#file-name: pdf_download.py
__author__ = 'rxread'
import requests
from bs4 import BeautifulSoup
def download_file(url, index):
    local_filename = index+"-"+url.split('/')[-1]
    # NOTE the stream=True parameter
    r = requests.get(url, stream=True)
    with open(local_filename, 'wb') as f:
        for chunk in r.iter_content(chunk_size=1024):
            if chunk: # filter out keep-alive new chunks
                f.write(chunk)
                f.flush()
    return local_filename




#Change Here To Change the Website
root_link="http://people.cs.umass.edu/~barring/cs250s14/lecture/"




r=requests.get(root_link)
if r.status_code==200:
    soup=BeautifulSoup(r.text)
    # print soup.prettify()

   
    index=1
    
    for link in soup.find_all('a'):
        new_link=root_link+link.get('href')
        if new_link.endswith(".pdf"):
            file_path=download_file(new_link,str(index))
            print "downloading:"+new_link+" -> "+file_path
            # index+=1
    print "all download finished"
else:
    print "errors occur."
