PHP流Streams、包装器wrapper概念与用法实例详解

<?php
/* 定义一个过滤器 */
class strtoupper_filter extends php_user_filter {
 function filter($in, $out, &$consumed, $closing)
 {
  while ($bucket = stream_bucket_make_writeable($in)) { //从流里面取出一段数据
   $bucket->data = strtoupper($bucket->data);
   $consumed += $bucket->datalen;
   stream_bucket_append($out, $bucket); //将修改后的数据送到输出的地方
  }
  return PSFS_PASS_ON;
 }
}
/* 注册过滤器到php */
stream_filter_register("strtoupper", "strtoupper_filter")
  or die("Failed to register filter");
$fp = fopen("foo-bar.txt", "w");
/* 应用过滤器到一个流 */
stream_filter_append($fp, "strtoupper");
fwrite($fp, "Line1\n");
fwrite($fp, "Word - 2\n");
fwrite($fp, "Easy As 123\n");
fclose($fp);
//读取并显示内容 将全部变为大写
readfile("foo-bar.txt");
?>