I want to create a web based app, written in PHP that work like a reminder app, so the user enters a line of text and a time to reminded, app gets these two and at the specified time reminds the user. I implemented the program completely, but for scheduling, I have a problem: the program should do other jobs in between setting reminder and reminding user, but the only function that I find that can do something similar is sleep(), but it seems that sleep() is not the best choice because in between setting the reminder and reminding the user, the program could not to do anything.
Is there a function in php that enables scheduling tasks and at the specified time, the PHP program runs the task.
I do not want cron, crontab , scheduled task or any other OS-dependent solution.
It isn't possible to execute a task at specified time in PHP only.
You may create a condition comparing current time with the time the task should be executed and run it on every request, but that doesn't guarantee the execution at the exact time, since there may be no user requests at all.
This is what cron is for.
This is not possible in PHP.
You may check if your host provide a cron-like option (mine provide an URL call scheduling).
Another option, if users are always connected to your web app, is to manage alerts in javascript and/or ajax.
Related
I am very wonder how to run php script always or specific time WITHOUT connection or call of user/admin. For example, I am making a push-messaging alarm application. This app sends message to user when time is 5:00 PM. But push-message system requires php server page that requests FCM(push-message server) request.(This app is just example, so please don't answer me how to make push message.)
This is not the only situation I have to solve. If I have many advertisers who want to advertise on my website, and some of advertisers pay for limited-time advertise, I have to stop providing that AD after 5:00 PM.
What I want to ask is: How to run php code in background? (likely purpose to make time-alart push message) and run code in PARTICULAR TIME or ALL TIME?
You can Use cronjob to run your file in specific time
What you need is a CRON job to run in background. CRON are scheduled jobs which are set to be executed at a particular time depending on your need.
Basically it will be just a file stored on your server, which will be executed by the cron daemon. (a background process)
Refer below link for an example :
https://code.tutsplus.com/tutorials/managing-cron-jobs-with-php--net-19428
Is there a way where I can automatically call a php script after a specified interval.
I have a php script(say remindusers.php) that uses mysql to query a database where people have submitted their weekly reports. This script automatically queries the database and sends an email reminder to people who have not sent in their weekly reports yet.
What I am now supposed to do is give the ADMIN an option to set a reminder start and reminder end date during which calls should be automatically made to my remindusers.php script and cease on reminder end date.
What I learnt from SO/google is that I can setup cron (in LINUX) to automatically call my remindusers.php, but I dont have any shell access to do this.
Else Can I write another php script to essentially sleep every 24 hours and automatically wake up to call my remindusers.php script.
Are there any other built-in methods ?
Any ideas?
Use your site's visitors to trigger the event. Send a message and then check if 1 day elapsed. Then send another. You still need to pay attention not to double/triple/... send deu to synchronization.
When the time has elapsed use a MySQL (or system) MUTEX to ensure only one send occurs.
Yes you can! What you need to do is to use cron jobs. Cron jobs are essentially telling the server to execute a script (PHP or otherwise) at regular intervals. Cron jobs are very powerful and customizable, as you can set virtually any interval for your cron.
If you are using CPanel to manage your site, there is a button in CPanel to view all the cron jobs you have set. There is also a tutorial on that page.
Hope this helps.
Try with this PHPCron
PHPCron is a simple PHP script which lets you run multiple tasks on a schedule or timer. It can be run either from the command-line or via a web browser. Its behaviour is very similar to the popular cron program for UNIX.
http://katyscode.wordpress.com/2006/10/17/phpcron-running-scheduled-tasks-from-php-on-a-web-server/
I understand that you don't have Shell access but have you had a look at the cPanel to see whether there is an option to setup a cron job in there?
I have this scenario:
User submits a link to my PHP website and closes the browser. Now that the server has got the link it will analyse the submitted link (page) for the broken links and after it has completely analysed the posted link, it will send an email to the user. I have a complete understanding of the second part i.e. how to analyse the page for the broken links and send the mail to the user. Only problem that I have is how may I achieve this first part i.e. make the server keep running the actions on it's own even even if there is no request made by the client end?
I have learned that "Crontab" or a "fork" may work for me. What do you say about these? Is it possible to achieve what I want, using these? What are the alternatives?
crontab would be the way to go for something like this.
Essentially you have two applications:
A web site where users submit data to a database.
An offline script, scheduled to run via cron, which checks for records in the database and performs the analysis, sending notifications of the results when complete.
Both of these applications share the same database, but are otherwise oblivious to each other.
A website itself isn't suited well for this sort of offline work, it's mainly a request/response system. But a scheduled task works for this. Unless the user is expecting an immediate response, a small delay of waiting for the next scheduled run of the offline task is fine.
The server should run the script independently of the browser. Once the request is submitted, the php server runs the script and returns the result to the browser (if it has a result to return)
An alternative would be to add the request to a database and then use crontab run the php script at a given interval. The script would then check the database to see if there's anything that needs to be processed. You could limit the script to run one database entry every minute (or whatever works). This will help prevent performance problems if you have a lot of requests at once, but will be slower to send the email.
A typical approach would be to enter the link into a database when the user submits it. You would then use a cron job to execute a script periodically, which will process any pending links.
