Question

在Linux（Ubuntu）上，当我运行wget www.example.com/file.zip -O file.zip时，我看到一个表示下载进度的进度条。如下图所示：

enter image description here

Python中有没有办法检索我用红色包围的所有信息？

我的意思是我希望将这些信息检索到单独的Python变量中：

正在下载的数据
下载速度
剩余时间

Answer 1

您可以使用wget库和urllib的自定义函数在Python中实现自己的reporthook

def reporthook(count_blocks, block_size, total_size):
    global start_time
    if count == 0:
      start_time = time.time()
      return
    duration = time.time() - start_time
    progress_size = int(count_blocks * block_size)
    print "downloaded %f%%" % count_blocks/float(total_size)
    # etc ...

urllib.urlretrieve(url, filename, reporthook)

（另见https://stackoverflow.com/a/4152008/2314737）

这是一个完整的Python 3实现：https://pypi.python.org/pypi/wget

Answer 2

您可以使用subprocess：

import subprocess

process = subprocess.Popen(
['wget', 'http://speedtest.dal01.softlayer.com/downloads/test10.zip', '-O', '/dev/null'],
stderr=subprocess.PIPE)

started = False
for line in process.stderr:
    line = line.decode("utf-8", "replace")
    if started:
        print(line.split())
    elif line == os.linesep:
        started = True

现在您只需要解析line.split()输出并更改wget参数（这仅用于测试而不保存下载的数据）。

这适用于使用python 3.4的Windows：

import subprocess
import os
import sys

wget = os.path.join("C:\\" , "Program Files (x86)", "GnuWin32", "bin", "wget.exe")

process = subprocess.Popen(
    [wget, 'http://speedtest.dal01.softlayer.com/downloads/test10.zip', '-O', 'NUL'],
    stderr=subprocess.PIPE)

started = False
for line in process.stderr:
    line = line.decode("utf-8", "replace")
    if started:
        splited = line.split()
        if len(splited) == 9:
            percentage = splited[6]
            speed = splited[7]
            remaining = splited[8]
            print("Downloaded {} with {} per second and {} left.".format(percentage, speed, remaining), end='\r')
    elif line == os.linesep:
        started = True

Answer 3

由于这些信息输出到stderr，因此您需要从sys.stderr中读取它们。我们可以使用select来读取stderr，因为输出正在改变。仅供参考，以下是一个例子：

# -*- coding: utf-8 -*-
from subprocess import PIPE, Popen
import fcntl
import os
import select
import sys

proc = Popen(['wget', 'http://speedtest.london.linode.com/100MB-london.bin'], stdin = PIPE, stderr = PIPE, stdout = PIPE)

while proc.poll() == None:
    fcntl.fcntl(
            proc.stderr.fileno(),
            fcntl.F_SETFL,
            fcntl.fcntl(proc.stderr.fileno(), fcntl.F_GETFL) | os.O_NONBLOCK,
            )

    buf = ''
    while proc.poll() == None:
        readx_err = select.select([proc.stderr.fileno()], [], [], 0.1)[0]
        if readx_err:
            chunk = proc.stderr.read().decode('utf-8')
            buf += chunk
            if '\n' in buf and '%' in buf and '.' in buf:
                print (buf.strip().split())
                buf = ''
        else:
            break
proc.wait()

如何使用Python获取wget命令信息？

3 个答案: