Implement historical finance data from Google Finance

pandas/io/data.py

@@ -58,6 +58,10 @@ def DataReader(name, data_source=None, start=None, end=None,
         return get_data_yahoo(symbols=name, start=start, end=end,
                               adjust_price=False, chunk=25,
                               retry_count=retry_count, pause=pause)
+    elif(data_source == "google"):
+        return get_data_google(symbols=name, start=start, end=end,
+                              adjust_price=False, chunk=25,
+                              retry_count=retry_count, pause=pause)
     elif(data_source == "fred"):
         return get_data_fred(name=name, start=start, end=end)
     elif(data_source == "famafrench"):
@@ -132,6 +136,9 @@ def get_quote_yahoo(symbols):
     return DataFrame(data, index=idx)
 
 
+def get_quote_google(symbols):
+    raise NotImplementedError("Google Finance doesn't have this functionality")
+
 def _get_hist_yahoo(sym=None, start=None, end=None, retry_count=3,
                     pause=0, **kwargs):
     """
@@ -178,6 +185,41 @@ def _get_hist_yahoo(sym=None, start=None, end=None, retry_count=3,
                     "return a 200 for url %s" % (pause, url))
 
 
+def _get_hist_google(sym=None, start=None, end=None, retry_count=3,
+                    pause=0, **kwargs):
+    """
+    Get historical data for the given name from yahoo.
+    Date format is datetime
+
+    Returns a DataFrame.
+    """
+    if(sym is None):
+        warnings.warn("Need to provide a name.")
+        return None
+
+    start, end = _sanitize_dates(start, end)
+
+    google_URL = 'http://www.google.com/finance/historical?'
+
+    # www.google.com/finance/historical?q=GOOG&startdate=Jun+9%2C+2011&enddate=Jun+8%2C+2013&output=csv
+    url = google_URL + urllib.urlencode({"q": sym, \
+        "startdate": start.strftime('%b %d, %Y'), \
+        "enddate": end.strftime('%b %d, %Y'), "output": "csv" })
+    for _ in range(retry_count):
+        resp = urllib2.urlopen(url)
+        if resp.code == 200:
+            lines = resp.read()
+            rs = read_csv(StringIO(bytes_to_str(lines)), index_col=0,
+                          parse_dates=True)[::-1]
+
+            return rs
+
+        time.sleep(pause)
+
+    raise Exception("after %d tries, Google did not "
+                    "return a 200 for url %s" % (pause, url))
+
+
 def _adjust_prices(hist_data, price_list=['Open', 'High', 'Low', 'Close']):
     """
     Return modifed DataFrame or Panel with adjusted prices based on
@@ -347,6 +389,72 @@ def dl_mult_symbols(symbols):
 
     return hist_data
 
+def get_data_google(symbols=None, start=None, end=None, retry_count=3, pause=0,
+                   chunksize=25, **kwargs):
+    """
+    Returns DataFrame/Panel of historical stock prices from symbols, over date
+    range, start to end. To avoid being penalized by Google Finance servers,
+    pauses between downloading 'chunks' of symbols can be specified.
+
+    Parameters
+    ----------
+    symbols : string, array-like object (list, tuple, Series), or DataFrame
+        Single stock symbol (ticker), array-like object of symbols or
+        DataFrame with index containing stock symbols.
+    start : string, (defaults to '1/1/2010')
+        Starting date, timestamp. Parses many different kind of date
+        representations (e.g., 'JAN-01-2010', '1/1/10', 'Jan, 1, 1980')
+    end : string, (defaults to today)
+        Ending date, timestamp. Same format as starting date.
+    retry_count : int, default 3
+        Number of times to retry query request.
+    pause : int, default 0
+        Time, in seconds, to pause between consecutive queries of chunks. If
+        single value given for symbol, represents the pause between retries.
+    chunksize : int, default 25
+        Number of symbols to download consecutively before intiating pause.
+
+    Returns
+    -------
+    hist_data : DataFrame (str) or Panel (array-like object, DataFrame)
+    """
+
+    def dl_mult_symbols(symbols):
+        stocks = {}
+        for sym_group in _in_chunks(symbols, chunksize):
+            for sym in sym_group:
+                try:
+                    stocks[sym] = _get_hist_google(sym, start=start,
+                                                  end=end, **kwargs)
+                except:
+                    warnings.warn('Error with sym: ' + sym + '... skipping.')
+
+            time.sleep(pause)
+
+        return Panel(stocks).swapaxes('items', 'minor')
+
+    if 'name' in kwargs:
+        warnings.warn("Arg 'name' is deprecated, please use 'symbols' instead.",
+                      FutureWarning)
+        symbols = kwargs['name']
+
+    #If a single symbol, (e.g., 'GOOG')
+    if isinstance(symbols, (str, int)):
+        sym = symbols
+        hist_data = _get_hist_google(sym, start=start, end=end)
+    #Or multiple symbols, (e.g., ['GOOG', 'AAPL', 'MSFT'])
+    elif isinstance(symbols, DataFrame):
+        try:
+            hist_data = dl_mult_symbols(Series(symbols.index))
+        except ValueError:
+            raise
+    else: #Guess a Series
+        try:
+            hist_data = dl_mult_symbols(symbols)
+        except TypeError:
+            hist_data = dl_mult_symbols(Series(symbols))
+
+    return hist_data
 
