I am developing a system in php which has different types of users like admin, A, B, C.
I need to allow log in just one user from the type at a time. Means
1) if there is already an admin user is logged in, no other admin user can log in.
2) And the logged in credentials cannot be used on other pc at the same time (just like yahoo messenger login system).
I have tried to store session with login logout time in database table when someone login and logout.
But it creates problem when someone close the browser without logging out, the logout entry time misses.
You can always set the session expiration time extremely short (say 60 seconds) and use a Ajax postback on each page timed out at say 25 seconds to keep the session alive. This is how Facebook knows if you are "online" for their facebook IM
1) if there is already an admin user is logged in, no other admin user can log in.
If you want to stop multiple logins from same system then set a session flag like $_SESSION['loggedin']=true; while a successful log in occurs, then before each login attempt, check this flag and only when the flag is falseproceed with the login process.
If you want to stop multiple logins from multiple system then create a temporary table in your database to hold the status of your logged-in users and before any login attempts occur check this table to find any logged in user, if you dont find any user then only proceed, or else prompt the user
2) And the logged in credentials cannot be used on other pc at the same time (just like yahoo messenger login system).
create a temporary table in your database, which will hold the status of your all logged in users, then when a user who is already logged-in, attempts to log in from another place, check the status of that userid in your temporary table, if he is already found logged-in then either prompt him or deny him or log him off from other computer before logging him in again.
Related
I'm wanting to know how I can check if a user is logged in, but then if someone else with the same login creditionals tries to login send them a message to say the user is already logged in somewhere else.
So for example:
Pete - Logs in with pete as the username and pete1 as the password, but pete gave his details to a friend to use and his friend Dave tries to loin with the same details at the same time, it needs to send Dave a message saying someone is already logged in with those details.
How can this be done please.
I already have a is_logged_in function that check the user is logged in.
You need a "user sessions" model to record logged in users,
on user log in, check if session exists in "user sessions", if yes send message of "already logged in"
then establish session on user side,
then add session to your model
on logout,
destroy session from user side and from the "user sessions" model
This will allow same user to login from multi devices, with notifying them.
however this might bring you up to the problem of having a "home device" which he usually logs in from, so that you don't spam him with "already logged in" messages
I did something very close to this a few years ago however i approached with a little differently. Basically I only allowed one 1 login per user and any subsequent login would result in the other users session being destroyed.
To get it to work this way I had to create a custom session manager to store the users username with the session ID in the DB. Then all i did was do a lookup to see if the user was already logged in, if they was then i just removed the DB session.
Your solution could easily be achieved by doing the same but changing the logic a little and just preventing the user getting past the lookup part.
All you have to do is extend the CodeIgniter session class and make your changes, its really not that difficult either.
Logging your sessions to the database will allow you to track this. See http://ellislab.com/codeigniter%20/user-guide/libraries/sessions.html
Search for "Saving Session Data to a Database" on the page.
Once sessions are stored in the database, you can check if that username is currently logged in. It does come with a caveat though - if the user does not log out before closing the browser, and the session is not set to expire properly, it will tell you the user is already logged in, even if he/she is not (based on whether the session data exists).
I solved this by checking cookies and setting a specific cookie for the user. If a user's session cookie does not match the system's session cookie, they that user is forced out and the new user takes control. This can be annoying though.
I have a website which has a login/logout feature. How can I ensure, 100%, also in a stable technique, that a user won't be a able to login to the same account from two different computers?
Javascript can't be used for this, since it's easy to disable it.
For example, .NET has a Session_End function that executes when a user aborts the connection with the server. How that can be done with PHP?
Thanks, Guy
Note: This technique would effectively logout the account on the first computer when logging in on a 2nd.
When a user logs in, log the session id for the user to the database or equivalent. On each page request, ensure the session id of the user matches the session id stored in the store for their account. Requests from a logged in account with a mismatched session id should be rejected and the user should be logged out.
It depends on how in depth you want to go. Most commonly:
Create a unique session id cookie on login and saved it in the database
All web pages check the session cookie to make sure it's valid
if the session isn't valid, the user is redirected to the login page
When another user tries to log in, it overwrites the previous session
This essentially kicks out the first user
Large companies will also store the IP address in the database as well (so session cookies can't be stolen)
I wonder how to disable logging into the one account, eq. admin from 2 different places/PC's/browsers/so on using CodeIgniter Session Class and MySQL database?
Any suggestions?
Keep a "uniqueID" field for each account.
When the account sucessfully logs in, generate a random unique id and store it in that account, as well as store it in the session.
At the top of every secured page, verify the unique id in the session with that in the database, if they match, hurray. If not, it means that since the time this account logs in from this browser, someone else has used the same account and logged in from another browser. Just kick the current user out of the system then.
I am developing the user management portion of a website that will host a webcast. The goal is to prrevent the same user nam (email address) from being used concurrently. That is, we don't want two individuals using one login to view the event.
