故障排除"警告:session_start():无法发送会话缓存限制器 - 已发送的标头"

Question

故障排除"警告:session_start():无法发送会话缓存限制器 - 已发送的标头"

我收到 警告:session_start()[function.session-start]:无法发送会话缓存限制器 - 已发送的标头(输出在 错误时启动)

如果我将表单数据提交到不同的文件进行处理,则可以正常工作.但是,如果我将表单数据提交到同一页面,则会出现此错误.

请提出

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<link href="style.css" rel="stylesheet" type="text/css" />
<title>Welcome</title>


<script type="text/javascript" src="jquery.js"></script>
    <script type="text/javascript">
$(document).ready(function () { 

    $('#nav li').hover(
        function () {
            //show its submenu
            $('ul', this).slideDown(100);

        }, 
        function () {
            //hide its submenu
            $('ul', this).slideUp(100);         
        }
    );

});
    </script>

</head>

<body>
<table width="100%" border="0" cellspacing="0" cellpadding="0">
  <tr>
    <td class="header">&nbsp;</td>
  </tr>
  <tr>
    <td class="menu"><table align="center" cellpadding="0" cellspacing="0" width="80%">
    <tr>
    <td>

    <ul id="nav">
    <li><a href="#">Catalog</a>
    <ul><li><a href="#">Products</a></li>
        <li><a href="#">Bulk Upload</a></li>
        </ul>
        <div class="clear"></div>
        </li>


    <li><a href="#">Purchase  </a>

    </li>
    <li><a href="#">Customer Service</a>
    <ul>
        <li><a href="#">Contact Us</a></li>
        <li><a href="#">CS Panel</a></li>

    </ul>           
        <div class="clear"></div>
    </li>
    <li><a href="#">All Reports</a></li>
    <li><a href="#">Configuration</a>
    <ul> <li><a href="#">Look and Feel </a></li>
         <li><a href="#">Business Details</a></li>
         <li><a href="#">CS Details</a></li>
         <li><a href="#">Emaqil Template</a></li>
         <li><a href="#">Domain and Analytics</a></li>
         <li><a href="#">Courier</a></li>
         </ul>
    <div class="clear"></div>
    </li>
    <li><a href="#">Accounts</a>
    <ul><li><a href="#">Ledgers</a></li>
        <li><a href="#">Account Details</a></li>
        </ul>
         <div class="clear"></div></li>

</ul></td></tr></table></td>
  </tr>
  <tr>
    <td valign="top"><table width="80%" border="0" align="center" cellpadding="0" cellspacing="0">
      <tr>
        <td valign="top"><table width="100%" border="0" cellspacing="0" cellpadding="2">
          <tr>
            <td width="22%" height="327" valign="top"><table width="100%" border="0" cellspacing="0" cellpadding="2">
              <tr>
                <td>&nbsp;</td>
                </tr>
              <tr>
                <td height="45"><strong>-&gt; Products</strong></td>
                </tr>
              <tr>
                <td height="61"><strong>-&gt; Categories</strong></td>
                </tr>
              <tr>
                <td height="48"><strong>-&gt; Sub Categories</strong></td>
                </tr>
            </table></td>
            <td width="78%" valign="top"><table width="100%" border="0" cellpadding="0" cellspacing="0">
              <tr>
                <td>&nbsp;</td>
                </tr>
              <tr>
                <td>
                  <table width="90%" border="0" cellspacing="0" cellpadding="0">
                    <tr>
                      <td width="26%">&nbsp;</td>
                      <td width="74%"><h2>Manage Categories</h2></td>
                    </tr>
                  </table></td>
                </tr>
              <tr>
                <td height="30">&nbsp;

                </td>
                </tr>
              <tr>
                <td>


</td>
                </tr>

                <tr>
                <td>
                <table width="49%" align="center" cellpadding="0" cellspacing="0">
                <tr><td>




<?php


                if (isset($_SESSION['error']))

                {

                    echo "<span id=\"error\"><p>" . $_SESSION['error'] . "</p></span>";

                    unset($_SESSION['error']);

                }

                ?>

                <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" enctype="multipart/form-data">

                <p>
                 <label class="style4">Category Name</label>

                   &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <input type="text" name="categoryname" /><br /><br />

                    <label class="style4">Category Image</label>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

