DZone Snippets: filename code

Generate unique filenames in PHP

jeffreybarke (Jeffrey Barke) — Tue, 03 Jun 2008 20:42:25 GMT

This code is from http://www.weberdev.com/get_example-3543.html.

It produces filenames similar to this: 4293d8fd-ab63-7c82.tmp



function uniqueFilename($strExt = '.tmp') {

	// explode the IP of the remote client into four parts

	$arrIp = explode('.', $_SERVER['REMOTE_ADDR']);

	// get both seconds and microseconds parts of the time

	list($usec, $sec) = explode(' ', microtime());

	// fudge the time we just got to create two 16 bit words

	$usec = (integer) ($usec * 65536);

	$sec = ((integer) $sec) & 0xFFFF;

	// fun bit--convert the remote client's IP into a 32 bit

	// hex number then tag on the time.

	// Result of this operation looks like this xxxxxxxx-xxxx-xxxx

	$strUid = sprintf("%08x-%04x-%04x", ($arrIp[0] << 24) | ($arrIp[1] << 16) | ($arrIp[2] << 8) | $arrIp[3], $sec, $usec);

	// tack on the extension and return the filename

	return $strUid . $strExt;

}

Rename *nix filenames

muipotu (Mui Potu) — Sat, 07 Oct 2006 02:31:00 GMT

I am a bit slow sometimes and it took me a while to find this unix command that most are probably already aware of. rename is a very useful tool. The example I have here will susbtitute "foo" for "bar" of any file with foo in the name. The really nice thing about this is that it can use and regular expression syntax (ie. "^", "$", etc..).



rename -n 's/foo/bar/' *foo*

Return the extension from a file name

duncanbeevers (Duncan Beevers) — Thu, 07 Sep 2006 02:06:00 GMT

// Return the extension from a file name



/(.*\.)(.*$)/.match(File.basename(file_name))[2]

PHP filename bad character filter

mvidberg () — Fri, 17 Feb 2006 09:43:55 GMT

// Function to filter out bad characters in a given filename



function replace_bad_filename_chars($filename) {

  $filtered_filename = "";



  $patterns = array(

    "/\s/", # Whitespace

    "/\&/", # Ampersand

    "/\+/"  # Plus

  );

  $replacements = array(

    "_",   # Whitespace

    "and", # Ampersand

    "plus" # Plus

  );

  

  $filename = preg_replace($patterns,$replacements,$filename);

  for ($i=0;$i    $current_char = substr($filename,$i,1);

    if (ctype_alnum($current_char) == TRUE || $current_char == "_" || $current_char == ".") {

      $filtered_filename .= $current_char;

    }

  }     

        

  return $filtered_filename;

}