Not getting refresh_token when authenticating with paypal API

@Preston PHX

Adding a comment here as the comments does not allow that many characters. Can I do something to get a refresh_token? Problems I have is that I am using node as a proxy with http-proxy-middleware.

app.use("/", PROXY_TO_PAYPAL);

On app startup I authenticate and store the token in a variable that will expire.

  console.log(`Starting proxy at ${HOST}:${PORT}`);
  console.log(`PAYPAL_TOKEN_URL: ${PAYPAL_TOKEN_URL}`);
  // set the token on startup
  getToken().then((data) => {
    token = data.access_token;
    console.log(`expires_in ${parseInt(data.expires_in)} seconds`);
    const timeoutDate = getTimeoutDate(parseInt(data.expires_in) * 1000);
    tokenTimeOut = timeoutDate.getUTCMilliseconds();
    console.log(`Token times out at ${timeoutDate.toUTCString()}`);
  });
});

I need to update the token BEFORE it expires, otherwise I risk that a proxy request will fail as it could potentially use an expired token. I created a scheduler that will watch the when the token is getting close to expire and will renew it (call the authentication again), like say 15 min before.

async function getToken() {
  return await axios(tokenOptions)
    .then((res) => {
      console.log(res.data.access_token);
      console.log(res.data.expires_in);
      console.log(res.data);
      return res.data;
    })
    .catch((err) => {
      console.log(err);
    });
}

cron.schedule("* * * * *", function () {
  console.log("running a task every minute");
  // refresh token
  if (tokenTimeOut - new Date().getUTCMilliseconds() < 900*1000) {
    getToken().then((data) => {
      token = data.access_token;
      const timeoutDate = getTimeoutDate(parseInt(data.expires_in) * 1000);
      tokenTimeOut = timeoutDate.getUTCMilliseconds();
      console.log(`Token times out at ${timeoutDate.toUTCString()}`);
    });
  }
});

I am adding the Bearer header on each request bore it is proxied

const middlewareOptions = {
  target: `${PAYPAL_BASE_URL}`, // target host
  changeOrigin: true,
  onProxyReq(proxyReq, req, res) {
    if (!token) {
      getToken().then((data) => {
        token = data.access_token;
        tokenTimeOut = data.expires_in;
      });
    }
    proxyReq.setHeader("Authorization", `Bearer ${token}`);
  },
};

I might get the same token again until I am closer to the expire date (I think) - which could work. Eventually I would get a new token and a new expire time.

I am confused about the documentation. Here they talk about the refresh_token https://developer.paypal.com/docs/connect-with-paypal/integrate/#6-get-access-token But here there are not refresh_token https://developer.paypal.com/docs/api/get-an-access-token-curl/

What I wanted to do is when I am close to the expire time I would use the refresh_token to get a new token.