                    <input type="file" name="image" /><br />

                    <input type="hidden" name="MAX_FILE_SIZE" value="100000" />

                   <br />
<br />
 <input type="submit" id="submit" value="UPLOAD" />

                </p>

                </form>




                             <?php

session_start();

require("includes/conn.php");


function is_valid_type($file)

{

    $valid_types = array("image/jpg", "image/jpeg", "image/bmp", "image/gif", "image/png");



    if (in_array($file['type'], $valid_types))

        return 1;

    return 0;
}

function showContents($array)

{

    echo "<pre>";

    print_r($array);

    echo "</pre>";
}


$TARGET_PATH = "images/category";

$cname = $_POST['categoryname'];

$image = $_FILES['image'];

$cname = mysql_real_escape_string($cname);

$image['name'] = mysql_real_escape_string($image['name']);

$TARGET_PATH .= $image['name'];

if ( $cname == "" || $image['name'] == "" )

{

    $_SESSION['error'] = "All fields are required";

    header("Location: managecategories.php");

    exit;

}

if (!is_valid_type($image))

{

    $_SESSION['error'] = "You must upload a jpeg, gif, or bmp";

    header("Location: managecategories.php");

    exit;

}




if (file_exists($TARGET_PATH))

{

    $_SESSION['error'] = "A file with that name already exists";

    header("Location: managecategories.php");

    exit;

}


if (move_uploaded_file($image['tmp_name'], $TARGET_PATH))

{



    $sql = "insert into Categories (CategoryName, FileName) values ('$cname', '" . $image['name'] . "')";

    $result = mysql_query($sql) or die ("Could not insert data into DB: " . mysql_error());

  header("Location: mangaecategories.php");

    exit;

}

else

{





    $_SESSION['error'] = "Could not upload file.  Check read/write persmissions on the directory";

    header("Location: mangagecategories.php");

    exit;

}

?>

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这是Display的代码

<?php  
                  require("includes/conn.php"); 



                $sql = "select CategoryID, CategoryName, FileName, Status from Categories";

                $result = mysql_query($sql) or die ("Could not access DB: " . mysql_error());



                while ($row = mysql_fetch_assoc($result))

                {

                     echo "<table border='0' cellpadding='10'>";


                                        echo "<tr><td>  </td><td>Category ID</td><td>Category Name</td><td>Status</td><td>Edit</td><td>Delete</td></tr>";

                                        echo "<tr><td> <img src=\"images/" . $row['FileName'] . "\" alt=\"\" /> </td>";
                                        echo "<td>". $row['CategoryID'] . "</td>";
                                            echo "<td>". $row['CategoryName'] . "</td>";
                                            echo "<td>". $row['Status']. "</td>";
                                            echo "<td> <a href= 'edit.php?CategoryID=" .$row['id']. "'> Edit </a></td>";
                                            echo "<td> <a href= 'delete.php?CategoryID=" .$row['id']. "'> Edit </a></td>";
                                         echo "</tr> </table>";

                }



            ?>

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这里什么都没发生.请建议

Answer 1

som*_*ath 16

你会发现我在页面的最顶部添加了session_start().我还在页面后面删除了session_start()调用.这个页面应该工作正常.

<?php
session_start();
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<link href="style.css" rel="stylesheet" type="text/css" />
<title>Welcome</title>


<script type="text/javascript" src="jquery.js"></script>
    <script type="text/javascript">
$(document).ready(function () { 

    $('#nav li').hover(
        function () {
            //show its submenu
            $('ul', this).slideDown(100);

        }, 
        function () {
            //hide its submenu
            $('ul', this).slideUp(100);         
        }
    );

});
    </script>

</head>

<body>
<table width="100%" border="0" cellspacing="0" cellpadding="0">
  <tr>
    <td class="header">&nbsp;</td>
  </tr>
  <tr>
    <td class="menu"><table align="center" cellpadding="0" cellspacing="0" width="80%">
    <tr>
    <td>

    <ul id="nav">
    <li><a href="#">Catalog</a>
    <ul><li><a href="#">Products</a></li>
        <li><a href="#">Bulk Upload</a></li>
        </ul>
        <div class="clear"></div>
        </li>


    <li><a href="#">Purchase  </a>

    </li>
    <li><a href="#">Customer Service</a>
    <ul>
        <li><a href="#">Contact Us</a></li>
        <li><a href="#">CS Panel</a></li>

    </ul>           
        <div class="clear"></div>
    </li>
    <li><a href="#">All Reports</a></li>
    <li><a href="#">Configuration</a>
    <ul> <li><a href="#">Look and Feel </a></li>
         <li><a href="#">Business Details</a></li>
         <li><a href="#">CS Details</a></li>
         <li><a href="#">Emaqil Template</a></li>
         <li><a href="#">Domain and Analytics</a></li>
         <li><a href="#">Courier</a></li>
         </ul>
    <div class="clear"></div>
    </li>
    <li><a href="#">Accounts</a>
    <ul><li><a href="#">Ledgers</a></li>
        <li><a href="#">Account Details</a></li>
        </ul>
         <div class="clear"></div></li>

</ul></td></tr></table></td>
  </tr>
  <tr>
    <td valign="top"><table width="80%" border="0" align="center" cellpadding="0" cellspacing="0">
      <tr>
        <td valign="top"><table width="100%" border="0" cellspacing="0" cellpadding="2">
          <tr>
            <td width="22%" height="327" valign="top"><table width="100%" border="0" cellspacing="0" cellpadding="2">
              <tr>
                <td>&nbsp;</td>
                </tr>
              <tr>
                <td height="45"><strong>-&gt; Products</strong></td>
                </tr>
              <tr>
                <td height="61"><strong>-&gt; Categories</strong></td>
                </tr>
              <tr>
                <td height="48"><strong>-&gt; Sub Categories</strong></td>
                </tr>
            </table></td>
            <td width="78%" valign="top"><table width="100%" border="0" cellpadding="0" cellspacing="0">
              <tr>
                <td>&nbsp;</td>
                </tr>
              <tr>
                <td>
                  <table width="90%" border="0" cellspacing="0" cellpadding="0">
                    <tr>
                      <td width="26%">&nbsp;</td>
                      <td width="74%"><h2>Manage Categories</h2></td>
                    </tr>
                  </table></td>
                </tr>
              <tr>
                <td height="30">&nbsp;

                </td>
                </tr>
              <tr>
                <td>


</td>
                </tr>

                <tr>
                <td>
                <table width="49%" align="center" cellpadding="0" cellspacing="0">
                <tr><td>




<?php


                if (isset($_SESSION['error']))

                {

                    echo "<span id=\"error\"><p>" . $_SESSION['error'] . "</p></span>";

                    unset($_SESSION['error']);

                }

                ?>

                <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" enctype="multipart/form-data">

                <p>
                 <label class="style4">Category Name</label>

                   &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <input type="text" name="categoryname" /><br /><br />

                    <label class="style4">Category Image</label>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

                    <input type="file" name="image" /><br />

                    <input type="hidden" name="MAX_FILE_SIZE" value="100000" />

                   <br />
<br />
 <input type="submit" id="submit" value="UPLOAD" />

                </p>

                </form>




                             <?php


require("includes/conn.php");


function is_valid_type($file)

{

    $valid_types = array("image/jpg", "image/jpeg", "image/bmp", "image/gif", "image/png");



    if (in_array($file['type'], $valid_types))

        return 1;

    return 0;
}

function showContents($array)

{

    echo "<pre>";

    print_r($array);

    echo "</pre>";
}


$TARGET_PATH = "images/category";

$cname = $_POST['categoryname'];

$image = $_FILES['image'];

$cname = mysql_real_escape_string($cname);

$image['name'] = mysql_real_escape_string($image['name']);

$TARGET_PATH .= $image['name'];

if ( $cname == "" || $image['name'] == "" )

{

    $_SESSION['error'] = "All fields are required";

    header("Location: managecategories.php");

    exit;

}

if (!is_valid_type($image))

{

    $_SESSION['error'] = "You must upload a jpeg, gif, or bmp";

    header("Location: managecategories.php");

    exit;

}




if (file_exists($TARGET_PATH))

{

    $_SESSION['error'] = "A file with that name already exists";

    header("Location: managecategories.php");

    exit;

}


if (move_uploaded_file($image['tmp_name'], $TARGET_PATH))

{



    $sql = "insert into Categories (CategoryName, FileName) values ('$cname', '" . $image['name'] . "')";

    $result = mysql_query($sql) or die ("Could not insert data into DB: " . mysql_error());

  header("Location: mangaecategories.php");

    exit;

}

else

{





    $_SESSION['error'] = "Could not upload file.  Check read/write persmissions on the directory";

    header("Location: mangagecategories.php");

    exit;

}

?>

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Answer 2

小智 10

Ross的答案就在上面.

