[Django]-Facebook Signed Request Decoding Incorrect Padding

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7👍

this is working for me

def base64_url_decode(inp):
    inp = inp.replace('-','+').replace('_','/')
    padding_factor = (4 - len(inp) % 4) % 4
    inp += "="*padding_factor
    return base64.decodestring(inp)


def parse_signed_request(signed_request='a.a', secret=FACEBOOK_APP_SECRET):
    l = signed_request.split('.', 2)
    encoded_sig = l[0]
    payload = l[1]

    sig = base64_url_decode(encoded_sig)
    data = json.loads(base64_url_decode(payload))

    if data.get('algorithm').upper() != 'HMAC-SHA256':
        print('Unknown algorithm')
        return None
    else:
        expected_sig = hmac.new(secret, msg=payload, digestmod=hashlib.sha256).digest()

    if sig != expected_sig:
        return None
    else:
        print('valid signed request received..')
        return data
👤Nour Wolf

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