How to properly make POST request

Question

I'm trying to make my first POST request to an API. For some reason, I always get status 403 in return. I suspect it's the signature that is being incorrectly generated. The api-key and client id is for sure correct.

My code

nonce <-as.integer(Sys.time())

post_message <- paste0(nonce, data_client.id, data_key) # data_client.id = client id # data_key = key

sha.message <- toupper(digest::hmac(data_secret, object = post_message, algo = 'sha256', serialize = TRUE))

url <- 'https://www.bitstamp.net/api/v2/balance/'


body = list('API-KEY' = data_key, 'nonce' = nonce, 'signature' = sha.message)

httr::POST(url, body = body, verbose())

Output

<- HTTP/1.1 403 Authentication Failed

I'm trying to access the Bitstamp API: https://www.bitstamp.net/api/?package=Rbitcoin&version=0.9.2

All private API calls require authentication. For a successful authentication you need to provide your API key, a signature and a nonce parameter.

API KEY

To get an API key, go to "Account", "Security" and then "API Access". Set permissions and click "Generate key".

NONCEN

once is a regular integer number. It must be increased with every request you make. Read more about it here. Example: if you set nonce to 1 in your first request, you must set it to at least 2 in your second request. You are not required to start with 1. A common practice is to use unix time for that parameter.

SIGNATURE

Signature is a HMAC-SHA256 encoded message containing nonce, customer ID (can be found here) and API key. The HMAC-SHA256 code must be generated using a secret key that was generated with your API key. This code must be converted to it's hexadecimal representation (64 uppercase characters).

Answer 1

I'm not sure if your question is still standing, but based on your code, I managed to get it working. In fact, the main problem is in the body, the API documentation shows it expects 'key' instead of 'API-KEY'. Also, serialize should be FALSE instead of TRUE.

At the moment this works (but the API may change):

nonce <-as.integer(Sys.time())

post_message <- paste0(nonce, data_client.id, data_key) # data_client.id = client id # data_key = key

sha.message <- toupper(digest::hmac(data_secret, object = post_message, algo = 'sha256', serialize = FALSE))

url <- 'https://www.bitstamp.net/api/v2/balance/'

body = list('key' = data_key, 'nonce' = nonce, 'signature' = sha.message)

httr::POST(url, body = body, verbose())