python coinbase pro sandbox authentication request error

Trying to use the example python from the coinbase pro api to do an authenticated request… it doesn’t work going to the sandbox. I get the following error. Isn’t there a simple request example that works on the web somewhere?

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

#sandbox api keys and url
API_KEY='XX...........'
API_PASS='XX.........'
API_SECRET='XX.............'
api_url='https://public.sandbox.pro.coinbase.com/'

def jprint(obj):
    # create a formatted string of the Python JSON object
    text = json.dumps(obj, sort_keys=True, indent=4)
    print(text)

# 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 b'').decode()
        hmac_key = base64.b64decode(self.secret_key)
        signature = hmac.new(hmac_key, message.encode(), hashlib.sha256)
        signature_b64 = base64.b64encode(signature.digest()).decode()

        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/'
#sandbox url
api_url='https://public.sandbox.pro.coinbase.com/'
auth = CoinbaseExchangeAuth(API_KEY, API_SECRET, API_PASS)

# Get accounts
r = requests.get(api_url + 'accounts', auth=auth)
print(r.status_code)
jprint(r.json())

# Place an order
order = {
    'size': 1.0,
    'price': 1.0,
    'side': 'buy',
    'product_id': 'BTC-USD',
}
r = requests.post(api_url + 'orders', json=order, auth=auth)
print(r.status_code)
jprint(r.json())

Here is what I get back….

200

Traceback (most recent call last):

File “/Users/rockie12_us/PythonScriptsDeanO/SandBoxClientTest/test9.py”, line 46, in jprint(r.json())

File “/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/requests/models.py”, line 897, in json return complexjson.loads(self.text, **kwargs)

File “/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/json/init.py”, line 346, in loads return _default_decoder.decode(s) File “/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/json/decoder.py”, line 337, in decode obj, end = self.raw_decode(s, idx=_w(s, 0).end())

File “/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/json/decoder.py”, line 355, in raw_decode raise JSONDecodeError(“Expecting value”, s, err.value) from None json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

[Finished in 0.6s with exit code 1]

Answer

To fix this I had to change this line

API_SECRET='XX.............'

to

API_SECRET= b'XX.............'

nothing in the api mentioned this needed to be binary string, that would have helped greatly.