[Haskell-cafe] Interfacing BTCe

Miro Karpis miroslav.karpis at gmail.com
Wed May 28 08:55:56 UTC 2014

Hi cafe,

I'm  trying to interface BTCe and get my account info.

I have found following peace of code, which I would like to build on top:

I have added to the request a POST method, but I'm still getting error from
"{\"success\":0,\"error\":\"*invalid nonce parameter; on key:0*, you

The API is documented here: https://btc-e.com/api/documentation
In short:

Authorization is performed by sending the following HTTP Headers:

*Key* — API key

*Sign* — POST data (?param=val&param1=val1) signed by a secret key
according to HMAC-SHA512 method;

Sent on *https://btc-e.com/tapi <https://btc-e.com/tapi>* .

All requests must also include a special *nonce* POST parameter with
increment integer. (>0)

The method name is sent via POST parameter method.

All the method parameters are sent via POST.

{-# LANGUAGE OverloadedStrings #-}

import Network.HTTP.Conduit
import Network.HTTP.Types.Header

import Data.Word
import Data.ByteString.Lazy(pack)
import qualified Data.ByteString.Char8 as B

import Data.Digest.Pure.SHA
import Data.Time.Clock.POSIX


toWord8 :: String -> [Word8]
toWord8 = Prelude.map (fromIntegral . fromEnum)


key :: B.ByteString
key = "key"

secret :: String
secret = "secret"

url :: String
url = "https://btc-e.com/tapi"


querystring :: Int -> String
querystring nonce = "?method=getInfo&nonce=" ++ show nonce

sign :: Int -> B.ByteString
sign nonce = B.pack $ show $
  hmacSha512 (pack $ toWord8 secret) (pack $ toWord8 $ querystring nonce)

main :: IO ()
main = do
  nonce <- fmap floor getPOSIXTime
  putStrLn $ url ++ (querystring nonce)
  ticker <- parseUrl $ url ++ (querystring nonce)
  let request = ticker
        { secure = True
        , method = "POST"
        , requestHeaders = (requestHeaders ticker)
                           ++ [ ("Content-Type",
                              , ("Host", "btc-e.com")
                              , ("User-Agent", "Haskell Trading Robot")
                              , ("Key", key)
                              , ("Sign", sign nonce)]}
  putStrLn $ show request
  response <- withManager $ httpLbs request
  print $ responseBody response

any ideas more than welcome
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