Archiv für das Jahr: 2012

Hello together.

Lets talk today about comments :)
When you start coding a script then is it useful to comment your code. So a small documentation in the script. Because as long as you are working on the script and it is in a relative small size, then you know still which line of source code is doing what.

But latest when you source code is growing bigger and/or you need to work on it after a few weeks or months… then is everything gone. How was it? What is this line doing? Where do I find this and this now? Everything gone… the code is just a big pile of confusing.
Latest now you’ll kick your ass that you haven’t commented the code.

Of course it takes a bit longer if you write also comments in the code… but some when it will pay back. Also (and especially) if the code will be handed over to another programmer is it important that the code is commented.

And it is soooo simple ;) 2 slashes (//) for one line and a slash with a star for a multiple-line comment (/* at the beginning and */ at the end). And it will look like that:

And a multiple line comment:

Best regards
Gordon

Hi together,

today I wand to answer the question how to delete a file with PHP.

First of all we have to separate. Files on the web server or files on the local hard disk. First yes, second no.
PHP doesn’t have access to files of the local file system of a visitor. No server side programming language can do it. Also client side languages (like Javascript) can’t do it. Else it would be easy for every single webpage to delete randomly files from your computer. That would be an disaster.

But on the web server is it – partly – possible to delete files. Partly means that you can’t delete every file. Also this would be a disaster.

The PHP-Script needs the right to delete files or at least specific files. Under Linux is the right system very strict.

But in the normal situation is it not so complicated like it sounds like. Because usually you delete a file which you created with the script. Like a temporary file or a file from a user upload (a picture for example). Such a file was created by the PHP script and inherit it’s user rights. And also the script has the right to delete this file again.

But how?
Very simple. All we need is the PHP command for deleting a file and the path of the file itself. It fits all in one code line.

$res = unlink("testdatei.hm");

That’s it. In $res we get a return value. 1 = successful deleted or 0 = Couldn’t delete the file.

You can use relative as well as absolute paths.

That’s it. Hope it was helpful :)