On Tue, Jan 19, 2010 at 12:42 PM, Paul M Foster <paulf@xxxxxxxxxxxxxxxxx>wrote: > On Tue, Jan 19, 2010 at 10:06:26PM +1100, clancy_1@xxxxxxxxxxxx wrote: > > > I am trying for the first time to use cookies. The manual contains the > > statement "Cookies > > are part of the HTTP header, so setcookie() must be called before any > > output is sent to > > the browser." > > > > When I first started using sessions, I was alarmed to read a very similar > > statement about > > sessions, but I soon found that if I started my program with the > statement > > "session_start();" I could then set up, access, modify or clear any > session > > variable at > > any time in my program. This is enormously useful, as I can put the > session > > handling at > > any convenient point in my program, and can precede them with diagnostics > > if I need to. > > > > However I have almost immediately found that while I appear to be able to > > read cookies at > > any time, I cannot set them when I would like to. Is there any similar > > trick which will > > work with cookies? If I really have to work out what they should be, > > and then set them up, > > before issuing any diagnostics, etc, it will make life decidely more > > complicated. (I > > assume that I can set several cookies using successive calls to > setcookie()?) > > Session variables are available throughout your session. Cookie > variables are only available if you read them into variables you can > access. Changes to session variables will the flushed to the server when > your page is terminated. Cookie variables are flushed to disk if you > make the appropriate *_cookie() function call, and even then I don't > know if this is actually echoed to disk until your page is terminated. > > > > > I was also somewhat surprised to find that a cookie is used to implement > > sessions. Does > > this place any limitations on using both sessions and cookies in the > > same program? > > I don't believe so. If I'm not mistaken, session values are stored on the > server, not on the client. What's stored on the client is the session > ID. > > Please bear in mind my understanding of cookies is fragmentary, and I > hope someone else will write in to correct any incorrect statements I've > made. > > Paul > > -- > Paul M. Foster > > -- > PHP General Mailing List (http://www.php.net/) > To unsubscribe, visit: http://www.php.net/unsub.php > > > > I was also somewhat surprised to find that a cookie is used to implement > sessions. Does > this place any limitations on using both sessions and cookies in the > same program? There shouldn't be any issue. By default, PHP uses a cookie named PHPSESSIONID to associate a particular visitor with their corresponding session data stored server-side. So, just be sure not to use a cookie called "PHPSESSIONID". -- Nephtali: PHP web framework that functions beautifully http://nephtaliproject.com
