File put contents fails if you try to put a file in a directory that doesn't exist. This creates the directory.
<?php
function file_force_contents($dir, $contents){
$parts = explode('/', $dir);
$file = array_pop($parts);
$dir = '';
foreach($parts as $part)
if(!is_dir($dir .= "/$part")) mkdir($dir);
file_put_contents("$dir/$file", $contents);
}
?>