According to my knowledge, session is stored at server and cookie is stored at client. But as soon as cookie is disabled, the session stops working. What is the reason behind this? Is it possible to make session work when cookie is disabled?
Few references I got:
http://php.net/manual/en/session.configuration.php
Well, because when cookie is disabled, the server has no idea which sessions a client belongs to (no information of the session is passed to the server). If you want to make session work when cookie is disabled, you may have to pass a PHPSESSID in your urls, something that looks like this:
http://example.com/myurl.php?PHPSESSID=[a long string]
PHPSESSID can be generated by using session_id() function.
That's because the cookie is used to identify which session on the server is associated with the current client.
Related
I've seen various questions like mine, though none provide the correct answer.
I've a PHP script:
session_start();
setcookie(session_name('DSWLogin'),session_id(),time()+2*7*24*60*60, '/');
//This will only be set once (when the user logs in)
$_SESSION['test'] = 'Yup, I am working';
if (isset($_SESSION['test'])){
echo 'Session is set and ready!';
} else {
echo 'No session was set...';
}
and that all works fine except after a browser restart, my PHP script ignores the session.
When my browser hasn't restarted yet, it'll echo 'Session is set and ready!'; just fine.
And when I look into my cookie tab, it indeed says a cookie, named DSWLogin has been set with a certain value.
When I restart my browser, my cookie tab still says that a cookie, named DSWLogin has been set with the same value it had before the restart, so it is still there!
But my PHP script apparently ignores is, and outputs 'No session was set...'...
Thanks in advance,
Isaiah v. Hunen
What you are trying to do is not really the correct way to achieve this. Sessions have two parts, a cookie with a session id set by default to expire at the end of the session (usually browser close) and a server side storage mechanism that is cleaned up automatically after a certain period of time after the last request was received.
What you are trying to do is extend the session to two weeks. While you could change the cookie settings and increase the timeout to session garbage collection doing this is not very reliable.
Instead you want to look at using a one time key stored in a cookie which acts as an alternate login path. This cookie can recreate the session just like a normal login would. There are some details that need to be considered for this to remain secure, but it will do what you are attempting to achieve.
Just because you are setting your session_id in some cookie doesn't mean it is THE session cookie. Most browsers will purge session cookies on browser close. This is what you are seeing. Look at the cookies in your browser that are set when your session is valid and compare this to the cookies that are still remaining after browser restart. You will notice your true session cookie has gone missing.
Quoting the manual:
The session name is reset to the default value stored in session.name
at request startup time. Thus, you need to call session_name() for
every request (and before session_start() or session_register() are
called).
Also if you want to change lifetime of session cookie, use session_set_cookie_params instead of forcing your own cookie.
Also read about session garbage collection and configuration, changing cookie lifetime might not be enough.
I have a weird problem. I have a web page, that on the main page sets a session variable for each user that visits, and then on the next pages if the session variable is set, some stuff is shown, and some other isn't. The variable i'm setting is just an "1".
$_SESSION['user_id'] = $user_id;
Everything is simple, everything is working great, but I have this one user, that the server doesn't save the session variable for. Just one guy as far as I know. What can be causing this behaviour? He is using a mac if that matters, but on other macs the website works great.
Thanks.
When you call session_start() PHP sets a cookie with just the PHPSESSID variable set. This variable is used to identify the client browser with the session data on the server. If your user has disabled cookies, then it is not possible to use sessions without passing PHPSESSID back and forth in every request via GET or POST.
HTTP is a stateless protocol. IF session would be only in server side, how could it be able to distinguish between users?
[HTTP is a stateless protocol means: HTTP requests are responded from the server, and it forgets who sent the request, where did that come from.]
This is why cookies are storing the session ids.
In other words, if a user is disabling the cookies, he is not allowing PHP to set the session for himself. This is the reason behind.
Today I had skype interview for a job as PHP developer, one of the questions asked was about Cookies and PHP Sessions.
The question was, can PHP session be set and read, used, if Cookies are disabled in users Browser?
I told them not, beacuse PHP Sessions by default depends on setting a session cookie. When PHP session starts, new session Cookie is set with default name PHPSESSID, and that cookie holds value of that session id, for example: ftu63d8al491s5gatuobj39gk7
Then on apache server in tmp folder file sess_ftu63d8al491s5gatuobj39gk7 is created and it holds content of that session, for example: test1|s:12:"SessionTest1";test2|s:12:"SessionTest2";
They told me that's not true, and that you can use PHP Sessions even if user disables cookies in his browser.
Then I told them that you can do that, but then session id would be passed through URL as GET variable. And that's not secure and you must set it up in php.ini.
