Convert ISO 8601 to NSDate

Question

I have a timestamp coming from server that looks like this:

2013-04-18T08:49:58.157+0000

I've tried removing the colons, I've tried all of these:

Converting an ISO 8601 timestamp into an NSDate: How does one deal with the UTC time offset?

Why NSDateFormatter can not parse date from ISO 8601 format

Here is where I am at:

+ (NSDate *)dateUsingStringFromAPI:(NSString *)dateString {


    NSDateFormatter *dateFormatter;
    dateFormatter = [[NSDateFormatter alloc] init];

    //@"yyyy-MM-dd'T'HH:mm:ss'Z'" - doesn't work
    //@"yyyy-MM-dd'T'HH:mm:ssZZZ" - doesn't work
    //@"yyyy-MM-dd'T'HH:mm:sss" - doesn't work 

    [dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss'Z'"];
    [dateFormatter setTimeZone:[NSTimeZone timeZoneWithName:@"GMT"]];

    // NSDateFormatter does not like ISO 8601 so strip the milliseconds and timezone
    dateString = [dateString substringWithRange:NSMakeRange(0, [dateString length]-5)];

    return [dateFormatter dateFromString:dateString];
}

One of my biggest questions is, is the date format I have above really ISO 8601? All the examples I have seen from people the formats of each are slightly different. Some have ...157-0000, others don't have anything at the end.

Answer 1

This works for me:

NSString *dateString = @"2013-04-18T08:49:58.157+0000";
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss.SSSZ"];
// Always use this locale when parsing fixed format date strings
NSLocale *posix = [[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"];
[formatter setLocale:posix];
NSDate *date = [formatter dateFromString:dateString];
NSLog(@"date = %@", date);

Answer 2

There is New API from Apple! NSISO8601DateFormatter

NSString *dateSTR = @"2005-06-27T21:00:00Z";
NSISO8601DateFormatter *formatter = [[NSISO8601DateFormatter alloc] init];
NSDate *date = [formatter dateFromString:dateSTR];
NSLog(@"%@", date);

Answer 3

I also have the native API, which is way cleaner... This is the implementation I got in my DateTimeManager class:

+ (NSDate *)getDateFromISO8601:(NSString *)strDate{

    NSISO8601DateFormatter *formatter = [[NSISO8601DateFormatter alloc] init];
    NSDate *date = [formatter dateFromString: strDate];
    return date;
}

Just copy and paste the method, it would do the trick. Enjoy it!

Answer 4

The perfect and best solution that worked for me is:

let isoFormatter = ISO8601DateFormatter();
isoFormatter.formatOptions = [ISO8601DateFormatter.Options.withColonSeparatorInTime,
                                      ISO8601DateFormatter.Options.withFractionalSeconds,
                                      ISO8601DateFormatter.Options.withFullDate,
                                      ISO8601DateFormatter.Options.withFullTime,
                                      ISO8601DateFormatter.Options.withTimeZone]
let date = isoFormatter.date(from: dateStr);

For further more detail, you can refer to apple's official documentation: https://developer.apple.com/documentation/foundation/nsiso8601dateformatter