I posted a similar question before, but never really got an answer that helped me, so I'm looking to try again. As a disclaimer, I know that a lot of the information in here doesn't follow perfect coding practices, but it is for exercise purposes only. I've tried a million things and nothing seems to be working because I'm not really sure where everything should go! I desperately need some (any!) help so thanks in advance if you can offer anything!
I'm trying to create a simple form / page that uses some basic cookie and session stuff to produce some user-specific data. I was moving along good until I came across a few problems that I can’t figure out. On my first page everything is good except for I just want the NAME of the browser the user is using. (for example, I want just the simple title: Firefox instead of the whole long version of the browser.) I've seen this be done so I think it’s possible, I just don’t know how to do it!
My real problems come up right about here, because I'm not exactly sure how to store the IP address, browser info and the current date/time (which I want shown on page 2) as session variables. Tried a few things I found, but I don’t think I was doing it right.
I also worked endlessly on trying to store the username and passwords as two separate cookies each...suggestions? Finally, what do I need to do to have a location header (used to call form_data.php) with output buffering?
(Not sure this will be that helpful, considering I probably did everything wrong! LOL) This is a totally stripped-down version of my code. Tried to post my cleanest version, even though it doesn't have much info, so that you could easily see what I was trying to do.
main file code:
<?php
header('Location: form_data.php');
setcookie('username', $_POST['username']);
setcookie('password', $_POST['password']);
//I know this isn't working.
//honestly I just left this in here as to show where I had been
//trying to save the cookie data. Pretty obvious how bad my
//trial and error with this went!
}
?>
<?php
$_SESSION['ip'] = $_SERVER['REMOTE_ADDR'];
echo " By the way, your IP address is: </b>".$_SESSION['ip']."<br />";
echo " You already know this, but the browser you are currently using
to view this page is:<br/>"; //What is the correct function that I should be using here?
echo "<form action=\"form_data.php\" method=\"post\">";
echo "username:<input type=\"text\" name=\"username\" size=\"20\" value=\"\"><br/>";
echo "password:<input type=\"password\" name=\"password\" size=\"20\" value=\"\"><br/>";
echo "<input type=\"submit\" value=\"Submit, please\" />";
echo "<br /><input type=\"hidden\" name=\"submitted\" value=\"true\" />";
?>
form_data.php
<?php
echo "Hello, ".$username;//I'm trying to get the cookie data for the username
echo "Your password is ".$password; //Samething here (want cookie data)
echo "The date and time you entered this form is: ".date("F j, Y")." -- ".date("g:i a");
echo "<br/>Your IP:".$_SESSION['ip'] = $_SERVER['REMOTE_ADDR'];
echo "<br/>Your broswer:".;//I want full broswer data here...dont know how to do it.
//Overall, was this the way to get the session variables for IP, date/time and browser?
echo "Thank you for filling out this form!";
?>
To get the browser, use the get_browser() function:
$browserinfo = get_browser($_SERVER['HTTP_USER_AGENT']);
$browsername = $browserinfo['browser'];
Your session and cookie storage will never work because you are making a header("Location"); call before attempting to set cookies. You cannot send any output before setting cookies or establishing a session.
Before any output to the screen, call session_start();
// attach to your session (or create if it doesn't exist)
// You must call session_start() on every page where you intend to access or set session vars
// and it must be called before any output (including whitespace at the top)
session_start();
// Store some stuff...
$_SESSION['ip'] = $_SERVER['REMOTE_ADDR'];
// Store user info in session, not cookie
$_SESSION['username'] = $_POST['username'];
// Set a cookie
// Not a super secure token, but better than user/pass in cookies.
// Point here is just to show that it must be done before any output or before the redirection header.
$_SESSION['token'] = sha1(time() . rand() . $_SERVER['SERVER_NAME']);
setcookie('token', $_SESSION['token']);
// In practice, you'd want to store this token in a database with the username so it's persistent.
