Reputation: 41
Instagram explains how they create their media ID in this blog post
https://instagram-engineering.com/sharding-ids-at-instagram-1cf5a71e5a5c
Each of our IDs consists of: 41 bits for time in milliseconds (gives us 41 years of IDs with a custom epoch) 13 bits that represent the logical shard ID 10 bits that represent an auto-incrementing sequence, modulus 1024. This means we can generate 1024 IDs, per shard, per millisecond.
our ‘epoch’ begins on January 1st, 2011 not sure if that's the actual production value or only for the example
How can I get the timestamp back from a media ID?
I have this two media ids where I know the timestamp, but I need to extract it from others
2384288897814875714 2020-08-26T13:43:27Z
2383568809444681765 2020-08-25T13:52:46Z
Upvotes: 3
Views: 1748
Reputation: 1537
package main
import (
"fmt"
"time"
)
const (
instaEpoch int64 = 1314220021721
mediaID int64 = 2384288897814875714
)
func main() {
extractedTimestamp := mediaID >> (64-41)
timeFromMediaID := extractedTimestamp + instaEpoch
fmt.Println(time.Unix(timeFromMediaID/1000,0).UTC())
}
Output:
2020-08-26 13:43:27 +0000 UTC
You can just right shift the id to get the timestamp back. Then you have to add the miliseconds to the epoch instagram is using.
Upvotes: 2