Re: [PHP] [RFC] HTTP timezone
On Monday 11 June 2007 16:05, Lester Caine wrote: Timezone information is only of use for the CURRENT day - even if it is wrong. It is ESSENTIAL that any changes also include the daylight saving information. Since this is not included, all current sites handling event related information in real time need to manually log a users PROPER time and daylight saving information so that they know if 8AM today is the same as 8AM tomorrow. Since HTTP is a query and response protocol, timezone information will be sent on each query. Lets say that it is XX of month Y 1:59 and that the timeoffset is changed at '2:00' by +1. A request sent at 1:59 will have an offset, lets say +0200. A request sent at 3:00 (that's one minute after 1:59) will have an offset of +0300. Full timezone information requires a POSIX 1003.1 timezone string that is quite complex to parse and support, since the server side script must be able to identify all of the available timezones. The first draft proposed this representation but was changed after the suggestions of ietf-http-wg mailing list people to only include the offset for simplicity. Timezone information is not meant to be stored as session information nor being used for anything else than one-time time/date representation. It is just a way for the client to say: If you're going to show me something that is time related then you should know that you should represent it using this offset from GMT. Something like the Accepted-Language header. Lets say you're viewing an MRTG generated graph. This graph uses the time as the X-axis value. Lets say that the server is in Greece where the offset is +0200 (+0300 during DST) and that the time is 14:10. The graph will end its X axis at the current time (14:10). Someone from the UK visits the graph page and he should see the same graph ending in 12:10 (UK is +). An incorrect timezone string will only result in 'bad' time representation which will be the case anyway (without TZ). There is no need to include the DST information since when on DST the client will be sending the propper offset. For example, EET+2EEST is +0200 during winter and +0300 during DST. Hope this clears things a bit... By the way, what makes you think that most people have an invalid timezone configured? Windows XP have NTP support that is enabled by default. Without a proper timezone this should result in an always invalid time. Linux and BSD systems have more experienced users that set their timezone correctly most of the time. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] [RFC] HTTP timezone
On Monday 11 June 2007 18:15, Lester Caine wrote: calender of events over a change in daylight saving I NEED to know !!! I believe that I finally understand your thoughts. You mean that you need to use the timezone information to know when in the future the time will change (or in the past). I believe that you're correct. I assume that providing the current offset and the timezone as two separate strings would be the most appropriate thing. The offset will provide simplicity for simple applications. The timezone will provide full information for applications that support it and the browser will not need to do much work since both of them are immediately available (Just a sprintf()). What about something like: Timezone: offset; posix_timezone for example: Timezone: +0200; EET-2EEST ? Correct, so people select the timezone that gives the right time, if the daylight saving switch is off. And then the calendar gives the wrong times when trying to display a weekend containing a daylight saving change. ( THAT one wasted a few hours before we twigged what was wrong - since the clock was right :) ) Your comments are of great importance to this attempt. I'll be glad if we can come with a solution that will fit your experienced needs on this subject. This may help other people too. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] [RFC] HTTP timezone
On Sunday 10 June 2007, Tijnema wrote: On 6/9/07, Richard Lynch [EMAIL PROTECTED] wrote: On Sat, June 9, 2007 8:06 am, Stefanos Harhalakis wrote: Timezone: +0200 that will specify their timezone offset. This way scripts will be able to provide appropriate date/time strings/representations and/or content. It's pretty useless and unreliable since user's clocks/timezone settings are incorrect far too often... YMMV I agree with you, clock settings are incorrect way too often, I just checked my own, and I see that the time is correct, but the Timezone is at GMT, while i live in GMT+1, but in summer, it's GMT+2. That brings me to the next point, what about DST? I've read your complete draft, and it doesn't say anything about DST, What should browsers send for my country? +0100 or +0200? In DST the offset from UTC is adjusted and thus it will become +2 in your case. Perhaps a note about DST would be usefull. The original idea was to use the POSIX 1003.1 timezone string that optionally includes the DST information but this introduces a lot of complexity and was changed to include just the current offset. Ps. what's the next thing we send to the browser? We already sent a lot of info through the user-agent header... Next year we send our computers specs to the server so that we get a site that is made for the performance of our computer? Perhaps you didn't had a need about this in the past. Have you ever tried looking at graphs that include time information in them? Just have a look at mrtg graphs or stock graphs and try to figure what time each point is supposed to represent. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] [RFC] HTTP timezone
On Sunday 10 June 2007, Tijnema wrote: To get back to the point, I think that the timezone should be defined on what time it actually is at his PC, and what time it is on time.nist.gov for example, and not lookng at some setting... Timezone setting is often wrong, people just update their time to match the time of their watch. This sets the UTC time wrong too, but still displays the right time to the user. So if you compare this time to time on web servers that are allways right, and you compare the difference between that, then you know the timezone that is probably right. Timezone is a property of the user and some times of the session. It is not a property of a system. Different users of a system may use different timezones (unless they use Windows where they can't). Anyway, I strongly believe that the issue of providing the correct timezone should be a concern of the end user and the browser. Any error checking and workarounds should be performed by those two and not by the server side scripts. In any way, there is no guarantee that the timezone information provided by clients will be correct. That's why it should only be used for informational purposes and not for security etc. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