They were talking how you can use PHP Sessions even if Cookies are disabled in browser. And what if we are building web shop, and some granny uses our web shop and disables cookies and she joust don't care. And that PHP Sessions are great because you can use them even if user disables Cookies. I was like wtf, wtf wtf?!?!
I made test with two files, index.php starts session and sets session variables. And then session.php tries to read that session variables.
This is how it looks:
index.php
<p>This is where I start and set php sessions.</p>
<?php
session_start();
$_SESSION['test1'] = "SessionTest1";
$_SESSION['test2'] = "SessionTest2";
?>
<p>This is a link, that starts new HTTP Request, and tries to read session set on this page:</p>
<p>Read Session</p>
session.php
<?php
session_start();
var_export($_SESSION);
?>
<p>Back</p>
Now, if you enable cookies in your browser, visit index.php, and the visit session.php , session would be printed out.
But, if you clear your browser history and cookies, and then visit index.php, and then visit session.php, you would see empty array right?
So basically my question is, am I right?
Can you use PHP sessions if you disable cookies in your browser?
And do PHP Session mechanism by default, depends on setting a session COOKIE?
Update:
I was going mad about this, so I called back the guy I was talking with. And asked him, can PHP session work without cookies by default? The guy said "yes". Then I told him he is wrong and he said: "yes, yes, if you say so..." and start laughing. Then I told him, ok if PHP session can work without setting cookie, how would server know current user/browser session id, if its not stored in a session cookie? (I wanted to see if he knows that session id can be passed as GET variable) And he was quiet for at least 20s, and told me that he is a System Administrator, and that I should ask that the Developer guy. And that he is 43 years old and has huge experience of 13 years in the bussines (he started with 30? wtf?), but he trusts me on this one. And I explained him how Session work and that you can use it without Cookie but then session id is passed as GET variable, and told him I told them that on interview, but they ware telling me no, no no... :S
So basically, the guy didn't have a clue about PHP and PHP Sessions, and yes he was the one that asked me about sessions telling me that PHP Session can work without cookie, even when I told him it cant be done, and that there is a way to use PHP Sessions without cookies but it won't work by default. He was like, no no no...
At the end he told me that he was thinking that sessions can work without cookies because he, as System Admin on his servers, can never see sessions in tmp folder?!?!?
Anyway, those guys suck at PHP, there is no way I will accept job offer from them, and after all this I dont think they will offer me a job anyway...
Thanks for all the comments!
"A visitor accessing your web site is assigned a unique id, the
so-called session id. This is either stored in a cookie on the user
side or is propagated in the URL. "
Sessions: Introduction
If session.use_cookies = 1 (Cookie enabled.)
If session.use_cookies = 0 (Cookie disabled.)
If session.use_cookies = 1 then session stores the sessionId into cookie. Calling session_id() get the stored sessionId from cookie and saved data into session array will be found on all the pages. If session.use_cookies = 0 In this case session does not store sessionId into cookie and you will get each time a new sessionId using session_id() and data stored into session on other pages will not be found on another pages.
Yes session will work when cookies is disabled.
But first apache check php configuration settings.
Like:
--enable-trans-sid
and
--enable-track-vars
if these value are set true the session will passed by POST automatically.
If "--enable-trans-sid" and "--enable-track-vars" values are set to FALSE, we need to pass session id by using the SID constant.
< a href="index.php?<?= SID ?>" >Navigate from here< /a >
Need to set php.ini
ini_set("session.use_cookies", 0);
ini_set("session.use_trans_sid", 1);
So basically my question is, am I right?
Mostly. In the real world: YES.
Can you use PHP sessions if you disable cookies in your browser?
You CAN use PHP sessions without cookies, as long as the browser identity is obtained somehow and yields a unique value (and this value is passed to the PHP session layer):
session ID in GET (which is the "standard" PHP way if cookies are not allowed, and the "other" way you described). This value is then propagated automatically by PHP, e.g. added to all A HREF's and so on. Where it is not propagated because the automagical link recognition failed (e.g. complex URL built in Javascript), it is your responsibility to provide accordingly.
Or - and here we're not in Kansas anymore:
passed among the nonces with Auth Digest (this is a dirty trick, and of course requires that the whole site is behind an Auth-Digest access authentication scheme. And you can no longer use a "dummy auth" (i.e. http://welcome:guest#www.example.com ) because some browsers, e.g. Internet Explorer, do not support them anymore for security reasons)
recognizing the browser some other way ("fingerprinting") (this is normally(1) suicidal)
Use LSO (Local Shared Objects) to generate a random UUID if it's not there already, and store it so that it can be retrieved on subsequent accesses.
other ways ( see http://en.wikipedia.org/wiki/Evercookie )
(1) if you were in a LAN where you can trust the IPs, you could associate a "session" to the user IP. You might enforce a strict "no cookies" policy in a small firm and still have user sessions without resorting to _GET/_POST for your session ID.
