Description

Using pipes and redirection in terminal allows to create more flexible CLI tools. Symfony doesn't offer a standard way to deal with this.

Example

Here is a simple implementation that does most of the job.

function readStdin(InputInterface $input): string {
  $stdin = $input instanceof StreamableInputInterface ? $input->getStream() : null;
  $stdin ??= fopen('php://stdin', 'r');
  
  $reads = [$stdin];
  $writes = [];
  $excepts = [];
  
  if (!stream_select($reads, $writes, $excepts, seconds: 0)) {
    return '';
  }
  
  return stream_get_contents($stdin) ?: '';
}

This implementation is impossible to test correctly under Symfony standard facilities: stdin will block if it is empty, a memory based stream is not even selectable.