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PHP Safe File Reading & Writing
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Always use locks when working with files or use a simple strategy with superior atomic renaming.


=======================================
PHP Writing
---------------------------------------

function safewrite($filepath, $data) {
  $dir = dirname($filepath);

  $tempfile = tempnam($dir, 'atomic_');
  if ($tempfile === false) return false;

  if (file_put_contents($tempfile, $data, LOCK_EX) === false) {
    @unlink($tempfile);
    return false;
  }

  if (@rename($tempfile, $filepath) === false) {
    @unlink($tempfile);
    return false;
  }

  return true;
}


=======================================
PHP Reading
---------------------------------------

function saferead($filepath) {
  if (!file_exists($filepath)) {
    return false;
  }

  $context = stream_context_create([
    'file' => ['lock' => LOCK_EX]
  ]);

  return file_get_contents($filepath, false, $context);
}


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Done
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