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如果我使用header（）函數，則登錄索引表單不適用於login.php

[英]Login index form is not working with login.php if i use header() function

 原文  2016-01-31 07:01:16  7   4    php/ html/ sql/ forms

問題描述

我是php的初學者。 我正在嘗試制作一個登錄表單（index1.php）。 如果我使用表單標記中的“ action”屬性將其重定向到login.php，則效果很好。 但是我也想在相同的索引形式上進行一些驗證。因此，我使用標頭函數將其重定向到“ login.php”，而不是在“ action”屬性中。

無論我是否輸入正確的用戶名和密碼，它都會在執行login.php的最后一個錯誤時給我錯誤變量'$ username'和'$ password'的錯誤（//該用戶不存在）。 請幫助我了解我的代碼有什么問題以及如何使它與login.php一起運行？

這是index1.php的代碼 

  <!DOCTYPE HTML>
<html>
<head><br>
<style>
.error {color: #FF0000;}
</style>
</head>
<body style="font-family: verdana, sans-serif;";>   
<hr />
<div style="width: 77%; height: 300px; padding: 30px; border: 5px solid #e3e3e3; background-color: #F8F8F8 ; color: #000; margin: 100px;" align="center">
 <br>
<?php

 $username=$password="";
 $Err="";

 if($_SERVER['REQUEST_METHOD']== "POST")
 {  

     $valid = true;

     if ((empty($_POST["username"])) || (empty($_POST["password"])))
    {
      $Err = "Please Enter your username and password";
      $valid = false; 
    }

   else 
    {

      $username = test_input($_POST["username"]);
      $password = test_input($_POST["password"]);
    }


   if($valid)
   { 
     header("location:login.php");
   }


 } 

 function test_input($data) 
{
   $data = trim($data);
   $data = stripslashes($data);
   $data = htmlspecialchars($data);
   return $data;
}

?>

 <span class="error"><?php echo $Err; ?></span>
 <h2>Login</h2>
 <form action="menubar.php?page=index1" method="post">
      <font size="3">Username:<input type="text" name="username" style="padding: 4px;"/><p>
      Password: <input type="password" name="password" style="padding: 4px;"/><p>
                 <input type="submit" value="Login" style="padding: 4px; width: 5em; height: 1.9em;"/></font>
    </form>
     <h5> No Account?<a href="menubar.php?page=register">Register!</a></h5>
    </div>
</body>
</html>

這是login.php的代碼。 

<?php

session_start();

$username=$_POST["username"];
$password=$_POST["password"];
$message[]="Fill up both username and password";

    $connect=mysql_connect("localhost","root","") or die("Couldnt connect to Database");
    mysql_select_db("login") or die("Couldnt find Database");
    $query = mysql_query("SELECT * FROM users WHERE username='$username'");

    $numrows = mysql_num_rows($query);

    if($numrows!==0)//username exists in database
    {
        while($row = mysql_fetch_assoc($query))
        {
            $dbusername = $row['username'];
            $dbpassword = $row['password'];
        }
        if($username==$dbusername&&$password==$dbpassword)//valid username and password
        {

            $_SESSION['username'] = $username;
           header("Location: menubar.php?page=home");
        }
        else//incorrect password or username
        die("incorrect password or username");

    }
    else//that user doesnt exit
    die("that user doesnt exit");//


?>

好吧，現在我改用“ sqli”

這是更新的login.php代碼 

<?php

session_start();

$username=$_POST["username"];
$password=$_POST["password"];
$message[]="Fill up both username and password";

    $connect=mysqli_connect("localhost","root","") or die("Couldnt connect to Database");
    mysqli_select_db($connect,'login') or die("Couldnt find Database");
    $query = mysqli_query("SELECT * FROM users WHERE username='$username'");

    $numrows = mysqli_num_rows($query);

    if($numrows!==0)//username exists in database
    {
        while($row = mysqli_fetch_assoc($query))
        {
            $dbusername = $row['username'];
            $dbpassword = $row['password'];
        }
        if($username==$dbusername&&$password==$dbpassword)//valid username and password
        {

            $_SESSION['username'] = $username;
           header("Location: menubar.php?page=home");
        }
        else//incorrect password or username
        die("incorrect password or username");

    }
    else//that user doesnt exit
    die("that user doesnt exit");//


?>

現在更新后，我沒有收到無效變量的錯誤。 但是它仍然沒有正確進行。無論我是否輸入正確的用戶名和密碼，它都會執行最里面的內容，即（//有效的用戶名和密碼）

謝謝....