// Now do the redirection:
// Supposed to be an absolute URL by the HTTP spec
header("Location: http://example.com/form_data.php");
// exit right after the redirection to prevent further processing.
exit();
ADDENDUM after comments
While you work, make sure PHP displays all errors on screen. Be sure to turn off display_errors when your code goes onto a live public server.
error_reporting(E_ALL);
ini_set('display_errors', 1);
To retrieve values from cookies as you said in your question you didn't know how to do, use the $_COOKIE superglobal:
// On the page that sets it...
setcookie('somename', 'somevalue', expiry, domain);
// On the page that retrieves it...
echo $_COOKIE['somename'];
> I'm trying to create a simple form /
> page that uses some basic cookie and
> session stuff to produce some
> user-specific data.
Sessions do use cookies under the cover(only store session_id inside cookie/set_cookie) and I advice you to use only sessions because cookies can leak information(store all the information inside cookie on that user's computer) which could be dangerous while session uses the server's filesystem/database or whatever you like when you override session_set_save_handler.
> On my first page everything is good
> except for I just want the NAME of the
> browser the user is using.
Like Michael said you can use get_browser for that:
Attempts to determine the capabilities
of the user's browser, by looking up
the browser's information in the
browscap.ini file.
Like the PHP page says it tries to determine and you should NOT rely on this information for anything important because it can be wrong(you can fool the system, if you like). What I mean is you should not use it to validate/proof something.
> My real problems come up right about
> here, because I’m not exactly sure how
> to store the IP address, browser info
> and the current date/time (which I
> want shown on page 2) as session
> variables.
More information to retrieve the IP address can be read here(proxy-server could mislead you a little bit maybe?). To store that information just store it inside a session by first issuing session_start() on top of every page(before outputting anything) that wants to use sessions(only those to not set cookies on every page which makes page a little slower) and next store the current time inside a session variable by doing something along the lines of $_SESSION['time'] = date(DATE_RFC822);. You can read more about retrieving the time at date() page.
So the code on page 1 looks something like:
<?php
session_start();
$_SESSION['ip'] = getRealIpAddr(); # no php function => See http://roshanbh.com.np/2007/12/getting-real-ip-address-in-php.html
$_SESSION['time'] = date(DATE_RFC822);
Then on page 2 you could retrieve this information using something like:
<?php
session_start();
echo $_SESSION['ip']; // retrieve IP
> I also worked endlessly on trying to
> store the username and passwords as
> two separate cookies
> each...suggestions?
Don't store them inside a cookie(only using set_cookie and not using sessions to store information) but store them inside a session for extra security. But sessions are also vulnerable to session fixation so after storing something critical inside your session you should regenerate session id and never output/show that information to the browser/user to prevent any leakage.
> Finally, what do I need to do to have
> a location header (used to call
> form_data.php) with output buffering?
Like Michael said you should be using header function and exit to terminate script after that
<?php
header("Location: http://www.example.com/"); /* Redirect browser */
/* Make sure that code below does not get executed when we redirect. */
exit;
?>
P.S: Never store any really sensitive information like creditcard(use paypal or something) numbers or anything in your own database. I also advice you not to store passwords inside your database but use something like openId(Google's) for example to handle your authentication for extra security.
Related
I read lot of articles and found session can not work without cookie but tried and found a way please provide feedback on this ?
step 1) first disable and clear cookie data of browser i am using chrome.
step 2) create a page one.php that have following code.
i have firstly detect user agent that ipaddress and my secret key convert it into MD5 same on second page for unique user detection.
$uagent = base64_encode($_SERVER["HTTP_USER_AGENT"]);
echo $ip = md5($_SERVER["REMOTE_ADDR"]."MYSECRETKEY".$uagent);
echo "<br>";
echo session_id($ip);
session_start();
$_SESSION['data'] = array("name"=>"bbbbbbbb","designation"=>"software_engineer");
print_r($_SESSION);
step3) create another page two.php
$uagent = base64_encode($_SERVER['HTTP_USER_AGENT']);
echo $ip = md5($_SERVER['REMOTE_ADDR']."MYSECRETKEY".$uagent);
echo "<br>";
echo session_id($ip);
session_start();
print_r($_SESSION);
I found data on two.php page.so we can set session and grab data without cookie.
Any feedback i am wrong or this is really a solution?
This would work as long as the user agent and the remote address are the same. But you can just hijack into a session if you know
someone's public IP
someone's user agent
The visitor submits this data to each site he visits, and cannot prevent that! A hijacking is a very simple task, if the visitor have visited a bad site before, which saved the data.
