Parse millisecond timestamp with DateTime in PHP - php

Question

I want to create a DateTime object from a millisecond timestamp but that does not seem to work:
$timestamp_in_ms = 1546300800000; // int or string no difference
var_dump(DateTime::createFromFormat("Uv", $timestamp_in_ms));
var_dump(DateTime::getLastErrors());
This results in:
bool(false)
array(4) {
["warning_count"]=>
int(0)
["warnings"]=>
array(0) {
}
["error_count"]=>
int(1)
["errors"]=>
array(1) {
[13]=>
string(12) "Data missing"
}
}
However if I use a slightly different notation it does work:
$timestamp_in_ms = "1546300800.000";
var_dump(DateTime::createFromFormat("U\.v", $timestamp_in_ms));
var_dump(DateTime::getLastErrors());
object(DateTime)#1 (3) {
["date"]=>
string(26) "2019-01-01 00:00:00.000000"
["timezone_type"]=>
int(1)
["timezone"]=>
string(6) "+00:00"
}
Yes I can do something like this:
$timestamp_with_dot = $timestamp_in_ms / 1000 + "." + $timestamp_in_ms % 1000;
The documentation does not provide any insight in this. Both U and v are supported.
Anybody more info on this issue? I am running PHP 7.4.10

Answer 1

With a division by 1000 you can convert your millisecond timestamp as a float in seconds.
$msTimeStamp = 1600790571478;
$floatSec = $msTimeStamp/1000.0;
When using DateTime::createFromFormat, you can also use the "U.u" format. The "u" format should be exactly 6 characters. This can be done with sprintf().
$dateTime = DateTime::createFromFormat("U\.u", sprintf('%1.6F',$floatSec));
//test
echo $dateTime->format('Y-m-d H:i:s.u');
//2020-09-22 16:02:51.478000
//Timezone "+00:00" (UTC)
The millisecond timestamp can also be a float and also contain microseconds.
The above code works on 32-bit systems too.