[PHP] [RFC] HTTP timezone
Hello there, I'm currently writting and Internet Draft candidate to describe an HTTP header that will be used to transfer timezone information from browsers to servers. Compliant browsers will need to send a timezone string: Timezone: +0200 that will specify their timezone offset. This way scripts will be able to provide appropriate date/time strings/representations and/or content. I'm sending this email as a request for comments. Any ideas/suggestions will be greatly appreciated and will help in forming the final document. You can find the current draft in: http://www.it.teithe.gr/~v13/draft-sharhalakis-httptz-02.txt This and all future versions will be available in the IETF I-D database at: https://datatracker.ietf.org/public/idindex.cgi Just search for 'httptz'. Revision 02 will be available really soon in the I-D DB too. Please CC me since I'm not subscribed to the mailing list. Harhalakis Stefanos -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] [RFC] HTTP timezone
On Saturday 09 June 2007, Daniel Brown wrote: On 6/9/07, Stefanos Harhalakis [EMAIL PROTECTED] wrote: I'm currently writting and Internet Draft candidate to describe an HTTP header that will be used to transfer timezone information from browsers to servers. Compliant browsers will need to send a timezone string: It's a good idea, but in no way related to PHP. Just wanted the opinion of PHP people/developers since PHP programmers will be most affected by this. Can you point me to the proper php related list to ask? -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] [RFC] HTTP timezone
On Saturday 09 June 2007, Stut wrote: Just wanted the opinion of PHP people/developers since PHP programmers will be most affected by this. Can you point me to the proper php related list to ask? I fail to see how PHP programmers will be most affected by this since it would equally apply to any web developer using any language. By saying PHP programmers I mean people using PHP to write programs and not developers of the PHP language. I'm saying 'most' since the majority of dynamic web pages are written in PHP. Of course anyone writting non-static web content will be able to use it. However, I like the idea but would modify it slightly such that it send an RFC 2822 formatted date which will include the timezone but would also allow the server to determine if the datetime on the client is wrong. This can be important for applications that make extensive use of client-side technologies such as Javascript. I've already thought about providing the full time but I didn't find any applications. Can you provide some examples about its usage? How can you tell whether a user has wrong time and not wrong timezone? -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] [RFC] HTTP timezone
On Saturday 09 June 2007, Stut wrote: Stefanos Harhalakis wrote: I meant people using PHP to write programs also. I would dispute your assertion that the majority of dynamic web pages are written in PHP. I would accept an assertion that PHP is one of the most widely used languages for web development. But this is all more off-topic than your original request. Should we stop CCing the list? However, I like the idea but would modify it slightly such that it send an RFC 2822 formatted date which will include the timezone but would also allow the server to determine if the datetime on the client is wrong. This can be important for applications that make extensive use of client-side technologies such as Javascript. I've already thought about providing the full time but I didn't find any applications. Can you provide some examples about its usage? How can you tell whether a user has wrong time and not wrong timezone? You can't. But just because we can't immediately think of a use doesn't mean uses don't exist. Now, to the point. Including the time would only slightly modify RFC 2616 which states that Clients SHOULD only send a Date header field in messages that include an entity-body, as in the case of PUT and POST requests, and even then it is optional (section 14.18). I don't know the reason for that clause excluding other requests, but you would be well-advised to find out why before submitting your RFC. In any event, adding a new header seems daft to me when there is an existing header that is currently acceptable in certain cases that includes the information your new header would provide. In my opinion your RFC should recommend that Clients SHOULD send a Date header with every request unless the client does not have a clock. A client without a clock MUST NOT send a Date header field in a request. I don't know the reason either but I'll ask the http-wg mailing list about it. As for the date, since HTTP1.1 covers this, an RFC that overlaps with it will not be accepted. Apart from that, it would need an RFC that would obsolete RFC2616 which I'd preffer not to do. Most probably we will need a new HTTP version since this will produce an incompatible protocol. As for the usage of client Date/Time information, as a programmer I know that I'd never use this at the server side because of errors and malicious usage. Knowing the clients time isn't something usefull since the server side already knows it, assuming that the client has correct time. If the client side has an incorrect clock setting the why should one use this? Even if there is a reason, I believe that javascript would fit this need. Finally, modifying the Date field to include the clients timezone offset would result once again in an incompatible protocol. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] [RFC] HTTP timezone
On Sunday 10 June 2007, Richard Lynch wrote: On Sat, June 9, 2007 8:06 am, Stefanos Harhalakis wrote: Timezone: +0200 that will specify their timezone offset. This way scripts will be able to provide appropriate date/time strings/representations and/or content. It's pretty useless and unreliable since user's clocks/timezone settings are incorrect far too often... I'm only considering the timezone information. I believe that this is not the proper way to think before making a start. The fact that many user's timezone is incorrect doesn't mean that this is not needed. Lets just hope that one day Windows will do the right thing and keep the time in UTC while displaying it using the appropriate timezone. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