 def get_data_fred(name=None, start=dt.datetime(2010, 1, 1),
                   end=dt.datetime.today()):

pandas/io/tests/test_google.py

@@ -0,0 +1,85 @@
+import unittest
+import nose
+from datetime import datetime
+
+import pandas as pd
+import pandas.io.data as web
+from pandas.util.testing import (network, assert_series_equal)
+from numpy.testing.decorators import slow
+
+import urllib2
+
+
+class TestGoogle(unittest.TestCase):
+
+    @slow
+    @network
+    def test_google(self):
+        # asserts that google is minimally working and that it throws
+        # an excecption when DataReader can't get a 200 response from
+        # google
+        start = datetime(2010, 1, 1)
+        end = datetime(2013, 01, 27)
+
+        try:
+            self.assertEquals(
+                web.DataReader("F", 'google', start, end)['Close'][-1],
+                13.68)
+
+            self.assertRaises(
+                Exception,
+                lambda: web.DataReader("NON EXISTENT TICKER", 'google',
+                                      start, end))
+        except urllib2.URLError:
+            try:
+                urllib2.urlopen('http://www.google.com')
+            except urllib2.URLError:
+                raise nose.SkipTest
+            else:
+                raise
+
+
+    @slow
+    @network
+    def test_get_quote(self):
+        self.assertRaises(NotImplementedError,
+                lambda: web.get_quote_google(pd.Series(['GOOG', 'AAPL', 'GOOG'])))
+
+    @slow
+    @network
+    def test_get_data(self):
+        import numpy as np
+        df = web.get_data_google('GOOG')
+        print(df.Volume.ix['OCT-08-2010'])
+        assert df.Volume.ix['OCT-08-2010'] == 2863473
+
+        sl = ['AAPL', 'AMZN', 'GOOG']
+        pan = web.get_data_google(sl, '2012')
+        ts = pan.Close.GOOG.index[pan.Close.AAPL > pan.Close.GOOG]
+        assert ts[0].dayofyear == 96
+
+        pan = web.get_data_google(['GE', 'MSFT', 'INTC'], 'JAN-01-12', 'JAN-31-12')
+        expected = [19.02, 28.23, 25.39]
+        result = pan.Close.ix['01-18-12'][['GE', 'MSFT', 'INTC']].tolist()
+        assert result == expected
+
+        # sanity checking
+        t= np.array(result)
+        assert     np.issubdtype(t.dtype, np.floating)
+        assert     t.shape == (3,)
+
+        expected = [[ 18.99,  28.4 ,  25.18],
+                    [ 18.58,  28.31,  25.13],
+                    [ 19.03,  28.16,  25.52],
+                    [ 18.81,  28.82,  25.87]]
+        result = pan.Open.ix['Jan-15-12':'Jan-20-12'][['GE', 'MSFT', 'INTC']].values
+        assert (result == expected).all()
+
+        # sanity checking
+        t= np.array(pan)
+        assert     np.issubdtype(t.dtype, np.floating)
+
+
+if __name__ == '__main__':
+    nose.runmodule(argv=[__file__, '-vvs', '-x', '--pdb', '--pdb-failure'],
+                   exit=False)