abstract exchange rates code into a "util".

lnbits/extensions/offlineshop/helpers.py

@@ -1,57 +1,9 @@
-import trio  # type: ignore
-import httpx
 import base64
 import struct
 import hmac
 import time
 
 
-async def get_fiat_rate(currency: str):
-    assert currency == "USD", "Only USD is supported as fiat currency."
-    return await get_usd_rate()
-
-
-async def get_usd_rate():
-    """
-    Returns an average satoshi price from multiple sources.
-    """
-
-    satoshi_prices = [None, None, None]
-
-    async def fetch_price(index, url, getter):
-        try:
-            async with httpx.AsyncClient() as client:
-                r = await client.get(url)
-                r.raise_for_status()
-                satoshi_price = int(100_000_000 / float(getter(r.json())))
-                satoshi_prices[index] = satoshi_price
-        except Exception:
-            pass
-
-    async with trio.open_nursery() as nursery:
-        nursery.start_soon(
-            fetch_price,
-            0,
-            "https://api.kraken.com/0/public/Ticker?pair=XXBTZUSD",
-            lambda d: d["result"]["XXBTCZUSD"]["c"][0],
-        )
-        nursery.start_soon(
-            fetch_price,
-            1,
-            "https://www.bitstamp.net/api/v2/ticker/btcusd",
-            lambda d: d["last"],
-        )
-        nursery.start_soon(
-            fetch_price,
-            2,
-            "https://api.coincap.io/v2/rates/bitcoin",
-            lambda d: d["data"]["rateUsd"],
-        )
-
-    satoshi_prices = [x for x in satoshi_prices if x]
-    return sum(satoshi_prices) / len(satoshi_prices)
-
-
 def hotp(key, counter, digits=6, digest="sha1"):
     key = base64.b32decode(key.upper() + "=" * ((8 - len(key)) % 8))
     counter = struct.pack(">Q", counter)

lnbits/extensions/offlineshop/lnurl.py

@@ -3,10 +3,10 @@ from quart import jsonify, url_for, request
 from lnurl import LnurlPayResponse, LnurlPayActionResponse, LnurlErrorResponse  # type: ignore
 
 from lnbits.core.services import create_invoice
+from lnbits.utils.exchange_rates import fiat_amount_as_satoshis
 
 from . import offlineshop_ext
 from .crud import get_shop, get_item
-from .helpers import get_fiat_rate
 
 
 @offlineshop_ext.route("/lnurl/<item_id>", methods=["GET"])
@@ -18,8 +18,7 @@ async def lnurl_response(item_id):
     if not item.enabled:
         return jsonify({"status": "ERROR", "reason": "Item disabled."})
 
-    rate = await get_fiat_rate(item.unit) if item.unit != "sat" else 1
-    price_msat = int(item.price * rate) * 1000
+    price_msat = (await fiat_amount_as_satoshis(item.price, item.unit) if item.unit != "sat" else item.price) * 1000
 
     resp = LnurlPayResponse(
         callback=url_for("offlineshop.lnurl_callback", item_id=item.id, _external=True),
@@ -41,10 +40,10 @@ async def lnurl_callback(item_id):
         min = item.price * 1000
         max = item.price * 1000
     else:
-        rate = await get_fiat_rate(item.unit)
+        price = await fiat_amount_as_satoshis(item.price, item.unit)
         # allow some fluctuation (the fiat price may have changed between the calls)
-        min = int(rate * item.price) * 995
-        max = int(rate * item.price) * 1010
+        min = price * 995
+        max = price * 1010
 
     amount_received = int(request.args.get("amount"))
     if amount_received < min: