PHP Having problems with find and replace in LARGE CSV - php

Question

I am writing a PHP script so that I can do a find and replace in a large CSV file. I wrote this script:
// FIND AND REPLACE
$sourcePath = 'custom.csv';
$tempPath = $sourcePath . 'temp';
$source = fopen($sourcePath, 'r');
$target = fopen($tempPath, 'w');
while(!feof($source)) {
$line = preg_replace ("village", "village/",fgets($source));
fwrite($target, $line);
}
fclose($source);
fclose($target);
unlink($sourcePath);
rename($tempPath, $sourcePath);
But I am getting these errors,
Warning: feof() expects parameter 1 to be resource, boolean given
Warning: fgets() expects parameter 1 to be resource, boolean given
Warning: preg_replace(): Delimiter must not be alphanumeric or backslash

Answer 1

$source = fopen($sourcePath, 'r'); isn't returning what you think it is.
It's likely returning false, which typically happens when PHP can't find the file at the path you provided. If you're certain the file exists, you should confirm that the user executing the script has the proper permissions to read the file.
You're second issue regarding preg_replace() is being caused by not using delimiters. They are needed in the first argument.
$line = preg_replace ("/village/", "village/",fgets($source));
However, regular expressions aren't needed with this simple of a replacement. You should instead use str_replace() and the script should run faster.
Your code should look like this:
<?php
$sourcePath = 'custom.csv';
$tempPath = $sourcePath . 'temp';
$source = fopen($sourcePath, 'r');
$target = fopen($tempPath, 'w');
if($source){
while(!feof($source)) {
$line = str_replace("Village\\", "Village",fgets($source));
fwrite($target, $line);
}
} else {
echo "$sourcePath not found, or using the wrong permissions.";
}
fclose($source);
fclose($target);
unlink($sourcePath);
rename($tempPath, $sourcePath);
?>

Answer 2

You are not checking if fopen is actually returning a file pointer resource or a false result. It is likely returning false and throwing the warning that a boolean is provided.
Also, you could use:
$line = str_replace("village", "village/", fgets($source));