How does rmongodb convert time (and how to do the reverse operation)?

Question

I use rmongodb to query a MongoDB. I connect to the DB which works nicely (require(rmongodb); mongo <- mongo.create("foo")) and I am generally able to get stuff out of the database. I just don't know what to do about the date formats..

TIME <- strptime("2013-11-11 15:00",format="%Y-%m-%d %H:%M",tz="CET")
query = mongo.bson.buffer.create()
mongo.bson.buffer.append(query, "timestamp", TIME)
query = mongo.bson.from.buffer(query)

when I look at this query it says:

timestamp : 9    1198930688

So mongo.bson.buffer.append has properly recognized that timestamp is a date class and does some conversion -- which I don't understand. This is not UNIX time and I would not really care if the values returned from the database weren't in this format as well. I'm particularly puzzled because quite some of these numeric date values are negative while all my dates are from 2013... Some more examples:

# 2013-10-10 12:15 --> -1579369312
# 2013-10-10 12:30 --> -1578469312
# 2013-11-10 12:30 -->  1103530688

So basically my question is: How can I convert this funny date format (1198930688) back to POSIXct?

Thanks a lot! skr

Answer 1

Try

myTIME <- mongo.bson.value( query, "timestamp" )
myTIME
[1] "2013-11-11 15:00:00 CET"