PHP Code to stop a script to run from browser

Question

Envoirnment : Linux, PHP

Scenario : I have written a script which will be set as a cron. Now the case is that I want the script to run only through cron and not through any browser (any web browser including mobile browsers). So I am looking for a function something like browserValidate.

The script is written in MVC framework and will be run as

/usr/bin/GET http://xyz.com/abc/pqr

Please help me with this.

Thanks in advance.

Answer 1

As @Mob said, the sure fire way to achieve this is to put the script in a place where it cannot be accessed through the web server. If this is not possible or you don't want to do it for some reason, you need to detect whether the script was called via a web server or through the command line.

My favourite approach for this (there are many) is:

$isRunningFromBrowser = !isset($GLOBALS['argv']);

This means that if $isRunningFromBrowser is true, you just exit/return an error message/whatever.

Answer 2

When executing the script from within crontab, you could use the $_SERVER superglobal to either check for Apache generated entries (HTTP_*) or - since $_SERVER reflects the executing binary's environment - define a certain environment variable prior to execution:

# in the crontab
FOOVAR=1 /usr/bin/php5 script.php

Then, in script.php, check for FOOVAR existence:

if (!isset($_SERVER['FOOVAR']))
   die('No browser access.');

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If your cronjob is being executed with wget and the client IP is the server's, you could add this to an .htaccess file:

SetEnvIf Remote_Addr "192.168.0.1" FOOVAR=1

This will set FOOVAR only if the client's IP address is "192.168.0.1".