Add CoinMarketCap source.

src/pricehist/sources/__init__.py

@@ -1,7 +1,9 @@
 from .coindesk import CoinDesk
+from .coinmarketcap import CoinMarketCap
 from .ecb import ECB
 
 by_id = {
     CoinDesk.id(): CoinDesk,
+    CoinMarketCap.id(): CoinMarketCap,
     ECB.id(): ECB
 }

src/pricehist/sources/coinmarketcap.py

@@ -0,0 +1,61 @@
+from datetime import datetime, timedelta
+from decimal import Decimal
+import json
+import requests
+from xml.etree import ElementTree
+
+from pricehist.price import Price
+
+class CoinMarketCap():
+
+    @staticmethod
+    def id():
+        return 'coinmarketcap'
+
+    @staticmethod
+    def name():
+        return 'CoinMarketCap'
+
+    @staticmethod
+    def description():
+        return "The world's most-referenced price-tracking website for cryptoassets"
+
+    @staticmethod
+    def source_url():
+        return 'https://coinmarketcap.com/'
+
+    # # currency metadata - these may max out at 5k items (crypto data is currently 4720 items)
+    # curl 'https://web-api.coinmarketcap.com/v1/fiat/map?include_metals=true' | jq . | tee fiat-map.json
+    # curl 'https://web-api.coinmarketcap.com/v1/cryptocurrency/map' | jq . | tee cryptocurrency-map.json
+
+    @staticmethod
+    def bases():
+        return []
+
+    @staticmethod
+    def quotes():
+        return []
+
+    def fetch(self, pair, start, end):
+        base, quote = pair.split('/')
+
+        url = f'https://web-api.coinmarketcap.com/v1/cryptocurrency/ohlcv/historical'
+        params = {
+            'symbol': base,
+            'convert': quote,
+            'time_start': int(datetime.strptime(start, '%Y-%m-%d').timestamp()),
+            'time_end': int(datetime.strptime(end, '%Y-%m-%d').timestamp()) + 24*60*60 # round up to include the last day
+        }
+
+        response = requests.get(url, params=params)
+        data = json.loads(response.content)
+
+        prices = []
+        for item in data['data']['quotes']:
+            d = item['time_open'][0:10]
+            high = Decimal(str(item['quote'][quote]['high']))
+            low = Decimal(str(item['quote'][quote]['low']))
+            mid = sum([high, low]) / 2
+            prices.append(Price(base, quote, d, mid))
+
+        return prices