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(输出开始于错误
如果我将表单数据提交到其他文件进行处理,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。
请提出建议
<!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"> </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> </td>
</tr>
<tr>
<td height="45"><strong>-> Products</strong></td>
</tr>
<tr>
<td height="61"><strong>-> Categories</strong></td>
</tr>
<tr>
<td height="48"><strong>-> Sub Categories</strong></td>
</tr>
</table></td>
<td width="78%" valign="top"><table width="100%" border="0" cellpadding="0" cellspacing="0">
<tr>
<td> </td>
</tr>
<tr>
<td>
<table width="90%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td width="26%"> </td>
<td width="74%"><h2>Manage Categories</h2></td>
</tr>
</table></td>
</tr>
<tr>
<td height="30">
</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 $_SERVER['PHP_SELF']; ?>" method="post" enctype="multipart/form-data">
<p>
<label class="style4">Category Name</label>
<input type="text" name="categoryname" /><br /><br />
<label class="style4">Category Image</label>
<input type="file" name="image" /><br />
<input type="hidden" name="MAX_FILE_SIZE" value="100000" />
<br />
<br />
<input type="submit" id="submit" value="UPLOAD" />
</p>
</form>
<?php
session_start();
require("includes/conn.php");
function is_valid_type($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;
}
?>
以下是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>";
}
?>
这里什么都没发生。请建议
答案 0 :(得分: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。这个页面应该可以正常工作。
<?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"> </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> </td>
</tr>
<tr>
<td height="45"><strong>-> Products</strong></td>
</tr>
<tr>
<td height="61"><strong>-> Categories</strong></td>
</tr>
<tr>
<td height="48"><strong>-> Sub Categories</strong></td>
</tr>
</table></td>
<td width="78%" valign="top"><table width="100%" border="0" cellpadding="0" cellspacing="0">
<tr>
<td> </td>
</tr>
<tr>
<td>
<table width="90%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td width="26%"> </td>
<td width="74%"><h2>Manage Categories</h2></td>
</tr>
</table></td>
</tr>
<tr>
<td height="30">
</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 $_SERVER['PHP_SELF']; ?>" method="post" enctype="multipart/form-data">
<p>
<label class="style4">Category Name</label>
<input type="text" name="categoryname" /><br /><br />
<label class="style4">Category Image</label>
<input type="file" name="image" /><br />
<input type="hidden" name="MAX_FILE_SIZE" value="100000" />
<br />
<br />
<input type="submit" id="submit" value="UPLOAD" />
</p>
</form>
<?php
require("includes/conn.php");
function is_valid_type($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
{
$_SESSION['error'] = "Could not upload file. Check read/write persmissions on the directory";
header("Location: mangagecategories.php");
exit;
}
?>
答案 1 :(得分:9)
我有同样的问题,但我的解决方案并不像建议的那样明显。事实证明我的php文件是用UTF-8编写的,这导致了问题。我将整个文件的内容复制/粘贴到一个新的php文件中(Notepad ++告诉我这是用ANSI而不是UTF-8编写的),现在它可以完美地工作。
答案 2 :(得分:8)
Ross的答案就在上面。
首先,将session_start()作为第一行代码将意味着您无法将任何对象正确地反序列化为会话变量。
