How do I use php so that when a user presses a specific button, they can write to a specific .txt file?

Question

Basically, as in other questions I've asked related to my php chat application, I am trying to get it so that there is a text field where $msg is displayed via msg.txt. Two users can communicate to another in this way. This would be easy if I wanted to use a simple include function. But I don't want to take all the trouble to make and upload all those pages to my server. So how can I have it where when the user, say named Aaron, clicks on a button titled Benjamin, and types to a file called aaronbenjamin.txt, and if Aaron wants to talk to another user, he can press on a button titled Chris, and type to a file called aaronchris.txt? And all from the same box and text field? Thanks, I appreciate it.

EDIT: This is my code-

http://key-mail.zxq.net/msg.txt

Answer 1

Well, you should learn about using forms with PHP, with regards to your comment. If you read that tutorial fully, it should answer all of your questions about forms and php.

As far as getting it to write to a different text file, since you seem worried about "uploading all those pages", you'll be happy to know there's an easy solution!

There's a function called file_put_contents, which will create or write into a file.

Since you're new(ish) to PHP, here's an example:

<?php

$file = 'hello.txt';
$text = 'Hello World!';

file_put_contents($file, $text);

?>

This puts the contents of the $text variable into the file with the name stored in $file.

Reading from a file is similarly easy, with file_get_contents.

Assuming the file hello.txt exists from before and has the same contents, you can use the following code to read from the file and output its contents:

<?php

$file = 'hello.txt';

echo(file_get_contents($file));

?>

That will show the contents of $file.

Now, moving into the specifics of your question, if your form sets a "to" and a "from" GET variable where "to" is your username already, then the following code would write the value in a "message" GET variable into the file based on the pattern you gave:

<?php

$to = addslashes($_GET['to']);
$from = addslashes($_GET['from']);
$msg = addslashes($_GET['message']);
//addslashes is used as a small security measure

$file = $to . $from . '.txt';
file_put_contents($file, $msg);

?>

This fetches our variables from the GET array, sanitizes them to some extent, sets the file name, and writes the message to the file.

If you have any questions about specific parts of this or you'd like me to go into more detail, please feel free to ask!

Answer 2

This is how to write to a file: http://php.net/manual/en/function.fopen.php

You're better off to use a database tho for sure.

To make different links do different things, you can use AJAX as you suggested or you can use GET variables to route functions on the PHP side. The latter is easier but means you will need to reload the page after the user presses the button.

here's a little demo:

<a href="thispage.php?clicked=1">click here</a>

then at the top of the page in php:

 if($_GET['clicked']==1){--write to file1---}
 else if($_GET['clicked']==2){--write to file2---}

Hope it helps