From calsify-bounces@ietf.org Thu Apr 15 17:34:18 2010 Return-Path: X-Original-To: calsify-archive-feit0ahl@lists.ietf.org Delivered-To: ietfarch-calsify-archive-Feit0ahl@core3.amsl.com Received: from [127.0.0.1] (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 2DD8A3A696E; Thu, 15 Apr 2010 17:34:18 -0700 (PDT) X-Original-To: calsify@core3.amsl.com Delivered-To: calsify@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 9D9E33A690C for ; Thu, 15 Apr 2010 17:34:16 -0700 (PDT) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: 0.001 X-Spam-Level: X-Spam-Status: No, score=0.001 tagged_above=-999 required=5 tests=[BAYES_50=0.001] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id FFkjkvK-x38m for ; Thu, 15 Apr 2010 17:34:15 -0700 (PDT) Received: from mail-gw0-f44.google.com (mail-gw0-f44.google.com [74.125.83.44]) by core3.amsl.com (Postfix) with ESMTP id 6D1833A69CB for ; Thu, 15 Apr 2010 17:34:15 -0700 (PDT) Received: by gwj19 with SMTP id 19so236031gwj.31 for ; Thu, 15 Apr 2010 17:34:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:date:received:message-id :subject:from:to:content-type; bh=hTIOIp2Jfkthisth1nhjkJ2VQN9I/be2fZ5u1CJe+Aw=; b=FTyYwBnat9YyCyvEAWxAlnQlXm03S2Fao85al70WAdenpb56aYoyaDnVGyjw+RNBVr b3UkEn98t0ayNJT+0eC0t9a0wiC7E6a9AqMhiAMyRcliqhpD8uaDasLCg9UdBoGKCsNS lHPVSm+lDlKSbkTo7AGgvLtCNxkj4D06pCga0= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=XSTStCAT9ak/+O3tIlqc/drGuE35QHg2HyW+uur3OH4khJTDMxapz9vP9PLa8siwCm WI0iiXye81FtoAYGa7WGviyLbQ6jIjXVRqfnc7IhI8ddi/cxz+vu2Ew4XBqtQvT5e8mW RE8OOjVT7mTbW4WpcAcRFqR6YwZ14/z1GttXU= MIME-Version: 1.0 Received: by 10.90.56.13 with HTTP; Thu, 15 Apr 2010 17:34:02 -0700 (PDT) Date: Thu, 15 Apr 2010 20:34:02 -0400 Received: by 10.90.39.6 with SMTP id m6mr540483agm.49.1271378042578; Thu, 15 Apr 2010 17:34:02 -0700 (PDT) Message-ID: From: Rick DeNatale To: calsify@ietf.org Subject: [calsify] VTIMEZONE vs. TZInfo - looking for confirmation X-BeenThere: calsify@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: calsify-bounces@ietf.org Errors-To: calsify-bounces@ietf.org Hi, I just spent the afternoon tracking down a problem with my ri_cal ruby gem. One of the things I do is generate VTIMEZONE components from tzinfo data, using the tz_info ruby gem. It seems that tzinfo and rfc 2445 have different views of when a time zone period starts in local time. Now the local time when a timezone period starts is a bit ambiguous, since at the transition, of say US Eastern time from EST to EDT last month, local time could be considered to either be 20100314T020000 or 20100314T030000 or both As I understand RFC 2445 the DTSTART for this timezone period would be the first. This understanding is what I want to confirm, although looking at sample ics files I'm pretty confident. The TZInfo gem uses the latter. I fixed this by using the local end time of the previous period (if a previous period exists), and if not I adjust the start time either forward or backward 1 hour depending on whether or not it's a daylight or standard period. There might be a subtle bug here in the latter case if some timezones use a DST shift other than an hour, but for now I'll live with that. -- Rick DeNatale Blog: http://talklikeaduck.denhaven2.com/ Github: http://github.com/rubyredrick Twitter: @RickDeNatale WWR: http://www.workingwithrails.com/person/9021-rick-denatale LinkedIn: http://www.linkedin.com/in/rickdenatale _______________________________________________ calsify mailing list calsify@ietf.org https://www.ietf.org/mailman/listinfo/calsify From rick.denatale@gmail.com Thu Apr 15 17:34:16 2010 Return-Path: X-Original-To: calsify@core3.amsl.com Delivered-To: calsify@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 9D9E33A690C for ; Thu, 15 Apr 2010 17:34:16 -0700 (PDT) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: 0.001 X-Spam-Level: X-Spam-Status: No, score=0.001 tagged_above=-999 required=5 tests=[BAYES_50=0.001] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id