write to top of file

Anon

Hello,

How do I write to THE TOP of a file? My script is:
<?
$file = fopen("file.txt", "a+");

flock($file, 2);
fputs($file, "HELLO\n");
flock($file, 3);
?>
//Ulrik Q K

brandonschnell

read in the entire file, write out to the file replacing whats there the new data followed by the old data.

Anon

The last post is completely right, and the code would look like this;

<?
$filename = "file.txt";

$whattoread = @fopen($filename, "r") or die("Couldn't open file");

// This saves the old content to a variable
$old_contents = fread($whattoread, filesize($filename));

fclose($whattoread);

// adds new contents
$file = fopen("file.txt", "a+");

flock($file, 2);
fputs($file, "HELLO<br>");
flock($file, 3);

// adds old contents
$file = fopen("file.txt", "a+");

flock($file, 2);
fputs($file, "$old_contents");
flock($file, 3);
?>

There we go simple!

kparker

You didn't actually test this method, did you? Here's what "a+" mode actually does (quoting right out of the manual):

  'a+' - Open for reading and writing; place the file pointer at the end
  of the file. If the file does not exist, attempt to create it.

In other words, everything you write is going to be appended to the existing content anyway.

In order to really "insert" a line in an existing text file, use "r+" mode, which allows reading and writing anywhere within the file:

$filename = "file.txt";

if ($fp = fopen( $filename, "r+" ))
  {
  flock( $fp, 2 );
  $old_data = fread( $fp, filesize( $filename ) );
  rewind( $fp ); // set current position back to beginning
  fwrite( $fp, "This is a new line at the top\n" );
  fwrite( $fp, $old_data );
  flock( $fp, 3 );
  fclose( $fp );
  }

Note this only works if the new contents are longer than the old contents. (Otherwise there would be some leftover garbage after the end of the last line.)

Anon

Thanks, I have got it. I have do it in another way, and it works!

//Ulrik Q K