PHP editing text file on remote server not working - php

Question

I have multiple sites, and have a text file on our main site with a list of domains to whitelist. I want to be able to edit this global file from each of the websites.
I have a couple of problems that I'm running into:
file_exists() and ftp_delete() are not finding the file even though it exists on the remote server.
ftp_fput() is adding a blank text file in the correct place with a zero filesize.
Here is my code:
// Check if we are updating the whitelist
if(isset($_POST['Submit'])){
// Make sure we have something to add or remove
if (isset($_POST['update']) && $_POST['update'] != '') {
// Get the text we need to add or remove
$add_or_remove_this = $_POST['update'];
eri_update_global_whitelist( $add_or_remove_this, 'add' );
// Say it was done
echo '<br>Script Completed...<br>';
}
}
echo '<form method="post">
<textarea name="update" cols="50" rows="10"></textarea><br><br>
<input name="Submit" type="submit" value="Update"/>
</form>';
function eri_update_global_whitelist( $string, $add_or_remove = 'add' ) {
// Validate the string
$domains = explode( ',', str_replace(' ', '', strtolower($string)) );
print_r($domains); // <-- WORKS AS EXPECTED
// Add invalid domains here
$invalid = [];
// Cycle
foreach ($domains as $key => $domain) {
// Check if it contains a dot
if (strpos($domain, '.') === false) {
// If not, remove it
unset($domains[$key]);
// Add it to invalid array'
$invalid[] = $domain;
}
}
print_r($domains); // <-- WORKS AS EXPECTED
// Only continue if we have domains to work with
if (!empty($domains)) {
// The whitelist filename
$filename = 'email_domain_whitelist.txt';
// File path on remote server
$file_url = 'https://example.com/eri-webtools-plugin/data/'.$filename;
// Get the file content
$file_contents = file_get_contents( $file_url );
// Only continue if we found the file
if ($file_contents) {
// Explode the old domains
$old_domains = explode( ',', str_replace(' ', '', $file_contents) );
print_r($old_domains); // <-- WORKS AS EXPECTED
// Are we adding or removing
if ($add_or_remove == 'add') {
// Merge the arrays without duplicates
$new_domains = array_unique (array_merge ($old_domains, $domains));
} else {
// Loop through them
foreach ($old_domains as $key => $old_domain) {
// Check if it matches one of the new domains
if (in_array($old_domain, $domains)) {
// If so, remove it
unset($old_domains[$key]);
}
}
// Change var
$new_domains = $old_domains;
}
print_r($new_domains); // <-- WORKS AS EXPECTED
// Include the ftp configuration file
require_once $_SERVER['DOCUMENT_ROOT'].'/wp-content/plugins/eri-webtools-plugin/ftp_config.php';
// Establishing ftp connection
$ftp_connection = ftp_connect($ftp_server)
or die("<br>Could not connect to $ftp_server");
// If connected
if ( $ftp_connection ) {
// Log in to established connection with ftp username password
$login = ftp_login( $ftp_connection, $ftp_username, $ftp_userpass );
// If we are logged in
if ( $login ){
echo '<br>Logged in successfully!'; // <-- WORKS AS EXPECTED
// Make passive
ftp_pasv($ftp_connection, true);
// File path to delete
$file_to_delete = 'https://example.com/eri-webtools-plugin/data/'.$filename; // <-- NOT SURE HOW TO USE ABSOLUTE PATH ON REMOTE SERVER ??
// Delete the old file
if (file_exists($file_to_delete)) {
if (ftp_delete($ftp_connection, $file_to_delete)) {
echo '<br>Successfully deleted '.$filename;
} else {
echo '<br>There was a problem while deleting '.$filename;
}
} else {
echo '<br>File does not exist at: '.$file_to_delete; // <-- RETURNS
}
// Create a new file
$open = fopen($filename, 'r+');
// If we didn't die, let's implode it
$new_domain_string = implode(', ', $new_domains);
print_r('<br>'.$new_domain_string); // <-- WORKS AS EXPECTED
// Write to the new text file
if (fwrite( $open, $new_domain_string )) {
echo '<br>Successfully wrote to file.'; // <-- RETURNS
} else {
echo '<br>Cannot write to file.';
}
// Add the new file
if (ftp_fput($ftp_connection, '/eri-webtools-plugin/data/2'.$filename, $open, FTP_ASCII)) {
echo '<br>Successfully uploaded '.$filename; // <-- RETURNS
} else {
echo '<br>There was a problem while uploading '.$filename;
}
} else {
echo '<br>Could not login...';
}
// Close the FTP connection
if(ftp_close($ftp_connection)) {
echo '<br>Connection closed Successfully!'; // <-- RETURNS
} else {
echo '<br>Connection could not close...';
}
} else {
echo '<br>Could not connect...';
}
} else {
echo '<br>Could not find the file...';
}
} else {
echo '<br>No valid domains to add or remove...';
}
// Check for invalid domains
if (!empty($invalid)) {
echo '<br>Invalid domains found: '.implode(', ', $invalid);
}
}

Answer 1

Finally figured it out. I ditched ftp_fput() and replaced it with ftp_put(). Then I referred to the temporary file location on the local server instead of the fopen() like so:
ftp_put($ftp_connection, '/eri-webtools-plugin/data/'.$filename, $filename, FTP_ASCII)
So to explain what's going on (in case someone else runs into this):
// Name the temporary path and file, preferably the same name as what you want to call it.
// The path doesn't need to be specified. It just gets temporarily stored at the root and then deleted afterwards.
$filename = 'filename.txt';
// Create a new file by opening one that doesn't exist
// This will be temporarily stored on the local server as noted above
$fp = fopen($filename, 'w+');
// Write to the new file
fwrite( $fp, 'Text content in the file' );
// Add the file where you want it
ftp_put($ftp_connection, '/desination_folder/'.$filename, $filename, FTP_ASCII);
// Close the file
fclose($fp);
I ended up finding out that using ftp_put() will replace a file if it already exists, so there is no need to delete the old one like I was trying to.