。我该怎么做呢？

def Download(self):
    video_url = self.lineEdit.text()
    save_location = self.lineEdit_2.text()
    if video_url == '' or save_location == '':
        QMessageBox.warning(self, "Data Error", "Provide a Valid Video URL or save Location")

    else:
        video = pafy.new(video_url)
        video_stream = video.streams
        video_quality = self.comboBox.currentIndex()

        download = video_stream[video_quality].download(filepath=save_location, callback=self.Handel_Progress, )

Answer 1

好的，这一条很有趣。

真正的问题从这里开始。

    download = video_stream[video_quality].download(filepath=save_location, callback=self.Handel_Progress, )

在这里，您将调用video_stream对象的download函数，该函数将filepath作为文件位置的参数，但不接受文件名，因为很明显，文件将以实际名称保存。

问题的根本原因：

如果你查看download函数的定义，你会发现如果存在一个同名的文件，它根本不会下载该文件。

现在来了，你如何确保它被下载，不管怎样：

您需要做两件事：

1. 检查是否存在同名文件，如果存在，则在文件名末尾的扩展名之前添加1。因此，如果abc.mp4存在，则保存abc1.mp4。我将告诉您如何处理abc.mp4、abc1.mp4等存在的情况，但现在，让我们回到问题上来。
2. 如何将文件名(abc1.mp4)传递给download方法？

下面这段代码可以同时处理这两种情况。我已经添加了一些评论，以供您理解。

import os
import re

import pafy
from pafy.util import xenc


# this function is used by pafy to generate file name while saving,
# so im using the same function to get the file name which I will use to check
# if file exists or not
# DO NOT CHANGE IT
def generate_filename(title, extension):
    max_length = 251

    """ Generate filename. """
    ok = re.compile(r'[^/]')

    if os.name == "nt":
        ok = re.compile(r'[^\\/:*?"<>|]')

    filename = "".join(x if ok.match(x) else "_" for x in title)

    if max_length:
        max_length = max_length + 1 + len(extension)
        if len(filename) > max_length:
            filename = filename[:max_length - 3] + '...'

    filename += "." + extension
    return xenc(filename)


def get_file_name_for_saving(save_location, full_name):
    file_path_with_name = os.path.join(save_location, full_name)

    # file exists, add 1 in the end, otherwise return filename as it is
    if os.path.exists(file_path_with_name):
        split = file_path_with_name.split(".")
        file_path_with_name = ".".join(split[:-1]) + "1." + split[-1]

    return file_path_with_name


def Download(self):
    video_url = self.lineEdit.text()
    save_location = self.lineEdit_2.text()
    if video_url == '' or save_location == '':
        QMessageBox.warning(self, "Data Error", "Provide a Valid Video URL or save Location")

    else:
        # video file
        video = pafy.new(video_url)

        # available video streams
        video_stream = video.streams
        video_quality = self.comboBox.currentIndex()

        # video title/name
        video_name = video.title

        # take out the extension of the file from video stream
        extension = video_stream[video_quality].extension

        # fullname with extension
        full_name = generate_filename(video_name, extension)

        final_path_with_file_name = get_file_name_for_saving(save_location, full_name)

        download = video_stream[video_quality].download(filepath=final_path_with_file_name,
                                                        callback=self.Handel_Progress, )

如果你遇到任何问题，请告诉我。