creating custom token in cloud function after reteiving data from realtime database

Question

i want to create custom token in cloud function but before that I want to check and compare timestamp from realtime database and with current time.if the timestamp is below 10 min then I want to create custom token and send back to client.please help me to achieve this.i am new to this cloud function firebase.

here is my code

export const authaccount = functions.https.onCall(async (data) => {
  try {
    const snap= await admin.database().ref("/register/"+data).get();
    const time=snap.val().timestamp;
    const now=new Date().getDate();
    const reg=new Date(time).getDate();
    const today=Math.abs(now-reg);
    const daydiff=Math.floor(today/1000/60/60/24);
    const nowminutes=new Date().getUTCMinutes();
    const regminutes=new Date(time).getUTCMinutes();
    const timediff=Math.abs(nowminutes-regminutes);
    if (timediff<10 && daydiff==0) {
      try {
        admin.auth().createCustomToken(data).then((customtoken)=>{
          console.log("auth created"+" "+timediff+" "+daydiff+" "+customtoken);
          return customtoken;
        });
      } catch (err1) {
        throw new functions.https.HttpsError("unknown", err1.message, err1);
      }
    } else {
      console.log("else "+" "+now+" "+reg+" "+time+" "+daydiff);
    }
  } catch (err2) {
    throw new functions.https.HttpsError("unknown", err2.message, err2);
  }
});

2:53:20.626 AM
authaccount
Error: Process exited with code 16 at process.<anonymous> (/layers/google.nodejs.functions-framework/functions-framework/node_modules/@google-cloud/functions-framework/build/src/invoker.js:275:22) at process.emit (events.js:314:20) at process.EventEmitter.emit (domain.js:483:12) at process.exit (internal/process/per_thread.js:168:15) at Object.sendCrashResponse (/layers/google.nodejs.functions-framework/functions-framework/node_modules/@google-cloud/functions-framework/build/src/logger.js:37:9) at process.<anonymous> (/layers/google.nodejs.functions-framework/functions-framework/node_modules/@google-cloud/functions-framework/build/src/invoker.js:271:22) at process.emit (events.js:314:20) at process.EventEmitter.emit (domain.js:483:12) at processPromiseRejections (internal/process/promises.js:209:33) at processTicksAndRejections (internal/process/task_queues.js:98:32)
2:53:19.559 AM
authaccount
Error: The caller does not have permission; Please refer to https://firebase.google.com/docs/auth/admin/create-custom-tokens for more details on how to use and troubleshoot this feature. at FirebaseAuthError.FirebaseError [as constructor] (/workspace/node_modules/firebase-admin/lib/utils/error.js:44:28) at FirebaseAuthError.PrefixedFirebaseError [as constructor] (/workspace/node_modules/firebase-admin/lib/utils/error.js:90:28) at new FirebaseAuthError (/workspace/node_modules/firebase-admin/lib/utils/error.js:149:16) at Function.FirebaseAuthError.fromServerError (/workspace/node_modules/firebase-admin/lib/utils/error.js:188:16) at /workspace/node_modules/firebase-admin/lib/auth/token-generator.js:114:53 at processTicksAndRejections (internal/process/task_queues.js:97:5) at async Promise.all (index 1)
2:53:19.558 AM
authaccount
Unhandled rejection
2:53:19.469 AM
authaccount
Function execution took 1386 ms, finished with status code: 200

please help to solve this problem. i don't know where I am making the mistake.

Answer 1

You will need to make sure your Firebase Admin sdk is initiated and running before the function proceeds

if (firebase.apps.length === 0) {
    firebase.initializeApp();
}

Resource: https://firebase.google.com/docs/admin/setup#initialize-without-parameters

I doubt you have modified the IAM permissions on your service account but as the comment suggested: https://firebase.google.com/docs/auth/admin/create-custom-tokens#service_account_does_not_have_required_permissions

Once that is confirmed to be working - you will need to ensure that the onCall data is a string and not null, some simple health checks can help you debug your process

console.log(typeof data);
console.warn("Data", data);

from there I would also debug your date times and the realtime database result, these are async and will require the promise to be resolved before you can use it.

Update:

All cloud functions should return a response to the client onCall uses promises on the client and supports a 'return Object' example:

return {
  token: myCustomToken,
  possible: otherValue
};

for comparison, onRequest uses fetch like responses and supports codes

response.status(500)
response.send({name:value})
return;

Source: https://firebase.google.com/docs/functions/callable#sending_back_the_result

Source: https://firebase.google.com/docs/functions/http-events#using_express_request_and_response_objects

Update:

all paths and promises need to resolve correctly, this includes awaiting promises to resolve and returning their result or storing the result for any secondary processing - I suggest cleaning up the code, remove the try/catch and use .then().catch() Example:

if (timediff<10 && daydiff==0) {
    return await admin.auth().createCustomToken(data)
        .then((customtoken)=>{
            console.log("auth created"+" "+timediff+" "+daydiff+" "+customtoken);
            return customtoken;
        })
        .catch (err) {
            return new functions.https.HttpsError("unknown", err.message, err);
         }
    } 
    else {
      console.log("else "+" "+now+" "+reg+" "+time+" "+daydiff);
    return "else "+" "+now+" "+reg+" "+time+" "+daydiff;
    }