CODEWITHSUNDEEP
phpmysqlcurlupdating
fishcracker
fishcracker

Reputation: 2499

Schedule PHP script to execute via cron

I have a script that will update some columns on my database. It is written in PHP, I execute it via URL (eg. http://foo.com/xyz/yzx/dbupt8r). I did this using crontab -e then curl on the script URL, because on my mind it is like somehow similar of what I am doing: accessing it via URL. Is there any advisable or better way of doing this? Am I at security or threat flaws?

Upvotes: 1

Views: 690

Answers (4)

morgant
morgant

Reputation: 2225

There are two ways to do this, the way that you're already doing it: (curling a publicly accessible URL); or executing the PHP script directly from your crontab.

Cron Curling

As you mentioned, this is often very convenient and comfortable since you're already developing a web application in PHP and so it's the way you're already working. There are a few risks:

  • Most importantly, security: You'll want to ensure that input is properly filtered, there are no risks of SQL injection, etc., in case someone discovers the URL and tries to take advantage of it. Hopefully you're covering most of this anyway since you're developing a web application.
  • Frequency & concurrency: You're scheduling it's execution from cron, so are there any issues if someone else starts calling the URL and making it fire more frequently or at the same time as a scheduled run is occurring?
  • Relying on curl: It also means you're relying on curl to execute your script, so you're opening yourself up to many points of failure (curl itself, DNS, etc.).

Running PHP from Cron

Alternatively, you may be able to run the script directly from your crontab. There are two ways of doing this:

  • Passing the PHP script to the PHP interpreter binary, which would look something like this (note the path to your PHP binary varies by platform, but should be specified as an absolute path as cron doesn't have access to many environment variables):

    */15 * * * *    /usr/bin/php -f /path/to/php/script.php

  • Alternatively, you can add a hashbang/shebang line to the first line of the PHP script as follows:

    #!/usr/bin/php

    Make it executable, for example:

    chmod 755 /path/to/php/script.php

    And add it directly to your crontab:

    */15 * * * *    /path/to/php/script.php

The advantages of this method are that you can put the script in a location that's not publicly accessible so you can ensure tighter control over its access & execution. It may also mean you can write lighter code if you don't have to handle the web side of things. That said, if you're using a PHP framework, you may find it difficult to develop a stand-alone script such as this.

Upvotes: 1

Charles-Édouard Coste
Charles-Édouard Coste

Reputation: 1682

Calling a URL exposes you to timeout problems which could lead to transaction errors in your database. I suggest you use command line interface (CLI) for this kind of process.

Upvotes: 0

PhilDin
PhilDin

Reputation: 2842

It depends on what you have access to. Personally, I wouldn't like to depend on an external curl script for required periodic jobs. One of the downsides to this approach is that you risk giving permission to the world to run your dbupt8r script. Please bear in mind that you can run PHP scripts without them being in the context of a web server so you could create a cron job on the web server that does

php /my/folder/dbupt8r.php

In this case, your periodic job will run regardless of whether the web server is available and without any risk of exposing it to the outside world.

Upvotes: 1

user974896
user974896

Reputation: 1813

You can always run it using the php command. Have your crontab run a "/path/to/script.sh" that contains:

 #!/bin/bash
 cat "/path/to/phpscript.php" | php -e

You can have it save the output if you want. You could also have CRON run "php -f /path/to/script.php"

Upvotes: 1

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