Validate Github Secret with Github Webhooks and API Gateway / Lambda

validate_github_signature_python.py

# GITHUB_SECRET
# 'fhe3UdxahLO0Txs......'

# >>> event['body']
# 'eyJ6ZW4iOi.......'

# >>> event['headers']['X-Hub-Signature']
# 'sha1=2c887c74da271045b170d224................'

import hashlib
import hmac

github_signature = event['headers']['X-Hub-Signature'].split('=')[1]

def validate_signature(github_secret, request_body, github_signature):
    encoded_secret = github_secret.encode()
    decoded_rbody = base64.b64decode(request_body)
    calculated_signature = hmac.new(encoded_secret, decoded_rbody, hashlib.sha1).hexdigest()
    response = hmac.compare_digest(calculated_signature, github_signature)
    return response

if validate_signature(GITHUB_SECRET, event['body'], github_signature):
    print('validated')