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Need to write at beginning of file with PHP

Answer 1

+6 A:

The quick and dirty:

$file_data = "Stuff you want to add\n"
$file_data .= file_get_contents('database.txt');
file_put_contents('database.txt', $file_data);

Ben 2009-11-19 02:36:16

I think there is no better way to insert data at the beginning of the file. You have to move all the data currently contained in the file anyway. For larger files you might need to read file part by part to fit it in the memory.

Kamil Szot 2009-11-19 02:43:53

Answer 2

A:

I think what you can do is first read the content of the file and hold it in a temporary variable, now insert the new data to the beginning of the file before also appending the content of the temporary variable.

$file = file_get_contents($filename);
$content = 'Your Content' . $file;
file_put_contents($content);

Kailash Badu 2009-11-19 02:36:25

Answer 3

A:

There is now way to write to the beginning of a file like you think. This is I guess due to reason how OS and HDD are seeing the file. It has got a fixed start and expanding end. If you want to add something in the middle or begging it requires some sliding. If it is a small file just read it all and do your manipulation and write back. But if not, and if you are always adding to the beginning just reverse line order, consider the end as beginning...

erdogany 2009-11-19 02:43:59

Answer 4

A:

You can use fseek to change the pointer in the note.

It has to be noted that if you use fwrite it will erase the current content. So basically you have to read the whole file, use fseek, write your new content, write the old data of the file.

$file_data = file_get_contents('database.txt')
$fp = fopen('database.txt', 'a');
fseek($fp,0);
fwrite($fp, 'new content');
fwrite($fp, $file_data);
fclose($fp);

If your file is really huge and you don't want to use too much memory, you might want to have two file approach like

$fp_source = fopen('database.txt', 'r');
$fp_dest = fopen('database_temp.txt', 'w'); // better to generate a real temp filename
fwrite($fp_dest, 'new content');
while (!feof($fp_source)) {
    $contents .= fread($fp_source, 8192);
    fwrite($fp_dest, $contents);
}
fclose($fp_source);
fclose($fp_dest);
unlink('database.txt');
rename('database_temp.txt','database.txt');

The solution of Ben seems to be more straightforward in my honest opinion.

One last point: I don't know what you are stocking in database.txt but you might do the same more easily using a database server.

RageZ 2009-11-19 02:44:01

Answer 5

A:

If you don't want to load the contents of the file into a variable, take a look at this blog entry. It gives code for a prepend() function that uses a temporary file and streams (PHP5+ only).

function prepend($string, $filename) {
  $context = stream_context_create();
  $fp = fopen($filename, 'r', 1, $context);
  $tmpname = md5($string);
  file_put_contents($tmpname, $string);
  file_put_contents($tmpname, $fp, FILE_APPEND);
  fclose($fp);
  unlink($filename);
  rename($tmpname, $filename);
}

To be more specific, it writes the string you want to prepend to a temporary file, then it writes the contents of the original file onto the end of the temporary file (using streams instead of copying the whole file into a variable), then it removes the original file and renames the temporary file to replace it.

Jordan 2009-11-19 02:46:25

Answer 6

A:

This code remembers data from the beginning of the file to protect them from being overwritten. Next it rewrites the all the data existing in file chunk by chunk.

$data = "new stuff to insert at the beggining of the file";
$buffer_size = 10000;

$f = fopen("database.txt", "r+");
$old_data_size = strlen($data);
$old_data = fread($f, $old_data_size);
while($old_data_size > 0) {
  fseek($f, SEEK_CUR, -$old_data_size);
  fwrite($f, $data);
  $data = $old_data;
  $old_data = fread($f, $buffer_size);
  $old_data_size = strlen($data);
}
fclose($f);

Kamil Szot 2009-11-19 02:55:35

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Need to write at beginning of file with PHP

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