Merge pull request #8091 from zouppen/convert_currency_cmd

Add command for currency conversions

electrum/commands.py

@@ -36,7 +36,7 @@ import inspect
 from collections import defaultdict
 from functools import wraps, partial
 from itertools import repeat
-from decimal import Decimal
+from decimal import Decimal, InvalidOperation
 from typing import Optional, TYPE_CHECKING, Dict, List
 import os
 
@@ -1322,6 +1322,43 @@ class Commands:
             'onchain_amount': format_satoshis(onchain_amount_sat),
         }
 
+    @command('n')
+    async def convert_currency(self, from_amount=1, from_ccy = '', to_ccy = ''):
+        """Converts the given amount of currency to another using the
+        configured exchange rate source.
+        """
+        if not self.daemon.fx.is_enabled():
+            raise Exception("FX is disabled. To enable, run: 'electrum setconfig use_exchange_rate true'")
+        # Currency codes are uppercase
+        from_ccy = from_ccy.upper()
+        to_ccy = to_ccy.upper()
+        # Default currencies
+        if from_ccy == '':
+            from_ccy = "BTC" if to_ccy != "BTC" else self.daemon.fx.ccy
+        if to_ccy == '':
+            to_ccy = "BTC" if from_ccy != "BTC" else self.daemon.fx.ccy
+        # Get current rates
+        rate_from = self.daemon.fx.exchange.get_cached_spot_quote(from_ccy)
+        rate_to = self.daemon.fx.exchange.get_cached_spot_quote(to_ccy)
+        # Test if currencies exist
+        if rate_from.is_nan():
+            raise Exception(f'Currency to convert from ({from_ccy}) is unknown or rate is unavailable')
+        if rate_to.is_nan():
+            raise Exception(f'Currency to convert to ({to_ccy}) is unknown or rate is unavailable')
+        # Conversion
+        try:
+            from_amount = Decimal(from_amount)
+            to_amount = from_amount / rate_from * rate_to
+        except InvalidOperation:
+            raise Exception("from_amount is not a number")
+        return {
+            "from_amount": self.daemon.fx.ccy_amount_str(from_amount, False, from_ccy),
+            "to_amount": self.daemon.fx.ccy_amount_str(to_amount, False, to_ccy),
+            "from_ccy": from_ccy,
+            "to_ccy": to_ccy,
+            "source": self.daemon.fx.exchange.name(),
+        }
+
 
 def eval_bool(x: str) -> bool:
     if x == 'false': return False
@@ -1400,6 +1437,9 @@ command_options = {
     'connection_string':      (None, "Lightning network node ID or network address"),
     'new_fee_rate': (None, "The Updated/Increased Transaction fee rate (in sat/byte)"),
     'strategies': (None, "Select RBF any one or multiple RBF strategies in any order, separated by ','; Options : 'CoinChooser','DecreaseChange','DecreasePayment' "),
+    'from_amount': (None, "Amount to convert (default: 1)"),
+    'from_ccy':    (None, "Currency to convert from"),
+    'to_ccy':      (None, "Currency to convert to"),
 }
 
 

electrum/exchange_rate.py

@@ -34,7 +34,10 @@ CCY_PRECISIONS = {'BHD': 3, 'BIF': 0, 'BYR': 0, 'CLF': 4, 'CLP': 0,
                   'JOD': 3, 'JPY': 0, 'KMF': 0, 'KRW': 0, 'KWD': 3,
                   'LYD': 3, 'MGA': 1, 'MRO': 1, 'OMR': 3, 'PYG': 0,
                   'RWF': 0, 'TND': 3, 'UGX': 0, 'UYI': 0, 'VND': 0,
-                  'VUV': 0, 'XAF': 0, 'XAU': 4, 'XOF': 0, 'XPF': 0}
+                  'VUV': 0, 'XAF': 0, 'XAU': 4, 'XOF': 0, 'XPF': 0,
+                  # Cryptocurrencies
+                  'BTC': 8, 'LTC': 8, 'XRP': 6, 'ETH': 18,
+                  }
 
 
 def to_decimal(x: Union[str, float, int, Decimal]) -> Decimal:
@@ -173,6 +176,8 @@ class ExchangeBase(Logger):
 
     def get_cached_spot_quote(self, ccy: str) -> Decimal:
         """Returns the cached exchange rate as a Decimal"""
+        if ccy == 'BTC':
+            return Decimal(1)
         rate = self._quotes.get(ccy)
         if rate is None:
             return Decimal('NaN')
@@ -554,8 +559,8 @@ class FxThread(ThreadJob, EventListener):
     def remove_thousands_separator(text):
         return text.replace(',', '') # FIXME use THOUSAND_SEPARATOR in util
 
-    def ccy_amount_str(self, amount, commas):
+    def ccy_amount_str(self, amount, commas, ccy=None):
-        prec = CCY_PRECISIONS.get(self.ccy, 2)
+        prec = CCY_PRECISIONS.get(self.ccy if ccy is None else ccy, 2)
         fmt_str = "{:%s.%df}" % ("," if commas else "", max(0, prec)) # FIXME use util.THOUSAND_SEPARATOR and util.DECIMAL_POINT
         try:
             rounded_amount = round(amount, prec)