I'm building a website using ASP.NET. It's a game which I connect two users randomly to play with each other.
What I need to do is when one of these two players logs out or has been inactive for a certain time, I finish the game and send the other player to some page to tell him or her the game is over.
My problem is I can't figure out how to track the user status every while. I know that ASP.NET has (LastActivityDate), but how can I check this value repeatedly every 30 seconds for example?
lets say you have 2 users
each user pings the server ( ajax) every 2 sec [using javascript's setInterval] and increase a counter - or set a new time in the Application or Cache ) - global accessed objects
once in a while - you scan those structures - and if the value ( lets say of DateTime) - is larger by X - so someone has stopeed sending pings - and thats how you know that someone has gone.
You should use jQuery or another Javascript library for using ajax simply. You need also to use 'setInterval' function that will verify that user still active.
Links:
http://api.jquery.com/jQuery.ajax/
http://www.w3schools.com/ajax/ajax_intro.asp
Related
Hello i am mostly a beginner at C# and now i'm doing an ATM program which will log the manager in, startup the system then the user can log in so they can view their balance and withdraw money from their account. However the problem i'm having is i want the label to say "Card Retained" when their attempts reach 5 but when i insert a breakpoint everytime the customer logs in the second time the attempts int is reset to 0 again. Hopefully this makes sense thanks in advance.
https://gyazo.com/0c6649df6abd88fc529c2cfafbe2cac9
For starters I'd advise against starting a new project in WebForms, given it's 2018.
Anyhow, variables reset with each request. You need to store the attempts somewhere more persistent, for example in a file on the server or in a database.
Yes, you could use viewstate as explained in Best way to save variables between postbacks asp.net? or sessions as explained in web forms: keep variables between requests, but then if the user removes their cookies or starts another browser, they have another five attempts.
i have a rental website and when someone wants to make an offer he has 7 min to pay, if he wont pay the offer will delete.
i have a timer on my form to check the time, and when the timer is on 0:00 and the user didn't pay his offer will delete.
MY question is how can i check if user log out? i mean user can exit from the site (by clicking X) and his session will end.
i want to delete his rent offer if user quit from the website.
Thanks for the helpers.
For this scenario, I don't think its a good idea to rely on browser events, such as onunload & onbeforeunload. User may have opened more than one tabs. So closing one tab will remove the offer. Furthermore, if the user click back button these events will be fired. So don't rely on browser events for this.
(But, if the user clicked on LogOut then you have enough information to delete the offer.)
Perhaps you can use following approach to handle your original problem:
When user create a new offer store these details in the database with two extra columns: OfferCreatedUtcDateTime and PaymentCompleted(which should be false).
If the user completed payment successfully, you can set PaymentCompleted to true.
Then you can use one of the following two options:
Option 1:
Create a windows service which will check above database columns. If the PaymentCompleted == false and OfferCreatedUtcDateTime + offer valid period > CurrentUtcDateTime then you can delete this offer.
Option 2:
As mentioned by #nvoigt in the answer, every time user search for a resource you can ignore or delete offers which satisfies the condition mentioned in Option 1.
Hope this helps.
First do not fulfill offers that are older than your timeout(7mins) I'm assuming that you have OfferCreatedDate timeStamp. Second create a job that will clean all unfulfilled and expired offers. Hope this helps
You cannot. Not reliably. The user will not send you a nice message when he does not do something.
You can program your site to send you a signal if something happens, but you need to know when something doesn't happen. And it can "not happen" in multiple ways, many of them not allowing a signal to be transmitted.
Just imagine your user's train goes into a tunnel or he kills his browser, his computer crashes or cell phone loses battery power. All events that happen daily and all of them will not notify you nicely. They cannot.
So what you need to do is figure out a way to delete all obsolete orders. Either on a timer in an independent service, or maybe before a user places any order. But you need do that in a place independent of the user playing nice with your frontend app.
One way of handling this would be to save the date and time of creation with every offer you give out. Every time you check available resources and create a new offer for a user, delete all offers that are older than your limit before giving out new offers, thereby freeing up the blocked resources.
What about not focusing on how to set the timer to 0 when user session end but check other users timer's when another user create one ?
Then you can still have the checking process for the connected user, when it goes to 0 it stopped but for the case the user close the windows or leave, when another user create a reservation you also and firstly check if there's timer still alive older than 7 minutes and you release them so the user currently doing a reservation can do this one that has just been set as available ?
I have a web-based (ASP.NET C#) game platform that has a racecourse. Each user should complete this racecourse. When an online user starts the game, stopwatch starts to count and shows the time in simultaneously. I have a callback method and timer which calls this method every 1 minute. However, the problem is that while an online user is playing the game and other online user starts playing the game, stopwatch shows the time which is belong the first online user, however, it has to Show 0 for new online user. I cannot handle this problem. Do you have any idea without using javascript and jquery?
Thank you
You'll have have to have a place to store the starttime for each player.
If you do not want to do that clientside - using javascript, you'll have to do it serverside, using the session cache.
So long story short, the company I work for, that is all about saving money, went from 1 service application, to 2 service web interfaces.
They're not secure, have no cert's, not even over SSL...yet, they have a timeout associated with each interface. Which then breaks the page you're viewing, and you have to refresh IE, and then proceed to login again, and reset your dropdowns etc...
So.
