PHP function to edit configuration file - php

Question

I'm looking for a PHP function that I can use to edit key/value pairs in a text file.
What I want to do (PHP):
changeValue(key, bar);
and have in setings.txt:
key = foo
key2 =foo2
Change to:
key = bar
key2 = foo2
What I got so far (not working):
function changeValue($input) {
$file = file_get_contents('/path/to/settings.txt');
preg_match('/\b$input[0]\b/', $file, $matches);
$file = str_replace($matches[1], $input, $file);
file_put_contents('/path/to/settings.txt', $file);
}
How to update an ini file with php? got me started. I read many other questions but I couldn't get it working.

Answer 1

I would use JSON with at least the JSON_PRETTY_PRINT option to write and json_decode() to read.
// read file into an array of key => foo
$settings = json_decode(file_get_contents('/path/to/settings.txt'), true);
// write array to file as JSON
file_put_contents('/path/to/settings.txt', json_encode($settings, JSON_PRETTY_PRINT));
Which will create a file such as:
{
"key": "foo",
"key2": "bar",
"key3": 1
}
Another possibility is var_export() using a similar approach, or another simple example for what you're asking:
// read file into an array of key => foo
$string = implode('&', file('/path/to/settings.txt', FILE_IGNORE_NEW_LINES));
parse_str($string, $settings);
// write array to file as key=foo
$data = implode("\n", $settings);
file_put_contents('/path/to/settings.txt', $data);
So read in the file, change the setting $setting['key'] = 'bar'; and then write it out.

Answer 2

Instead of using file_get_contents use file, this reads each line in as an array.
Under you see working code. Had a little problem with write array added more breaks but not sure why.
changeValue("key", "test123");
function changeValue($key, $value)
{
//get each line as an array.
$file = file("test.txt");
//go through the array, the value is references so when it is changed the value in the array is changed.
foreach($file as &$val)
{
//check if the string line contains the current key. If it contains the key replace the value. substr takes everything before "=" so not to run if the value is the same as the key.
if(strpos(substr($val, 0, strpos($val, "=")), $key) !== false)
{
//clear the string
$val = substr($val, 0, strpos($val, "="));
//add the value
$val .= "= " . $value;
}
}
//send the changed array writeArray();
writeArray($file);
}
function writeArray($array)
{
$str = "";
foreach($array as $value)
{
$str .= $value . "\n";
}
//write the array.
file_put_contents('test.txt', $str);
}
?>