Is it possible to tell PHP to execute a piece of code on a given date and time? For example, Blogger.com allows someone to set a blogpost to be published in the future (e.g. 12/12/14 6:00AM).
Can PHP do something similar?
(Sorry, I don't even know what the correct term for events like these would be to be able to even search for them! :( )
You can do this using a cron job (or scheduled task on Windows); although they are typically used for reoccurring jobs.
If you're using a database, most platforms come with a scheduler.
You can schedule your action in your database and use a cronjob on your server or use a cron job service To run your actions.
https://www.setcronjob.com/
For example when you want to publish your blog in the future, you save your publish date in the future and set some sort of auto-publish bit.
Then every hour a PHP script is ran by a cronjob, this script checks the database for all blogs which need to be published.
It's not possible to tell PHP to do this itself, since it would require a process to run forever to periodically call your PHP code. Thankfully though, there's a couple of things which do this:
1) Call a PHP script from a cron job, which then does any necessary work. If you don't have access to a crontab, you can periodically call this when a user pings your site instead, although that will be less reliable, of course.
2) Use at. This works in basically the same way as cron on Linux systems, but will schedule once and at an exact time.
for "triggering code at a certain time", cron works. But for something as simple as publishing an article at a specific time, it isn't needed. You can just store a publish date with your article. When displaying a list of articles you can adjust your query to something like WHERE PUBLISH_DATE <= NOW() and on the article page check if the article's publish date has passed before showing the article.
On Unix-like systems, there's Cron. You can manage Cron from PHP.
On Windows, there are scheduled tasks - you can also use PHP to manage scheduled tasks.
Be careful with this though - it's kinda hard to test, and you may end up with a schedule that cripples your server.
Related
I have no idea where to start with this one:
I have a database that stores postID and Date.
What I want to do is have my website auto delete all rows where Date is less than today. This script can't have any user input at all. No button clicks, nothing. The script must run every day at midnight.
I've been looking all over the place for something that does this and I've found absolutely nothing.
You can use PHP script and use cron job on your cpanel.
Example:
cronjobcommand.php
<?php
include 'your_db_connection';
mysql_query("DELETE FROM your_table_name WHERE Date < NOW()");
?>
I have attached a screenshot below for your more reference.
For those out there who are on a shared hosting, like 1and1's, and can't use cron, here are 2 alternatives :
mysql events enable you to place a time trigger on mysql, which will execute when you'll want, without having to be fired by any kind of user input
if you cannot create mysql events because you're on 1and1 :(, an alternative is to use webcron
You just need to tell webcron the url of the php script you'd like to be run, and they'll trigger it for you at the intervals you want
Why using cronjobs everyday?? Why not filter data on output. For example in your select check if post date equals today with adding a simple where:
SELECT * FROM `posts`
WHERE (DATE(`post_date`) = DATE(NOW()));
This way you're not required to do your database managements/cronjobs on any special time and it will be used just for database managements. Afterwards you can delete unnecessary data at any time using by mysql command like:
DELETE FROM `posts` WHERE (
DATE(`post_date`) < DATE(NOW())
)
Most hosts provide a cron(8) service that can execute commands at specific times. You use the crontab(1) program to manage the crontab(5) file the describes when to run which commands.
There's a lot of functionality available to you, but if you write a program (shell script, php script, C program, whatever) that runs the appropriate MySQL commands, you can call the program via cron(8) in an entirely hands-off fashion.
Run crontab -e to edit your current crontab(5) file. If none exists, hopefully you'll get one with a helpful header. If not, copy this:
# m h dom mon dow command
The columns indicate the minute, hour, day of month, month, and day of week to execute commands. All the numbers in the columns are essentially ANDed together to decide when to run commands.
Thus, midnight every night would look like this:
0 0 * * * /path/to/executable
It's remarkably flexible, so put some time into the documentation, and you'll find many uses for it.
You should set cron job (scheduled tack.) for it.
A cron job is an automated program setup for Linux and Unix operating systems. It allows the user to execute several commands or functions at a specific time and date.
you have cron Job in your cpanel setup. first you need to make a php script with your logic for delete record after each date. take date from server and write script for delete.
then go to cron tab in your cpanel and do settings for time interval to run cron and give path of your php script file.
MySQL doesn't have a task scheduler. So you have to use the task scheduler of your Operating System (CRON under Linux), or to lunch a basic task checker sub-script during the script of the main page (on another page that is supposed to display the changing data).
I've search on the web and apparently there is no way to launch a php script without user interaction.
Few advisors recommend me Cron but I am not sure this is the right way to go.
I am building a website where auctions are possible just like ebay. And after an amount of time the objects are not available anymore and the auction is considered as finished.
I would like to know a way to interact with the database automatically.
When do you need to know if an object is available? -> Only if someone asks.
And then you have the user interaction you are searching for.
