Python

HTTP client in Python using requests. Reuses a Session to keep the headers and the connection pool. Also includes a webhook receiver with Flask and HMAC verification.

Setup


pip install requests

Complete client


# lxs_client.py
import os, uuid, hmac, hashlib
from typing import Optional
import requests
 
 
class LxsClient:
    def __init__(self, api_key: str, base_url: str = "https://api.pos.lxsyscr.com"):
        self.base_url = base_url
        self.session = requests.Session()
        self.session.headers.update({
            "X-Api-Key": api_key,
            "Content-Type": "application/json",
            "Accept": "application/json"
        })
        self.session.timeout = 30
 
    def emitir(self, data: dict, idempotency_key: Optional[str] = None) -> dict:
        key = idempotency_key or str(uuid.uuid4())
        r = self.session.post(
            f"{self.base_url}/api/v1/facturas",
            json=data,
            headers={"Idempotency-Key": key}
        )
        r.raise_for_status()
        return r.json()
 
    def consultar(self, clave: str) -> dict:
        r = self.session.get(f"{self.base_url}/api/v1/facturas/{clave}")
        r.raise_for_status()
        return r.json()
 
    def descargar_pdf(self, clave: str) -> bytes:
        r = self.session.get(f"{self.base_url}/api/v1/facturas/{clave}/pdf")
        r.raise_for_status()
        return r.content
 
    def descargar_xml(self, clave: str) -> str:
        r = self.session.get(f"{self.base_url}/api/v1/facturas/{clave}/xml")
        r.raise_for_status()
        return r.text
 
    def reenviar_email(self, clave: str) -> dict:
        r = self.session.post(f"{self.base_url}/api/v1/facturas/{clave}/email")
        r.raise_for_status()
        return r.json()
 
    def anular(self, clave: str) -> None:
        r = self.session.delete(f"{self.base_url}/api/v1/facturas/{clave}")
        r.raise_for_status()
 
    def proximo_consecutivo(self, tipo: str) -> int:
        r = self.session.get(f"{self.base_url}/api/v1/consecutivos/proximo", params={"tipo": tipo})
        r.raise_for_status()
        return r.json()["proximo"]
 
 
# Usage:
client = LxsClient(os.environ["LXS_API_KEY"])
 
factura = client.emitir({
    "tipo": "FacturaElectronica",
    "idUsuario": 7,
    "cliente": {"idCliente": 42},
    "condicionVenta": "01",
    "medioPago": "01",
    "moneda": "CRC",
    "lineas": [{"idProducto": 100, "cantidad": 2}]
})
 
print(f"Key: {factura['clave']}")

Webhook receiver (Flask)

You must use request.get_data() to get the body as bytes before computing the HMAC. If get_json() is called first and then serialized again, the signature will not match.


# webhook_server.py
import os, hmac, hashlib, json
from flask import Flask, request, abort
 
app = Flask(__name__)
WEBHOOK_SECRET = os.environ["LXS_WEBHOOK_SECRET"]
 
@app.post("/webhooks/lxs")
def webhook():
    signature = (request.headers.get("X-Lxs-Signature") or "").replace("sha256=", "")
    expected = hmac.new(WEBHOOK_SECRET.encode(), request.get_data(), hashlib.sha256).hexdigest()
 
    if not hmac.compare_digest(signature, expected):
        abort(401)
 
    evento = request.get_json()
    procesar_evento(evento)
    return "", 200
 
 
def procesar_evento(evento: dict):
    # Dedup by nonce
    # Update DB
    pass
 
 
if __name__ == "__main__":
    app.run(port=3000)