Firebase获取服务器时间戳

Question

I am trying to structure my firebase database as such.

year/month/date/message eg 2017/08/26/message

Therefore, I need to get the firebase server time to set the new message reference path. I have used Firebase.database.ServerValue.TIMESTAMP but it returns a placeholder that only gets converted to epoch time during inserting. Therefore my 'createdAt' field is correct. But I need a way to create my desired path structure.

let epoch = Firebase.database.ServerValue.TIMESTAMP
console.log(`epoch : ${epoch}`) // it returns an object
let date = new Date(epoch) // date creation fail here
console.log(`date : ${date}`)
let messagesRef = db.ref(`messages/${date.getFullYear()}/${date.getMonth()}/${date.getDate()}`)
let newMessage = {
  createdAt: epoch    
}
messagesRef.push(newMessage)

Answer 1

There are ways but weird, easiest way I can think of is push the message, and then grab the message to get the timestamp you just pushed.

Another way is get the key of a new pushRef

 messagesRef.push().key 

And then get timestamp from decoding the firebase key (since they are generated by timestamp) decode firebasekey

@cartant state you can use server clock offset

 var offsetRef = firebase.database().ref(".info/serverTimeOffset"); offsetRef.on("value", function(snap) { var offset = snap.val(); var estimatedServerTimeMs = new Date().getTime() + offset; });