ob_start() 和 ob_end_flush() 的 PHP 标头问题 [英] PHP Header issue with ob_start() and ob_end_flush()

问题描述

我在页面开头使用 ob_start() 并在最后使用 ob_end_flush() 时遇到标题问题.因为我在执行一些查询后使用了 header 函数.

I get header problem while I use ob_start() in the beginning of a page and ob_end_flush() at the end. Because I use header function after some query execution.

 ob_start();
 include_once("header.php");
 global $db;

 $countstmt="SELECT COUNT(*) FROM tbl_lib_hours dh WHERE book_id IN(SELECT book_id FROM tbl_book WHERE user_id=".$_SESSION['uid'].") ";       
 $delHourExist=$db->query($countstmt);  
 if($delHourExist){
      header("location:edit_delivery_hours.php");
 }
 ....
include_once('footer.php');
ob_end_flush();

在 header.php 中，我还添加了 ob_start(); 并在 footer.php 中添加了 ob_end_flush(); ，但我认为这不是问题，尽管其他页面正在使用我上面编写的相同脚本运行

In header.php there I also added ob_start(); and in footer.php i added ob_end_flush(); , but I think that is not problem, although other pages are running with same script I write above

我得到的错误:

警告:无法修改标头信息 - 标头已在第 9 行的 D:xampphtdocsprojectadd_book_hours.php 中发送

Warning: Cannot modify header information - headers already sent in D:xampphtdocsprojectadd_book_hours.php on line 9

推荐答案

我有点困惑，警告消息不包含导致第一个内容发送到客户端的代码的位置.headers_sent() 函数也可以返回该位置.因此，出于调试目的，请尝试

I'm a bit baffled the warning message doesn't include the location of the code that caused the first content to be sent to the client. The function headers_sent() can return that location, too. So, for debugging purposes, please try

if($delHourExist)
{
  if ( headers_sent($path, $lineno) ) {
    echo '<pre>Debug: output started at ', $path, ':', $lineno, "</pre>
";
  }
  header("location: edit_delivery_hours.php");
}

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