It's something different if you want to, let's say, send an email to the winner of an auction. In this case you'd need some timer set to the ending time of the auction. The easiest way to do this would be a cron job...
There are several ways to do this. Cron is a valid one of them and the one I would recommend if its available.
Another is to check before handling each request related to an object whether it is still valid. If it is not, you can delete it from the database on-the-fly (or do whatever you need to) and display a different page.
Also you could store the time at which your time-based script was run last in the database and compare that time with the current time. If the delay is large enough, you can run your time based code. However, this is prone to race conditions if multiple users hit the page at the same time, so the script may run multiple times (maybe this can be avoided using locks or anything though).
To edit cronjobs from the shell: crontab -e
A job to run every 10 minutes: */10 * * * * curl "http://example.com/finished.php"
TheGeekStuff.com cron Examples
Use heartbeat/bot implement
ation
Cron job that runs pretty frequently or a program that starts on boot and runs continuously (maybe sleeping periodically) is the way to go. With a cron job you'll need to make sure that you don't have two running at any given time or write it such that it doesn't matter if you have more than one working at any given time. With "resident" program you'll need to figure out how to handle the case when it crashes unexpectedly.
I wouldn't rely on this mechanism to actually close the auction, though. That should be handled in your database/web site. That is, the auction has a close time and either the database constraints or your code makes it impossible to bid on a closed auction. Notifying the winner and seller, setting up the payment process, etc. are things your service/scheduled task could do.
is there any other option other than cron to schedule the running of a php backup script at a certain time?. I know you can use php itself to schedule things, but it will only fire if the site is getting traffic.
Are there any other options ?.
Thanks :-)
If you're talking about a database backup, then MySQL 5.1 and above has CREATE EVENT which can be used to trigger events (such as stored procedures that can dump table structure/data to file) at regular intervals or set times
Well, cron jobs is a solution. But not necessary in most cases.
If your script is doing something off the site (like sending an email or something), it must be a cron-job.
But...
I made a textbased rpg-game once where several actions were stored in the database waiting to get triggered at a specified time. I found out that it did not make any difference if the script fired at the time it should, or when the first person visiting the page after the time is beyond the timestamp. You could do these events before displaying the content of the page. (I used a file called monitor, to keep it simple).
Would you like to say more about your "event"?
Unless you feel like writing a daemon/service/etc., cron would be your best bet. If you need a job ran more often than minutely, use a lockfile solution and a looping script.
Well not really, Crons are your best bet.
Other than that call a script, and if certain parameters are met such as time elapsed then run the script.
I need to develop a website that runs jobs at certain times (every 15 minutes) I'll use a cron to run the webpage.
What is the best way to store the jobs information in? Some jobs will be daily, others every 8 hours etc. To complicate matters, I also need to take into consideration the timezone differences. This shouldn't be too difficult as PHP has many timezone functions, but how do I integrate it in the programming of the next job to run?
Another question, is how will the user enter the information for the jobs to run? One option, similar to http://www.webcron.org, is to ask the user to select how often the jobs must run, but how do I store that info in a database?
Any assistance will be greatly appreciated!
I would use the crontab syntax, store it in a DB and run a separate crontab invoking the execution script every minute.
There are GPL classes that do that for you already, like : http://www.phpclasses.org/package/4140-PHP-Database-driven-PHP-job-scheduler-like-cron.html
Create a MySQL Event, that will take care also the storing, recurrence, execution.
How can I set up a program in which a certain piece of data for a user is updated every hour. One example I can give is Mafia Wars. When you obtain property, your money is incremented every set amount of time based on which property it is. I'm not asking to spit out code for me, but rather to guide me in the right direction for a solution. I tried looking into cron jobs, but that only runs a script on a set time. Different users are going to be using this, and they may have different times to update their information. So thus, cron jobs are not applicable here.
You could still have cron jobs, just lots of them (not one per user, but maybe one per minute).
Also, Mafia Wars strikes me as not very interactive, so it may be enough to just update the data (after the fact) when the user (or some other part of the system) next looks at it. So when you log in after 37 hours, you get all the updates for the last 37 hours retroactively applied. Cheap trick, but if there is no need for a consistent global view, that might work, too.
A solution that I came up with when wondering how to implement such a thing is that whenever the player saves the game, the game saves the current time. Then, when the player loads the game back up, it calculates how many minutes have passed and figures out how much money the game should give the player. Then, you could update the SQL database to reflect the changes.
Why do you dismiss cron jobs? Have a cron job that runs a script in short intervals. Within this script, include logic to check which specific updates on the database have to be done.
A cron job that runs something is your friend.
What that something is, is up to you. It could be a PHP script that runs some mysql queries or procedures, or it could straight mysql command from the command line.
Either way, Cron (and other similiar tools) are exactly the bill for these tasks. It's lightweight, on nearly every server in the land, lots of help avaliable for it, and it 99.9999% of the time, it just works!