abstract exchange rates code into a "util".

2021-03-14 20:43:39 -03:00
parent 5142f1e29f
commit adc3e62573
7 changed files with 272 additions and 107 deletions
@@ -0,0 +1,262 @@
+import trio  # type: ignore
+import httpx
+from typing import Callable, NamedTuple
+
+currencies = {
+    "AED": "United Arab Emirates Dirham",
+    "AFN": "Afghan Afghani",
+    "ALL": "Albanian Lek",
+    "AMD": "Armenian Dram",
+    "ANG": "Netherlands Antillean Gulden",
+    "AOA": "Angolan Kwanza",
+    "ARS": "Argentine Peso",
+    "AUD": "Australian Dollar",
+    "AWG": "Aruban Florin",
+    "AZN": "Azerbaijani Manat",
+    "BAM": "Bosnia and Herzegovina Convertible Mark",
+    "BBD": "Barbadian Dollar",
+    "BDT": "Bangladeshi Taka",
+    "BGN": "Bulgarian Lev",
+    "BHD": "Bahraini Dinar",
+    "BIF": "Burundian Franc",
+    "BMD": "Bermudian Dollar",
+    "BND": "Brunei Dollar",
+    "BOB": "Bolivian Boliviano",
+    "BRL": "Brazilian Real",
+    "BSD": "Bahamian Dollar",
+    "BTN": "Bhutanese Ngultrum",
+    "BWP": "Botswana Pula",
+    "BYN": "Belarusian Ruble",
+    "BYR": "Belarusian Ruble",
+    "BZD": "Belize Dollar",
+    "CAD": "Canadian Dollar",
+    "CDF": "Congolese Franc",
+    "CHF": "Swiss Franc",
+    "CLF": "Unidad de Fomento",
+    "CLP": "Chilean Peso",
+    "CNH": "Chinese Renminbi Yuan Offshore",
+    "CNY": "Chinese Renminbi Yuan",
+    "COP": "Colombian Peso",
+    "CRC": "Costa Rican Colón",
+    "CUC": "Cuban Convertible Peso",
+    "CVE": "Cape Verdean Escudo",
+    "CZK": "Czech Koruna",
+    "DJF": "Djiboutian Franc",
+    "DKK": "Danish Krone",
+    "DOP": "Dominican Peso",
+    "DZD": "Algerian Dinar",
+    "EGP": "Egyptian Pound",
+    "ERN": "Eritrean Nakfa",
+    "ETB": "Ethiopian Birr",
+    "EUR": "Euro",
+    "FJD": "Fijian Dollar",
+    "FKP": "Falkland Pound",
+    "GBP": "British Pound",
+    "GEL": "Georgian Lari",
+    "GGP": "Guernsey Pound",
+    "GHS": "Ghanaian Cedi",
+    "GIP": "Gibraltar Pound",
+    "GMD": "Gambian Dalasi",
+    "GNF": "Guinean Franc",
+    "GTQ": "Guatemalan Quetzal",
+    "GYD": "Guyanese Dollar",
+    "HKD": "Hong Kong Dollar",
+    "HNL": "Honduran Lempira",
+    "HRK": "Croatian Kuna",
+    "HTG": "Haitian Gourde",
+    "HUF": "Hungarian Forint",
+    "IDR": "Indonesian Rupiah",
+    "ILS": "Israeli New Sheqel",
+    "IMP": "Isle of Man Pound",
+    "INR": "Indian Rupee",
+    "IQD": "Iraqi Dinar",
+    "ISK": "Icelandic Króna",
+    "JEP": "Jersey Pound",
+    "JMD": "Jamaican Dollar",
+    "JOD": "Jordanian Dinar",
+    "JPY": "Japanese Yen",
+    "KES": "Kenyan Shilling",
+    "KGS": "Kyrgyzstani Som",
+    "KHR": "Cambodian Riel",
+    "KMF": "Comorian Franc",
+    "KRW": "South Korean Won",
+    "KWD": "Kuwaiti Dinar",
+    "KYD": "Cayman Islands Dollar",
+    "KZT": "Kazakhstani Tenge",
+    "LAK": "Lao Kip",
+    "LBP": "Lebanese Pound",
+    "LKR": "Sri Lankan Rupee",
+    "LRD": "Liberian Dollar",
+    "LSL": "Lesotho Loti",
+    "LYD": "Libyan Dinar",
+    "MAD": "Moroccan Dirham",
+    "MDL": "Moldovan Leu",
+    "MGA": "Malagasy Ariary",
+    "MKD": "Macedonian Denar",
+    "MMK": "Myanmar Kyat",
+    "MNT": "Mongolian Tögrög",
+    "MOP": "Macanese Pataca",
+    "MRO": "Mauritanian Ouguiya",
+    "MUR": "Mauritian Rupee",
+    "MVR": "Maldivian Rufiyaa",
+    "MWK": "Malawian Kwacha",
+    "MXN": "Mexican Peso",
+    "MYR": "Malaysian Ringgit",
+    "MZN": "Mozambican Metical",
+    "NAD": "Namibian Dollar",
+    "NGN": "Nigerian Naira",
+    "NIO": "Nicaraguan Córdoba",
+    "NOK": "Norwegian Krone",
+    "NPR": "Nepalese Rupee",
+    "NZD": "New Zealand Dollar",
+    "OMR": "Omani Rial",
+    "PAB": "Panamanian Balboa",
+    "PEN": "Peruvian Sol",
+    "PGK": "Papua New Guinean Kina",
+    "PHP": "Philippine Peso",
+    "PKR": "Pakistani Rupee",
+    "PLN": "Polish Złoty",
+    "PYG": "Paraguayan Guaraní",
+    "QAR": "Qatari Riyal",
+    "RON": "Romanian Leu",
+    "RSD": "Serbian Dinar",
+    "RUB": "Russian Ruble",
+    "RWF": "Rwandan Franc",
+    "SAR": "Saudi Riyal",
+    "SBD": "Solomon Islands Dollar",
+    "SCR": "Seychellois Rupee",
+    "SEK": "Swedish Krona",
+    "SGD": "Singapore Dollar",
+    "SHP": "Saint Helenian Pound",
+    "SLL": "Sierra Leonean Leone",
+    "SOS": "Somali Shilling",
