doc_event_push_example.py

import requests
from base64 import b64encode
import json

def push_po(doc, method):
  # additional business logic or other validations
  # prune document fields and turn into json

  payload = json.loads({"docfield": doc})
  api_key, api_secret = frappe.get_value("User", frappe.session.user, ["api_key", "api_secret"])
  url = "http://frappe.local:8000**/api/resource/Purchase Order"
  headers = {'Authorization': "Basic %s" % b64encode(api_key:api_secret)}
  response = requests.request("POST", url, headers=headers)