Fetching Intraday data from Google using Python

# Copyright (c) 2011, Mark Chenoweth
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without modification, are permitted 
# provided that the following conditions are met:
#
# - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
#
# - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following 
#   disclaimer in the documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 
# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 
# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 
# ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

import urllib,time,datetime
import  pandas as pd


class Quote(object):
  
  DATE_FMT = '%Y-%m-%d'
  TIME_FMT = '%H:%M:%S'
  
  def __init__(self):
    self.symbol = ''
    self.date,self.time,self.open_,self.high,self.low,self.close,self.volume = ([] for _ in range(7))

  def append(self,dt,open_,high,low,close,volume):
    self.date.append(dt.date())
    self.time.append(dt.time())
    self.open_.append(float(open_))
    self.high.append(float(high))
    self.low.append(float(low))
    self.close.append(float(close))
    self.volume.append(int(volume))
      
  def to_csv(self):
    return ''.join(["{0},{1},{2},{3:.2f},{4:.2f},{5:.2f},{6:.2f},{7}\n".format(self.symbol,
              self.date[bar].strftime('%Y-%m-%d'),self.time[bar].strftime('%H:%M:%S'),
              self.open_[bar],self.high[bar],self.low[bar],self.close[bar],self.volume[bar]) 
              for bar in xrange(len(self.close))])
    
  def write_csv(self,filename):
    with open(filename,'w') as f:
      f.write(self.to_csv())
        
  def read_csv(self,filename):
    self.symbol = ''
    self.date,self.time,self.open_,self.high,self.low,self.close,self.volume = ([] for _ in range(7))
    for line in open(filename,'r'):
      symbol,ds,ts,open_,high,low,close,volume = line.rstrip().split(',')
      self.symbol = symbol
      dt = datetime.datetime.strptime(ds+' '+ts,self.DATE_FMT+' '+self.TIME_FMT)
      self.append(dt,open_,high,low,close,volume)
    return True

  def __repr__(self):
    return self.to_csv()

class GoogleIntradayQuote(Quote):
  ''' Intraday quotes from Google. Specify interval seconds and number of days '''
  def __init__(self,symbol,interval_seconds=300,num_days=5):
    super(GoogleIntradayQuote,self).__init__()
    self.symbol = symbol.upper()
    url_string = "http://www.google.com/finance/getprices?q={0}".format(self.symbol)
    url_string += "&x=NSE&i={0}&p={1}d&f=d,o,h,l,c,v".format(interval_seconds,num_days)
    csv = urllib.urlopen(url_string).readlines()
    for bar in xrange(7,len(csv)):
      if csv[bar].count(',')!=5: continue
      offset,close,high,low,open_,volume = csv[bar].split(',')
      if offset[0]=='a':
        day = float(offset[1:])
        offset = 0
      else:
        offset = float(offset)
      open_,high,low,close = [float(x) for x in [open_,high,low,close]]
      dt = datetime.datetime.fromtimestamp(day+(interval_seconds*offset))
      self.append(dt,open_,high,low,close,volume)
   
   
if __name__ == '__main__':
  q = GoogleIntradayQuote('RCOM',300,30)
  #print q                                           # print it out
  q.write_csv('c://data//rcom.csv')