session_start(); Warning?

Question

I've recently switched to another hoster ... So I had to change the whole database names and credentials, but now one of my logins is not working anymore.

My user login works perfectly, but my admin login doesn't work since I changed the hoster.

He now gives me this error:

Warning: session_start() [function.session-start]: Cannot start session when headers already sent in /****/*************/***/********/news_login.php on line 2

I would appreciate an answer :)

I have no idea what to do

<?php
    session_start();

    require_once 'mysql.php';
    $db = new DB();
  ?>

<html>
    <head>
      <meta charset="utf-8">
      <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

      <title>Euro Trans GmbH | Admin LogIn</title>

      <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">

      <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
      <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js" integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1" crossorigin="anonymous"></script>
      <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"></script>
      <script src="https://kit.fontawesome.com/c96bf7b876.js"></script>

      <style>
        .bd-placeholder-img {
          font-size: 1.125rem;
          text-anchor: middle;
          -webkit-user-select: none;
          -moz-user-select: none;
          -ms-user-select: none;
          user-select: none;
        }

        @media (min-width: 768px) {
          .bd-placeholder-img-lg {
            font-size: 3.5rem;
          }
        }

        body {
          display: -ms-flexbox;
          display: flex;
          -ms-flex-align: center;
          align-items: center;
          padding-top: 40px;
          padding-bottom: 40px;
          background-color: #333333;
        }

        form {
          position: absolute;
          top: 50%;
          left: 50%;
          transform: translateX(-50%) translateY(-50%);
        }
      </style>
    </head>
    <body class="text-center">

      <?php
          if($db->isUserLoggedIn() === TRUE) {
            echo "<div style='position: absolute; top: 50%; left: 50%; transform: translateX(-50%) translateY(-50%);'><p style='color: white;'>Du bist bereits eingeloggt!</p><a href='logout.php' class='btn btn-outline-success my-2 my-sm-0' type='submit' alt='Ausloggen'>Ausloggen</a></div>";
          } else {
            if(isset($_POST['einloggen'])) {
              $email = $_POST['email'];
              $passwort = sha1($_POST['passwort']);

              if($db->login($email, $passwort) === TRUE) {
                echo "<br /><p>Erfolgreich eingeloggt!</p><br />";
              } else {
                echo "<br />Einloggen fehlgeschlagen!<br />";
              }
            }
       ?>

      <form class="form-signin" action="news_login.php" method="POST">
        <img src="images/default.png" alt="logo" width="200" height="200" style="border-radius: 20px; margin-right: 5%;">
        <h1 class="h3 mb-3 font-weight-normal" style="color: white;">Administrator Login</h1>
        <label for="inputEmail" class="sr-only">Email-Adresse</label>
          <input type="email" style="margin-top: 30px;" name="email" class="form-control" placeholder="Email-Adresse" required autofocus>
        <label for="inputPassword" class="sr-only">Passwort</label>
          <input type="password" style="margin-top: 3px;" name="passwort" class="form-control" placeholder="Passwort" required>
        <button class="btn btn-lg btn-primary btn-block" type="submit" name="einloggen" style="margin-top: 20px;">Einloggen</button>
        <br>
        <p><a href="index.php" style="color: white; text-decoration: underline;">Zurück zu Startseite</a></p>
        <p class="mt-5 mb-3 text-muted">&copy; <script>document.write(new Date().getFullYear());</script> by Euro Trans GmbH. All Rights Reserved</p>
      </form>

      <?php
    }
       ?>
    </body>
  </html>

<?php

    class DB {
      private static $_db_username      = "***********";
      private static $_db_password      = "***************";
      private static $_db_host          = "*******";
      private static $_db_name          = "*************";
      private static $_db;

      function __construct() {
        try {
          self::$_db = new PDO("mysql:host=" . self::$_db_host . ";dbname=" . self::$_db_name, self::$_db_username, self::$_db_password);
        } catch (PDOException $e) {
          echo "Datenbankverbindung gescheitert!";
          die();
        }
      }

      function isUserLoggedIn() {
        $stmt = self::$_db->prepare("SELECT user_id FROM admins WHERE Session=:sid");
        $sid = session_id();
        $stmt->bindParam(":sid", $sid);
        $stmt->execute();

        if($stmt->rowCount() === 1) {
          return true;
        } else {
          return false;
        }
      }

      function login($userMail, $pw) {
        $stmt = self::$_db->prepare("SELECT user_id FROM admins WHERE Email=:usermail AND Passwort=:pw");
        $stmt->bindParam(":usermail", $userMail);
        $stmt->bindParam(":pw", $pw);
        $stmt->execute();

        if ($stmt->rowCount() === 1) {
          $stmt = self::$_db->prepare("Update admins SET Session=:sid WHERE Email=:usermail AND Passwort=:pw");
          $sid = session_id();
          $stmt->bindParam(":sid", $sid);
          $stmt->bindParam(":usermail", $userMail);
          $stmt->bindParam(":pw", $pw);
          $stmt->execute();

