即使在Windows上的backgroud中运行命令后，PHP脚本仍卡在exec上

Question

我想要一个可以执行程序的php脚本，如果它在2秒钟内未完成执行，则终止它。 我正在使用Windows。 我尝试了以下代码：

exec("start /B program.exe");
sleep(2);
exec('taskkill /F /IM "program.exe"');

只要未将program.exe执行完毕，脚本就停留在第一个exec语句上，这似乎不起作用。 我不知道如何解决此问题。

Answer 1

是的， exec()将阻塞直到执行完成。 这个问题对于如何使用超时exec()有很好的答案。 我认为这可能最适合您。 为了完整起见，我将代码发布在这里（但我不能功劳！）：

/**
 * Execute a command and return it's output. Either wait until the command exits or the timeout has expired.
 *
 * @param string $cmd     Command to execute.
 * @param number $timeout Timeout in seconds.
 * @return string Output of the command.
 * @throws \Exception
 */
function exec_timeout($cmd, $timeout) {
  // File descriptors passed to the process.
  $descriptors = array(
    0 => array('pipe', 'r'),  // stdin
    1 => array('pipe', 'w'),  // stdout
    2 => array('pipe', 'w')   // stderr
  );

  // Start the process.
  $process = proc_open('exec ' . $cmd, $descriptors, $pipes);

  if (!is_resource($process)) {
    throw new \Exception('Could not execute process');
  }

  // Set the stdout stream to none-blocking.
  stream_set_blocking($pipes[1], 0);

  // Turn the timeout into microseconds.
  $timeout = $timeout * 1000000;

  // Output buffer.
  $buffer = '';

  // While we have time to wait.
  while ($timeout > 0) {
    $start = microtime(true);

    // Wait until we have output or the timer expired.
    $read  = array($pipes[1]);
    $other = array();
    stream_select($read, $other, $other, 0, $timeout);

    // Get the status of the process.
    // Do this before we read from the stream,
    // this way we can't lose the last bit of output if the process dies between these     functions.
    $status = proc_get_status($process);

    // Read the contents from the buffer.
    // This function will always return immediately as the stream is none-blocking.
    $buffer .= stream_get_contents($pipes[1]);

    if (!$status['running']) {
      // Break from this loop if the process exited before the timeout.
      break;
    }

    // Subtract the number of microseconds that we waited.
    $timeout -= (microtime(true) - $start) * 1000000;
  }

  // Check if there were any errors.
  $errors = stream_get_contents($pipes[2]);

  if (!empty($errors)) {
    throw new \Exception($errors);
  }

  // Kill the process in case the timeout expired and it's still running.
  // If the process already exited this won't do anything.
  proc_terminate($process, 9);

  // Close all streams.
  fclose($pipes[0]);
  fclose($pipes[1]);
  fclose($pipes[2]);

  proc_close($process);

  return $buffer;
}

编辑

proc_open()的“ exec”部分可能无法在Windows上运行，但可能没有必要。

Answer 2

您是否正在使用php cli（命令行）执行此操作？ 以管理员身份打开命令提示符 。
为了不被等待程序阻塞而关闭程序的打开过程 。

php myscript.php

pclose(popen("start /B program.exe", "r"));
sleep(2);
exec('taskkill /F /IM program.exe');
exit(0);

将exec开始放入一个单独的脚本并使用exec触发该脚本也可以

Answer 3

exec()手册页的第一条注释显示了一个非常简单的示例。