import json
import urllib3


urllib3.disable_warnings()

URL = ""
USER = ""
PASSWORD = ""

STEP = 1000

HTTP = urllib3.PoolManager()


def safe_json_decode(v):
    try:
        return json.loads(v)
    except ValueError:
        return None


def body(start, limit):
    d = {'action': 'DeviceRouter',
         'data': [{'keys': ['name', 'ipAddressString'],
                   'limit': limit,
                   'start': start,
                   },
                  ],
         'method': 'getDevices',
         'tid': 1}
    return json.dumps(d)


def headers():
    h = urllib3.make_headers(basic_auth='{0}:{1}'.format(USER, PASSWORD))
    h["Content-Type"] = "application/json"
    return h


def do_request(start, limit):
    resp = HTTP.request("POST", URL, headers=headers(), body=body(start, limit), timeout=50)
    return resp.data.decode()


def get_devices_list():
    start = 0
    rv = dict()
    done = False

    while True:
        raw = do_request(start, STEP)
        data = safe_json_decode(raw)

        if not data:
            break

        devices = data['result']['devices']
        count = len(devices)

        rv.update(
            dict((v['ipAddressString'], v['name']) for v in devices),
        )

        if count < STEP:
            done = True
            break

        start = start + count

    return rv if done else None


d = get_devices_list()

print(d)