Question

I was looking to find a way to optimize my code when I heard some good things about threads and urllib3. Apparently, people disagree which solution is the best.

The problem with my script below is the execution time: so slow!

Step 1: I fetch this page
http://www.cambridgeesol.org/institutions/results.php?region=Afghanistan&type=&BULATS=on

Step 2: I parse the page with BeautifulSoup

Step 3: I put the data in an excel doc

Step 4: I do it again, and again, and again for all the countries in my list (big list)
(I am just changing “Afghanistan” in the url to another country)

Here is my code:

ws = wb.add_sheet("BULATS_IA") #We add a new tab in the excel doc
    x = 0 # We need x and y for pulling the data into the excel doc
    y = 0
    Countries_List = ['Afghanistan','Albania','Andorra','Argentina','Armenia','Australia','Austria','Azerbaijan','Bahrain','Bangladesh','Belgium','Belize','Bolivia','Bosnia and Herzegovina','Brazil','Brunei Darussalam','Bulgaria','Cameroon','Canada','Central African Republic','Chile','China','Colombia','Costa Rica','Croatia','Cuba','Cyprus','Czech Republic','Denmark','Dominican Republic','Ecuador','Egypt','Eritrea','Estonia','Ethiopia','Faroe Islands','Fiji','Finland','France','French Polynesia','Georgia','Germany','Gibraltar','Greece','Grenada','Hong Kong','Hungary','Iceland','India','Indonesia','Iran','Iraq','Ireland','Israel','Italy','Jamaica','Japan','Jordan','Kazakhstan','Kenya','Kuwait','Latvia','Lebanon','Libya','Liechtenstein','Lithuania','Luxembourg','Macau','Macedonia','Malaysia','Maldives','Malta','Mexico','Monaco','Montenegro','Morocco','Mozambique','Myanmar (Burma)','Nepal','Netherlands','New Caledonia','New Zealand','Nigeria','Norway','Oman','Pakistan','Palestine','Papua New Guinea','Paraguay','Peru','Philippines','Poland','Portugal','Qatar','Romania','Russia','Saudi Arabia','Serbia','Singapore','Slovakia','Slovenia','South Africa','South Korea','Spain','Sri Lanka','Sweden','Switzerland','Syria','Taiwan','Thailand','Trinadad and Tobago','Tunisia','Turkey','Ukraine','United Arab Emirates','United Kingdom','United States','Uruguay','Uzbekistan','Venezuela','Vietnam']
    Longueur = len(Countries_List)



    for Countries in Countries_List:
        y = 0

        htmlSource = urllib.urlopen("http://www.cambridgeesol.org/institutions/results.php?region=%s&type=&BULATS=on" % (Countries)).read() # I am opening the page with the name of the correspondant country in the url
        s = soup(htmlSource)
        tableGood = s.findAll('table')
        try:
            rows = tableGood[3].findAll('tr')
            for tr in rows:
                cols = tr.findAll('td')
                y = 0
                x = x + 1
                for td in cols:
                    hum =  td.text
                    ws.write(x,y,hum)
                    y = y + 1
                    wb.save("%s.xls" % name_excel)

        except (IndexError):
            pass

So I know that all is not perfect but I am looking forward to learn new things in Python ! The script is very slow because urllib2 is not that fast, and BeautifulSoup. For the soup thing, I guess I can’t really make it better, but for urllib2, I don’t.

EDIT 1 :
Multiprocessing useless with urllib2?
Seems to be interesting in my case.
What do you guys think about this potential solution ?!

# Make sure that the queue is thread-safe!!

def producer(self):
    # Only need one producer, although you could have multiple
    with fh = open('urllist.txt', 'r'):
        for line in fh:
            self.queue.enqueue(line.strip())

def consumer(self):
    # Fire up N of these babies for some speed
    while True:
        url = self.queue.dequeue()
        dh = urllib2.urlopen(url)
        with fh = open('/dev/null', 'w'): # gotta put it somewhere
            fh.write(dh.read())

EDIT 2: URLLIB3
Can anyone tell me more things about that ?

Re-use the same socket connection for multiple requests
(HTTPConnectionPool and HTTPSConnectionPool) (with optional
client-side certificate verification).
https://github.com/shazow/urllib3

As far as I am requesting 122 times the same website for different pages, I guess reusing the same socket connection can be interesting, am I wrong ?
Cant it be faster ? …

http = urllib3.PoolManager()
r = http.request('GET', 'http://www.bulats.org')
for Pages in Pages_List:
    r = http.request('GET', 'http://www.bulats.org/agents/find-an-agent?field_continent_tid=All&field_country_tid=All&page=%s' % (Pages))
    s = soup(r.data)

Answer 1

Consider using something like workerpool. Referring to the Mass Downloader example, combined with urllib3 would look something like:

import workerpool
import urllib3

URL_LIST = [] # Fill this from somewhere

NUM_SOCKETS = 3
NUM_WORKERS = 5

# We want a few more workers than sockets so that they have extra
# time to parse things and such.

http = urllib3.PoolManager(maxsize=NUM_SOCKETS)
workers = workerpool.WorkerPool(size=NUM_WORKERS)

class MyJob(workerpool.Job):
    def __init__(self, url):
       self.url = url

    def run(self):
        r = http.request('GET', self.url)
        # ... do parsing stuff here


for url in URL_LIST:
    workers.put(MyJob(url))

# Send shutdown jobs to all threads, and wait until all the jobs have been completed
# (If you don't do this, the script might hang due to a rogue undead thread.)
workers.shutdown()
workers.wait()

You may note from the Mass Downloader examples that there are multiple ways of doing this. I chose this particular example just because it’s less magical, but any of the other strategies are valid also.

Disclaimer: I am the author of both, urllib3 and workerpool.