How to encode Unicode objects in Python?

Question

I've been trying to find a solution here for my problem for a long time but nothing seems to work. I am trying to authenticate with the Coinbase Pro API in Python but I am getting

"Unicode-Objects must be encoded before hashing" error.

Please see the code below for your reference.

import json, hmac, hashlib, time, requests, base64
from requests.auth import AuthBase

# Create custom authentication for Exchange
class CoinbaseExchangeAuth(AuthBase):
    def __init__(self, api_key, secret_key, passphrase):
        self.api_key = api_key
        self.secret_key = secret_key
        self.passphrase = passphrase

    def __call__(self, request):
        timestamp = str(time.time())
        message = timestamp + request.method + request.path_url + (request.body or '')
        hmac_key = base64.b64decode(self.secret_key)
        signature = hmac.new(hmac_key, message, hashlib.sha256)
        signature_b64 = signature.digest().encode('base64').rstrip('\n')

        request.headers.update({
            'CB-ACCESS-SIGN': signature_b64,
            'CB-ACCESS-TIMESTAMP': timestamp,
            'CB-ACCESS-KEY': self.api_key,
            'CB-ACCESS-PASSPHRASE': self.passphrase,
            'Content-Type': 'application/json'
        })
        return request

api_url = 'https://api.pro.coinbase.com/'
auth = CoinbaseExchangeAuth(api_key='XXXX',
                            secret_key='XXXX',
                            passphrase='XXXX')

# Get accounts
r = requests.get(api_url + 'accounts', auth=auth)

It would be great if someone can point me to the right direction. I couldn't find the correct solution after searching.

Answer 1

hashlib takes bytes or bytearray . Try this -

...
message = message.encode('UTF-8')
hmac_key = self.secret_key.encode('UTF-8')
signature = hmac.new(hmac_key, message, hashlib.sha256)

Answer 2

After some debugging I found that the following solution worked for me:

def __call__(self, request):
    print(request.body)
    timestamp = str(time.time())
    message = (timestamp + (request.method).upper() + request.path_url + (request.body or ''))
    message = message.encode('UTF-8')
    hmac_key = base64.b64decode(self.secret_key)
    signature = hmac.new(hmac_key, message, hashlib.sha256).digest()
    signature_b64 = base64.b64encode(signature)

Answer 3

Here is how I solved it, message.encode('utf-8')

   def __call__(self, request):
    timestamp = str(time.time())
    message = timestamp + request.method + request.path_url +     (request.body or '')
    hmac_key = base64.b64decode(self.secret_key)
    signature = hmac.new(hmac_key, message.encode('utf-8'), hashlib.sha256)
    signature_b64 = base64.b64encode(signature.digest())