Fast ISO8601 date parser and writer for iOS & Mac.

Installation

Carthage is the recommended way to install ISO8601. Add the following to your Cartfile:

github "soffes/ISO8601"

You can also install with CocoaPods:

pod 'ISO8601'

For manual installation, I recommend adding the project as a subproject to your project or workspace and adding the framework as a target dependency.

Usage

First, import the appropriate header:

@import ISO8601; // Use #import <ISO8601/ISO8601.h> if you're using CocoaPods

This library uses NSDateComponents for reading and writing. Here's an example:

// Reading
NSDateComponents *dateComponents = [ISO8601Serialization dateComponentsForString:@"1999-05-19T23:55:21+09:00"];

// Writing
NSString *ISO8601String = [ISO8601Serialization stringForDateComponents:dateComponents];

There is an NSDate category for convenient conversion:

// Reading
NSDate *date = [NSDate dateWithISO8601String:@"1999-05-19T23:55:21+09:00"];

// Writing
NSString *ISO8601String = [date ISO8601String];

If you require more control over conversion or need to know the input time zone, you can use the advanced methods the category provides:

// Reading
NSTimeZone *timeZone;
NSDate *date = [NSDate dateWithISO8601String:@"1999-05-19T23:55:21+09:00" timeZone:&timeZone usingCalendar:calendarOrNil];

// Writing
NSString *ISO8601String = [date ISO8601StringWithTimeZone:timeZoneOrNil usingCalendar:calendarOrNil];

Notes

NSDateComponents is the core data structure because NSDate doesn't perserve time zone information well.

It's worth noting that a value in the NSDateComponents will be nil if it is not in the input string. For example, 1999-05-19T23:55:21 will have a nil time zone, but 1999-05-19T23:55:21+00:00 and 1999-05-19T23:55:21Z will have a UTC time zone.

The +[NSDate dateWithISO8601String:] category will always return a UTC date. If you want a date in another time zone, you should use +[NSDate ISO8601StringWithTimeZone:usingCalendar:] (you may pass nil for the calendar parameter to use the current calendar).

Enjoy.