首先,将session_start()作为第一行代码将意味着您无法将任何对象正确地反序列化为会话变量.

得到此问题的原因是,在包含文件末尾有99%可能是尾随空格(是的 - 我知道这听起来不太可能,但只是尝试一下).违规文件位于错误消息中.我想支持罗斯的答案,这对我有用,但这个网站反直觉.

IGNORE胡说八道的答案.删除尾随空格,换行符等......一切都会好的.罗斯知道他在说什么.将session_start()放在文件的顶部是可行的,但它不是正确的解决方案.

只需完全删除关闭`？>`,这将永远不会发生.它不是必需的,也不推荐 (2认同)

Answer 3

Bir*_*irb 9

我有同样的问题,但我的解决方案并不像建议的那样明显.事实证明我的php文件是用UTF-8编写的,这导致了问题.我将整个文件的内容复制/粘贴到一个新的php文件中(Notepad ++告诉我这是用ANSI而不是UTF-8编写的),现在它可以完美地工作.

@JulianB:确保编码设置为"UTF-8无BOM". (3认同)

Answer 4

Sat*_*tya 6

更换session_start();用@session_start();在你的代码

这是一个好的解决方案。但是，这只是忽略警告而不是修复它。 (2认同)

Answer 5

som*_*ath 5

这应该可以解决您的问题.在将任何字符发送回浏览器之前,应调用session_start().在您的情况下,在调用session_start()之前发送了HTML和空行.文档在这里.

为了进一步解释当你提交到不同页面时它为何起作用的问题,该页面要么在将任何字符发送回客户端之前不使用session_start()或调用session_start()!另一方面,当很多HTML被发送回客户端(浏览器)时,此页面调用了session_start().

更好的编码方法是使用一个公共头文件调用连接到MySQL数据库,调用session_start()并为所有页面执行其他常见操作,并将该文件包含在每个页面的顶部,如下所示:

include "header.php";

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这将阻止您遇到的问题,因为您还可以使用一组通用代码来管理项目.在查看你的代码之后,你肯定会想到我会建议的东西.

<?php
session_start();

                if (isset($_SESSION['error']))

                {

                    echo "<span id=\"error\"><p>" . $_SESSION['error'] . "</p></span>";

                    unset($_SESSION['error']);

                }

                ?>

                <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" enctype="multipart/form-data">

                <p>
                 <label class="style4">Category Name</label>

                   &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <input type="text" name="categoryname" /><br /><br />

                    <label class="style4">Category Image</label>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

                    <input type="file" name="image" /><br />

                    <input type="hidden" name="MAX_FILE_SIZE" value="100000" />

                   <br />
<br />
 <input type="submit" id="submit" value="UPLOAD" />

                </p>

                </form>




                             <?php



require("includes/conn.php");


function is_valid_type($file)

{

    $valid_types = array("image/jpg", "image/jpeg", "image/bmp", "image/gif", "image/png");



    if (in_array($file['type'], $valid_types))

        return 1;

    return 0;
}

function showContents($array)

{

    echo "<pre>";

    print_r($array);

    echo "</pre>";
}


$TARGET_PATH = "images/category";

$cname = $_POST['categoryname'];

$image = $_FILES['image'];

$cname = mysql_real_escape_string($cname);

$image['name'] = mysql_real_escape_string($image['name']);

$TARGET_PATH .= $image['name'];

if ( $cname == "" || $image['name'] == "" )

{

    $_SESSION['error'] = "All fields are required";

    header("Location: managecategories.php");

    exit;

}

if (!is_valid_type($image))

{

    $_SESSION['error'] = "You must upload a jpeg, gif, or bmp";

    header("Location: managecategories.php");

    exit;

}




if (file_exists($TARGET_PATH))

{

    $_SESSION['error'] = "A file with that name already exists";

    header("Location: managecategories.php");

    exit;

}


if (move_uploaded_file($image['tmp_name'], $TARGET_PATH))

{



    $sql = "insert into Categories (CategoryName, FileName) values ('$cname', '" . $image['name'] . "')";

    $result = mysql_query($sql) or die ("Could not insert data into DB: " . mysql_error());

  header("Location: mangaecategories.php");

    exit;

}

else

{





    $_SESSION['error'] = "Could not upload file.  Check read/write persmissions on the directory";

    header("Location: mangagecategories.php");

    exit;

}

?>

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