fopen \ unlink learning

[Darius Boteand]

Hello!
I am new to php, and I am trying to learn it.

Here is a code that I have been trying to make to work:
<?php    if(file_exists("messages.txt")){        echo "            <form action=\"practice2.php\">                The file messages.txt already exists.<br><br>                <input type=\"submit\" name=\"delete\" value=\"delete\" onclick=\"delete()\"/>            </form>        ";    }else{        echo "            <form action=\"practice2.php\">                The fil messages.txt has not been found.<br>                Would you like to create a new one?<br><br>                <input type=\"submit\" name=\"create\" value=\"create\" onclick=\"create()\" />            </form>        ";        }    if ($_GET) {        if (isset($_GET['create'])) {            create();        } elseif(isset($_GET['delete'])) {            delete();        }    }    function create() {        $file = fopen('messages.txt', 'w+');        fwrite($file, 'A computer science portal for geeks!');        fclose($file);      }    function delete() {        unlink('messages.txt');    }     ?>

In this practice, I am trying to make a simple webpage that creates a file, and deletes it afterwards.
You see, this code works, but not as I would like it to:

First of all, once I load the page and press on the button that creates the new text file containing a message, I actually need to press on it a second time before it decides to even change the page to the next one. And you see, the exact same thing happens then I decide to delete that file. Of course it is calling that same page (called "practice2.php"), from which a different outcome would be resulted depending on if that text file exists or not.

Secondly, from the looks of it, I cannot manage to save the name of the file that has to be created and deleted, as apparently it is considered as "fopen('', 'w+')" instead of "fopen('messages.txt','w+')", of course error message displayed in "/Applications/XAMPP/xamppfiles/logs/php_error_log". And, the same thing would happen when I decide to unlink that file.

Finally, as you can see in the code, I have used "$file = fopen('messages.txt', 'w+');", line 28, inside of a function. Is there a way to declare outside of it, without having the page doing the "fopen" action when loading or reloading the page? I feel that this will become an issue if I would want to have different functions that would need to call this.

Could someone please help me correct my mistakes?
Please bear with me, i'm trying to learn php.

[Tim Holloway]

HTTP does not maintain a continuous network connection between request/response cycles, so it would be extremely poor practice to attempt to fopen() a file once and expect it to still be there for a later request. Always fopen/fclose within the request!

I didn't quite understand the rest of it, but you are using a relative pathname for your file and that, also, is not recommended practice for a web application, since there's no real concept of a "current directory" in webapps.