Problem HTTP error 403 in Python 3 Web Scraping

I was trying to scrape a website for practice, but I kept on getting the HTTP Error 403 (does it think I'm a bot)?

Here is my code:

#import requests
import urllib.request
from bs4 import BeautifulSoup
#from urllib import urlopen
import re

webpage = urllib.request.urlopen('http://www.cmegroup.com/trading/products/#sortField=oi&sortAsc=false&venues=3&page=1&cleared=1&group=1').read
findrows = re.compile('<tr class="- banding(?:On|Off)>(.*?)</tr>')
findlink = re.compile('<a href =">(.*)</a>')

row_array = re.findall(findrows, webpage)
links = re.finall(findlink, webpate)

print(len(row_array))

iterator = []

The error I get is:

 File "C:\Python33\lib\urllib\request.py", line 160, in urlopen
    return opener.open(url, data, timeout)
  File "C:\Python33\lib\urllib\request.py", line 479, in open
    response = meth(req, response)
  File "C:\Python33\lib\urllib\request.py", line 591, in http_response
    'http', request, response, code, msg, hdrs)
  File "C:\Python33\lib\urllib\request.py", line 517, in error
    return self._call_chain(*args)
  File "C:\Python33\lib\urllib\request.py", line 451, in _call_chain
    result = func(*args)
  File "C:\Python33\lib\urllib\request.py", line 599, in http_error_default
    raise HTTPError(req.full_url, code, msg, hdrs, fp)
urllib.error.HTTPError: HTTP Error 403: Forbidden

This is probably because of mod_security or some similar server security feature which blocks known spider/bot user agents (urllib uses something like python urllib/3.3.0, it's easily detected). Try setting a known browser user agent with:

from urllib.request import Request, urlopen

req = Request('http://www.cmegroup.com/trading/products/#sortField=oi&sortAsc=false&venues=3&page=1&cleared=1&group=1', headers={'User-Agent': 'Mozilla/5.0'})
webpage = urlopen(req).read()

This works for me.

By the way, in your code you are missing the () after .read in the urlopen line, but I think that it's a typo.

TIP: since this is exercise, choose a different, non restrictive site. Maybe they are blocking urllib for some reason...

Definitely it's blocking because of your use of urllib based on the user agent. This same thing is happening to me with OfferUp. You can create a new class called AppURLopener which overrides the user-agent with Mozilla.

import urllib.request

class AppURLopener(urllib.request.FancyURLopener):
    version = "Mozilla/5.0"

opener = AppURLopener()
response = opener.open('http://httpbin.org/user-agent')

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