You will need to put the session ID in the URL. You will need to make a change in your php.ini file so if you are on a shared host you will need to contact them to see what they will do for you.
stymiee
He's No Good To Me Dead
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1) Set a cookie
2) Check for that cookie. If you don't see it, then they don't accept cookies.
stymiee
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Unfortunately that's the only reliable way. If you are going to do that be sure to wait until you are actually going to start the session before doing it. That way users with cookies turned off can still surf the site without being bothered with that message. While doing so they may decide it is worth turning cookies on to do what they need to do.
stymiee
He's No Good To Me Dead
3,360 posts since May 2006
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As soon as they hit your site set a cookie regardless of what page they enter from. Don't check for it right away though. Some people will just want to browse and that's fine. But as soon as they try to use a feature that requires cookies look for the cookie you set. If it isn't there take them to a page that explains why they need to have cookies enabled.
stymiee
He's No Good To Me Dead
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Thanks for the replies but unless there is some way of intercepting between when the customer hits the submit button ('Add to Cart') and when the page submits to itself there is no way of knowing if the reload is from the submit button or a new visitor. I see other web sites are linked to this forum so if you want to have a look at my site go to http://www.biodistributors.com.au/Testing/PriceListFiles/health.php and disable cookies and see what happens when you try to add items to the cart. The idea is that the "view cart' button doesn't show if the cart is empty. What I am developing now is to show the "view cart' button all the time and when a user who has disabled cookies hits it they get the explanation about cookies needing to be set. Before that the page will just reload unchanged.
Ric
You can tell a new visitor on that page because they will be sending a HTTP GET Request. Thus your $_GET will be populated instead of $_POST.
When the submit button is clicked, they you will have a HTTP POST Request. Thus you'll have $_POST populated.
You'll also have
$_POST['submit']; // = 'Add selected items to cart'
This is the value of the submit button.
If you set a cookie (say 'test') on every page like mentioned, then when you get to the point where the "Add to cart" button is clicked, you should either have:
// cookie support
$_POST['submit']; // = 'Add selected items to cart'
$_COOKIE['test']; // = '1';
or:
// no cookie support
$_POST['submit']; // = 'Add selected items to cart'
$_COOKIE['test']; // = '';
If you get the second one, display the message to turn on cookies.
You can also have the sessionID appended to the URL instead of placed in a cookie as mentioned before. The problem with this approach is that it is vulnerable to a number of social based attacks.
---
If you are not satisfied with having to have the user request a second page in order to know whether or not cookies are supported, you could use javascript to check for cookie support, and update the cart with JS.
The problem with this is that it requires JS enabled, so you'll still have to have the PHP fallback methods.
eg: JS
<script>
<script>
// check support of cookies and add an alert to the form.onsubmit() event
function check_cookie_support() {
document.cookie = 'test=1'
if (!document.cookie.match(/test=1/)) {
// say if your form has the id=cart_form
var form = document.getElementById('cart_form');
if (form) {
form.onsubmit = function() {
alert('sorry, please enabled cookies to use the cart'); // warn user
return false; // stops form submission
};
}
}
}
window.onload = check_cookie_support; // check support after DOM has loaded
</script>
</script>
digital-ether
Nearly a Posting Virtuoso
1,293 posts since Sep 2005
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[QUOTE=ric1950;403022]
$_POST['submit']; // = 'Add selected items to cart'
]
Thanks for that - it works a treat. I didn't realise you could retrieve the value of the submit button.
Ric
Glad that helped.
I blogged on this topic some time back:
One of the drawbacks of this method is that it intrudes on the presentation layer. If you check for the value of the submit button, then you make changes to that value in the HTML (presentation) subject to changes in your PHP code (logic) also. (If you plan to update HTML later, you break the php code)
A better alternative if you have only one submit button is the method suggested byw_3rabi.
if u want a way to tell thats a page is submitted or just loaded
u could use a hidden input in the form
then check if the name of this var is in the $_POST
then it is submitted else it is just the first load
The hidden input is not part of the presentation layer, but instead part of your php logic.
Or you can just check if the submit button was clicked, and not its value.if (isset($_POST['submit'])) {
// form submission
}
digital-ether
Nearly a Posting Virtuoso
1,293 posts since Sep 2005
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Regarding the check for cookies enabled or not, I use a different method:
I check for the SID constant - if cookies are enabled, than SID is an empty string, if cookies are disabled, SID is a string like this "session_name()=session_id()".
So,
if (SID == '') {
echo "cookies are enabled";
}
else {
echo "cookies are disabled; SID should be appended to url":
}
Of course, session should be started before all these!!!
johny_d
Junior Poster in Training
94 posts since May 2007
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johny_d
Junior Poster in Training
94 posts since May 2007
Reputation Points: 33
Solved Threads: 7
Regarding the check for cookies enabled or not, I use a different method:
I check for the SID constant - if cookies are enabled, than SID is an empty string, if cookies are disabled, SID is a string like this "session_name()=session_id()".
So,
if (SID == '') {
echo "cookies are enabled";
}
else {
echo "cookies are disabled; SID should be appended to url":
}
Of course, session should be started before all these!!!
Just so you'll understand what you're doing better if you go with Jonny_d's solutions.
The SID being set does not mean cookies are supported. It means that PHP was able to register a PHP session.
The SID will be set under two conditions:
1) The HTTP Request from the browser contained a PHP session cookie.
2) The HTTP Request from the browser contained a $_GET variable that PHP interprets as the Session ID.
If the condition was (2) then cookies are not supported, but a PHP session was registered via the URL.
This is the best test for the ability of PHP to keep a session, but not for the ability to persist cookies.
If you explicitly state in your PHP configuration (php.ini) that PHP sessions should be restricted to cookies (which I believe is default for later versions) then the SID constant test will implicitly test for cookies. It still requires at least one previous HTTP Request to set the cookie (2 page loads).
It still brings you to your first problem, where you would not know if the user just landed on the page, or submitted the form.
Hope that sheds some more light on the subject.
digital-ether
Nearly a Posting Virtuoso
1,293 posts since Sep 2005
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