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Regular Expression Details

Title	Test Find RFC 2822 Date Regex
Expression	^(?:\s(Sun\|Mon\|Tue\|Wed\|Thu\|Fri\|Sat),\s)?(0?[1-9]\|[1-2][0-9]\|3[01])\s+(Jan\|Feb\|Mar\|Apr\|May\|Jun\|Jul\|Aug\|Sep\|Oct\|Nov\|Dec)\s+(19[0-9]{2}\|[2-9][0-9]{3}\|[0-9]{2})\s+(2[0-3]\|[0-1][0-9]):([0-5][0-9])(?::(60\|[0-5][0-9]))?\s+([-\+][0-9]{2}[0-5][0-9]\|(?:UT\|GMT\|(?:E\|C\|M\|P)(?:ST\|DT)\|[A-IK-Z]))(\s$(\\\(\|\\$\|(?<=[^\\])$(?<C>)\|(?<=[^\\])$(?<-C>)\|[^])(?(C)(?!))\))\s*$
Description	This is the best RFC 2822 ( http://www.faqs.org/rfcs/rfc2822 ) date format regular expression I could come up with. I've tested it, not very extensively though. This regex also validates obsolete standard, excluding comments anywhere.
Matches	Thu, 6 Jan 2005 18:44:56 -0500 \| Thu, 21 Dec 2000 16:01:07 +0200 ($proper$ & (nested) comment)
Non-Matches	Thu, 0 Jan 1856 18: 44:56 -0500 \| Thu, 21 Dec 2000 16:01:07 +0200 (\(improper) comment) \| blah
Author	Rating: Ivik Injerd
Source
Your Rating	Bad 1 2 3 4 5 Good

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Existing User Comments

Title: Enhanced
Name: Ivik
Date: 7/19/2007 1:44:55 AM
Comment:
Thank you Doekman! I went ahead and modified what you provided to not match day 0 and match 2 digit years and nested comments (after much research and testing). Please tell me if you find any problems. Enjoy! ^_^

Title: Enhancement
Name: Doekman
Date: 7/11/2007 4:31:21 PM
Comment:
I've enhanced the regex. The day can now also start with a zero (02), and I've added some non-capturing "?:" markers. Math: for the record; it already matched "Sun, 30 Jan 2005 05:01:28 GMT". The new RegExp is: /^(?:(Sun|Mon|Tue|Wed|Thu|Fri|Sat),\s+)?(0[1-9]|[1-2]?[0-9]|3[01])\s+(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\s+(19[0-9]{2}|[2-9][0-9]{3})\s+(2[0-3]|[0-1][0-9]):([0-5][0-9])(?::(60|[0-5][0-9]))?\s+([-\+][0-9]{2}[0-5][0-9]|(?:UT|GMT|(?:E|C|M|P)(?:ST|DT)|[A-IK-Z]))(\s+|$([^\($]+|\\$|\\$)*\))*$/

Title: Fixed
Name: Ivik
Date: 4/30/2005 4:30:26 PM
Comment:
I knew it wasn't perfect... it should work now. Thanks!

Title: You fail on a common format
Name: Matt
Date: 4/28/2005 3:35:25 AM
Comment:
Your Regex doesn't even parse "Sun, 30 Jan 2005 05:01:28 GMT" Lame.

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