php form submitting info twice - php

Question

I have a form that's supposed to enter a reply to a forum topic into the database and redirect the user back to the same topic. After much trial and error I have finally got the form to work, only it is putting two identical entries into the db every time. I cannot figure out why. I have looked up this same problem and most of the other people were not redirecting after the form submission or they were using AJAX or jquery or something. Here is my page info:
<?php
session_start();
include_once('includes/config.php');
include_once('classes/topic.php');
include_once('classes/post.php');
include('includes/header.php');
?>
<link rel="stylesheet" href="css/dd.css">
<?php
$topic = new Topic;
if (isset($_GET['id']))
{
$topic_id = $_GET['id'];
$data = $topic->fetch_data($topic_id);
if (isset($_POST['content']))
{
// someone posted a reply
$date = date('Y-m-d H:i:s');
$by = $_SESSION['user_id'];
$query = $pdo->prepare("INSERT INTO dd_posts (post_content, post_date, post_by, post_topic) VALUES (? ,? ,?, ?)");
$query->bindParam(1, $_POST['content']);
$query->bindParam(2, $date);
$query->bindParam(3, $by);
$query->bindParam(4, $_GET['id']);
$query->execute();
$result = $query->execute();
header("location:topic.php?id=".$_GET['id']);
exit;
}
?>
<div id ="wrapper">
<div class="drop-section">
<div id="menu">
<a class="item" href="drop_index.php">Dead Drop</a>
<a class="item" href="add_topic.php">New Post</a>
<a class="item" href="admin/add_cat.php">New Category</a>
<div id="userbar">
<?php
if( $user->is_logged_in() ) {
echo 'Hello ' . $_SESSION['user_name'] . '. How are you?';
} else {
echo '<a class="item" href="login.php">Sign in</a> or <a class="item" href="index.php">Create an account</a>';
}
?>
</div>
</div>
<table>
<tr class = "header-row">
<div id = "sans">
<?php echo $data['topic_subject']; ?>
- <small>started by <?php echo $data['user_name']; ?> </small><br />
<?php echo $data['topic_content']; ?>
</div>
</tr>
<?php
// retrieve all the replies to the original topic
$post = new Post;
$topic_id = $_GET['id'];
$posts = $post->fetch_all_posts_by_topic($topic_id);
?>
<tr>
<td class="first-column">
<?php foreach ($posts as $post) { ?>
<div class="drop-content-box">
<li><?php echo $post['post_content']; ?><br />
<div class = "forum-user-info">
<a href="player.php?id=<?php echo $post['user_id']; ?>">
<?php echo $post['user_name']; ?></a> - level:
<?php echo $post['user_level']; ?>
</div>
</li>
</div>
<?php } ?>
</td>
</tr>
</table>
<?php
if( $user->is_logged_in() )
{
?>
<div id = "header-section">Reply</div>
<?php if (isset($error)) { ?>
<small><?php echo $error; ?></small>
<?php } ?>
<form action="<?php echo "topic.php?id=".$_GET['id']?>" method="post" autocomplete="off">
<small><i>Do not post the actual answer to any level.</i></small><br />
<textarea rows="15" cols="50" name="content" placeholder="Give us your thoughts..."></textarea><br />
<input type="submit" value="Post" />
</form>
</div>
</div>
<?php
} else {
echo '<div id = "errors"><small>You must be signed in to reply.</div></small>';
}
}
include_once('includes/footer.php');
?>

Answer 1

You're executing the query twice.
$query->execute();
$result = $query->execute();