PHP create and write form - php

Question

I have a form with two fields. The first textbox the users enter information into is what I would like to name the file that is being saved, and the second textarea is for what I would like written into the file. I am able to write to a file I have already created using php coding below which I did simply to test the function:
<?php
// If a session already exists, this doesn't have any effect.
session_start();
// Sets the current directory to the directory this script is running in
chdir(dirname(__FILE__));
// Breakpoint
if( empty($_SESSION['username']) || $_SESSION['username'] == '' ) echo 'There is no session username';
if( empty($_POST['CodeDescription']) || $_POST['CodeDescription'] == '' ) echo 'There is no POST CodeDescription';
// Get current working directory
echo getcwd();
// This should output /home/revo/public_html/evo/users
// This is assuming we are working from the current directory that is running this PHP file.
$USER_DIRECTORY = 'users/'.$_SESSION['username'];
// Makes the directory if it doesn't exist
if(!is_dir($USER_DIRECTORY)):
mkdir($USER_DIRECTORY);
endif;
// Put together the full path of the file we want to create
$FILENAME = $USER_DIRECTORY.'/'.$_POST['CodeDescription'].'.txt';
if( is_file( $FILENAME ) ):
// Open the text file
$f = fopen($FILENAME, "w");
// Write text
file_put_contents($FILENAME, $_POST['Code']);
// Close the text file
fclose($f);
// Open file for reading, and read the line
$f = fopen($FILENAME, "r");
else:
echo 'Filename already exists';
endif;
?>
However I am unsure how to check to see if a file with the name they enter into the first box exists, and then if not create it, then write the information from the second box into the file.

Answer 1

<?php
// If a session already exists, this doesn't have any effect.
session_start();
// Sets the current directory to the directory this script is running in
chdir(dirname(__FILE__));
// Breakpoint
if( empty($_SESSION['username']) || $_SESSION['username'] == '' ) echo 'There is no session username';
if( empty($_POST['CodeDescription']) || $_POST['CodeDescription'] == '' ) echo 'There is no POST desired filename';
// Get current working directoty
//echo getcwd(); // Debugging output
// This is assuming we are working from the current directory that is running this PHP file.
$USER_DIRECTORY = 'users/'.$_SESSION['username'];
// Makes the directory if it doesn't exist
if(!is_dir($USER_DIRECTORY)) mkdir($USER_DIRECTORY);
// Put together the full path of the file we want to create
$FILENAME = $USER_DIRECTORY.'/'.$_POST['CodeDescription'].'.txt';
//echo $FILENAME; // Debugging output
if( !is_file( $FILENAME ) ):
// Open the text file, write the contents, and close it.
file_put_contents($FILENAME, $_POST['Code']);
// Use file_get_contents() to read the file.
// $read_contents = file_get_contents($FILENAME);
else:
echo 'Filename already exists';
endif;
?>

Answer 2

you can use $_POST to get the contents of the textarea and input field.
$file_name = $_POST['filename'];
$contents = $_POST['code'];
$file = '../evo/avsave/'.$file_name . '.txt';
//writing the file
if(!file_exists($file)){
file_put_contents($file,$contents);
}else{
echo 'File exists';
}