4

我正在玩socket_select，但在一个主机上，这个函数会做一些奇怪的事情：

  • 立即返回，而不是等待 5 秒
  • 返回false，表示有错误
  • 但socket_last_error()返回 0（成功）。

phpinfo()此服务器的：http: //jsfiddle.net/Lmrfe/embedded/result/

$server = socket_create( AF_UNIX, SOCK_STREAM, 0 );
$r = socket_bind( $server, '/some/file/somewhere');
$r = socket_listen( $server );
// none of the above socket_* returns false

$t = microtime(true);
socket_clear_error();

$read = array( $server ); $write = null; $except = null;
$read = array( $server ); $write = array(); $except = array();
$read = array(); $write = array(); $except = array();
$read = null; $write = null; $except = null;

$changed = socket_select( $read, $write, $except, 5,0 );
$changed = socket_select( $read, $write, $except, null );
$changed = socket_select( $read, $write, $except, 5000000 );
$changed = socket_select( $read, $write, $except, 5000000, 0 );
$changed = socket_select( $read, $write, $except, 5000000, 5000000 );

/* Results:

   microtime(true) - $t  == almost zero

   $changed === false

   socket_last_error() === 0
   socket_strerror(socket_last_error()) === Success

   $read === array(1) {
     [0]=>
     resource(2) of type (Socket)
   }
   $write  === NULL
   $except === NULL
*/

$s = socket_read( $server, 1024, PHP_BINARY_READ );
// $s === false

这里发生了什么？

更新的测试脚本：仍然在瞬间运行：

header('Content-Type: text/plain; charset=utf-8');
error_reporting(-1);

for( $i = 0; $i < 4; $i++ ){
for( $j = 0; $j < 5; $j++ ){
  echo "\n\n\n\n\n[i,j]=[{$i},{$j}]\n";

  $socket = socket_create( AF_UNIX, SOCK_STREAM, 0 );
  var_dump('socket_create', $socket ); echo "\n"; if( $socket === false ) continue;

  $socket_file = dirname(__FILE__)."/test_socket_i{$i}_j{$j}";
  if( file_exists( $socket_file )) unlink( $socket_file );

  $r = socket_bind( $socket, $socket_file );
  var_dump('socket_bind', $r ); echo "\n"; if( $r === false ) continue;

  $r = socket_listen( $socket );
  var_dump('socket_listen', $r ); echo "\n"; if( $r === false ) continue;

  $t = microtime(true);
  socket_clear_error();

  if($i==0){ $read = null;             $write = null;    $except = null; }
  if($i==1){ $read = array();          $write = array(); $except = array(); }
  if($i==2){ $read = array( $socket ); $write = null;    $except = null; }
  if($i==3){ $read = array( $socket ); $write = array(); $except = array(); }

  if($j==0){ $changed = socket_select( $read, $write, $except, 5,0 ); } // 5 seconds
  if($j==1){ $changed = socket_select( $read, $write, $except, null ); } // forever
  if($j==2){ $changed = socket_select( $read, $write, $except, 5000000 ); }
  if($j==3){ $changed = socket_select( $read, $write, $except, 5000000, 0 ); }
  if($j==4){ $changed = socket_select( $read, $write, $except, 5000000, 5000000 ); }

  var_dump('•socket_select returned:', $changed );echo "\n";
  var_dump('•$read/$write/$except:',$read,$write,$except);echo "\n";
  var_dump('•error:', socket_last_error(), socket_strerror(socket_last_error()) );echo "\n";
  var_dump('time: ', microtime(true) - $t );echo "\n";               // almost zero
}}
4

4 回答 4

3

您可能想使用 stream_* 函数而不是套接字。

流函数更通用并且是 PHP 核心的一部分，而需要安装 Socket 支持。流函数基本上为您提供了更多控制权。

http://www.php.net/manual/en/intro.stream.php

于 2013-02-12T09:20:04.447 回答
3

检查这个 http://php.net/manual/en/function.socket-select.php

由于当前 Zend 引擎的限制，不可能将像 NULL 这样的常量修饰符直接作为参数传递给期望此参数通过引用传递的函数。而是使用临时变量或表达式，最左边的成员是临时变量：

所以问题是你正在初始化$write = null

于 2013-02-14T10:42:41.857 回答
2

正如@Amez 指出的那样，您不应将空值传递给选择。socket_select()相反，为未使用的参数创建一个空数组：

$read    = array( $server );
$write   = array();
$except  = array();
$changed = socket_select( $read, $write, $except, 5,0 );

我最近在 python 中偶然发现了同样的问题（我不知道为什么 PHP/Python 不会简单地在内部用空数组替换空值，因为 select 这似乎是预期的行为）。

于 2013-02-17T02:14:47.677 回答
0

如果你遇到这个错误，你可以使用类似的东西来解决它：

$socket_select_timeout_seconds = 5;

while(true){
  $time_start = microtime(true);
  $c = socket_select($r,$w,$e, $socket_select_timeout_seconds );

  if( /* something happened */ ){
    // handle socket events
  }else if( microtime(true) - $time_start < 0.01){
    // nothing happened, but buggy socket_select didn't wait
    // wait manually
    usleep( $socket_select_timeout_seconds * 1000000 );
  }

}
于 2013-02-18T15:12:13.973 回答