This is not really a secure solution! Do not use it!
EDIT: Ok, you have to spoof the IP address which is a bit complicate :-) But in public networks, the problem persists, there can be even collisions.
My goal is to share session between requests, I meant every request could reach a data. First I was thinking that simply sharing via filesystem could be good, but I find out this by myself:
session_id('0');
session_start();
echo session_id();
var_dump ($_SESSION);
if (!isset($_SESSION['x']))
{
$_SESSION['x'] = 0;
}
$_SESSION['x']++;
var_dump ($_SESSION);
this way I can see the same from browsers. My question is, is it a good practice?
EDIT: here is the full working version:
$m = microtime(true);
session_start();
if (session_id() == '0') // this happens when somehow our session id sticks, it should not happen ever, but if so, lets erase it
{
setcookie (session_name(), '', time() - 3600);
session_destroy();
session_write_close();
echo 'reload'; die;
}
if (!isset($_SESSION['x']))
{
$_SESSION['x'] = 0;
}
$_SESSION['x']++;
$saveId = session_id();
session_write_close();
// switch to common storage
session_id('0');
session_start();
if (!isset($_SESSION['common']))
{
$_SESSION['common'] = 0;
}
$_SESSION['common']++;
session_write_close();
// back to our own session
session_id($saveId);
session_start();
echo $_SESSION['x'].'<br>'.(microtime(true) - $m); die;
I dont thing its very time consuming.
It's tricky to know if SESSION is the right place to put this data, but it's worthwhile bearing some things in mind.
SESSION is designed to store data related to an individual user's visit to your site (normally being distinguished the combination of machine and browser, thanks to the session id being stored in a client side cookie).
Default behaviour of the PHP session handler is to:
Store the data in a file on the server.
Block concurrent access to that file.
It is possible to have multiple sessions for a given request, but that means ensuring you start and end each session and ensure that you keep track of the session IDs - I'm not entirely sure how you would do this without manually writing data into the client's cookie.
All in all you'll probably find that your performance using the session will be slower that just checking the existence of the file anyway (which is simpler than using the session, in terms of work done by PHP).
That said, if you're writing to that file then you're just going to have concurrency issues that you'll have to solve in much the same way as php sessions do anyway.
I'd say, if you're writing data, then look to your DB. It's what they're designed for.
If you don't want to write to your primary DB and have good reason for that, then maybe consider something like a memcache DB, or some other secondary storage.
i'm having a bit of a problem. I'm trying to set up a simple webpage with only three .php pages. I want a session variable $_SESSION['userID'] to be set when a user is logged in and I want the index page to show extra info if someone is logged in.
On index.php I want to show some info, if a user is logged in I want to show some extra info.
login.php - simple log in form.
login_exe.php - takes care of database connection and verification.
So this was my idea:
On index.php, check if session is started, if not: start.
<?php
if (!isset($_SESSION)) {
session_start();
echo "session started";
}
later on, check if $_SESSION['userID'] contains a value, if so: print a string
if($_SESSION['userID'] != null){
echo "User logged in";
}
On login_exe.php i've almost the same code:
<?php
if (!isset($_SESSION)) {
session_start();
echo "session started";
}
in verification function:
$_SESSION['userID'] = $data['userID'];
header("Location: index.php");
The problem is that a new session is started on every page. How can I fix this and only start the session once? Thanks in advance
You should just put session_start() on top of documents that using sessions. Say, if you have 5 .php files that using sessions, then put 5 times the session_start() on top of them.
This is because session_start() sends headers and headers must be sent before any output (for example, any echo or whitespace).
Then, you should use something like isset($_SESSION["foo"]) and not just the entire $_SESSION array, where foo is something you set previously.
If you dont want sessions at all or need to reset the entire array, just call session_destroy() which effectively destroy the current session. Use unset($_SESSION["foo"]) when you want to get rid of a key.
Finally, you might get weird cases where you cannot read session key you write at. In these cases check what is the path of sessions and if they're writeable, or change their path:
$path = session_save_path(); // what is the path
is_writable($path); // can i write to it?
session_save_path("my/new/path"); // change the darn path;
// put -even- before session_start()!
