HTTP request failed! HTTP/1.1 411 Length Required

     $opts = array(
        'http'=>array(
          'method'=>"POST",
'header'  => 'Content-Length: 0'   //这里不要写其他header
        )
      );
      $context = stream_context_create($opts);
      $token_url = "https://ssssssss/cmtlists/gentoken";
      $post_id_str = file_get_contents($token_url, false, $context);