php session 没有从数据库中获取 id

Question

我正在尝试从数据库中获取 $_SESSION['id'] ，我可以从 session 获取用户名和其他信息，但我无法获取 id。 我知道我错过了一些非常简单的东西。 我在每个页面上都有一个配置文件，其中 session_start() 在页面顶部。

所以问题是我没有从数据库中收到 session id 这是 mysql 查询。

$sql = ("SELECT  persons.name, images.file_name, images.user_id FROM persons  INNER JOIN images  ON 
    persons.id = images.user_id WHERE persons.id =" . $_SESSION['id'].""  );

$result = $db->query($sql);
//echo $_SESSION['id'];
var_dump($sql);
print_r($result); 
$result = $db->query($sql) or die($db->error);
// Include the database configuration file
//include_once 'config/config.php';

// Get images from the database
//$query = $db->query("SELECT file_name FROM images INNER JOIN persons  ON persons.id=images.user_id ORDER BY id DESC ");
?>

<?php
if($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
//    $id = $row['id'];
    $imageURL = 'uploads/'.$row["file_name"];
    //echo "<br>username:" . $_SESSION['id'];
?>

<img src="<?php echo $imageURL; ?>" alt="" width="250" height="250" />
<?php
    }
} else { ?>
    <p>No image(s) found...</p>
<?php } ?> 

登录表单：

<form action="" method="post" enctype="multipart/form-data">
      <?php login(); ?>

       <input type="text" name="username">
       <input type="text" name="password">
       <input type="submit" name="login">
</form>

Session 数据：

if(!empty($_SESSION['id'])) {
    echo "welcome " . $_SESSION['id'];
} else {
    //header("Location: index.php");
}

这是我的function.php我知道它根本不安全，无法运行或仅在本地计算机上运行。

<?php

         // if(!empty($_SESSION['id'])) {
         //  echo "welcome " . $_SESSION['id'];
         // }

    // Include the database configuration file
    require_once "config.php";


       function uploads() {
       global $db;
       if(isset($_POST['submit'])){ 
 
        $user_id = $_POST['user_id'];
        $_SESSION['persons.id'] = $id;
        // File upload configuration 
        $targetDir = "uploads/"; 
        $allowTypes = array('jpg','png','jpeg','gif'); 
 
        $statusMsg = $errorMsg = $insertValuesSQL = $errorUpload = 
        $errorUploadType = ''; 
        $fileNames = array_filter($_FILES['files']['name']); 
        if(!empty($fileNames)){ 
        foreach($_FILES['files']['name'] as $key=>$val){ 
        // File upload path 
        $fileName = basename($_FILES['files']['name'][$key]); 
        $targetFilePath = $targetDir . $fileName; 
         
        // Check whether file type is valid 
        $fileType = pathinfo($targetFilePath, PATHINFO_EXTENSION); 
        if(in_array($fileType, $allowTypes)){ 
            // Upload file to server 
            if(move_uploaded_file($_FILES["files"]["tmp_name"][$key], 
         $targetFilePath)){ 
                // Image db insert sql 
                $insertValuesSQL .= "('".$user_id."', '".$fileName."', 
         NOW()),"; 
            }else{ 
                $errorUpload .= $_FILES['files']['name'][$key].' | '; 
            } 
        }else{ 
            $errorUploadType .= $_FILES['files']['name'][$key].' | '; 
        } 
    } 
     
    if(!empty($insertValuesSQL)){ 
        $insertValuesSQL = trim($insertValuesSQL, ','); 
        // Insert image file name into database 
        $insert = $db->query("INSERT INTO images (user_id, file_name, 
      uploaded_on) VALUES   $insertValuesSQL "); 
        
        if($insert){ 
            $errorUpload = !empty($errorUpload)?'Upload Error: 
    '.trim($errorUpload, ' | '):''; 
            $errorUploadType = !empty($errorUploadType)?'File Type Error: 
      '.trim($errorUploadType, ' | '):''; 
            $errorMsg = 
    
  !empty($errorUpload)?'<br/>'.$errorUpload.'<br/>'.$errorUploadType:'<br/>' 
  .$errorUploadType; 
            $statusMsg = "Files are uploaded successfully.".$errorMsg; 
        }else{ 
            $statusMsg = "Sorry, there was an error uploading your file."; 
        } 
      } 
    }else{ 
    $statusMsg = 'Please select a file to upload.'; 
    } 
 
    // Display status message 
    echo $statusMsg; 
   } 

  }

  function register() {
   global $db;

   try {
   if (isset($_POST['join'])) {
    $name = $_POST['name'];
    $surname = $_POST['surname'];
    $email = $_POST['username'];
    $password = $_POST['password'];

    $insert = $db->query("INSERT INTO persons (name, surname, username, 
    password) VALUES ('$name', '$surname', '$email', '$password')");

       if($insert){ 
            $errorUpload = !empty($errorUpload)?'Upload Error: 
     '.trim($errorUpload, ' | '):''; 
            $errorUploadType = !empty($errorUploadType)?'File Type Error: 
     '.trim($errorUploadType, ' | '):''; 
            $errorMsg = 

    
   !empty($errorUpload)?'<br/>'.$errorUpload.'<br/>'.$errorUploadType:'<br/>' 
      .$errorUploadType; 
            $statusMsg = "Files are uploaded successfully.".$errorMsg; 
        }else{ 
            $statusMsg = "Sorry, there was an error inserting you."; 
        } 
    
     }else{ 
    $statusMsg = 'Please select a file to upload.'; 
    } 
 
   //Display status message 
    echo $statusMsg; 
   echo "all good";


    } catch (Expetion $e) {
    echo "something has gone wrong.";
   }
 }


 //login
 function login() {
global $db;

try {

   
    if(isset($_POST['login'])) {
         $id = $_SESSION['id'] = $id;
         $username = $_POST['username'];
    $password = $_POST['password'];
    $name = $_POST['name'];
    $sql = ("SELECT id,name, username, password FROM persons where username = 
    '$username' AND password = '$password' ");
    $result = $db->query($sql);
    // $rows = mysqli_num_rows($result);
    if($result->num_rows > 0) {
        //echo  $_SESSION['id'];
        //echo "this " .  $username . " " . $password;
        echo "all good";
        $_SESSION['username'] = $username;
        $_SESSION['name'] = $name;
        $_SESSION['id'] = $id;
        echo " hello there: " . $username;
        header("Location: page.php");
        } else {
        echo "wrong user or pass";
    }

   }
   } catch (Expection $e) {
    echo "Sorry try agian.";
  }
}


 function getId() {
 global $db;

try {
    if(isset($_POST['login'])) {
    $id = $_SESSION['id'] = $id;
    $sql = ("SELECT id FROM persons WHERE id =   " . $id . "" );
    $result = $db->query($sql);
   
    while($row = $result->fetch_assoc()) {

    $id = $row['id'];
    echo $id;
    }
  }  
   
   } catch (Expection $e) {
     echo "Could not get user.";
  }

}

Answer 1

所以我找出了我做错了什么，这是在我的SQL statement我有这个$sql = ("SELECT persons.id, persons.name, images.file_name, images.user_id FROM persons INNER JOIN images ON persons.id = images.user_id WHERE persons.id = ". $id. "" ); 它应该是这样的： $sql = ("SELECT persons.id, persons.name, images.file_name, images.user_id FROM persons INNER JOIN images ON persons.id = images.user_id WHERE persons.id = ". "'$id'". "" ); 我以为这里有人会解决这个问题 谢谢