coinmarketcap: fix quote output.

src/pricehist/beanprice/exchangeratehost.py

@@ -0,0 +1,4 @@
+from pricehist import beanprice
+from pricehist.sources.exchangeratehost import ExchangeRateHost
+
+Source = beanprice.source(ExchangeRateHost())

src/pricehist/sources/coinmarketcap.py

@@ -166,17 +166,18 @@ class CoinMarketCap(BaseSource):
     def _output_pair(self, base, quote, data):
         data_base = data["symbol"]
 
+        symbols = {i["id"]: (i["symbol"] or i["code"]) for i in self._symbol_data()}
+
         data_quote = None
         if len(data["quotes"]) > 0:
-            data_quote = next(iter(data["quotes"][0]["quote"].keys()))
+            data_quote = symbols[int(data["quotes"][0]["quote"]["name"])]
 
         lookup_quote = None
         if quote.startswith("ID="):
-            symbols = {i["id"]: (i["symbol"] or i["code"]) for i in self._symbol_data()}
             lookup_quote = symbols[int(quote[3:])]
 
         output_base = data_base
-        output_quote = lookup_quote or data_quote or quote
+        output_quote = data_quote or lookup_quote or quote
 
         return (output_base, output_quote)
 

src/pricehist/sources/exchangeratehost.py

@@ -0,0 +1,122 @@
+import dataclasses
+import json
+from decimal import Decimal
+
+import requests
+
+from pricehist import exceptions
+from pricehist.price import Price
+
+from .basesource import BaseSource
+
+
+class ExchangeRateHost(BaseSource):
+    def id(self):
+        return "exchangeratehost"
+
+    def name(self):
+        return "exchangerate.host Exchange rates API"
+
+    def description(self):
+        return (
+            "Exchange rates API is a simple and lightweight free service for "
+            "current and historical foreign exchange rates & crypto exchange "
+            "rates."
+        )
+
+    def source_url(self):
+        return "https://exchangerate.host/"
+
+    def start(self):
+        return "1999-01-01"
+
+    def types(self):
+        return ["close"]
+
+    def notes(self):
+        return ""
+
+    def symbols(self):
+        url = "https://api.coindesk.com/v1/bpi/supported-currencies.json"
+
+        try:
+            response = self.log_curl(requests.get(url))
+        except Exception as e:
+            raise exceptions.RequestError(str(e)) from e
+
+        try:
+            response.raise_for_status()
+        except Exception as e:
+            raise exceptions.BadResponse(str(e)) from e
+
+        try:
+            data = json.loads(response.content)
+            relevant = [i for i in data if i["currency"] not in ["BTC", "XBT"]]
+            results = [
+                (f"BTC/{i['currency']}", f"Bitcoin against {i['country']}")
+                for i in sorted(relevant, key=lambda i: i["currency"])
+            ]
+        except Exception as e:
+            raise exceptions.ResponseParsingError(str(e)) from e
+
+        if not results:
+            raise exceptions.ResponseParsingError("Expected data not found")
+        else:
+            return results
+
+    def fetch(self, series):
+        if series.base != "BTC" or series.quote in ["BTC", "XBT"]:
+            # BTC is the only valid base.
+            # BTC as the quote will return BTC/USD, which we don't want.
+            # XBT as the quote will fail with HTTP status 500.
+            raise exceptions.InvalidPair(series.base, series.quote, self)
+
+        data = self._data(series)
+
+        prices = []
+        for (d, v) in data.get("bpi", {}).items():
+            prices.append(Price(d, Decimal(str(v))))
+
+        return dataclasses.replace(series, prices=prices)
+
+    def _data(self, series):
+        url = "https://api.coindesk.com/v1/bpi/historical/close.json"
+        params = {
+            "currency": series.quote,
+            "start": series.start,
+            "end": series.end,
+        }
+
+        try:
+            response = self.log_curl(requests.get(url, params=params))
+        except Exception as e:
+            raise exceptions.RequestError(str(e)) from e
+
+        code = response.status_code
+        text = response.text
+        if code == 404 and "currency was not found" in text:
+            raise exceptions.InvalidPair(series.base, series.quote, self)
+        elif code == 404 and "only covers data from" in text:
+            raise exceptions.BadResponse(text)
+        elif code == 404 and "end date is before" in text and series.end < series.start:
+            raise exceptions.BadResponse("End date is before start date.")
+        elif code == 404 and "end date is before" in text:
+            raise exceptions.BadResponse("The start date must be in the past.")
+        elif code == 500 and "No results returned from database" in text:
+            raise exceptions.BadResponse(
+                "No results returned from database. This can happen when data "
+                "for a valid quote currency (e.g. CUP) doesn't go all the way "
+                "back to the start date, and potentially for other reasons."
+            )
+        else:
+            try:
+                response.raise_for_status()
+            except Exception as e:
+                raise exceptions.BadResponse(str(e)) from e
+
+        try:
+            result = json.loads(response.content)
+        except Exception as e:
+            raise exceptions.ResponseParsingError(str(e)) from e
+
+        return result