:)
glad i help
I think the PHP manuals are really good compared to ...ahm, so just read about session_start(). It says:
session_start() creates a session or resumes the current one (...)
so all you need is session_start() very early in your code. This must be executed on every request (maybe as include).
Your code checking the userId looks fine, one important hint here: you should know exactly what isset(), empty() and the like mean in PHP, so always have the comparision of comparison at hand.
You should not ask new answers (edit: questions) in comments. Be as systematic here as you are in coding.
How to end a session:
This gives room for discussion, because there is the session cookie, which is client side, and the session data, which is server side.
I recommend:
$_SESSION = null;
Reason: this will clear all login and other associated data immediately. It leaves the cookie intact, which is normally of no concern, since all associated data is gone.
I am a beginner for PHP and studying to use cookie for login. Would any body please check my code to see what is my problem, or let me how to fix this problem.
When I open the page at the first time, the cookie will not work. It will work when I repeated to open that link. However, I still could not make it work after I use function include and header One of codes is :
One code cookie.php is :
<?php
setcookie("cookiename",$_REQUEST['name']);
if(isset($_COOKIE['cookiename'])){
$cookieSet = ' The Cookie is ' . $_COOKIE['cookiename'];
} else {
$cookieset = ' No Cookie has been set';
}
setcookie("cookiepwd",$_REQUEST['pwd']);
print_r($_COOKIE);
?>
When I run this code first time, it will does not show any thing. I can see cookie data at second time. From some website it is said that cookie would not be read at the same page.
So I moved print_r($_COOKIE) to second php file as well as added function include() or header() to above file, but both neither works.
Cookie2.php:
<?php
setcookie("cookiename",$_REQUEST['name']);
if(isset($_COOKIE['cookiename'])){
$cookieSet = ' The Cookie is ' . $_COOKIE['cookiename'];
} else {
$cookieset = ' No Cookie has been set';
}
setcookie("cookiepwd",$_REQUEST['pwd']);
include(‘printcookie.php’);
//or header("Location: printcookie.php")
?>
printcookie.php:
<?php
print_r($_COOKIE);
?>
Thank you very much for answering in advance!
Michelle
setcookie only sets up the header, that is being sent to the client. It doesn't change the $_COOKIE superglobal.
In other hand - $_COOKIE is filled up with the cookies sent from the client
So at first step - you set the cookie with setcookie and have nothing in $_COOKIE because client hasn't sent it yet, and will only on the next request.
And there is no way of doing what you want, rather than modifying $_COOKIE manually
PS: it is a bad idea to put user's password in the cookie
Give zerkms the answer, but I just want to reiterate:
Cookies are not bad for storing bits of info like the user's theme preferences or preferred start page, etc. They get their bad rep from being used for identity and authentication handling. There are cookies out there that basically have "isAdmin=0" in order to control user access. It is very easy to change that to isAdmin=1 and have a field day. Since you are new to PHP, take the time to learn about sessions now while it's all new to you.
When you set a cookie using setcookie, you are sending an HTTP header to the browser with the cookie info. The browser will then pass back that cookie in any future requests to the server. The $_COOKIE global variable holds the cookie info passed in from the browser to the server.
Since you are using $_REQUEST to get the cookie name, you don't need to check the cookie (otherwise you wouldn't have the data to set it right?). So consider going this route:
if(!isset($_COOKIE['cookiename'])) {
$name = $_POST['name']);
setcookie("cookiename",$name);
} else {
$name = $_COOKIE['cookiename']);
}
echo "Welcome back $name!";
This will also help out if they clear cookies, etc.
But really, the safer route is:
session_start();
if(!isset($_SESSION['name'])){
$_SESSION['name'] = $_POST['name']);
}
if(!isset($_SESSION['pwd'])){
$_SESSION['pwd'] = $_POST['pwd']);
}
$name = $_SESSION['name'];
$pwd = $_SESSION['pwd'];
And even this would be frowned upon for serious web security, where you should simply check the password against a stored hash and then delete it, using other global variables to confirm session integrity. But there's now a whole StackExchange for that.
As a workaround you could use location() after checking the cookie to have access to the stored data.
But be aware that location() fails, if anything (including breaks and blanks in your script) already sent to the browser.
