I'll try to explain my question the best way I can.
I'm not asking for codes, only for the best method of doing it.
I want to create a browser game and use time for upgrading stuff, building etc.
For example, to build 1 house will take 1 hour.
So I will began with saving the timestamp+(60*60) at the moment the user did his action.
My question is, how to update it the best way?
One way I thought of was to add function that check every page view of the user if it's done.
But then if he's not logged in the update wont happen.
Second way i thought about is for every page view of any user to check for every user registered. But it's not effective and there is a problem if no user is logged in.
Any suggestions?
I had my game doing it simply, without crons.
When a player wanted something that takes time, i just updated his database information with the appropriate time of ending that job (columns are just examples)
UPDATE player SET jobend = UNIX_TIMESTAMP() + (60*60*4) # ending in 4 hours
Then, every page that had an information about the remaining time, i just used something like this:
SELECT (jobend - UNIX_TIMESTAMP()) AS jobremaining FROM player
I formatted correctly the time using strftime and i displayed that to the user.
In the case the remaining time was negative, the job was done.
There was no-need for absolute counting since user was able to do something with the job when he was connected.
When the player just changed pages or doing something else i had a function where i just checked all timely events while the user was online (so to catch any negative timer), then presented with javascript any change (i posted javascript counters for every page)
Now, if you talk about updating in real-time, cron is the way but are you sure you're going to need it for a game? I asked that question myself too and the answer was not.
EDIT
If another player sees the buildings on schedule page (an hypothetical page) i am doing the same calculations; if a time just got negative for a specific player (regardless if another player see the page), i just reward him with the building (in database i make all the changes), even if he's offline. There's no harm in this, since he can't do anything anyway. The other players will just see he has a building. The key here is that i execute the required updating PHP code regardless of player's connection to the game; as long at least ONE player is logged-in i'm executing the progress function for everything.
This isn't so slow as it sounds (updating all players by using just a connected player that visits a specific page). You just have a table of 'jobs' and check timers against the current time. More like a single query of getting the negative ones.
Related
I am currently working on a Javascript multiplayer game.
When users want to play, they enter a waiting room where they wait for players to play with.
It is stored in a SQL database this way :
I have a table named USER with some data on the players, and another table named WAITINGROOM which associates the id USERID of the user waiting for a game with other infos.
When players leave the waiting room or close their browser, I delete the row with their id in table WAITINGROOM.
But let's suppose the user loses his internet connection while looking for a game. How can I know he is offline so I can remove the row containing his id ?
The player is offline so it is definitely not client side I can deal with this.
Maybe server side in PHP ? Or directly in the database using timeouts or something...
I assume you have a script (probably called via ajax) which fetches the online users for the current user. Simply add a column like 'last_seen_online' with a timestamp. Update the field every time the user calls this script. Now you can filter it in your sql for example get all users which have been online during the last minute. - Everything not active since one minute is considered offline like this.
To get rid of users which went offline you can implement a garbage collection(like php with sessions does). You grab all users which havent been seen since the last (for example)5 minutes. You place this garbage collection in the same script. To keep the load low. You dont call it every time, just like 50% of the time with if(rand(1,100) > 50) or any percentage you like.
I know the title is complicated, but i was looking for some advise on this and found nothing.
Just want to ask if i'm thinking the right way.
I need to make a top facebook shared page with about 10 items or so for my website items (images, articles etc.)
And this is simple, i will just get the share count from facebook graph api and update in database, i don't want to make it in some ajax call based on fb share, it could be misused.
Every item has datetime of last update, create date and likes fields in database.
I will also need to make top shared url in 24h, 7 days and month so the idea is simple:
User views an item, every 10 minutes the shared count is obtained from fb graph api for this url and updated in database, database also stores last update time.
Every time user is viewing the item, the site checks last update datetime, if it is more than 10 minutes it makes fb api call and updates. It is every 10 minutes to lower fb api calls.
This basically works, but there is a problem - concurrency.
When the item is selected then in php i check if last update was 10 minutes ago or more, and only then i make a call to fb api and then update the share count (if bigger than current) and rest of data, because a remote call is costly and to lower fb api usage.
So, till users view items, they are updated, but the update is depending on select and i can't make it in one SQL statement because of time check and the remote call, so one user can enter and then another, both after 10 minutes and then there is a chance it will call fb api many times, and update many times, the more users, the more calls and updates and THIS IS NOT GOOD.
Any advise how to fix this? I'm doing it right? Maybe there is a better way?
You can either decouple the api check from user interaction completely and have a separate scheduled process collect the facebook data every 10 minutes, regardless of users
Or, if you'd rather pursue this event-driven model, then you need to look at using a 'mutex'. Basically, set a flag somewhere (in a file, or a database, etc) which indicates that a checking process is currently running, and not to run another one.
I have an inline chat application which I got from Ajax Chat, which is working brilliantly. The application allows a user to chat with users that are registered on the system. Ie:
Now I need to show if the user is online or offline.
So my question is how do I show online users using PHP?
Thank You
Basically what you need is a way to register users activity.