          return true;
        } else {
          return false;
        }
      }

      function logout() {
        $stmt = self::$_db->prepare("Update admins SET Session='' WHERE Session=:sid");
        $sid = session_id();
        $stmt->bindParam(":sid", $sid);
        $stmt->execute();
      }

      function getAllEntries($sort = "DESC") {
        if ($sort != "ASC" && $sort != "DESC") {
          return -1;
        }
          $stmt = self::$_db->prepare("SELECT eintraege.eintrag_id, eintraege.header, eintraege.datum, eintraege.eintrag, admins.Vorname, admins.Nachname FROM eintraege INNER JOIN admins ON eintraege.autor = admins.user_id ORDER BY datum " . $sort);
          $stmt->execute();

          return $stmt->fetchAll(PDO::FETCH_ASSOC);
      }

      function createNewNews($titel, $news) {
        $stmt = self::$_db->prepare("INSERT INTO eintraege (header, eintrag, autor) VALUES(:titel, :news, :autor)");
        $autorID = self::getUserID();
        $stmt->bindParam(":titel", $titel);
        $stmt->bindParam(":news", $news);
        $stmt->bindParam(":autor", $autorID);
        if($stmt->execute()) {
          return true;
        } else {
          return false;
        }
      }

      function getUserID() {
        $stmt = self::$_db->prepare("SELECT user_id FROM admins WHERE Session=:sid");
        $sid = session_id();
        $stmt->bindParam(":sid", $sid);
        $stmt->execute();

        return $stmt->fetch(PDO::FETCH_OBJ)->user_id;
      }

      function getUserName() {
        $stmt = self::$_db->prepare("SELECT Vorname, Nachname FROM admins WHERE Session=:sid");
        $sid = session_id();
        $stmt->bindParam(":sid", $sid);
        $stmt->execute();

        $user = $stmt->fetch(PDO::FETCH_OBJ);

        return $user->Vorname . " " . $user->Nachname;
      }

      function getUserNameByID($userID) {
        $stmt = self::$_db->prepare("SELECT Vorname, Nachname FROM admins WHERE user_id=:userid");
        $stmt->bindParam(":userid", $userID);
        if($stmt->execute()) {
          if ($stmt->rowCount() === 1) {
          $user = $stmt->fetch(PDO::FETCH_OBJ);

          return $user->Vorname . " " . $user->Nachname;
          } else {
            return "";
          }
        } else {
          return "";
        }
      }

      function getEntryByID($id) {
        $stmt = self::$_db->prepare("SELECT * FROM eintraege INNER JOIN admins ON eintraege.Autor = admins.user_id WHERE eintrag_id=:id");
        $stmt->bindParam(":id", $id);

        if ($stmt->execute()) {
          if ($stmt->rowCount() === 1) {
            return $stmt->fetch(PDO::FETCH_OBJ);
          } else {
            return false;
          }
        } else {
          return false;
        }
      }

      function editEntry($titel, $news, $date, $id) {
          $stmt = self::$_db->prepare("UPDATE eintraege SET
                datum=:datum,
                header=:titel,
                eintrag=:news
                WHERE eintrag_id=:id");

          $date = date('Y-m-d H:i:s', strtotime($date));

          $stmt->bindParam(":id", $id);
          $stmt->bindParam(":datum", $date);
          $stmt->bindParam(":news", $news);
          $stmt->bindParam(":titel", $titel);

          if($stmt->execute()) {
              return true;
          } else {
              return false;
          }
      }

      function deleteEntry($id) {
        $stmt = self::$_db->prepare("DELETE FROM eintraege WHERE eintrag_id=:id");
        $stmt->bindParam(":id", $id);

        if($stmt->execute()) {
            return true;
        } else {
            return false;
        }
      }
    }
 ?>

I expect no errors, but actually I have an error...

The ERROR:

"Warning: session_start() [function.session-start]: Cannot start session when headers already sent in /*****/*******/*******/****/news_login.php on line 2"

Vidal · Answer 1 · 2019-08-11T13:44:23.030

1

You have print or send output to the user/brower before session_start(); was called.

Check that you don't have any white space, carriage return or newline characters before your <?php tags.

edited Aug 11 '19 at 13:44

answered Aug 11 '19 at 13:40

Vidal

2,605
2
16
32

So what should I do? – Julian Schaefers Aug 11 '19 at 13:42
the error is on line 2, maybe you have a white space or a character before the php tag. – Vidal Aug 11 '19 at 13:45
Now the Error is away, but the style is completely destroyed – Julian Schaefers Aug 11 '19 at 13:52
Here is a picture [Picture](https://i.imgur.com/JmpZr82.png) – Julian Schaefers Aug 11 '19 at 13:56
now the login doesn't work – Julian Schaefers Aug 11 '19 at 16:01
The Warning is away but the login does not work anyway – Julian Schaefers Aug 11 '19 at 16:02
I have solved it..... – Julian Schaefers Aug 11 '19 at 16:32
the form tag was deleted from me.... – Julian Schaefers Aug 11 '19 at 16:32

session_start(); Warning?

1 Answers1