How to Implement Software Licensing in Python

from datetime import datetime, timezone
import requests

API_KEY = "YOUR_API_KEY"  # role ROLE_APIKEY_LICENSEE
HOSTS = ["https://go.netlicensing.io", "https://netlicensing.labs64.com"]  # primary, backup


def validate(licensee_number, product_number=None, module_params=None, timeout=10):
    """Return (results_by_module, ttl) for a licensee.

    module_params: {"M-FLOAT": {"sessionId": "host-1", "action": "checkOut"}, ...}
    """
    data = {}
    if product_number:
        data["productNumber"] = product_number  # needed only for licensee auto-create
    for i, (module, params) in enumerate((module_params or {}).items()):
        data[f"productModuleNumber{i}"] = module
        for key, value in params.items():
            data[f"{key}{i}"] = value

    last_error = None
    for host in HOSTS:
        try:
            response = requests.post(
                f"{host}/core/v2/rest/licensee/{licensee_number}/validate",
                data=data,
                auth=("apiKey", API_KEY),
                headers={"Accept": "application/json"},
                timeout=timeout,
            )
            break
        except requests.ConnectionError as error:  # DNS or network failure: try the backup host
            last_error = error
    else:
        raise last_error

    body = response.json()
    if response.status_code >= 400:
        messages = [info["value"] for info in (body.get("infos") or {}).get("info", [])]
        raise RuntimeError(f"Validation failed ({response.status_code}): {'; '.join(messages)}")

    results = {}
    for item in (body.get("items") or {}).get("item", []):
        if item.get("type") != "ProductModuleValidation":
            continue
        props = {p["name"]: p["value"] for p in item.get("property", [])}
        props["lists"] = {
            lst["name"]: {p["name"]: p["value"] for p in lst.get("property", [])}
            for lst in item.get("list", []) or []
        }
        results[props["productModuleNumber"]] = props

    ttl = datetime.fromisoformat(body["ttl"].replace("Z", "+00:00")) if body.get("ttl") else None
    return results, ttl


results, ttl = validate("CUSTOMER-123", product_number="YOUR_PRODUCT_NUMBER")
module = results.get("YOUR_PRODUCT_MODULE_NUMBER", {})
licensed = module.get("valid") == "true"

# Node-Locked: device fingerprint generated by your application
validate("CUSTOMER-123", module_params={"M-NODE": {"nodeSecret": fingerprint}})

# Floating: check out a concurrent session
validate("CUSTOMER-123", module_params={"M-FLOAT": {"sessionId": session_id, "action": "checkOut"}})

# Pay-per-Use: report consumed credits (post-payment mode)
validate("CUSTOMER-123", module_params={"M-PPU": {"usedQuantity": "5"}})

_cache = {}

def is_licensed(licensee_number, module_number):
    cached = _cache.get(licensee_number)
    if not cached or not cached[1] or datetime.now(timezone.utc) >= cached[1]:
        cached = _cache[licensee_number] = validate(licensee_number)
    return cached[0].get(module_number, {}).get("valid") == "true"