Adding to the $PATH environment variable in a PHP script

I have a PHP script that is using wget to download some images. However, wget was installed using Homebrew so it’s not available to the user running the PHP script. When I run exec('echo $PATH') I don’t get the /usr/local/bin directory that contains wget. How do I add /usr/local/bin to the environment path so the PHP script can find wget?

Update: I forgot to mention the reason I can’t specify the exact location is because the location may be different depending on which machine this script is being run on.

Solution:

This is what I ended up with:

//help PHP find wget since it may be in /usr/local/bin
putenv('PATH=' . getenv('PATH') . PATH_SEPARATOR . '/usr/local/bin');
if (exec('which wget') == null) {
    throw new Exception('Could not find wget, so image could not be downloaded.');
}

//now we know wget is available, so download the image
exec('wget ...');

Answer

In order of preference:

1. You can simply specify the full path /usr/local/bin/wget when you are calling the subprocess. This is probably the simplest and best approach.
2. You can use proc_open instead of exec, which allows you to pass environment variables as an argument.
3. You can use putenv to change the current environment (which will be inherited by subprocesses).