为什么我不能从php脚本中删除该文件？

Question

Basically, I am proxying a file using a php script and then deleting it straight after... only, the file isn't deleting and I can't work out why.

This is a little out of context, so, happy to explain more should you need it.

exec("wget http://xxxx/123_" .$matches[1] . " --no-check-certificate -P /usr/share/nginx/www/" );

$file = "/usr/share/nginx/www/123_" . $matches[1];

if (file_exists($file)) {
    header('Content-Type: text/plain');
    header('Content-Length: ' . filesize($file));
    ob_clean();
    flush();
    readfile($file);
    exec("rm /usr/share/nginx/www/123_" . $matches[1] );

    exit;
}

Answer 1

Try this code, which will not create a local file that needs to be deleted:

// Define URL
$url = "http://xxxx/123_{$matches[1]}";

// Open pointer to remote resource
if (!$remoteFP = @fopen($url, 'r')) {
  header("{$_SERVER['SERVER_PROTOCOL']} 500 Internal Server Error");
  exit;
}

// Get content length and type from remote server's headers
$length = $type = NULL;
foreach ($http_response_header as $header) { // Loop headers (see http://php.net/manual/en/reserved.variables.httpresponseheader.php)
  list($name, $val) = explode(':', $header, 2); // Split to key/value
  switch (strtolower(trim($name))) { // See if it's a value we want
    case 'content-length':
      $length = (int) trim($val);
      break;
    case 'content-type':
      $type = trim($val);
      break;
  }
  if ($length !== NULL && $type !== NULL) break; // if we have found both we can stop looping
}

// Send headers
if ($type === NULL) $type = 'text/plain';
header("Content-Type: $type");
if ($length) header("Content-Length: $length"); // Only send content-length if the server sent one. You may want to do the same for content-type.

// Open a file pointer for the output buffer
$localFP = fopen('php://output', 'w');

// Send the data to the remote party
stream_copy_to_stream($remoteFP, $localFP);

// Close streams and exit
fclose($remoteFP);
fclose($localFP);
exit;

This uses the fopen() approach over cURL etc because it allows one to forward the entity straight to the output buffer, as well as giving access to the remote server's response headers before the body have been fully received. It is the most resource-efficient way to proxy using PHP.

If your server has allow_url_fopen disabled, you may be able to use cURL, which will also allow you to pass the data straight to the output buffer, but does not allow you to parse and forward the headers from the remote server.