PHP: Creating your own custom ini config file

In a continuing effort to make my life more difficult I've decided to write my own MVC. I could have easily used one of many frameworks(Zend Framework, Cake, Symfony, etc ...) but I was really interested in what it takes to write one. So far it's been a great experience and I've learned a lot about PHP5.

One of the things I noticed about a lot of the MVCs is they store settings in an external ini file. I had no idea how they pulled the information out of them until I ran across this article on IBM's website. They mentioned a function called parse_ini_file. This function has been around since PHP4, but I never knew about it. You could fill the grand canyon with the things I don't know, but let's focus on this for now.

This function allows you to read a external ini file and it returns an array of properties. You can also configure it to return an associative array of values grouped by category.

This allowed me to move a lot of settings into an external file and clean up a huge chunk of code. The problem is many of the variables I defined were dynamic. parse_ini_file doesn't evaluate external PHP code. The trick to that is to run eval on things you want it to parse.

Here is an example of some code I have stored in an external file.

[define]
PATH_HTTP = "http://{$_SERVER['HTTP_HOST']}/test_site/"

I created a function that will parse the ini file and will run eval on anything in the define group.

//configure define. this will parse php code
if(isset($ini['define']))
{
  foreach($ini['define'] as $key=>$item)
  {
    define($key, eval("return \"{$item}\";"));
  }
}

The important part to note when using eval is that it doesn't return a value. If you want to capture the evaluated variable prefix the variable with "return" and make sure to end the line with a ;.

Update
An important thing to note is that ini files can be read very easily in a web browser. You'll want to set up a .htaccess file that blocks viewing of ini files. You can copy-paste this into a .htaccess file at the root of your site.

<files *.ini>
order allow,deny
deny from all
</files>

MAMP (Pro): Making changes to php.ini

I'm using MAMP Pro and trying to get an old project built in PHP4 up and running. The project depends on register_globals to be turned on. I tried to update the php.ini file located in MAMP/conf/php4/php.ini, but nothing would change when I looked at the phpinfo() output.

After banging my head against the wall for awhile I turned to the forums at mamp.info. There is an importance difference between MAMP and MAMP PRO. If you want to update any of the ini file settings while using MAMP PRO goto File => Edit Template and select the ini you want to update.

The full forum post can be found here.