I've tried using a generic webbrowser interface in C# to have a foundation in which I can refresh the connection to the server with the page open, as to avert the timeout.
But, first attempt results in my app, going to the appropriate page, then opening a new IE window when a service ticket is opened, and there must be a lack of cached data, which results in the new IE window that opens, to revert back to the main page which prompts me to login.
The interfaces are Jsp, but I'm more familiar with c#...
Tried catching link clicks to navigate the destination in the current window, but it seems that the data you double click that prompts the new page to open, is merely a data in a table, and not technically a "link"....
I've brought this to the attention of management, but like most huge corporations, I know nothing, and they never have to deal with it, so as they say in every meeting, "silence means compliance"....
Any thoughts?
Probably not the right answer, but...
Session cookies?
Session cookies = fail..
No 'remember me' option...
I can however enter a link in each browser to "goto the home" section of each app, which each page is already at, so it keeps the connection alive, and doesn't navigate away from the current page (keeping the dropdowns etc that are set after login)
But still, the above problem exists where if I use all this in a C# browser, etc...
I told my boss first thing 'they can't tell me the timeout is for security!' heh
And I still didn't get a positive answer from 'well at 10 seconds per re-logon, per x amount of people = thousands of dollars a year spent on re-logging on...'
:D
Use ajax.
poll a server page in a small interval (a minute)
if it returns "timeouted=true" (or whatever convention you like), refresh the page with javascript.
include the ajax snippet on every page (using <jsp:include>, for example)
i have a page with a series of checkboxes that authenticated users can change. I need to make this page only editable by one person at a time. So if a user goes into it and edits one of the checkboxes, noone else can go into the page and change other checkboxes.
I thought about an edit page link and a readonly page link (all controls disabled), then set a database flag if user enters under edit mode, but my concern is i wouldn't know if the user changed something, then just x'd out of the browser/app, locking everyone else out.
This is an internal app to company. Has anybody done something like this?
Any ideas or thoughts or suggestions?
Thanks
We have this functionality on an older ASP app. The user will load data with some type of primary key. We put in a DB entry to "lock" that page. If they correctly move through the site, it will unlock the resources at that time.
Other users opening this page will receive indication that the page is locked and a read-only version is rendered.
It would be fairly trivial to code a unPageUnload AJAX call to reset the lock for browser closing. We don't find this to be much of an issue and old locks are just cleared by an evening process if more than 4 hours old.
Our situation is where the pages are tied to specific regions of data. If this is a general config screen, I think a more dynamic AJAX solution that pushed the updates back and pings for changes might make sense. You would have to decide if you want to disable changes from others after the first update is received or implement collision detection for the data.
Some type of hashing of the page data would probably make this easier to detect changes.
You do what you said, but add a client side timer which will ping the server and tell you they are still there. If you don't get a ping within x mins you could let a new user go into edit mode but perhaps warn them (or not).
What about letting all users edit this page and how your script check in for page updates? Just like SO does, while you are typing in an answer, an orange message appears above saying "At least one new answer has been posted". You could display something like "The page has been modified since you last opened it".
There was something like timer in ASP.NET AJAX. You could use that to talk to the server to send "IN EDIT" status updates. You can even go further. Say you send "LOCKOUT REQUEST" requests every 15 seconds asynchronously and you expect to receive the "LOCKOUT GRANTED" response from server. If the response hasn't been received, you disable all controls on the page until maybe the next request receives the confirmation (the previous message could have been lost in the network). This way, if one user closes the browser, the other won't have to wait many minutes or hours until they get the edit permission.
Essentially, you need a distributed implementation for a critical section concept. It maube a challenge to implement it over HTTP. But that's a very interesting challenge, isn't it?
If you're trying to prevent two users from updating a db record and over-writing each other, perhaps it would be easier to detect this than prevent it.
On strategy for this is to include a "version" field in the record, and save that in a hidden field when rendering the page.
Then you simply include that as a condition of your update (i.e. UPDATE ... WHERE ID = myID AND VERSION = myversion) - if your update returns 0 rows, you know that someone else modified the data, and you can then decide what to do - reload the new data, offer the user a chance to compare them, etc.
How about an alternative to an extended lock?
Since you appear to be manipulating relatively small amounts of data, it would be more polite to put an encoded version of original state of the data in a hidden form field (or a datestamp, though that's less reliable; a hash of the values would work for larger amounts of data). In a transaction, check the state of the database against the hidden form values; if the original record has changed since the user submitted the changes, you reject the update. If not, accept the update, and commit the transacation.
Another approach could be to have an Application variable that contained a map or dictionary of locked items.
So, when one user hits edit, add an entry to the AppVariable Map or Dictionary, with the Key set to the primary ID of the field being edited. Then for all further requests, when they change between records, do a check of the ID within the map and if its being edited, Toggle off any update buttons. If you want to do it AJAXy, add a timer and an UpdatePanel and poll to see when the lock is released, then refresh the page with the updated data and enable the update buttons again.
Or, as a slightly greater UI, allow the users to edit while waiting for the lock to release ( the Map item to be removed ), then when it is removed, compare the fields they have been working on, with the updated database values and allow them to overwrite/merge their changes.
The only real downside is, 1) You would need to create one Application level Dictionary or Map for each table that you want to lock/unlock. 2) If you get into a webfarm environment, it breaks and you would have to use a different system.
Does that make sense?