Cómo Automatizar el WhatsApp de una Empresa con la Cloud API

import os
from fastapi import FastAPI, Request, Response, BackgroundTasks

app = FastAPI()
VERIFY_TOKEN = os.environ["WA_VERIFY_TOKEN"]

@app.get("/webhook")
async def verificar(request: Request):
    p = request.query_params
    if p.get("hub.mode") == "subscribe" and p.get("hub.verify_token") == VERIFY_TOKEN:
        # Texto simples, não JSON: a Meta compara byte a byte.
        return Response(content=p.get("hub.challenge"), media_type="text/plain")
    return Response(status_code=403)

@app.post("/webhook")
async def receber(request: Request, tarefas: BackgroundTasks):
    body = await request.json()
    for entry in body.get("entry", []):
        for change in entry.get("changes", []):
            for msg in change["value"].get("messages", []):
                tarefas.add_task(tratar, msg["from"], msg.get("text", {}).get("body", ""))
    # Confirmar já: a Meta repete a entrega se demorares.
    return Response(status_code=200)

import os, httpx

PHONE_ID = os.environ["WA_PHONE_NUMBER_ID"]
TOKEN    = os.environ["WA_TOKEN"]
BASE     = f"https://graph.facebook.com/v21.0/{PHONE_ID}/messages"
HEADERS  = {"Authorization": f"Bearer {TOKEN}"}

async def responder(para: str, texto: str):
    """Texto livre. Só funciona dentro da janela de 24 horas."""
    async with httpx.AsyncClient(timeout=15) as c:
        r = await c.post(BASE, headers=HEADERS, json={
            "messaging_product": "whatsapp",
            "to": para,
            "type": "text",
            "text": {"body": texto},
        })
        r.raise_for_status()

async def enviar_modelo(para: str, nome: str, variaveis: list[str]):
    """Fora da janela, só modelos previamente aprovados pela Meta."""
    async with httpx.AsyncClient(timeout=15) as c:
        r = await c.post(BASE, headers=HEADERS, json={
            "messaging_product": "whatsapp",
            "to": para,
            "type": "template",
            "template": {
                "name": nome,
                "language": {"code": "pt_PT"},
                "components": [{
                    "type": "body",
                    "parameters": [{"type": "text", "text": v} for v in variaveis],
                }],
            },
        })
        r.raise_for_status()