Format RFC3339 dates

Question

I am receiving the following date in string format from the API

2015-04-18 06:08:28.000000

I want the date to be in the format of d/M/yyyy

I tried the following

NSString *datevalue = (NSString*)value;
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"d/M/yyyy"];
NSDate *date =  [formatter dateFromString:datevalue];
NSString *currentDate = [formatter stringFromDate:date];

This returns NIL, what could be the possible issue, or how do i format such dates in objective-c?

Thanks.

Answer 1

You should use the yyyy-MM-dd HH:mm:ss.SSSSSSS format string for the date formatter converting the API date into a NSDate object, as discussed by the others. But, you also want to consider the timeZone and locale properties of this formatter.

• Usually RFC 3339 dates are exchanged in GMT. Confirm this with your API, but it's generally GMT/UTC/Zulu. If so, you will probably also want to explicitly set the timezone:

  formatter.timeZone = [NSTimeZone timeZoneForSecondsFromGMT:0];
  

  But confirm what timezone the API expects.

• A more subtle issue is the handling users with non-Gregorian calendars

  formatter.locale = [[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"];
  

For more information, see Apple Technical Q&A 1480.

Clearly, these dateFormat, timeZone, and locale properties are simply for converting the API date string into a NSDate object. When then outputting the date for the end user, you would use a separate formatter, defaulting to the standard timeZone and locale properties and use whatever dateFormat string you want for the output. (Frankly, I wouldn't generally advise using dateFormat string for user output formatters, but rather just use the appropriate values for the dateStyle and timeStyle properties.)