stockretriever.py

"""A wrapper for the Yahoo! Finance YQL api."""

import sys, httplib, urllib

try: import simplejson as json
except ImportError: import json

PUBLIC_API_URL = 'http://query.yahooapis.com/v1/public/yql'
DATATABLES_URL = 'store://datatables.org/alltableswithkeys'
HISTORICAL_URL = 'http://ichart.finance.yahoo.com/table.csv?s='
RSS_URL = 'http://finance.yahoo.com/rss/headline?s='
FINANCE_TABLES = {'quotes': 'yahoo.finance.quotes',
                 'options': 'yahoo.finance.options',
                 'quoteslist': 'yahoo.finance.quoteslist',
                 'sectors': 'yahoo.finance.sectors',
                 'industry': 'yahoo.finance.industry'}

				 
def executeYQLQuery(yql):
	conn = httplib.HTTPConnection('query.yahooapis.com')
	queryString = urllib.urlencode({'q': yql, 'format': 'json', 'env': DATATABLES_URL})
	conn.request('GET', PUBLIC_API_URL + '?' + queryString)
	return json.loads(conn.getresponse().read())

	
class QueryError(Exception):

	def __init__(self, value):
		self.value = value



	def __str__(self):
		return repr(self.value)
  
  

def __format_symbol_list(symbolList):
	return ",".join(["\""+stock+"\"" for stock in symbolList])
	


def __is_valid_response(response, field):
	return 'query' in response and 'results' in response['query'] \
		and field in response['query']['results']
    


def __validate_response(response, tagToCheck):
	if __is_valid_response(response, tagToCheck):
		quoteInfo = response['query']['results'][tagToCheck]
	else:
		if 'error' in response:
			raise QueryError('YQL query failed with error: "%s".' 
				% response['error']['description'])
		else:
			raise QueryError('YQL response malformed.')
	return quoteInfo


        
def get_current_info(symbolList, columnsToRetrieve='*'):
	"""Retrieves the latest data (15 minute delay) for the 
	provided symbols."""
	
	columns = ','.join(columnsToRetrieve)
	symbols = __format_symbol_list(symbolList)

	yql = 'select %s from %s where symbol in (%s)' \
		  %(columns, FINANCE_TABLES['quotes'], symbols)
	response = executeYQLQuery(yql)
	return __validate_response(response, 'quote')



def get_historical_info(symbol):
	"""Retrieves historical stock data for the provided symbol.
	Historical data includes date, open, close, high, low, volume,
	and adjusted close."""
	
	yql = 'select * from csv where url=\'%s\'' \
		  ' and columns=\"Date,Open,High,Low,Close,Volume,AdjClose\"' \
		   % (HISTORICAL_URL + symbol)
	results = executeYQLQuery(yql)
	# delete first row which contains column names
	del results['query']['results']['row'][0]
	return results['query']['results']['row']
	


def get_news_feed(symbol):
	"""Retrieves the rss feed for the provided symbol."""
	
	feedUrl = RSS_URL + symbol
	yql = 'select title, link, description, pubDate from rss where url=\'%s\'' % feedUrl
	response = executeYQLQuery(yql)
	if response['query']['results']['item'][0]['title'].find('not found') > 0:
		raise QueryError('Feed for %s does not exist.' % symbol)
	else:
		return response['query']['results']['item']


	
def get_options_info(symbol, expiration='', columnsToRetrieve ='*'):
	"""Retrieves options data for the provided symbol."""
	
	columns = ','.join(columnsToRetrieve)
	yql = 'select %s from %s where symbol = \'%s\'' \
		  % (columns, FINANCE_TABLES['options'], symbol)
	
	if expiration != '':
		yql += " and expiration='%s'" %(expiration)
	
	response = executeYQLQuery(yql)
	return __validate_response(response, 'optionsChain')


	
def get_index_summary(index, columnsToRetrieve='*'):
	columns = ','.join(columnsToRetrieve)
	yql = 'select %s from %s where symbol = \'@%s\'' \
		  % (columns, FINANCE_TABLES['quoteslist'], index)
	response = executeYQLQuery(yql)
	return __validate_response(response, 'quote')



def get_industry_ids():
	"""retrieves all industry names and ids."""
	
	yql = 'select * from %s' % FINANCE_TABLES['sectors']
	response = executeYQLQuery(yql)
	return __validate_response(response, 'sector')



def get_industry_index(id):
	"""retrieves all symbols that belong to an industry."""
	
	yql = 'select * from %s where id =\'%s\'' \
		  % (FINANCE_TABLES['industry'], id)
	response = executeYQLQuery(yql)
	return __validate_response(response, 'industry')
        

if __name__ == "__main__":
    try:
        print get_current_info(sys.argv[1:])
        #print get_industry_ids()
        #get_news_feed('yhoo')
    except QueryError, e:
        print e
        sys.exit(2)