Dynamically update variables into an existing file? - php

Question

I'm trying to build a small CMS using CodeIgniter, and I need to be able to dynamically update some variables within the application/config.php
So far I did:
private function update_file ($file, $var, $var_name) {
$start_tag = "<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');\n";
if (file_exists($file)) {
require_once ($file);
$updated_array = array_merge($$var_name, $var);
$data = $start_tag."\$".$var_name." = ".var_export($updated_array, true).";";
file_put_contents($file, $data);
} else {
return false;
}
}
Everything works just fine! The result in the config.php file will be:
<?php ...;
$config = array (
'base_url' => '',
...
...
);
But what if I would like to maintain the original config.php file format with comments, spaces and
separated declared $config['key'] = 'value' ... ?
Is that possible ?
EDIT:
Thank you for your answers, very precious.
I found a slightly different solution for my needs, performing a preg_replace on the return of file_get_contents() and then write back on the file the new resulting string. File maintains the exact original clean format.
private function update_file ($file, $var, $var_name) {
if (file_exists($file)) {
require_once ($file);
$contents = file_get_contents($file);
$updated_array = array_merge($$var_name, $var);
$search = array();
$replace = array();
foreach($$var_name as $key => $val) {
$pattern = '/\$'.$var_name.'\[\\\''.$key.'\\\'\]\s+=\s+[^\;]+/';
$replace_string = "\$".$var_name."['".$key."'] = ".var_export($updated_array[$key], true);
array_push($search, $pattern);
array_push($replace, $replace_string);
}
$new_contents = preg_replace($search, $replace, $contents);
write_file($file, $new_contents);
}
Maybe it requires some slight performance improvements. But this is my baseline idea.

Answer 1

create the keys with empty values
$config['base_url'] = '';
then set them inside any of your controllers.
This works best if you store the values in the db, and initialize them in MY_Controller.
$this->config->set_item('base_url', 'value');

Answer 2

It is possible. I can't find the code , but once i have written something like that. Whole idea was based on tokenizing template file and substitute values in an array, preserving key order, line numbers and comments from the template.
[+] Found it. It's purpose was to fill values from template that looked like this (it was much bigger of course):
<?php
$_CFG = array(
// DB section
'db_host' => 'localhost',
'db_user' => 'root',
'db_pass' => '',
'db_name' => 'test',
// Site specific
'lang' => array('pl','en'),
'admin' => 'admin#example.com',
);
And the code that was doing all the magic:
$tokens = token_get_all(file_get_contents('tpl/config.php'));
$level = -1;
$buffer = '';
$last_key = 0;
$iteration = 0;
foreach($tokens as $t){
if($t === ')'){
$iteration = 0;
$last_key = 0;
$level--;
}
if(is_array($t)){
if($t[0] == T_ARRAY && strtolower($t[1]) === 'array')
$level++;
if($t[0] == T_CONSTANT_ENCAPSED_STRING){
if($last_key){
if($level){
if(isset($new_config[$last_key][$iteration])){
$buffer .= var_export($new_config[$last_key][$iteration], TRUE);
}
else
$buffer .= 'null';
$iteration++;
}
else{
if(isset($new_config[$last_key]))
$buffer .= var_export($new_config[$last_key], TRUE);
else
$buffer .= 'null';
$last_key = 0;
}
}
else{
$buffer .= $t[1];
$last_key = trim($t[1],"'");
}
}
else
$buffer .= $t[1];
}
else
$buffer .= $t;
}
file_put_contents('config.php',$buffer);