I can't seem to find a straightforward answer to this question. Is there a way in which I can force a logged in user to logout? My login system essentially just relies on a session containing the user's unique ID (which is stored in a mysql database). So essentially just...
if (isset($_SESSION['user_id'])) {
echo "You're logged in!";
} else {
echo "You need to login!";
}
But let's say I want to ban this user, well I can change their status to banned in my database but this won't do anything until the user logs out and attempts to log back in... So, how do I force this user to logout? Preferably without checking every single time they view a page whether or not their status has been switched to "banned" because that seems like unnecessary stress on my server. Any help is appreciated, thank you.
Either you need to check every time they load a page, or possibly look at an Ajax call at set intervals to check their status from the DB.
Then you can use session_destroy(); to end their session. This will destroy their entire session.
Otherwise you can use unset($_SESSION['user_id']); to unset a single session variable
Preferably without checking every single time they view a page whether or not their status has been switched to "banned" because that seems like unnecessary stress on my server.
Loading the user from the database on every page load, rather than storing a copy of the user in the session, is a perfectly reasonable solution. It also prevents the user from getting out of sync with the copy in the database (so that, for instance, you can change a user's properties or permissions without them having to log out and back in).
Try to put this on every page...
if (isset($_SESSION['user_id'])) {
$sql = "SELECT from tbl where status='banned' and user_id=$_SESSION['user_id'] ";
$query = mysql_query($sql);
if(!empty(mysql_num_rows($query))){ // found the banned user
//redirect to logout or
//session_destroy();
}
} else {
echo "You need to login!";
}
if the user is still logged in... check if his/her status is banned or not... if banned.. then logout
You can unset it.
unset($_SESSION['user_id'])
You could use Custom Session Handlers this way you have full control where and how the session data is stored on the server.
So you could store the session data for a particular user in a file called <user_id>.session for example. Then, to logout the user, just delete that file.
Ajax calls in an interval will put extra load on server. If you want real-time response to your actions(e.g. the user will be signed out right when you ban them from your system backend), then you should look into something like Server Push.
The idea is to keep a tunnel open from Server to Browser whenever a user is browsing your website, so that you can communicate with them from server-side too. If you want them to be banned, push a logout request and the process that in your page(i.e. force logout by unsetting session).
This worked for me am using pHP 5.4
include 'connect.php';
session_start();
if(session_destroy())
{
header("Location: login.php");
}
You can use session_save_path() to find the path where PHP saves the session files, and then delete them using unlink().
Once you delete the session file stored in the sever, the client side PHPSESSID cookie will no longer be valid for authentication and the user will be automatically be logger out of your application.
Please be very careful while using this approach, if the path in question turns out to be the global /tmp directory! There's bound to be other processes other than PHP storing temporary data there. If PHP has its own directory set aside for session data it should be fairly safe though.
There is a few ways to do this the best in my opinion based on security is:
NOTE: THIS IS REALLY ROUGH.... I know the syntax is wrong, its just for you to get an idea.
$con = mysql_connect("localhost","sampleuser","samplepass");
if (!$con)
{
$error = "Could not connect to server";
}
mysql_select_db("sampledb", $con);
$result = mysql_query("SELECT * FROM `sampletable` WHERE `username`='".$_SESSION['user_id']."'");
$userdeets = mysql_fetch_array($result);
if($_SESSION['sessionvalue'] != $userdeets['sessionvalue'])
{
session_destroy();
Header('Location: logout.php');
}
else
{
$result2 = mysql_query("UPDATE `sessionvalue` WHERE `username`='".$_SESSION['user_id']."' SET `sessionvalue` = RANDOMVALUE''");
$sesval = mysql_fetch_array($result2);
$_SESSION['sessionvalue'] = $seshval
}
Now I know thats not the very code but in essence what you need to do to be secure and have this ability is:
Everytime a page load check a Session value matches a value in the DB.
Every time a page loads set a new session value based on a random generated DB value. you will need to store the username in a session as well.
if the Session ID's do not match then you destroy the session and redirect them.
if it does match you make the new session ID.
if you want to ban a user you can set their sessionvalue in the DB to a value like "BANNED". this value will not allow them to log in either. this way you can control user through a simple web form and you can also generate list of banned users very easily etc etc. I wish I had more time to explain it I hope this helps.