a few more gotcha's: * when storing a UTC timestamp and you need to get a datetime object back in order to add dates or do some calcualtions, make sure you use

a few more gotcha's: * when storing a UTC timestamp and you need to get a datetime object back in order to add dates or do some calcualtions, make sure you use datetime.datetime.utcfromtimestamp(), eg. >>> datetime.datetime.utcfromtimestamp(1310727758.472) datetime.datetime(2011, 7, 15, 11, 2, 38, 472000) * python timestamps are longs and represent time in seconds. in Javascript it is the number of milliseconds since epoch, so you need to divide/multiple by 1000 depending on which way you are going. for eg. > new Date().valueOf() 1310728084389 >>> datetime.datetime.utcfromtimestamp(1310728084389) Traceback (most recent call last): File "<stdin>", line 1, in <module> ValueError: year is out of range >>> datetime.datetime.utcfromtimestamp(1310728084389 / 1000) datetime.datetime(2011, 7, 15, 11, 8, 4) * always set your server to UTC, always use the utc* functions (eg. utctimetuple, utcfromtimestamp, utctime etc.), store as a long, and when passing back to the client send the current UTC timestamp as well rather than relying on the client system clock, which is frequently wrong. You can also use: http://json-time.appspot.com/time.json?tz=UTC http://json-time.appspot.com/time.json?tz=UTC or implement something similar. I resorted to always outputting the current UTC time into a javascript variable and using that to calibrate the local computer time (again, never trusting client time) * never use time.time() to get a timestamp back because it will munge the value and re-add tz info * in Javascript, to go from your server-provided UTC timestamp to a local date object that you can then work with, use: > new Date(1310728084 * 1000).toUTCString() "Fri, 15 Jul 2011 11:08:04 GMT" * If you are providing an API or a feed, please include a UTC timestamp in the output - parsing all the different date formats and timestamp info and attempting to work out when something happen (such as when a post was published) is a real pain in the ass. store the timezone in a sep field called 'utc_offset' or similar