Express Swift Date().timeIntervalSince1970 to Firebase Epoch Time

Question

I followed different answers from here and here

I'm just getting started learning Cloud Tasks from here. In that blog post Doug says "What I want is for expirationAtSeconds to be the time of expiration expressed in epoch seconds".

I want the Task to delete the post when that time is set. In my iOS app I create a post that expires at a specific time:

let timeStamp = Date().timeIntervalSince1970

let postDate: Date = Date(timeIntervalSince1970: timeStamp)
var expirationDate: Date? = Calendar.current.date(byAdding: .hour, value: +24, to: postDate)
guard let exp = expirationDate else { return }

let expiresAt = exp.timeIntervalSince1970

dict.updateValue(expiresAt, forKey: "expiresAt")
dict.updateValue(timeStamp, forKey: "postDate")
// other values ...

ref.updateChildValues(dict)

which gives me a database value like:

posts
  some_post_Id
    -"expiresAt": 1632627680.340107
    // other values ...

In my cloud function I want the expiresAt date which is a Double expressed in Epoch seconds. I'm not sure if I should use expDate1, expDate2, expDate3, or expDate4:

exports.onCreatePost = functions.database.ref('/posts/{postId}').onCreate((snapshot, context) => {

    const post = snapshot.data();

    const expiresAt = snapshot.child("expiresAt").val();
    const expirationDate = expiresAt.valueOf(); // 1632627680.340107

    var expDate1 = DateTime.fromMillisecondsSinceEpoch(expirationDate * 1000)

    var expDate2 = DateTime.fromMicrosecondsSinceEpoch(expirationDate * 1000000)

    var expDate3 = DateTime.fromMicrosecondsSinceEpoch(expirationDate.microsecondsSinceEpoch)

    var expDate4 = expirationDate.toDate()

    const expirationAtSeconds = either expDate1, expDate2, expDate3, or expDate4

    // continue on with the rest of the code ...
});

did you try `expDate1` and the rest? what was wrong with them? — Jesper, Sep 30 '21 at 09:20
@Jesper I'm still working on the code from the blog post. I haven't even gotten a chance to run it yet because I'm slowly trying to understand everything else. Javascript isn't native to me and after I read that quote from Doug, I found 4 different answers so I didn't know which to choose from. But based on your question it seems like `expDate1` would be the best choice. I can figure it out from here on using print statements. Thanks! — Lance Samaria, Sep 30 '21 at 09:34

Lance Samaria · Answer 1 · 2021-10-07T13:41:02.773

From my question none of the above DateTime methods worked for me because I kept getting an error TypeError: Cannot read property 'DateTime' of undefined.

I had to use new Date(expirationDate * 1000) and I got the conversion to epoch seconds from here

Code:

const functions = require("firebase-functions");
const admin = require('firebase-admin');
admin.initializeApp();

exports.onCreatePost = functions.database.ref('/posts/{postId}').onCreate((snapshot, context) => {

    const post = snapshot.data();

    const expiresAt = snapshot.child("expiresAt").val();
    const expirationDate = expiresAt.valueOf(); // 1632627680.340107

    const expDate = new Date(expirationDate * 1000); // <--------Here

    const expirationAtSeconds = expDate.getTime()/1000.0; // <-------- this will be epoch seconds conversion

    console.log("expDate: " + expDate + " | expirationAtSeconds:" + expirationAtSeconds);

    // continue on with the rest of the code ...
});

Express Swift Date().timeIntervalSince1970 to Firebase Epoch Time

1 Answers1