MySQL Query Issue - PHP variable not passed through includes - php

Question

So as the title suggests, I am having trouble executing a MySQL query. The query works almost successfully, as all data fields are stored into my database except for one. The query itself is a commenting system for signed in users to comment on any given blog post. The issue I am having is that the variable '$post_id' is not recognized, and therefore '$comment_post_ID' is not stored in my database.
'$post_id' is defined in blogs.php, and after echoing this variable it does exist and is successfully defined. However, this variable is not passed onto commentsubmit.php, which is included in the same file where the variable is defined. Why is this happening?
Here are all the pieces of my code:
blogs.php (shows all posts from all users, or just one post if ?id is set in the url. If ?id is set, users can comment on the single post they are viewing.)
<?php
if (isset($_GET['id'])) {
$conn = mysqli_connect("localhost", "root", "mypassword", "mydbname");
if (mysqli_connect_errno($conn)) {
echo "Failed to connect to MySQL: " . mysqli_connect_error();
exit;
}
$post_id = mysqli_real_escape_string($conn, $_GET['id']);
$blog_post = "SELECT * FROM blogs WHERE id = '$post_id'";
$blog_query = mysqli_query($conn, $blog_post);
while ($row = mysqli_fetch_array($blog_query)) {
$title = $row['title'];
$body = $row['body'];
$author = $row['author'];
$author_username = $row['author_username'];
$datetime = time_ago($row['datetime'], $granularity=2);
}
include ("./fullpageblog.php");
if (isset($_SESSION['id'])) {
include ("./blogcomment.php");
include ("./commentsubmit.php");
}
echo "$post_id";
mysqli_close($conn);
}
?>
blogcomment.php (form for users to make a comment)
<div class="row col-sm-12">
<div id="fullPageBlog">
<div id="center-border"></div>
<form action="commentsubmit.php" method="post">
<textarea maxlength="1000" id="blogComment" name="content" placeholder="Write your response..."></textarea>
<input type="submit" name="comment" value="Publish" />
</form>
<script type="text/javascript">$('#blogPost').elastic();</script>
</div>
</div>
commentsubmit.php (comment query itself)
<?php
session_start();
if (isset($_POST['comment'])) {
$conn = mysqli_connect("localhost", "root", "mypassword", "mydbname");
if (mysqli_connect_errno($conn)) {
echo "Failed to connect to MySQL: " . mysqli_connect_error();
exit;
}
$comment_post_ID = $post_id;
$comment_author = $_SESSION['full_name'];
$comment_author_email = $_SESSION['email'];
$comment_author_username = $_SESSION['username'];
$comment_date = date("Y-m-d H:i:s");
$comment_content = mysqli_real_escape_string($conn, $_POST['content']);
$user_ID = $_SESSION['id'];
$comment_submit = "INSERT INTO comments (comment_ID, comment_post_ID, comment_author, comment_author_email, comment_author_username, comment_date, comment_content, user_ID) VALUES ('', '$comment_post_ID', '$comment_author', '$comment_author_email', '$comment_author_username', '$comment_date', '$comment_content', '$user_ID') ";
$comment_query = mysqli_query($conn, $comment_submit);
mysqli_close($conn);
header("Location: blogs.php");
die();
}
?>

Answer 1

You don't include/require the blogs.php script from the commentsubmit.php script, so the code in blogs.php would never be run after a POST that is made directly to commentsubmit.php unless you have some other request processing (i.e. a server-side rewrite or similar) that happens automatically on the server before the request ultimately reaches the portion of code shown in commentsubmit.php above.

Answer 2

<?php
$con = mysql_connect("localhost","root","password");
$con=mysql_select_db("database_name");
error_reporting(0);
session_start();
if(isset($_POST["submit"])){
$comment_author = $_POST['full_name'];
$comment_author_email = $_POST['email'];
$comment_author_username = $_POST['username'];
$sql="select * from table_name where `full_name`='"$comment_author "',`email`='"$comment_author_email "',`username`='"$comment_author_username "'";
$qur=mysql_query($sql);
$row= mysql_fetch_array($qur);
$num= mysql_num_rows($qur);
}
if($num>0){
$_SESSION["full_name"]=$full_name;
$_SESSION["email"]=$comment_author_email;
$_SESSION["username"]=$comment_author_username;
}
else{
echo"Username and Password are wrong";
}
?>