Exactly how to setup a cron job (or equivalent scheduled task) depends on your server. If you have a host which provides a web-based admin tool (such as CPanel), there will often be a way to do it in there.
PHP script will keep running after the client closes the broser (terminating the connection).
Only keep in mind PHP scripts maximum execution time is limited to "max_execution_time" directive value.
Of course here I suppose the link submission happens calling your script page... I don't understand if this is your use case...
For the sake of simplicity, a cronjob could do the wonders. User submits a link, the web handler simply saves the link into a DB (let me pretend here that the table is named "queued_links"). Then a cronjob scheduled to run each minute (for example), selects every link from queued_links, does the application logic (finds broken page links) and sends the email. It then also deletes the link from queued_links (or updates a flag to represent the fact that the link has already been processed.
In the sake of scale and speed, a cronjob wouldn't fit as well as a Message Queue (see rabbitmq, activemq, gearman, and beanstalkd (gearman and beanstalk are my favorite 2, simple and fit well with php)). In lieu of spawning a cronjob every minute, a queue processor listens for 'events' and asynchronously processes the 'events' (think 'onLinkSubmission($link)'), and processes the messages ASAP. The cronjob solution is just a simplified implementation of one of these MQ solutions, will result in better / more predictable results, but at the cost of adding new services to maintain, etc.
well, there are couple of ways, simplest of them would be:
When user submit a request, save this request some where, let's call it jobs table, and inform customer that his request has been received, they'll be updated site finish processing your request, or whatever suites you.
Now, create a (or multiple) scripts (depending upon requirement) and run this script from Cron, this script will pick requests from Job table, process it, do whatever required.
Alternatively, you can evaluate possibility of message_queue or may be using a Job server for this.
so, it all depends on your requirement.
I need to reset a MySQL Field value automatically at midnight. It is a specific column in a specific row in a table. I know how to do this in PHP but I do not know how to execute the PHP Script at midnight without someone having to do it themselves. Do you have any viable solutions?
Edit:--------------------
Preferably without using Cron Jobs.
If you are running on linux you would use a cronjob
On most distros there is a command called crontab that schedules tasks for you and a specific format you need:
0 0 * * * php /path/to/file.php
EDIT:
Wrote this before you edited yours :p I'm not sure there is any other way. Do you have a specific reason not to use a cronjob?
You may not even need to specify the php part if the php file is marked as executable i.e
0 0 * * * /path/to/file.php
Just do "chmod +x /path/to/file.php" form the linux command line
There are web based cron services too. Basically you set up an account and then they visit an URL of your choosing at a regular interval. On your server you set up a page that does what you need to get done. Preferably give it a unlikely-to-find-name like myjob789273634ahhh8s2nhw8sghusgf874wfu.php. You get the idea. (Remember that PHP-scripts timeout after like 30secs.)
Here's a google search:
**oops I'm new so I can't post URL apparently. Just search for "web based cron".
Good luck
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You could write a job scheduler into your program that runs jobs in a cron-like way. It would require a user to interact with the system to trigger, but it might be good enough depending on your needs. This is much more complicated than just running a cronjob, and does not ensure prefect timing (since it wont run until a user hits a page).
You'd probably need to add a table into you database that would list the job, the time you want them done, and a locking flag to avoid concurrent attempts to run the job. Each time your script runs, you'd check this table for overdue jobs and run them as needed.
Asking how to reliably set off a script at the same time every night without cron (or a scheduled task, on Windows) is like asking how to make a dynamic website without a server-side language.
If your app absolutely relies on a script running exactly at midnight, cron is a requirement. If your users have a hosting company that (stupidly) does not permit cron, they're going to be out of luck.
i am doing a project where i need to notify a user through email if his account has expired,
that is when a user signsup his sign up date and expire date is inserted into the database
now what i need to do is , i need to fire a function when the users expire date is passed
and send an email notifying user about the expiration of his account .
and this needs to be done automatically through the function .
how can i achieve this ?
The simplest thing to do is create a basic cron job that runs on a regular interval (like hourly or daily) that runs a PHP script that queries the database for any newly expired users and then emails them.
You can have a cronjob that runs every hour or so (or quicker if you need to). This cronjob would run a PHP script that gets a list of all expired accounts and sends emails to them.
Here's a tutorial on how to use crontab.
Here is a SO question on Cronjob and PHP
Getting started with cron jobs and PHP (Zend Framework)
Timed Tasks (cron-like) in PHP
PHP: running scheduled jobs (cron jobs)
What is the best method for scheduled tasks in PHP
Write a cron job (running as often as you think appropriate) to call a script (possibly PHP CLI) that does a select for all expired accounts and mails them. And what does this have to do with JavaScript?
Probably the easiest way to do this would be using either at or cron. Either one of these could be set up to call a PHP or whatever script at the time of expiration, or it could be just run once an hour, each time checking if there are any newly expired entries.
A less efficient approach would be to have the header or footer script of your pages to check the database every time any page is loaded, but I would not recommend this approach unless you absolutely can't use cron or at.
By the way, if you are not using a unix / linux system but a Windows one, you could use Scheduled Tasks and call a script.