how to check if file exists in Firebase Storage?

Question

When using the database you can do snapshot.exists() to check if certain data exists. According to the docs there isn\'t a similar method with storage.

Answer 1

I believe that the FB storage API is setup in a way that the user only request a file that exists.

Thus a non-existing file will have to be handled as an error: https://firebase.google.com/docs/storage/web/handle-errors

Answer 2

I've found a nice solution while keeping within the Node.js Firebase Gogole Cloud Storage SDK using the File.exists, taught it would be ideal to share for those searching.

const admin = require("firebase-admin");
const bucket = admin.storage().bucket('my-bucket');

const storageFile = bucket.file('path/to/file.txt');
storageFile
  .exists()
  .then(() => {
    console.log("File exists");
  })
  .catch(() => {
    console.log("File doesn't exist");
  });

Google Cloud Storage: Node.js SDK version 5.1.1 (2020-06-19) at the time of writing

Answer 3

You can use getDownloadURL which returns a Promise, which can in turn be used to catch a "not found" error, or process the file if it exists. For example:

storageRef.child("file.png").getDownloadURL().then(onResolve, onReject);

function onResolve(foundURL) {
    //stuff
}

function onReject(error) {
    console.log(error.code);
}