Python 3 example

#!/usr/bin/env python3
import requests
import pprint

MANAGER_URL = "https://manager.example.com/rhn/manager/api"
MANAGER_LOGIN = "username"
MANAGER_PASSWORD = "password"
SSLVERIFY = "/path/to/CA" # or False to disable verify;

data = {"login": MANAGER_LOGIN, "password": MANAGER_PASSWORD}
response = requests.post(MANAGER_URL + '/auth/login', json=data, verify=SSLVERIFY)
print("LOGIN: {}:{}".format(response.status_code, response.json()))

cookies = response.cookies
res2 = requests.get(MANAGER_URL + '/system/listActiveSystems', cookies=cookies, verify=SSLVERIFY)
print("RETCODE: {}".format(res2.status_code))
pprint.pprint(res2.json())

sysinfo = res2.json()['result'][0]

note = {"sid": sysinfo['id'], "subject": "Title", "body": "Content of the Note"}
res2 = requests.post(MANAGER_URL + '/system/addNote', json=note, cookies=cookies, verify=SSLVERIFY)
print("RETCODE: {}".format(res2.status_code))
pprint.pprint(res2.json())

res2 = requests.get(MANAGER_URL + '/system/listNotes?sid={}'.format(sysinfo['id']), cookies=cookies, verify=SSLVERIFY)
print("RETCODE: {}".format(res2.status_code))
pprint.pprint(res2.json())

res2 = requests.post(MANAGER_URL + '/auth/logout', cookies=cookies, verify=SSLVERIFY)
print("RETCODE: {}".format(res2.status_code))
pprint.pprint(res2.json())