hledger-get-crypto-prices json fetcher prototype

hledger-get-crypto-prices.hs

#!/usr/bin/env stack
{- stack runghc --verbosity info
   --package hledger-lib
   --package hledger
   --package here
   --package aeson
   --package http-conduit
   --package conduit-extra
   --package decimal
   --package text
   --package time
-}

-- Get a few cryptocurrency prices.
-- Trying to replicate "curl -s 'https://min-api.cryptocompare.com/data/pricemulti?fsyms=BTC,ETH,LTC&tsyms=USD' | python -m json.tool" :)

-- {-# OPTIONS_GHC -Wno-missing-signatures -Wno-name-shadowing #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE QuasiQuotes #-}
{-# LANGUAGE TypeSynonymInstances #-}
{-# LANGUAGE FlexibleInstances #-}

import Data.String.Here
import Conduit
import Control.Monad (mzero)
import Data.Aeson -- (Value(..), FromJSON, parseJSON)
-- import Data.Aeson (decode)
import Data.Conduit.Binary (sinkLbs)
import Data.Decimal
import Data.Map
import Data.Text
import Data.Time.Calendar (fromGregorian)
import GHC.Generics (Generic)
import Hledger
import Hledger.Cli
import Network.HTTP.Client.Conduit

------------------------------------------------------------------------------
cmdmode = hledgerCommandMode
  [here| get-crypto-prices
Fetch today's prices (in USD) for common cryptocurrencies (BTC, ETH, LTC) from
cryptocompare.com and print them as P market price directives, to be appended
to a journal or prices file.
FLAGS
  |]
  []
  [generalflagsgroup1]
  []
  ([], Nothing) -- Just $ argsFlag "[]")
------------------------------------------------------------------------------

main :: IO ()
main = do
    let url = "https://min-api.cryptocompare.com/data/pricemulti?fsyms=BTC,ETH,LTC&tsyms=USD"
    req <- parseRequest url
    pricesjson <- withManager $ runResourceT $ withResponse req $ \rsp -> responseBody rsp $$ sinkLbs
    print (decode pricesjson :: Maybe (Map Text (Map Text Double)))  -- Decimal
    -- d <- getCurrentDay

-- instance Generic Decimal
-- instance FromJSON Decimal where parseJSON = genericParseJSON defaultOptions
--   -- fromJSON = fromJSON . read

-- type MarketPrices = [MarketPrice]

-- instance FromJSON MarketPrice where
--   parseJSON (Object v) = MarketPrice
--     <$> pure (fromGregorian 1 1 1)  --, -- dummy date to be replaced at runtime
--     <*> pure ("XXX")
--     <*> pure (Amount{acommodity="YYY", aquantity=1.1, aprice=NoPrice, astyle=amountstyle, amultiplier=False})
--   -- TVShow
--       -- <$> v .: "id"
--       -- <*> v .: "name"
--       -- <*> v .: "overview"
--   parseJSON _ = mzero

-- instance FromJSON MarketPrice where
--   parseJSON (Object v) = TVShow
--       <$> v .: "id"
--       <*> v .: "name"
--       <*> v .: "overview"
--   parseJSON _ = mzero