[Python编程(第4版)].(Programming.Python.4th.Edition).Mark.Lutz.文字版

We can use such a higher-level interface to download anything with an address on the

Web—files published by FTP sites (using URLs that start with ftp://); web pages and

output of scripts that live on remote servers (using http:// URLs); and even local files

(using file:// URLs). For instance, the script in Example 13-2 does the same as the one

in Example 13-1, but it uses the general urllib.request module to fetch the source

distribution file, instead of the protocol-specific ftplib.

Example 13-2. PP4E\Internet\Ftp\getone-urllib.py

#!/usr/local/bin/python

"""

A Python script to download a file by FTP by its URL string; use higher-level

urllib instead of ftplib to fetch file; urllib supports FTP, HTTP, client-side

HTTPS, and local files, and handles proxies, redirects, cookies, and more;

urllib also allows downloads of html pages, images, text, etc.; see also

Python html/xml parsers for web pages fetched by urllib in Chapter 19;

"""

import os, getpass

from urllib.request import urlopen # socket-based web tools

Figure 13-1. Image file downloaded by FTP and opened locally

858 | Chapter 13: Client-Side Scripting

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