Sessions variable unseen in multiple pages - php

Question

I don't understand the thing with sessions in php. It says that after you start a session, the session variable are stored and can be seen in multiple pages.But in my pages that are not seen. For example I have my index.php page where I start the session_start(). Then I click a button to login and if everything is ok it should redirect me to profile.php page where I print the session email. But it doesn't recognize my session variable.My code:
if($_POST['actiune'] == 'login'){
$email = $_POST['email'];
$_SESSION['username'] = $email;
$password = $_POST['password'];
$pass = getPassword($email);
$verify = password_verify($password, $pass);
if ($verify) {
header("Location: index.php?page=profile");
}
else {
header("Location: index.php?page=login&msg=PleaseRegister");
}
}
profile.php
echo $_SESSION['username'] ; die();
Any help?
UPDATE:
profile.php
<?php
session_start();
echo $_SESSION['username'] ;
?>
<div id="profile">
<p id="welcome">Welcome :<?php echo $_SESSION['username']; ?></p>
<?php
if ($_SESSION['avatar'] == ""){
?>
<img src = "http://placehold.it/400x200/0000ff/&text=Upload a picture" alt =""/>
<?php
}
else if ($_SESSION['avatar'] != ""){
?>
<img src="avatars/<?php echo $user['file'];?>">
<?php
}
?>
<p id="modifyPf"> Modify</p>
<p id="reset"> Reset password</p>
<p id="articlePf"> Article page</p>
<form action="action.scripts.php" method="POST" enctype="multipart/form-data">
<input type="hidden" name="actiune" value="avatar">
<input type="hidden" name="id" value="<?php echo $user['id'];?>">
<p><label for="avatar">Upload an avatar:</label></p>
<p><input type="file" name="avatar" id="fileToUpload"></p>
<p><input id ="button" class="btn btn-primary" type="submit" name="button" value="Send"/></p>
</form>

Answer 1

You need to call session_start(); in profile.php also.
session_start() creates a session or resumes the current one based on
a session identifier passed via a GET or POST request, or passed via a
cookie.
Update
<?php
if(!isset($_SESSION))
{
session_start();
}
if (isset($_SESSION['username'])){
?>
<div id="profile">
<p id="welcome">Welcome :<?php echo $_SESSION['username']; ?></p>
<?php if ($_SESSION['avatar'] == ""){ ?>
<img src = "http://placehold.it/400x200/0000ff/&text=Upload a picture" alt =""/>
<?php
}
else if ($_SESSION['avatar'] != ""){
?>
<img src="avatars/<?php echo $user['file'];?>">
<?php
}
?>
<p id="modifyPf"> Modify</p>
<p id="reset"> Reset password</p>
<p id="articlePf"> Article page</p>
<form action="action.scripts.php" method="POST" enctype="multipart/form-data">
<input type="hidden" name="actiune" value="avatar">
<input type="hidden" name="id" value="<?php echo $user['id'];?>">
<p><label for="avatar">Upload an avatar:</label></p>
<p><input type="file" name="avatar" id="fileToUpload"></p>
<p><input id ="button" class="btn btn-primary" type="submit" name="button" value="Send"/></p>
</form>
</div>
<?php
}
else {
echo '<pre>';
var_dump($_SESSION);
echo '</pre>';
}
?>
Index.php
<?php
session_start();
if($_POST['actiune'] == 'login'){
$email = $_POST['email'];
$_SESSION['username'] = $email;
$password = $_POST['password'];
$pass = getPassword($email);
$verify = password_verify($password, $pass);
if ($verify) {
header("Location: index.php?page=profile");
}
else {
header("Location: index.php?page=login&msg=PleaseRegister");
}
}
else {
echo 'POST actiune is not login';
}
?>

Answer 2

You need session_start() at the top of every page request - exactly one time per request. It doesn't just create the session; it's required for every request in which you want to use the session. From the docs:
session_start() creates a session or resumes the current one based on a session identifier passed via a GET or POST request, or passed via a cookie.