I've already setup a table that holds the user registration data with regID as primary key. My thought is to create a login history table with username as primary key, foreign key to user name in registration table. The login history table would simply timestamp when the user logs into the site. However, this won't accomplsih my goal of preventing more than one individual from using the same login name.
Instead, would it be better to have a login status field either in the login history or user table that is set to 1 for logged in and 0 for logged out? It would need a stored procedure to update the value at login and at logout, and would need to be validated when a user logs in such that if login status = 1, user already logged in and cannot login a second time. Is this a feasible approach?
Please share other methods you've used to prevent the same login credential from being shared amongst multiple individuals.
Thanks,
Sid
If it is OK to logout an already logged in user if someone else logs in with the same credentials then you could do the following: when a user logs in generate a random ID in your database for that user and the same in a cookie session. The two must match to authenticate.
Without rolling your own session handler, you could do a little parallel tracking. When a user logs in, you can store the user's session ID and login time in the database (maybe inside the user information table). The login script could then check for the existence if this sessionID and allow/deny login based on the presence of the session ID. If the ID's null/blank, then the user logs in. If there's a session ID present, and it's more than X minutes old, allow the login. Otherwise deny them.
Of course, you'd probably want to roll your own session cleanup handler at that point, so that when stale session files get deleted, you can remove the associated IDs from the database at the same time.
The problem here is detecting the user is logged in (i.e. whether he didn't logout).
One possible way is to register in the database the time of his last activity and the time of his explicit logout. You could then deny a login if it this was attempted less than say 5 minutes ago relatively to his latest activity and if he didn't login in between.
You could force "activity" by having the website pages periodically poll the server with Javascript.
It's easy to determine when someone logs in. It's much harder to determine when someone logs out. If you have a mechanism of killing the webcast streaming to a particular user quickly, you might want to have something which pops up asking the user if they want to kill their other session if you think there might be one active.
How are you doing user sessions on the server? If you store them in the db, you could query the active sessions anytime someone attempts to log in and see if they're already in there. Of course you'd probably also have to check some kind of timestamp since you're not guaranteed that sessions will disappear at session.gc_maxlifetime.
You might want to consider making a global variable in php to store a hash array with login status. This has the benefit that if the application has to be restarted for some reason, the user isn't stuck in the wrong state in the database.
You can store a mapping from user ID to IP or session cookie and redirect requests that come with different information to the login page. If the user logs in, the other session would be invalidated and further requests in the last session forward to the login page.
how do you check if a user already has logged in?
so that if a user in another browser cant log in with the same account.
also, is this a good solution or should i let the user log in in the other browser and then log out the current user and display a message (you are logged in from another location) just like messenger does?
Using sessions is a good way to do this, and is a very common method for controlling authentication.
The flow usually looks something like this:
User visits site, and session_start() is called. A unique session identifier is set for that visitor (ie. a cookie).
User submits his login credentials to a login form
Login credentials are verified, and this fact is stored in the session data with $_SESSION['logged_in'] = true, or something similar
For the rest of the user's time on the site, you can check $_SESSION['logged_in'] to see if the user has logged in.
In order to control a user's logins, you could simply have a field in a database (users table is fine) indicating what the current session id is (retrieved with session_id()) for the user, and if it doesn't match the cookie value you just received, then you immediately call session_destroy() for that id, and consider the user as logged out.
Using $_SESSION means you don't have to worry about generating your own tokens, and gives you the power of the built-in superglobals to facilitate storing information about the user's authentication status.
Personally, I would allow multiple sessions to be active for a user for most web sites, as there's usually not a good reason not to, but it obviously depends on the nature of the site. However, storing the current active session id as mentioned above is a pretty simple way to accomplish this.
Generate a random token upon signing in (or use the sessionid), and store this in the database and in the users cookie. With each page access, ensure that the users token matches the database entry. If the two don't match, alert the user that they've logged in elsewhere.
You could also store the login time, which subsequently would be the time the token was assigned, and require 30 minutes before permitting another user to login with the same ID.
The first half of the question was answered well with how to detect the multiple users but how to treat them I think still needs a bit of work.
First if a user logs in correctly let them in, don't prevent them if they are logged on some other place. If you really don't want the user to have two open sessions then log out the old one or simply update the session id that you are saving so you can bounce out the old connection. You can inform if you want but I would only message the session that you invalidated. If you message the user logging in it becomes annoying when you are only dealing with the case of a user switching computers and they forgot to log out of the old session.
Well All solutions mentioned above will work but if on every page access you are making a call to database and checking for the session token to see weather its the same token assigned to user .. will kill your response time. what i'll suggest is use a caching mechanism instead of database in above said solutions. storing session token into database will add extra field to your database which is actually not required. Use open source caching solution like memcache.
you can make a table like userLoginStatus with fields like clockIn time & clockOut time,
and insert current time in clockIn when user is do login, leave clockOut time blank at that time, it should be updated only when user do clock over logout button,
so you can check specific user's current status, where clockOut is empty that user should be logged in. because it updated only when user do logout.