I want to run a PHP script every 5 seconds without using cronjobs. How is it possible in PHP?
I want to update user data every 5 seconds. The program will execute when I refresh the page but I want to run that script if the page is open or not in browser.
How can I achieve this ?
One way to do it would be to have a text file or a database entry that holds the time of the last run in UNIX time.
Then on all (or selected) pages you add something like;
If($lastrun +5 < strtotime(now)){
//Run the user update
}
This means when a user or visitor on your page goes to one of the "selected" pages with the code above this visitor will "run the update"
You must have some basics about PHP. PHP only runs when you request a page. So it's impossible to run php without requesting the page. Somehow you must reload the page every 5 seconds then you can run it every 5 sec.
So you must use cron or something like this. Or, you can you can use an old computer (NOT RECOMMENDED) which will relaod the page. To relaod the page you can use browser plugins like auto reload (for chrome).
But almost every hosting companies provide free cron job. Please search your cpanel for that. Or, mail your hosting provider for help. Cron is the best way to do this job for free.
Related
Is it possible to make a script, which will execute every day at particular time, and this script would login to specific website?
On some sites there are bonuses for each day login so it would be very good thing to automate.
I have only the idea, I have completely no idea how it can be done. Maybe PHP, JavaScript or something else.
cron jobs on linux systems or task manager on windows can start a script on fixed intervals. You don't write how you need to login. Most common login systems uses a cookie an the client side. PHP's curl library can store cookies
Automatic script execution is possible to use Cron jobs which available in PHP engines in most servers.
if you need to make login every day an specific website, i think you don't need to write any script you can put your home page for the login page and you would say remember password for your computer, so every time you open your browser it automatically opens and make login.
I want to perform a task with a php file, (updating a feed) which I want to do automatically once a day. I DON'T want to have to load the file in a browser by hand. The file itself could be anything (very small and fast) but it needs to be run every day without using Cron jobs
If you're on a Windows machine, you can use a scheduled task (here are the instructions for Windows 7, but Google "run scheduled task " to find similar pages for other versions). It has much the same options as Cron, with a simple interface.
Two other possible hacks:
Have the URL for the feed itself be a PHP script that updates the feed and outputs it directly. Then you could but a cache in front of that URL so it only refreshes once a day (for instance the free level of Cloudfare).
Have the PHP script create a webpage that refreshes itself once a day, using the meta refresh tag. Then open a browser window and never close it.
If the page you have created is exposed to network, you could theoretically run a cron-job from another machine on the said network and call a curl to the page:
curl http://server/yourphp
i started to learn programming like a month ago. I already knew html and css, i thought i should learn PHP. I learned alot of it from from tutorials and books, now I am making mysql based websites for practice.
I always used to play browser based strategy games like travian when i was a kid. I was thinking about how those sites worked. I didnt have any problem till i realized that the game actually worked after you closed the browser. For example; you log in to your account and start a construction and log off. But even after you close the browser, game knows that in "x" amount of time it needs to update your data of that specific building.
can someone tell me how that works? is it something with php or MySQL or some other programming language? even if you can tell me what to search online, it would be enough.
Despite being someone who loves tackling steep learning curves, I would advise against trying jump into something that requires background processes until you have a bit more programming experience.
But either way, here's what you need to know:
Normal PHP Process
The way that PHP normally works is the following:
User types a url into the browser and hits enter (or just clicks on a link)
Request is sent to a bunch of servers and magically finds its way to the right web server (beyond scope of this answer)
Server program like Apache or IIS listening on port 80 grabs the request
Apache sees that there's a .php extension on the requested page
Apache looks up if any processors have been assigned to .php and finds php.exe
The requested page is fed into php.exe
php.exe starts up a new process for the specific user, runs everything on the script, returns its result
The result is then sent back to the user
When the user closes the browser and ends the "session", the process started by php exits
So the problem you encounter when you want something running in the background is that PHP in most cases is generally accessed through the web server, and hence usually requires a browser (and user making requests through the browser). And since closing the browser ends the process, so you need a way to run php scripts without a browser.
Luckily PHP can be accessed outside of just the webserver as a normal process on the server. But then the problem is that you have to access the server. You probably don't want your users to ssh into your server in order to manually run scripts (and I'm assuming you don't want to do it manually on behalf of your users every single time either). Hence you have the options either creating cronjobs that will automatically execute a command at a specific frequency as if you had typed it in yourself on your server's commandline. Another option is to manually start a script once that doesn't shutdown unless your server shuts down.
Triggering a Script based on Time:
Cron that is a task scheduler on *nix systems and Windows Task Scheduler on Windows. What you can do is set up a cronjob to run a specific php file at a specific frequency, and execute all the "background" tasks you need to run from within there.
