Merge pull request #11 from tarioch/feature/alphavantage_fx_rates

Also support fetching fx rates (including crypto) from alphavantage

README.rst

@@ -32,6 +32,17 @@ Requires the environment variable ``ALPHAVANTAGE_API_KEY`` to be set with your p
   2019-01-01 commodity VWRL
     price: "CHF:tariochbctools.plugins.prices.alphavantage/VWRL.SW"
 
+**alphavantagefx**
+
+Fetches fx rates from `Alphavantage <https://www.alphavantage.co/>`_
+Requires the environment variable ``ALPHAVANTAGE_API_KEY`` to be set with your personal api key.
+
+::
+
+  2019-01-01 commodity BTC
+    price: "CHF:tariochbctools.plugins.prices.alphavantagefx/BTC"
+
+
 **bitstamp**
 
 Fetches prices from `Bitstamp <https://www.bitstamp.com/>`_

src/tariochbctools/plugins/prices/alphavantagefx.py

@@ -0,0 +1,36 @@
+from beancount.prices import source
+from dateutil import tz
+from dateutil.parser import parse
+from beancount.core.number import D
+import requests
+from os import environ
+from time import sleep
+
+
+class Source(source.Source):
+    def get_latest_price(self, ticker):
+        params = {
+            'function': 'CURRENCY_EXCHANGE_RATE',
+            'from_currency': ticker,
+            'to_currency': 'CHF',
+            'apikey': environ['ALPHAVANTAGE_API_KEY'],
+        }
+
+        resp = requests.get(url='https://www.alphavantage.co/query', params=params)
+        data = resp.json()
+        if 'Note' in data:
+            sleep(60)
+            resp = requests.get(url='https://www.alphavantage.co/query', params=params)
+            data = resp.json()
+
+        priceData = data['Realtime Currency Exchange Rate']
+
+        price = D(priceData['5. Exchange Rate'])
+        date = parse(priceData['6. Last Refreshed'])
+
+        us_timezone = tz.gettz("Europe/Zurich")
+        time = date.astimezone(us_timezone)
+        return source.SourcePrice(price, time, 'CHF')
+
+    def get_historical_price(self, ticker, time):
+        return None