Random Walk on Youtube

ytrw.py

#!/usr/bin/env python

import random
import sys
import urllib2
from bs4 import BeautifulSoup

def video_open(vid):
    url = 'http://www.youtube.com' + vid
    return urllib2.urlopen(url)

def select_video(vids):
    lamb = 0.5
    i = min(int(random.expovariate(lamb)), len(vids) - 1)
    return vids[i]

def related_videos(vid):
    soup = BeautifulSoup(video_open(vid))
    wr = soup.find(id='watch-related')
    r = []
    for c in wr.children:
        if 'video-list-item' not in c['class']:
            continue
        link = c.find('a')
        href = link['href']
        if 'relchannel' in href:
            continue
        title = link.find(attrs={'class': 'title'})['title']
        r.append ((href, title))
    return r

def main():
    vid = '/watch?v=mbUVtfUWwF8' # Chuck testa song
    if len(sys.argv) > 1:
        vid = '/watch?v=' + sys.argv[1]

    for i in range(0, 30):
        vids = related_videos(vid)
        newvid = select_video(vids)
        print "http://youtube.com%-50s %s" % newvid
        vid = newvid[0]

if __name__ == '__main__':
    main()