获得此问题的原因是,在包含文件末尾有99%可能是尾随空格(是的 - 我知道这听起来不太可能,但只是尝试一下)。违规文件位于错误消息中。我想支持罗斯的答案,这对我有用,但这个网站反直觉。
IGNORE胡说八道的答案。删除尾随空格,换行符等......一切都会好的。罗斯知道他在说什么。 将session_start()放在文件的顶部是可行的,但它不是正确的解决方案。
答案 3 :(得分:5)
这应该可以解决您的问题。在将任何字符发送回浏览器之前,应调用session_start()。在您的情况下,在调用session_start()之前发送了HTML和空行。 Documentation here
为了进一步解释当你提交到不同页面时它为何起作用的问题,该页面要么在将任何字符发送回客户端之前不使用session_start()或调用session_start()!另一方面,当很多HTML被发送回客户端(浏览器)时,此页面调用了session_start()。
更好的代码方法是使用一个公共头文件调用连接到MySQL数据库,调用session_start()并为所有页面执行其他常见操作,并将该文件包含在每个页面的顶部,如下所示:
include "header.php";
这将阻止您遇到的问题,因为您还可以使用一组通用代码来管理项目。在查看你的代码后,你肯定会想到我会建议的东西。
<?php
session_start();
if (isset($_SESSION['error']))
{
echo "<span id=\"error\"><p>" . $_SESSION['error'] . "</p></span>";
unset($_SESSION['error']);
}
?>
<form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" enctype="multipart/form-data">
<p>
<label class="style4">Category Name</label>
<input type="text" name="categoryname" /><br /><br />
<label class="style4">Category Image</label>
<input type="file" name="image" /><br />
<input type="hidden" name="MAX_FILE_SIZE" value="100000" />
<br />
<br />
<input type="submit" id="submit" value="UPLOAD" />
</p>
</form>
<?php
require("includes/conn.php");
function is_valid_type($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;
}
?>
答案 4 :(得分:4)
将session_start();
替换为代码中的@session_start();
答案 5 :(得分:4)
在页面顶部ob_start();
之前使用session_start();
,如下所示
<?php
ob_start();
session_start();
答案 6 :(得分:3)
在页面顶部使用session_start()
。
有关详细信息,请阅读链接session_start
答案 7 :(得分:3)
对于可能遇到此问题的其他人 - 如果有人不小心从php包含文件中留下尾随空格,也会发生这种情况。例如:
<?php
require_once('mylib.php');
session_start();
?>
在上面的例子中,如果mylib.php在关闭后有空格?>标记,这将导致错误。如果您包含/需要许多文件,这显然会让人讨厌。幸运的是,错误告诉您哪个文件有问题。
HTH
答案 8 :(得分:3)
通常在回显或打印后发送标题时会出现此错误。如果在特定页面上出现此错误,请确保在调用start_session()之前页面没有回显任何内容。
不可预测的错误示例:
<?php //a white-space before <?php also send for output and arise error
session_start();
session_regenerate_id();
//your page content
又一个例子:
<?php
includes 'functions.php';
?> <!-- This new line will also arise error -->
<?php
session_start();
session_regenerate_id();
//your page content
结论:在调用session_start()或header()函数之前,不要输出任何字符,甚至不是空格或换行符
答案 9 :(得分:2)
我只需移除Warning: session_start(): Cannot send session cache limiter - headers already sent
标记前面的空格即可解决类似的<?php
。
有效。
答案 10 :(得分:1)
在我的情况下,我必须设置没有BOM的文件编码。
答案 11 :(得分:1)
我有一个网站从一个主机转移到另一个主机,它似乎在旧主机上工作正常,但新主机上的几个页面引发了错误
Warning: session_start(): Cannot send session cache limiter - headers already sent虽然我总是保持
<?php session_start();
在页面顶部没有空格,没有插入任何内容
它真的让我感到烦恼的是我在会话开始时盯着每一页,它在某些页面上工作并在其他页面上运行错误 我选择了有问题的页面,备份它们,创建了新的空白页面,只是按原样复制和粘贴代码,保存和上传,繁荣,问题消失了!
这是你们可能需要考虑的事情,它可能是页面的编码,或者某些东西,不确定问题的确切来源,但这里是一个修复,看看你们遇到的问题类似的问题
喝彩!
答案 12 :(得分:0)
只需将session_start替换为此。
if (!session_id() && !headers_sent()) {
session_start();
}
你可以把它放在任何地方,即使在最后:) 对我来说很好。 $ _SESSION也可以访问。
答案 13 :(得分:0)
当我将网站重定向到https://(用于SSL证书)时,这开始了。根据我对这个问题的经验,session_start()
必须在浏览器看到任何HTML代码之前。对于我的示例,我在nav.php中使用session_start()
来确定导航栏的选项。我最终将session_start()
放在index.php文件和每个称为nav.php的页面中的php注释之后。我能够保留session_start()
之前的php注释,但不能保留php上方的HTML注释。
答案 14 :(得分:0)
检查php标记前是否有多余空间。