One way of doing this would be to have a mysql table containing things that need to be executed along with when they need to be executed. The script then queries the table based on time to retrieve which tasks need to be executed, executes them, and then marks them executed (or just deletes them) in the mysql table.
This is a basic form of process queuing.
Building a Queue Server
This is a lot more advanced, but here's a tutorial for creating a script that will queue processes in the background without the need for any external databases: Building a Queue Server in PHP .
Let me know if this makes sense or if you have any questions :)
PHP is a server side language. Any time anybody accesses a PHP program on the server, it runs, irrespective of who is a client.
So, imagine a program that holds a counter. It stores this in a database. Every time updatecounter.php is called, the counter gets updated by one.
You browse to updatecounter.php, and it tells you that the counter is now at 34.
Next time you browse to updatecounter.php it tells you that the counter is at 53.
Its gone up by 18 more counts than you were expecting.
This is because updatecounter.php was being run without your intervention. It was being run by other people.
Now, if you looked at updatecounter.php, you might see code like this:
require_once("my_code.php);
$counterValue = increment_counter_value();
echo "New Counter Value = ".$counterValue;
Notice that the main core of the program is stored in a separate program than the program that you are calling.
Also, notice that instead of calling increment_counter_value, you could call anything. So every time somebody browsed to updatecounter.php, or whatever your game would be called, the internal game mechanics could be run. You could for instance, have an hourly stat management routine which would check each time it was called if it had been run in the last hour, and if it hadn't it would perform all the stats.
Now, what if nobody else is playing your game? If that happens, then the hourly stat management wouldn't get called, and your game world would die. So what you would need to do is create another program who's sole function is to run your stats. You would then schedule that program on the server to run at an hourly interval. You do this using something called a CRON job. You will probably find that your host already has this facility built in, if you are on Apache. I won't go into any more detail about task scheduling as without knowing your environment its impossible to give the correct answer. But basically, you would need to schedule a PHP program to run on the server to perform the hourly maintenance.
Here's a tutorial on CRON jobs:
http://net.tutsplus.com/tutorials/other/scheduling-tasks-with-cron-jobs/
I haven't used it myself but I've had no problems with other stuff on tutsplus so you should be ok.
This is not only php . Browser based game are combination of php/mysql/javascript/html . There are lot of technologies being used for this kind of work. When you are doing something on the browser, lets say adding a building ,an ajax request is being sent to the server so the server updates the database (can't wait until logout because then other users won't know your status to play (in case of multiparty) .
I want to implement something that do every X time some actions. I want that this thread worker are always executing in my server (PHP).
For example:
I have a blog and i want that someone process deletes comments with keyword "XXXX". I want that this process can sleep every X minutes and when it wakes up, gain, it will going to delete the comments.
I dont want the solution, i only want how can implement this type of process in PHP server (Apache).
You can use a cron job to run a PHP script every x minutes etc
All you need to do is make a PHP file to do what you need, and then point the cron to the PHP file and it will run for whatever time you specify
If you use something like Plesk or cPanel cronjobs are built in and very easy to use.
http://en.wikipedia.org/wiki/Cron
I created a script that gets data from some web services and our database, formats a report, then zips it and makes it available for download. When I first started I made it a command line script to see the output as it came out and to get around the script timeout limit you get when viewing in a browser. But because I don't want my user to have to use it from the command line or have to run php on their computer, I want to make this run from our webserver instead.
Because this script could take minutes to run, I need a way to let it process in the background and then start the download once the file has been created successfully. What's the best way to let this script run without triggering the timeout? I've attempted this before (using the backticks to run the script separately and such) but gave up, so I'm asking here. Ideally, the user would click the submit button on the form to start the request, then be returned to the page instead of making them stare at a blank browser window. When the zip file they exists (meaning the process has finished), it should notify them (via AJAX? reloaded page? I don't know yet).
This is on windows server 2007.
You should run it in a different process. Make a daemon that runs continuously, hits a database and looks for a flag, like "ShouldProcessData". Then when you hit that website switch the flag to true. Your daemon process will see the flag on it's next iteration and begin the processing. Stick the results in to the database. Use the database as the communication mechanism between the website and the long running process.
In PHP you have to tell what time-out you want for your process
See PHP manual set_time_limit()
You may have another problem: the time-out of the browser itself (could be around 1~2 minutes). While that time-out should be changeable within the browser (for each browser), you can usually prevent the time-out user side to be triggered by sending some data to the browser every 20 seconds for instance (like the header for download, you can then send other headers, like encoding etc...).
Gearman is very handy for it (create a background task, let javascript poll for progress). It does of course require having gearman installed & workers created. See: http://www.php.net/gearman
Why don't you make an ajax call from the page where you want to offer the download and then just wait for the ajax call to return and also set_time_limit(0) on the other page.