You are right, Session cannot work without cookies.
To illustrate this try doing the following actions.
Login To Gmail.
After login disabled the cookies.
Refresh the page.
You will be redirected to the login page again as the server cannot identify the session.
Now again enable the cookies.
Refresh the page. (Note: Don't click on login button).
You will be automatically redirected to the Gmail inbox.
Hence, we can say without cookies session will not work.
Also, If you are trying to login into the gmail( taking as example you can take any website) with diabled cookies then it will message as "Your browser has cookies disabled. Make sure your cookies are enabled and try again."
If it was me, I would say "Yes"
Since you could store session in form / url somewhere to passed to next page (very bad idea). So, based on his question "can PHP session be set and read, used, if Cookies are disabled in users Browser?"
Then, it should be yes. It can read and used.
However, If user close browser, then it's gone, and that's it. (since that guy didn't ask about this part)
Yes.. It will Work
1.PHP will pass one GET parameter in URL with the name PHPSESSID but it can be changed session.name in php.ini file.
2. It add one hidden input in forms with same name.
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.
// tell the PHP we want to use cookies from the session
ini_set('session.use_cookies', '0');
ini_set('session.use_only_cookies', '0');
ini_set('session.use_trans_sid','1');
session_start();
// then pass the session ID in the URL(inspect, navigate the network refresh the page you will see in the headers your session ID)
We can send some cookies to visitor's browser by setcookie(). When defining a value with $_SESSION['value'], if using session.use_only_cookies, the session will be only stored on the visitor's browsers. What is the difference of these two cases?
EDIT: Obviously, they are basically different. I just meant the difference in their application. We can set a value on the client-side, which can be retrieved any time (before expiration of course) with $_COOKIE or $_SESSION equally; e.g. to identify a returning visitor.
A cookie is stored on the client-side(i.e. "within" the client/browser).
_SESSION is serialized and then stored on the server. This data is associated with a session id. E.g. when using the default filesystem session handler the filename reflects the session id. The client (or your script) has to provide that session id in subsequent requests so that php's session management can/will load the session data again. One mechanis for this is to use cookies. session.use_only_cookies=On lets php's session mechanism look only for session ids in cookies.
No, when you set session.use_only_cookies, the data from the session are not stored client-side. This settings only affects the way the session ID is transmitted between the client and the server.
Basically there are 2 ways of transmitting this session ID :
Cookie based
URL based (with a GET variable like PHPSESSID=...)
When using the setting session.use_only_cookies, it prevents the use of the URL to transmit the session ID, only the cookie can be used.
These are completely different things:
setcookie() sets a cookie in the browser, but this normally isn't the session cookie. The session cookie you create with session_start().
$_SESSION[] sets/gets a value to/from the session on server side.
session.use_only_cookies will make sure, that the session id is sent only with a cookie, and not for example in the url.
I'm playing around with cookies. And I dont have any cookies called PHPSESSID.
Do i need it? Can i remove it?
Whats the "function" of it?
if (count($_POST)) {
setcookie("TestCookie", htmlspecialchars($_POST['val']), time()+3600);
}
print_r($_COOKIE);
Prints:
Array
(
[TestCookie] => blabla
[PHPSESSID] => el4ukv0kqbvoirg7nkp4dncpk3
)
PHP uses one of two methods to keep track of sessions. If cookies are enabled, like in your case, it uses them.
If cookies are disabled, it uses the URL. Although this can be done securely, it's harder and it often, well, isn't. See, e.g., session fixation.
Search for it, you will get lots of SEO advice. The conventional wisdom is that you should use the cookies, but php will keep track of the session either way.
PHPSESSID reveals you are using PHP. If you don't want this you can easily change the name using the session.name in your php.ini file or using the session_name() function.
It's the identifier for your current session in PHP. If you delete it, you won't be able to access/make use of session variables. I'd suggest you keep it.
Check php.ini for auto session id.
If you enable it, you will have PHPSESSID in your cookies.
PHPSESSID is an auto generated session cookie by the server which contains a random long number which is given out by the server itself
Using cookies in PHPv7.4 and Microsoft Edge browser, PHPSESSID only seems to be generated when first loading/initializing a web app. If I remove the cookie the browser setting (but keep the web application tab open), it kills the session and forces me to login again. However when I log back into the web application the PHPSESSID cookie does not regenerate and yet I still have my session variables working as expected.
I was testing this because I have a web app that loads an external form (from another site) within an iframe and when the form submits and redirects back to my web app (within the iframe) it loses the session within the iframe. Removing the PHPSESSID cookie fixed the problem of losing the session, but I'm not sure why the cookie is the problem (but that is for another thread).