4 個解決方案

解決方案1
 2 已采納  2016-01-31 08:45:10

  1. 正如已經建議的，將所有PHP代碼放在任何HTML輸出之前
  2. 您沒有通過header（）函數傳遞POST變量，可以使用會話或POST到同一頁面

所以你的代碼將是這樣的 

<?php

 $username=$password="";
 $Err="";

 if($_SERVER['REQUEST_METHOD']== "POST")
 {  

     $valid = true;

     if ((empty($_POST["username"])) || (empty($_POST["password"])))
    {
      $Err = "Please Enter your username and password";
      $valid = false; 
    }

   else 
    {

      $username = test_input($_POST["username"]);
      $password = test_input($_POST["password"]);
    }


   if($valid)
   { 
     include("login.php");
   }


 } 

 function test_input($data) 
{
   $data = trim($data);
   $data = stripslashes($data);
   $data = htmlspecialchars($data);
   return $data;
}

?>

  <!DOCTYPE HTML>
<html>
<head><br>
<style>
.error {color: #FF0000;}
</style>
</head>
<body style="font-family: verdana, sans-serif;";>   
<hr />
<div style="width: 77%; height: 300px; padding: 30px; border: 5px solid #e3e3e3; background-color: #F8F8F8 ; color: #000; margin: 100px;" align="center">
 <br>

 <span class="error"><?php echo $Err; ?></span>
 <h2>Login</h2>
 <form action="menubar.php?page=index1" method="post">
      <font size="3">Username:<input type="text" name="username" style="padding: 4px;"/><p>
      Password: <input type="password" name="password" style="padding: 4px;"/><p>
                 <input type="submit" value="Login" style="padding: 4px; width: 5em; height: 1.9em;"/></font>
    </form>
     <h5> No Account?<a href="menubar.php?page=register">Register!</a></h5>
    </div>
</body>
</html>

解決方案2
 1  2016-01-31 07:22:03

請務必注意，在設置標頭之前，您不應該向客戶端發送任何輸出-

header("Location: menubar.php?page=home");//or login.php

因此，在發送任何數據之前，請驗證您的數據並設置標題，如果無效數據則發送正常數據。

更新：以下是完整的經過測試的代碼

index1.php 

<?php session_start();?>
<!DOCTYPE HTML>
<html>
<head><br>
<style>
    .error {color: #FF0000;}
</style>
</head>
<body style="font-family: verdana, sans-serif;";>   
<hr />
<div style="width: 77%; height: 300px; padding: 30px; border: 5px solid #e3e3e3; background-color: #F8F8F8 ; color: #000; margin: 100px;" align="center">
 <br>
 <?php if(isset($_SESSION['message'])){ echo  "<span class='error'>".$_SESSION['message']."</span>"; $_SESSION['message']=null;}?>
 <h2>Login</h2>
 <form action="login.php" method="post">
         <font size="3">Username:<input type="text" name="username" style="padding: 4px;"/><p>
  Password: <input type="password" name="password" style="padding: 4px;"/><p>
             <input type="submit" value="Login" style="padding: 4px; width: 5em; height: 1.9em;"/></font>
</form>
 <h5> No Account?<a href="menubar.php?page=register">Register!</a></h5>
</div>
</body>
</html>

的login.php 

<?php

session_start();
$username=$password="";
$Err="";

if($_SERVER['REQUEST_METHOD']== "POST")
 {
    $valid = true;
 if ((empty($_POST["username"])) || (empty($_POST["password"])))
{
  $Err = "Please Enter your username and password";
  $valid = false; 
}
else 
{

