PHP include mysql query, use header to prevent query re-execution, but where to echo out the notifications?

Question

My code when F5 re-executes a query:

if (isset($_POST['addnewproject']) )
{
    include("query/pm_addnewproject.php");
    echo $emailnotificationmessage;
}

To prevent query re-execution after pressing F5 or page reload I have to modify a header and place it in the first rules (before any output) of the .php page. So:

    if (isset($_POST['addnewproject']) ) 
    {
        include("query/pm_addnewproject.php");
        header("Location:pm_configureaccounting.php?edit=$_SESSION[accidsession]");

        echo $emailnotificationmessage; exit();

    }

Because of the header, I now lose the $emailnotificationmessage I wanted to echo out somewhere middle of the page.

What's the best thing to do now when I want to still echo this out?

Now I changed the $emailnotificationmessages to $_SESSION['emailnotificationmessage'] and echo it out where I want it.

But I need to unset this session too, else it keeps showing the user.

So when I place echo $_SESSION['bla'] somewhere middle of the page, it has a value there. It works. But I need to clear it after so when the user visits again, it wont show any message unless project is added again. So I place $_SESSION['bla'] = ""; at the end of the page, and still, this SESSION gets the value "" ?! How is this possible?

Answer 1

Alright. Why dont you write the code in the below way:

<?php 

if (isset($_POST['addnewproject']) ) 
{
    include("query/pm_addnewproject.php");
    $_SESSION['emailMsg'] = $emailnotificationmessage;
    header("Location:pm_configureaccounting.php?edit=$_SESSION[accidsession]");

    exit();

}else{
    echo $_SESSION['emailMsg']; 
}

?>