One way you can do this is doing it by sessions within PHP, and you log these. There are tons of ways to register then your activity in a log. If the activity is not updated for example in 5 minutes, the user is offline. Bassically you just need then a sessionId, and a timestamp (and i would recommend this also to hang to a userid). If offline, there is no userId assigned and when online you add a userId. If you have those, its pretty easy. Its a matter of updating them constantly when a new page is loaded and if they log out, you simply destroy the session, or update it so it wont be linked to the user.
It may not be the best system, but it works, and it might help you.
I don't know your specific needs. Pardon me, If I am wrong.
If Jabber support is there with Ajax Chat, why not try ejabberd kind of XMPP servers rather than re-inventing the wheels on your own. And you could have a look at Apache Vysper too, since it has support of extension modules too. If XMPP server is there, users presence handling and message transfer would become a cake walk.
What you need is a constantly update for a table in your database that save the last change in an user and save the date time... so if that date is more than 5 or 10 min, the user ir off..you can do it with ajax...
What i would do is have a script that the clients run to do an ajax call to update a entry in your database with a time stamp for last seen. Not too often or you will overload your server.
you can also put some if statements where it checks for keystrokes, mouse movement, and if the window is active if you really want to get technical and do a away status.
then in active chats just check the time stamp for active messages or when the user list is open. anything outside a acceptable range will show the user as off line. 5 minutes seems pretty long to me. poll for a check every 10 seconds maybe?
I'm not awesome enough to write a chat application, and I'm trying to get one to work, and I've recently downloaded one from here, it's pretty good so far, as I've tested it out on XAMPP, but I have a slight problem. I'm trying to generate a list of online users to give it a more practical application-like feel, but the problem with that, is I have no clue how to do it easily.
When users login to my site, a session named g_username is created, (the chat says 'username', but I'll fix that) and from what I see so far, the easiest method would be to store their username in a database called OnlineUsers and call that data via Ajax, but, the other problem, is that it's session based, and sometimes the users can just leave, without logging out, and I intended to run a script to logout the user from both the OnlineUsers table, and by deleting the session.
If they leave without logging out, they'd be online forever! I could potentially suffix a bit of code on every page, that toggled an ajax event on page close, the event being a script that kills their OnlineUsers table record, but then again, that would load the server with useless queries as users jump between pages, as far as I'm aware.
Creating my entire site in Ajax isn't really an option, as it's a load of different sites combined in to 1 'place' with a social 'layer' (if you will) from a social service.
Does anyone see a way to do this that would make sense, and be easy to integrate, and do with Apache, without command line access?
You could so something like storing a timestamp of the users last action in a database, comparing that timestamp when outputting online users and making sure that it was done at most 1 min ago.
Run on all/vital pages:
(Deciding if the last action is outdated, you could also check if it was done for one minute ago to reduce the database-load)
if($user['lastAction'] < time()) {
//update into database, last action is outdated
}
When calculating the amount of users online and is within the loop of each timestamp
//If the users last action was within a minute, the user is most likely online
if(($row['lastAction']- time()) > 60*60)
//count user as online
you could have a cron job [if you have cpanel] running on the server once every 60secs or so, that checks when a user last sent anything via the chat if they have not in the last lets say 5mins then remove their entry from the online users list.
At the moment I'm using this SQL to check if a user is connected:
date_add(last_activity, INTERVAL 3 MINUTE) > NOW()
This is passive and will only trigger when a page is loaded.
What I'd like to do is a system that checks if a user has remained connected during a given span of time and give them bonus points.
What do you suggest to achieve this? Use polling or another approach?
You need to use some kind of java script that will report activity using ajax to your site in intervals of like 1 min. You need to implement some sort of mechanism to check if user is active, like if the mouse moves or page is scrolled, because some users can use the same page for long times. If the page is not used since the last min(should be a global var in javascript, set to true every mouse move, and to false every time a message is sent) you don't send a message.
When you receive the ajax notifications in the server you check the time between the last ajax notification(should be stored in database) and current notification and if its smaller than an interval (maybe 2 mins) give the user points for it.
As said you can use AJAX and alternatively the Refresh META tag. Note that if I see a browser tab constantly refreshing, I close it as it is distracting. Of course, if you're offering a service that requires frequent refreshes (chat / shoutbox, ticker) then it's less disturbing.
I currently have 14 tabs open, some of which for days which I haven't really looked at, so you gotta ask how valuable your information is. As far as I know, javascript is unable to get the current mouse position if it's not moving over something that has the mousemove event handled, so implementing "is the page in view and the user moving her mouse" may prove to fire a lot of events when user is active.
I may be oversimplifying here, and this probably won't help much if you're trying to charge for time on the site or something like that, but this is something google analytics takes care of. Time on site is a metric they actively record.
Ok. So here is my idea. As I mentioned in comment my way would be javascript timeout and AJAX.
So the idea would be something like this:
Make a global variable for mouse position.
Set timeout for function to fire in around 10 second intervals (which can grow in time).
Function compares last mouse position with current mouse position. If it has changed user is presumably active.
Update global variable for mouse position. And send data to server-side.
Rinse and repeat...
Actually thing that changed can be anything if you want, but mouse position would be most suiting I think.