  $username = test_input($_POST["username"]);
  $password = test_input($_POST["password"]);
}
   if($valid) {
    $valid = false;//reset $valid value to validate for Database test

    //$username=$_POST["username"];
    //$password=$_POST["password"];
    //$message[]="Fill up both username and password";

    $connect=mysqli_connect("localhost","root","") or die("Couldnt connect to Database");
    mysqli_select_db($connect,'login') or die("Couldnt find Database");
//Note: mysqi_query() returns results of query
    $result = mysqli_query($connect, "SELECT * FROM users WHERE username='$username'");//update here pass the $connect parameter

    $numrows = mysqli_num_rows($result);//change here

if($numrows!==0)//username exists in database
{
    $dbusername = null;//move it up for visibility after while block
    $dbpassword = null;
    while($row = mysqli_fetch_assoc($result))//Note here pass the result
    {
        $dbusername = $row['username'];
        $dbpassword = $row['password'];
    }
    if($username == $dbusername&&$password==$dbpassword)//valid username and password
    {

        $_SESSION['username'] = $username;
       header("Location: menubar.php?page=home");//the landing page
       die();
    }
    else{
        //incorrect password or username
        $Err = "incorrect password or username";
        $valid = false;
    }

}
else {
    //that user doesnt exit
    $Err = "that user doesnt exit";
    $valid = false;
}   
 //header("location:index.php");
}   
if(!$valid) {
    $_SESSION['message'] = $Err;//Put the message in $_SESSION variable
    header("location:index1.php");
}
 }
function test_input($data) 
{
   $data = trim($data);
   $data = stripslashes($data);
   $data = htmlspecialchars($data);
   return $data;
}
?>

menubar.php 

<?php

session_start();

$page=isset($_GET["page"])?$_GET["page"]:"";
if(isset($page)) {
    header("location: ".$page.".php");
} else {
    header("location: 404.php");
}
?>

解決方案3
 1  2016-01-31 08:52:34

您代碼中的問題是在login.php ，從未設置$_POST["username"]和$_POST["password"] ，所以最好的辦法是不使用header而只使用require_once 

<!DOCTYPE HTML>
<html>
<head><br>
<style>
.error {color: #FF0000;}
</style>
</head>
<body style="font-family: verdana, sans-serif;";>   
<hr />
<div style="width: 77%; height: 300px; padding: 30px; border: 5px solid #e3e3e3; background-color: #F8F8F8 ; color: #000; margin: 100px;" align="center">
 <br>
<?php

 $username=$password="";
 $Err="";

 if($_SERVER['REQUEST_METHOD']== "POST"){  

     $valid = true;

     if ((empty($_POST["username"])) || (empty($_POST["password"]))){

      $Err = "Please Enter your username and password";
      $valid = false; 

    }else{

      $username = test_input($_POST["username"]);
      $password = test_input($_POST["password"]);

    }


   if($valid)
   { 
     require_once('login.php');
   }


} 

 function test_input($data) {
   $data = trim($data);
   $data = stripslashes($data);
   $data = htmlspecialchars($data);
   return $data;
}

?>

 <span class="error"><?php echo $Err; ?></span>
 <h2>Login</h2>
 <form action="menubar.php?page=index1" method="post">
      <font size="3">Username:<input type="text" name="username" style="padding: 4px;"/><p>
      Password: <input type="password" name="password" style="padding: 4px;"/><p>
                 <input type="submit" value="Login" style="padding: 4px; width: 5em; height: 1.9em;"/></font>
    </form>
     <h5> No Account?<a href="menubar.php?page=register">Register!</a></h5>
    </div>
</body>
</html>

解決方案4
 0  2016-01-31 08:27:44

那是因為您有一個輸出： 

?>
<?php

導致空白行輸出。

在發送任何實際輸出之前，必須通過常規HTML標記，文件中的空白行或從PHP中調用header（）

合並所有PHP代碼，並確保文件開頭沒有空格。

同樣在header('location: index.php'); 添加exit(); 如果您還有其他腳本，請在下面。

還要將您的重定向標頭移到最后一個if之后。

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