Postman Pre-request Script

Copy this to your pre-request script either in the Request call, or the Folder.

// Function to parse JWT token and extract expiration time
function parseJwt(token) {
  let base64Url = token.split(".")[1];
  let base64 = base64Url.replace(/-/g, "+").replace(/_/g, "/");
  let jsonPayload = decodeURIComponent(
    atob(base64)
      .split("")
      .map(function (c) {
        return "%" + ("00" + c.charCodeAt(0).toString(16)).slice(-2);
      })
      .join(""),
  );

  return JSON.parse(jsonPayload);
}

// Get token and expiration time from environment variables
const storedToken = pm.environment.get("signin_token");
const tokenExpirationTime = pm.environment.get("token_expiration_time");

if (
  storedToken &&
  tokenExpirationTime &&
  new Date().getTime() / 1000 < tokenExpirationTime
) {
  // Token is not expired, use the existing token
  console.log("Using existing token");
} else {
  // Token is expired or not available, request a new one
  const rawBody = JSON.stringify({
    email: "your_email@example.com",
    password: "your_password",
    returnSecureToken: true,
  });

  pm.sendRequest(
    {
      url: "https://identitytoolkit.googleapis.com/v1/accounts:signInWithPassword?key={API_KEY}",
      method: "POST",
      body: rawBody,
    },
    function (err, response) {
      const jsonResponse = response.json();
      // Store the new token and its expiration time
      if (jsonResponse.idToken) {
        pm.environment.set("signin_token", jsonResponse.idToken);
        const parsedToken = parseJwt(jsonResponse.idToken);
        pm.environment.set("token_expiration_time", parsedToken.exp);
        console.log("New token obtained and stored");
      }
    },
  );
}

Under "Authorization" tab

Input {{signin_token}} into the Token