RFC822 date-string to NSDate

• Steve Byan RFC822 date-string to NSDate Jun 30 2008, 20:35
  I'm having trouble grokking NSDateFormatter on OS X 10.4. Does it
  support RFC822-style dates? I'm parsing an XML document; here's the
  pertinent code snippet:
  
          NSLog(@"observation_time_rfc822 element end");
          NSDateFormatter * dateFormatter = [[NSDateFormatter alloc]
  init];
          [dateFormatter
  setFormatterBehavior:NSDateFormatterBehavior10_4];
          myObservationTime = [dateFormatter
  dateFromString:myCurrentStringValue];
          NSLog(@"myObservationTime %@", myObservationTime);
          myObservationTimeRFC822 = [[NSString alloc]
  initWithString:myCurrentStringValue];
  
  The myObservationTimeRFC822 string is "Mon, 30 Jun 2008 13:56:00
  -0400 EDT", but NSLog(@"myObservationTime %@", myObservationTime)
  prints "myObservationTime 1969-12-31 19:00:00 -0500".
  
  Best regards,
  -Steve
  
  --
  Steve Byan <stevebyan...>
  Littleton, MA 01460
• Andy Lee Re: RFC822 date-string to NSDate Jun 30 2008, 20:50
  I'm not too familiar with NSDateFormatter.  Do you need to call -
  setDateFormat:?
  
  --Andy
  
  On Jun 30, 2008, at 2:35 PM, Steve Byan wrote:
  
  

  > I'm having trouble grokking NSDateFormatter on OS X 10.4. Does it
  > support RFC822-style dates? I'm parsing an XML document; here's the
  > pertinent code snippet:
  >
  > NSLog(@"observation_time_rfc822 element end");
  > NSDateFormatter * dateFormatter = [[NSDateFormatter alloc]
  > init];
  > [dateFormatter
  > setFormatterBehavior:NSDateFormatterBehavior10_4];
  > myObservationTime = [dateFormatter
  > dateFromString:myCurrentStringValue];
  > NSLog(@"myObservationTime %@", myObservationTime);
  > myObservationTimeRFC822 = [[NSString alloc]
  > initWithString:myCurrentStringValue];
  >
  > The myObservationTimeRFC822 string is "Mon, 30 Jun 2008 13:56:00
  > -0400 EDT", but NSLog(@"myObservationTime %@", myObservationTime)
  > prints "myObservationTime 1969-12-31 19:00:00 -0500".
  >
  > Best regards,
  > -Steve
  >
  > --
  > Steve Byan <stevebyan...>
  > Littleton, MA 01460
  
• Nick Zitzmann Re: RFC822 date-string to NSDate Jun 30 2008, 20:54
  On Jun 30, 2008, at 12:35 PM, Steve Byan wrote:
  
  

  > I'm having trouble grokking NSDateFormatter on OS X 10.4. Does it
  > support RFC822-style dates?
  

  
  It should, but you'll have to make your own format string to do that.
  NSDateFormatter does make some guesses at the format when getting the
  date from a string, but only when it's using 10.0-style behavior, and
  even then it's better to just make your own format string.
  
  Nick Zitzmann
  <http://www.chronosnet.com/>
• Steve Byan Re: RFC822 date-string to NSDate Jun 30 2008, 21:14
  On Jun 30, 2008, at 2:50 PM, Andy Lee wrote:
  
  

  > I'm not too familiar with NSDateFormatter.  Do you need to call -
  > setDateFormat:?
  

  
  Ah, thanks, I missed the statement hidden on page 23 of "Data
  Formatting Programming Guide for Cocoa", which says:
  
  "You use the format string is used to specify both the input to and
  the output from date formatter objects."
  
  That's a bummer, because RFC822 dates have some optional elements and
  so don't conform to a fixed format. I hoped that the default parsing
  was smart.
  
  Anyone have any pointers to some Objective-C RFC822-date-time parsing
  code? An NSDateFormatter category containing
  dateFromRFC822DateTimeString: would be great :-)
  
  Best regards,
  -Steve
  
  --
  Steve Byan <stevebyan...>
  Littleton, MA 01460
• Kyle Sluder Re: RFC822 date-string to NSDate Jun 30 2008, 21:55
  On Mon, Jun 30, 2008 at 3:14 PM, Steve Byan <stevebyan...> wrote:
  

  > That's a bummer, because RFC822 dates have some optional elements and so
  > don't conform to a fixed format. I hoped that the default parsing was smart.
  

  
  Well it looks like the RFC822 date grammar is context-free so
  implementing a parser shouldn't be that hard.  You'll have to deal
  with Y2K, though.
  
  --Kyle Sluder