FFkjkvK-x38m for ; Thu, 15 Apr 2010 17:34:15 -0700 (PDT) Received: from mail-gw0-f44.google.com (mail-gw0-f44.google.com [74.125.83.44]) by core3.amsl.com (Postfix) with ESMTP id 6D1833A69CB for ; Thu, 15 Apr 2010 17:34:15 -0700 (PDT) Received: by gwj19 with SMTP id 19so236031gwj.31 for ; Thu, 15 Apr 2010 17:34:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:date:received:message-id :subject:from:to:content-type; bh=hTIOIp2Jfkthisth1nhjkJ2VQN9I/be2fZ5u1CJe+Aw=; b=FTyYwBnat9YyCyvEAWxAlnQlXm03S2Fao85al70WAdenpb56aYoyaDnVGyjw+RNBVr b3UkEn98t0ayNJT+0eC0t9a0wiC7E6a9AqMhiAMyRcliqhpD8uaDasLCg9UdBoGKCsNS lHPVSm+lDlKSbkTo7AGgvLtCNxkj4D06pCga0= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=XSTStCAT9ak/+O3tIlqc/drGuE35QHg2HyW+uur3OH4khJTDMxapz9vP9PLa8siwCm WI0iiXye81FtoAYGa7WGviyLbQ6jIjXVRqfnc7IhI8ddi/cxz+vu2Ew4XBqtQvT5e8mW RE8OOjVT7mTbW4WpcAcRFqR6YwZ14/z1GttXU= MIME-Version: 1.0 Received: by 10.90.56.13 with HTTP; Thu, 15 Apr 2010 17:34:02 -0700 (PDT) Date: Thu, 15 Apr 2010 20:34:02 -0400 Received: by 10.90.39.6 with SMTP id m6mr540483agm.49.1271378042578; Thu, 15 Apr 2010 17:34:02 -0700 (PDT) Message-ID: From: Rick DeNatale To: calsify@ietf.org Content-Type: text/plain; charset=ISO-8859-1 Subject: [calsify] VTIMEZONE vs. TZInfo - looking for confirmation X-BeenThere: calsify@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 16 Apr 2010 00:34:16 -0000 Hi, I just spent the afternoon tracking down a problem with my ri_cal ruby gem. One of the things I do is generate VTIMEZONE components from tzinfo data, using the tz_info ruby gem. It seems that tzinfo and rfc 2445 have different views of when a time zone period starts in local time. Now the local time when a timezone period starts is a bit ambiguous, since at the transition, of say US Eastern time from EST to EDT last month, local time could be considered to either be 20100314T020000 or 20100314T030000 or both As I understand RFC 2445 the DTSTART for this timezone period would be the first. This understanding is what I want to confirm, although looking at sample ics files I'm pretty confident. The TZInfo gem uses the latter. I fixed this by using the local end time of the previous period (if a previous period exists), and if not I adjust the start time either forward or backward 1 hour depending on whether or not it's a daylight or standard period. There might be a subtle bug here in the latter case if some timezones use a DST shift other than an hour, but for now I'll live with that. -- Rick DeNatale Blog: http://talklikeaduck.denhaven2.com/ Github: http://github.com/rubyredrick Twitter: @RickDeNatale WWR: http://www.workingwithrails.com/person/9021-rick-denatale LinkedIn: http://www.linkedin.com/in/rickdenatale From cyrus@daboo.name Thu Apr 15 17:42:51 2010 Return-Path: X-Original-To: calsify@core3.amsl.com Delivered-To: calsify@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id BA1AF3A69F4 for ; Thu, 15 Apr 2010 17:42:51 -0700 (PDT) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -0.555 X-Spam-Level: X-Spam-Status: No, score=-0.555 tagged_above=-999 required=5 tests=[AWL=0.555, BAYES_05=-1.11] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id a4amuxA6tUTs for ; Thu, 15 Apr 2010 17:42:51 -0700 (PDT) Received: from daboo.name (daboo.name [151.201.22.177]) by core3.amsl.com (Postfix) with ESMTP id DB6403A69C3 for ; Thu, 15 Apr 2010 17:42:50 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by daboo.name (Postfix) with ESMTP id D5458147FD48A; Thu, 15 Apr 2010 20:42:43 -0400 (EDT) X-Virus-Scanned: amavisd-new at daboo.name Received: from daboo.name ([127.0.0.1]) by localhost (chewy.mulberrymail.