Re: [PHP] Question about session_id() and session_start()

thank you.
I read the source code and it helps a lot, now I know the behavior
of the code is consistent with the NOTE.
I think the reason is that If the 'new' session_id we want to set
already exists on the server, but does not exist on the client's
cookie, the server must send a set-cookie header to the client.


On Tue, May 21, 2013 at 3:50 PM, Tim Schofield <[email protected]> wrote:

> On 20/05/2013, Maciek Sokolewicz <[email protected]> wrote:
> > On 20-5-2013 22:14, Tim Schofield wrote:
> >> Matijn
> >>
> >> There are well over half a million lines of source code in PHP. It seems
> >> a
> >> little unhelpful to tell someone to go and read half a million lines of
> C
> >> when you could just tell them the answer?
> >>
> >> Thanks
> >> Tim
> >>
> >> Course View Towers,
> >> Plot 21 Yusuf Lule Road,
> >> Kampala
> >> T +256 (0) 312 314 418
> >> M +256 (0) 752 963 325
> >> www.weberpafrica.com
> >> Twitter: @TimSchofield2
> >> Blog: http://weberpafrica.blogspot.co.uk
> >> On May 20, 2013 6:24 PM, "Matijn Woudt" <[email protected]> wrote:
> >>
> >>> On Mon, May 20, 2013 at 5:33 AM, 孟远涛 <[email protected]> wrote:
> >>>
> >>>> I find the Note in PHP document.
> >>>> http://www.php.net/manual/en/function.session-id.php
> >>>>
> >>>> "Note: When using session cookies, specifying an id for session_id()
> >>>> will
> >>>> always send a new cookie when session_start() is called, regardless if
> >>> the
> >>>> current session id is identical to the one being set."
> >>>>
> >>>> I feel puzzled about this feature. Even if the current session id is
> >>>> identical to the one one being set, session_start will send a new
> >>> cookie. I
> >>>> want to know why session_start behave in this way.
> >>>>
> >>>> Forgive my poor English. Thanks in advance.
> >>>>
> >>>
> >>> You will find the answer in the PHP source code.
> >>> If you don't want this to happen, check if the current session id
> >>> matches
> >>> with the value you want to set it to, and don't set if they match.
> >>>
> >>> - Matijn
> >>>
> >>
> >
> > Tim,
> >
> > first of all, please bottom-post on this list.
>
> Tell that to the designers of the android gmail app :-)
>
> > Secondly, a simple google search for "php c session_start" resulted in
> > this:
> > https://github.com/php/php-src/blob/master/ext/session/session.c#L1303
>
> That wasn't the advice given. The advice given was to read the source
> code. My point was that is not very helpful advice. With a few notable
> exceptions the help given on this list has become less and less
> friendly over the years I have been reading it. This can't be good for
> the PHP community.
>
> >
> > - Tul
> >
> >
>
> Tim
>
> --
> Course View Towers,
> Plot 21 Yusuf Lule Road,
> Kampala
> T   +256 (0) 312 314 418
> M +256 (0) 752 963 325
> www.weberpafrica.com
> @TimSchofield2
> Blog: http://weberpafrica.blogspot.co.uk/
>
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