how to check if file exists in Firebase Storage?

问题

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.

https://firebase.google.com/docs/reference/js/firebase.storage.Reference

What is the proper way of checking if a certain file exists in Firebase Storage?

回答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

回答2:

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);
}

来源：https://stackoverflow.com/questions/37751202/how-to-check-if-file-exists-in-firebase-storage