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id AhY-d-099-4A; Thu, 15 Apr 2010 20:42:43 -0400 (EDT) Received: from [10.0.1.7] (unknown [10.0.1.1]) by daboo.name (Postfix) with ESMTPSA id 1E4F4147FD47F; Thu, 15 Apr 2010 20:42:42 -0400 (EDT) Date: Thu, 15 Apr 2010 20:42:39 -0400 From: Cyrus Daboo To: Rick DeNatale , calsify@ietf.org Message-ID: In-Reply-To: References: X-Mailer: Mulberry/4.1.0a1 (Mac OS X) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline; size=838 Subject: Re: [calsify] VTIMEZONE vs. TZInfo - looking for confirmation X-BeenThere: calsify@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 16 Apr 2010 00:42:51 -0000 Hi Rick, --On April 15, 2010 8:34:02 PM -0400 Rick DeNatale wrote: > Now the local time when a timezone period starts is a bit ambiguous, > since at the transition, of say US Eastern time from EST to EDT last > month, local time could be considered to either be > > 20100314T020000 > or > 20100314T030000 > > or both > > As I understand RFC 2445 the DTSTART for this timezone period would be > the first. > > This understanding is what I want to confirm, although looking at > sample ics files I'm pretty confident. Correct. There is a simple logic to this. Basically you want to know the current local time at which the DST transition needs to occur. i.e. when my local clock reaches 2 am I know to move ahead or back an hour. That is basically what the DTSTART in VTIMEZONE tells you. -- Cyrus Daboo From calsify-bounces@ietf.org Thu Apr 15 17:42:52 2010 Return-Path: X-Original-To: calsify-archive-feit0ahl@lists.ietf.org Delivered-To: ietfarch-calsify-archive-Feit0ahl@core3.amsl.com Received: from [127.0.0.1] (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id D93313A6A09; Thu, 15 Apr 2010 17:42:52 -0700 (PDT) X-Original-To: calsify@core3.amsl.com Delivered-To: calsify@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id BA1AF3A69F4 for ; Thu, 15 Apr 2010 17:42:51 -0700 (PDT) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -0.555 X-Spam-Level: X-Spam-Status: No, score=-0.555 tagged_above=-999 required=5 tests=[AWL=0.555, BAYES_05=-1.11] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id a4amuxA6tUTs for ; Thu, 15 Apr 2010 17:42:51 -0700 (PDT) Received: from daboo.name (daboo.name [151.201.22.177]) by core3.amsl.com (Postfix) with ESMTP id DB6403A69C3 for ; Thu, 15 Apr 2010 17:42:50 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by daboo.name (Postfix) with ESMTP id D5458147FD48A; Thu, 15 Apr 2010 20:42:43 -0400 (EDT) X-Virus-Scanned: amavisd-new at daboo.name Received: from daboo.name ([127.0.0.1]) by localhost (chewy.mulberrymail.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id AhY-d-099-4A; Thu, 15 Apr 2010 20:42:43 -0400 (EDT) Received: from [10.0.1.7] (unknown [10.0.1.1]) by daboo.name (Postfix) with ESMTPSA id 1E4F4147FD47F; Thu, 15 Apr 2010 20:42:42 -0400 (EDT) Date: Thu, 15 Apr 2010 20:42:39 -0400 From: Cyrus Daboo To: Rick DeNatale , calsify@ietf.org Message-ID: In-Reply-To: References: X-Mailer: Mulberry/4.1.0a1 (Mac OS X) MIME-Version: 1.0 Content-Disposition: inline; size=838 Subject: Re: [calsify] VTIMEZONE vs. TZInfo - looking for confirmation X-BeenThere: calsify@ietf.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: calsify-bounces@ietf.org Errors-To: calsify-bounces@ietf.org Hi Rick, --On April 15, 2010 8:34:02 PM -0400 Rick DeNatale wrote: > Now the local time when a timezone period starts is a bit ambiguous, > since at the transition, of say US Eastern time from EST to EDT last > month, local time could be considered to either be > > 20100314T020000 > or > 20100314T030000 > > or both > > As I understand RFC 2445 the DTSTART for this timezone period would be > the first. > > This understanding is what I want to confirm, although looking at > sample ics files I'm pretty confident. Correct. There is a simple logic to this. Basically you want to know the current local time at which the DST transition needs to occur. i.e. when my local clock reaches 2 am I know to move ahead or back an hour. That is basically what the DTSTART in VTIMEZONE tells you. -- Cyrus Daboo _______________________________________________ calsify mailing list calsify@ietf.org https://www.ietf.org/mailman/listinfo/calsify