Shaping the creation of files in a public directory?

Here's an idea. I am trying to create a file from a PHP script. The file can be created in any public place on the server (in the public root or in its subdirectories). At the bottom of the line, I want to write a function like this (it should work on both unix servers and windows).

function create_file($path, $filename, $content, $overwrite=false) {
  # body
  ...

  }

      

        
        
        
      

    

Parameters:

• $ path - path to the file (empty or ends with /
  
  )
• $ filename - any valid filename (requires period + extension)
• $ content - file-content (something)
• $ overwrite - if set to true , the existing file will be overwritten (default is false ).

Result:

The function returns TRUE

and creates a file with the contents or FALSE

, if the file cannot be created for some reason.

Description of the problem:

I expect this function to return TRUE

and create the file $ filename at $ path or FALSE

if for some reason this is not possible. Also, if the file was successfully opened for writing, you need to add $ content to it .

Argument $ path - relative path to a shared directory, $ filename - any valid file name. Of course I want to avoid generating files if the path points are outside the public directory . The function can be called from script subdirectories like this example

# PHP : /scripts/test.php
create_file('../data/', 'test.info', 'some contents');
# result file: /data/test.info

      

        
        
        
      

    

What have I tried so far?

I've tried to do this with fopen () and fwrite () and it works on some servers and doesn't work on some. I guess it's a problem with writing permissions and chmod () , but to be honest, I'm not very familiar with chmod attributes. Also I couldn't check if the $ path is outside the server's public directory.

In short, I want this function to create a file and return TRUE

if the file does not exist or the file exists, and $owerwrite=true

. Otherwise, nothing happens and the function returns FALSE

.

Also, I would like to know the reason why the file cannot be created in some path (in theory). Wrong path / filename is just what's on my mind and I'm sure there is more to this problem.

Thanks in advance for any example / example / suggestion.

update code

So far I have this code ...

  function create_file($path, $filename, $content, $overwrite=false) {
    $reldir = explode('/', trim(str_replace('\\', '/', dirname($_SERVER['PHP_SELF'])), '/'));
    $dirdepth = sizeof($reldir);
    $rpadd = $dirdepth > 0 ? '(\.\./){0,' . $dirdepth . '}' : '';
    $ptpath = '#^/?' . $rpadd . '([a-z0-9]\w*/)*$#i';
    $ptname = '/^[a-z]\w*\.[a-z0-9]+$/i'; 
    if ($res = preg_match($ptpath, $path) && preg_match($ptname, $filename)) {
      $res = false;
      if ($overwrite === true || !file_exists($path.$filename)) {
        if ($f = @fopen($path.$filename, 'w')) {
          fwrite($f, $content);
          fclose($f);
          $res = true;
          }
        }
      }
    return $res;
    }