Python, 基础题 : How do I download multiple url's with urllib. request.urlretrieve

Question

我有以下功能齐全的工作代码:

import urllib.request
import zipfile

url = "http://url.com/archive.zip?key=7UCxcuCzFpYeu7tz18JgGZFAAgXQ2sop"
filename = "C:/test/archive.zip"
destinationPath = "C:/test"

urllib.request.urlretrieve(url,filename)
sourceZip = zipfile.ZipFile(filename, 'r')

for name in sourceZip.namelist():
    sourceZip.extract(name, destinationPath)
sourceZip.close()

它会完美运行几次，但因为我从中检索文件的服务器有一些限制，一旦达到每日限制，我就会收到此错误:

Traceback (most recent call last):
  File "script.py", line 11, in <module>
    urllib.request.urlretrieve(url,filename)
  File "C:\Python32\lib\urllib\request.py", line 150, in urlretrieve
    return _urlopener.retrieve(url, filename, reporthook, data)
  File "C:\Python32\lib\urllib\request.py", line 1591, in retrieve
    block = fp.read(bs)
ValueError: read of closed file

如何更改脚本，使其包含多个 url 的列表，而不是一个 url，并且脚本一直尝试从列表中下载直到成功，然后继续解压缩。我只需要一次成功下载。

很抱歉我是 Python 的新手，但我无法理解这一点。我假设我必须将变量更改为如下所示:

url = {
"http://url.com/archive.zip?key=7UCxcuCzFpYeu7tz18JgGZFAAgXQ2soe",
"http://url.com/archive.zip?key=7UCxcuCzFpYeu7tz18JgGZFAAgXQ2sod",
"http://url.com/archive.zip?key=7UCxcuCzFpYeu7tz18JgGZFAAgXQ2soc",
"http://url.com/archive.zip?key=7UCxcuCzFpYeu7tz18JgGZFAAgXQ2sob",
"http://url.com/archive.zip?key=7UCxcuCzFpYeu7tz18JgGZFAAgXQ2soa",
}

然后将这一行更改为某种循环:

urllib.request.urlretrieve(url,filename)

Answer 1

您想将您的网址放在一个列表中，然后遍历该列表并尝试每一个。您捕获但忽略它们抛出的异常，并在成功后中断循环。试试这个:

import urllib.request
import zipfile

urls = ["http://url.com/archive.zip?key=7UCxcuCzFpYeu7tz18JgGZFAAgXQ2sop", "other url", "another url"]
filename = "C:/test/test.zip"
destinationPath = "C:/test"

for url in urls:
    try:
        urllib.request.urlretrieve(url,filename)
        sourceZip = zipfile.ZipFile(filename, 'r')
        break
    except ValueError:
        pass

for name in sourceZip.namelist():
    sourceZip.extract(name, destinationPath)
sourceZip.close()