页面未重定向并显示错误无法修改标题信息答案

【问题标题】：Page not redirecting and displaying error Cannot modify header info页面未重定向并显示错误无法修改标题信息
【发布时间】：2015-09-26 10:58:37
【问题描述】：

我用谷歌搜索了很多，但以前的问题都无法解决我的问题。我最近更改了主机，从那时起我在用户登录时收到此错误，但设置为按标题重定向的页面没有重定向到主页。相同的代码在以前的托管合作伙伴和本地主机上工作。

警告：无法修改标头信息 - 标头已由（输出开始于 /home/rwrdguy/public_html/header.php:31） /home/rwrdguy/public_html/login.php 在第 34 行 //HEADER.PHP

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
    <meta http-equiv="Content-type" content="text/html; charset=UTF-8" />
    <title>100% CashBack on Shopping Online!</title>
 <meta charset="utf-8">
<meta name="author" content="Abhishek Singh">
<meta property="og:title" content="100% CashBack on Shopping Online!">
<meta property="og:type" content="Website">
<meta property="og:url" content="http://www.rewardadda.com/">
<meta property="og:image" content="http://www.rewardadda.com/images/recharged-facebook-thumb.png">
<meta property="og:description" content="100% CashBack on Shopping Online!"><meta property="og:site_name" content="Rewardadda.com-100% CashBack on Shopping Online!"><meta name="robots" content="index, follow, archive">
<meta name="description" content="How about getting free Recharges, Gift Vouchers and Bank Transfers every time you buy something, on top of existing coupons and offers?">
<meta name="keywords" content="free recharges, India, flipkart offers, offer, shopping offers, online offers, flipkart deals, amazon deals, cashback">
<link rel="icon" type="image/png" href="images/favicon.png"/>
<link href='http://fonts.googleapis.com/css?family=Bree+Serif' rel='stylesheet' type='text/css'>
<link rel="stylesheet" type="text/css" href="stylesheet.css">
<link rel="stylesheet" type="text/css" href="footer.css">
<script>
  (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
  (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
  m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
  })(window,document,'script','//www.google-analytics.com/analytics.js','ga');
  ga('create', 'UA-66870051-1', 'auto');
  ga('send', 'pageview');
</script>
</head>

//LOGIN.PHP

<?php
session_start();
    $pageTitle = 'Log in';
    $metaRobots = 'index, follow, archive';
    $metaDescription = 'Log in page at Rewardadda';
    $metaKeywords = 'recharge, cashback';
    require_once('navig.php');
    require_once('connect.php');
    ?>
<div id="wrap">
<div id="contain">

<?php

require_once('connect.php');
if (!isset($_SESSION['user_id']) && !isset($_POST['loginbtn']) && !isset($_POST['signupbtn'])) {
require_once("logsign.php");
}
else if (!isset($_SESSION['user_id']) && isset($_POST['loginbtn']) && !isset($_POST['signupbtn'])) {
    $dbc = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME)
        or die('Error communicating to MySQL server.');

        $ab_name = @mysqli_real_escape_string($dbc, trim($_POST['li_email']));
        $ab_password = @mysqli_real_escape_string($dbc, trim($_POST['li_password']));


        $logincheck = "SELECT user_id FROM userdata WHERE email='$ab_name' AND password='$ab_password'";
        $eidresult = mysqli_query($dbc, $logincheck); 

        if(mysqli_num_rows($eidresult) == 1) {
            $yoarray = mysqli_fetch_array($eidresult);
            $uid = $yoarray['user_id'];
            $_SESSION['user_id'] = $uid;
            header('refresh: 0; url = "index.php"');
        }
        else {
            echo "<script>alert('Email and password do not match our records. Please try again.')</script>;";
            require_once("logsign.php");
        }


    mysqli_close($dbc);
}

else if (!isset($_SESSION['user_id']) && !isset($_POST['loginbtn']) && isset($_POST['signupbtn'])) {
    $dbc = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME)
        or die('Error communicating to MySQL server.');
    $selected_val = $_POST['Operator'];
        $yo_name = @mysqli_real_escape_string($dbc, trim($_POST['su_name']));
        $yo_email = @mysqli_real_escape_string($dbc, trim($_POST['su_email']));
        $yo_password = @mysqli_real_escape_string($dbc, trim($_POST['su_password']));
        $yo_refer=@mysqli_real_escape_string($dbc, trim($_POST['su_refer']));
            $yo_mobile=@mysqli_real_escape_string($dbc, trim($_POST['su_mobile']));

            $signcheck = "SELECT user_id FROM userdata WHERE email='$yo_email'";
        $idresult = mysqli_query($dbc, $signcheck); 
        if(mysqli_num_rows($idresult) >= 1) {
                echo "<script>alert('Email is already registered with us. Please use other email.')</script>;";
            require_once("logsign.php");
        }
        else{


        $query = "INSERT INTO userdata (email, name, password,refer,mobile,operator) ".
                        "VALUES ('$yo_email', '$yo_name', '$yo_password','$yo_refer','$yo_mobile','$selected_val')";
        $get_uid = "SELECT user_id FROM userdata WHERE email = '$yo_email'";

        mysqli_query ($dbc, $query); 
        $uidresult = mysqli_query($dbc, $get_uid); //Query to get id so that we can log him in below
        $uidresarray = mysqli_fetch_array($uidresult);
        $uid = $uidresarray['user_id'];

        $_SESSION['user_id'] = $uid;


        header('Location: index.php');
        }
    mysqli_close($dbc);
}
else {?>
    <div id="damn"><h2>You are already logged in. Redirecting you to your HomePage.</h2></div>
    <?php
    header('refresh: 3; url = "index.php"');
}
    echo '</div></div>';

?>

【问题讨论】：

Warning: Cannot modify header information的可能重复
之前看过这些问题，但我的问题没有解决。
@ABHI_SINGH veerey kahan masla hai？ koi error ya phir 意外行为 aya code mein apkay？ ;-)
兄弟，当我尝试注册或登录网站时，如果成功，页面将重定向到其他页面，尽管用户已登录或注册，但该页面并未发生
@ABHI_SINGH 试试这个：header("refresh:3; url=index.php");

标签： php session redirect web-hosting request-headers

【解决方案1】：

因为如果你显示任何东西。即使是 <div id="damn"><h2>You are already logged in. Redirecting you to your HomePage.</h2></div>then header() 也不再起作用

您通常会在页面开头测试if(isset($_SESSION['user_id'])) header("Location /")。

无需发送消息说用户“已经是bla bla bla”，一旦您已经登录，您将无法看到登录页面。

【讨论】：