Fetch a Wikipedia article with Python

You need to use the urllib2 that superseedes urllib in the python std library in order to change the user agent.

Straight from the examples

import urllib2
opener = urllib2.build_opener()
opener.addheaders = [('User-agent', 'Mozilla/5.0')]
infile = opener.open('http://en.wikipedia.org/w/index.php?title=Albert_Einstein&printable=yes')
page = infile.read()

It is not a solution to the specific problem. But it might be intersting for you to use the mwclient library (http://botwiki.sno.cc/wiki/Python:Mwclient) instead. That would be so much easier. Especially since you will directly get the article contents which removes the need for you to parse the html.

I have used it myself for two projects, and it works very well.

Rather than trying to trick Wikipedia, you should consider using their High-Level API.

The general solution I use for any site is to access the page using Firefox and, using an extension such as Firebug, record all details of the HTTP request including any cookies.

In your program (in this case in Python) you should try to send a HTTP request as similar as necessary to the one that worked from Firefox. This often includes setting the User-Agent, Referer and Cookie fields, but there may be others.

Try changing the user agent header you are sending in your request to something like: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.1) Gecko/2008072820 Ubuntu/8.04 (hardy) Firefox/3.0.1 (Linux Mint)

You don't need to impersonate a browser user-agent; any user-agent at all will work, just not a blank one.

import urllib
s = urllib.urlopen('http://en.wikipedia.org/w/index.php?action=raw&title=Albert_Einstein').read()

This seems to work for me without changing the user agent. Without the "action=raw" it does not work for me.