Infor LN ION API OAuth 2.0 REST Call Generator (Python)

"""Call an Infor LN REST service through ION API Gateway with a .ionapi service account file."""
import json
import sys

import requests

IONAPI_FILE = r"C:\ionapi\LN_backend.ionapi"
SERVICE_PATH = "REPLACE/WITH/PATH/FROM/API/GATEWAY/DOCUMENTATION"
TOP = "10"
ODATA_FILTER = "[$filter (optional)]"
COMPANY_HEADER = "[Company header name (if required)]"
COMPANY = "100"


def load_ionapi(path):
    with open(path, encoding="utf-8") as f:
        cfg = json.load(f)
    for key in ("ti", "ci", "cs", "iu", "pu", "ot", "saak", "sask"):
        if key not in cfg:
            sys.exit("Key '" + key + "' missing: is this a backend service .ionapi file?")
    return cfg


def get_token(cfg):
    token_url = cfg["pu"] + cfg["ot"]
    resp = requests.post(
        token_url,
        data={
            "grant_type": "password",
            "username": cfg["saak"],
            "password": cfg["sask"],
            "client_id": cfg["ci"],
            "client_secret": cfg["cs"],
        },
        timeout=60,
    )
    if resp.status_code != 200:
        sys.exit("Token request failed: " + str(resp.status_code) + " " + resp.text)
    return resp.json()["access_token"]


def call_ln(cfg, token):
    url = cfg["iu"].rstrip("/") + "/" + cfg["ti"] + "/" + SERVICE_PATH.lstrip("/")
    headers = {"Authorization": "Bearer " + token, "Accept": "application/json"}
    if COMPANY_HEADER:
        headers[COMPANY_HEADER] = COMPANY
    params = {"$top": TOP}
    if ODATA_FILTER:
        params["$filter"] = ODATA_FILTER
    resp = requests.get(url, headers=headers, params=params, timeout=120)
    if resp.status_code == 401:
        sys.exit("401: token rejected. Check the service account and the .ionapi file.")
    if resp.status_code == 404:
        sys.exit("404: path not found. Check SERVICE_PATH, service activation and entitlement.")
    if resp.status_code == 503:
        sys.exit("503: service unavailable. Check that the LN service is activated and running.")
    resp.raise_for_status()
    return resp.json()


if __name__ == "__main__":
    config = load_ionapi(IONAPI_FILE)
    access_token = get_token(config)
    result = call_ln(config, access_token)
    print(json.dumps(result, indent=2))

pip install requests
python lnapi_call.py