+    "SRD": "Surinamese Dollar",
+    "SSP": "South Sudanese Pound",
+    "STD": "São Tomé and Príncipe Dobra",
+    "SVC": "Salvadoran Colón",
+    "SZL": "Swazi Lilangeni",
+    "THB": "Thai Baht",
+    "TJS": "Tajikistani Somoni",
+    "TMT": "Turkmenistani Manat",
+    "TND": "Tunisian Dinar",
+    "TOP": "Tongan Paʻanga",
+    "TRY": "Turkish Lira",
+    "TTD": "Trinidad and Tobago Dollar",
+    "TWD": "New Taiwan Dollar",
+    "TZS": "Tanzanian Shilling",
+    "UAH": "Ukrainian Hryvnia",
+    "UGX": "Ugandan Shilling",
+    "USD": "US Dollar",
+    "UYU": "Uruguayan Peso",
+    "UZS": "Uzbekistan Som",
+    "VEF": "Venezuelan Bolívar",
+    "VES": "Venezuelan Bolívar Soberano",
+    "VND": "Vietnamese Đồng",
+    "VUV": "Vanuatu Vatu",
+    "WST": "Samoan Tala",
+    "XAF": "Central African Cfa Franc",
+    "XAG": "Silver (Troy Ounce)",
+    "XAU": "Gold (Troy Ounce)",
+    "XCD": "East Caribbean Dollar",
+    "XDR": "Special Drawing Rights",
+    "XOF": "West African Cfa Franc",
+    "XPD": "Palladium",
+    "XPF": "Cfp Franc",
+    "XPT": "Platinum",
+    "YER": "Yemeni Rial",
+    "ZAR": "South African Rand",
+    "ZMW": "Zambian Kwacha",
+    "ZWL": "Zimbabwean Dollar",
+}
+
+
+class Provider(NamedTuple):
+    name: str
+    domain: str
+    api_url: str
+    getter: Callable
+
+
+exchange_rate_providers = {
+    "bitfinex": Provider(
+        "Bitfinex",
+        "bitfinex.com",
+        "https://api.bitfinex.com/v1/pubticker/{from}{to}",
+        lambda data, replacements: data["last_price"],
+    ),
+    "bitstamp": Provider(
+        "Bitstamp",
+        "bitstamp.net",
+        "https://www.bitstamp.net/api/v2/ticker/{from}{to}/",
+        lambda data, replacements: data["last"],
+    ),
+    "coinbase": Provider(
+        "Coinbase",
+        "coinbase.com",
+        "https://api.coinbase.com/v2/exchange-rates?currency={FROM}",
+        lambda data, replacements: data["data"]["rates"][replacements["TO"]],
+    ),
+    "coinmate": Provider(
+        "CoinMate",
+        "coinmate.io",
+        "https://coinmate.io/api/ticker?currencyPair={FROM}_{TO}",
+        lambda data, replacements: data["data"]["last"],
+    ),
+    "kraken": Provider(
+        "Kraken",
+        "kraken.com",
+        "https://api.kraken.com/0/public/Ticker?pair=XBT{TO}",
+        lambda data, replacements: data["result"]["XXBTZ" + replacements["TO"]]["c"][0],
+    ),
+}
+
+
+async def btc_price(currency: str) -> float:
+    replacements = {"FROM": "BTC", "from": "btc", "TO": currency.upper(), "to": currency.lower()}
+    rates = []
+    send_channel, receive_channel = trio.open_memory_channel(0)
+
+    async def controller(nursery):
+        failures = 0
+        while True:
+            rate = await receive_channel.receive()
+            if rate:
+                rates.append(rate)
+            else:
+                failures += 1
+            if len(rates) >= 2 or len(rates) == 1 and failures >= 2:
+                nursery.cancel_scope.cancel()
+                break
+            if failures == len(exchange_rate_providers):
+                nursery.cancel_scope.cancel()
+                break
+
+    async def fetch_price(key: str, provider: Provider):
+        try:
+            url = provider.api_url.format(**replacements)
+            async with httpx.AsyncClient() as client:
+                r = await client.get(url, timeout=0.5)
+                r.raise_for_status()
+                data = r.json()
+                rate = float(provider.getter(data, replacements))
+                await send_channel.send(rate)
+        except Exception:
+            await send_channel.send(None)
+
+    async with trio.open_nursery() as nursery:
+        nursery.start_soon(controller, nursery)
+        for key, provider in exchange_rate_providers.items():
+            nursery.start_soon(fetch_price, key, provider)
+
+    if not rates:
+        return 9999999999
+
+    return sum([rate for rate in rates]) / len(rates)
+
+
+async def get_fiat_rate_satoshis(currency: str) -> float:
+    return int(100_000_000 / (await btc_price(currency)))
+
+
+async def fiat_amount_as_satoshis(amount: float, currency: str) -> int:
+    return int(amount * (await get_fiat_rate_satoshis(currency)))