Undefined Index error for checkbox

PHP
1

Hey everyone,

So I have a simple form with some simple sql executions to output data from a database. For some reason, I am getting a Undefined index error.

Notice: Undefined index: published in C:\Program Files (x86)\EasyPHP-DevServer-14.1VC11\data\localweb\my portable files\blogCMS\admin\new_page.php on line 61

I’ve declared that the variable is(set) near the top of the page, yet it still gives me an error for the checkbox I have to check whether or not a page is set to published or not (i.e. 1 or 0). Here is my code for all of it. Any help would be greatly appreciated to figure out where my fault lies. Thank you!

<?php
include('includes/config.php');
include('includes/db.php');
include('includes/header.php');
include('includes/sidebar.php');

if(isset($_POST['Update_Page'])){
  $title = mysqli_real_escape_string($db, $_POST['title']);
  $body = mysqli_real_escape_string($db, $_POST['body']);
  $published = mysqli_real_escape_string($db, $_POST['published']);
  
  if(isset($_POST['id'])){
    $id = mysqli_real_escape_string($db, $_POST['id']);
    $query = "UPDATE pages SET title='$title',body='$body',published='$published' WHERE id='$id'";
    
  }else{
    
    $query = "INSERT INTO pages (title,body,published)
    VALUES('$title', '$body', '$published')";
  }
  
  
  
  $db->query($query);
}

if(isset($_GET['id'])){
  $id = mysqli_real_escape_string($db, $_GET['id']);
  $p = $db->query("SELECT * FROM pages WHERE id = '$id'");
  $p = $p->fetch_assoc();
}

?>



          <h1 class="page-header">Add New Page</h1>

          <div class="table-responsive">
            <form method="post">
	        <?php if(isset($p)){
		  echo "<input type='hidden' value='$id' name='id' />";
		} ?>
	      <div class="form-group">
		<label>
		  Page Title : 
		</label>
		  <input class="form-control" value="<?php echo @$p['title']; ?>" name="title" >
	      </div>
				
	      <div class="form-group">
		<label>
		  Post Body : 
		</label>
		  <textarea name="body" class="form-control" ><?php echo @$p['body']; ?></textarea>
	      </div>
				
	      <div class="form-group">
		<label for="published">
		  <input type="checkbox" name="published" id="published" class="form-control" value=1
		    <?php if($_POST['published'] == 1){echo "checked";} ?>
		  > Publish?
		</label>
	      </div>
				
	      <button type="submit" name="Update_Page" class="btn btn-primary pull-right">Update Page</button>
			
	    </form>
          </div>
        </div>
      </div>
    </div>
  </body>
</html>
2

…Within a condition.
The variable is only set if the form has been submitted.

1 Like
3

It’s fixed! I passed the isset() function at the beginning of the code where I’m gathering the data from the form below. Thank You!

4

What some do to prevent this is to set variables with blank strings at the start of the script so they are defined even if there is no content.
Eg.

<?php
$published = '' ;
if ($_SERVER['REQUEST_METHOD'] == 'POST') { 
    $published = preg_replace('#[^0-1]#i', '', $_POST['published']);
    // Other stuff
}
5

Checkbox fields are only sent to PHP if they’ve been checked. If they’ve not been checked, they don’t get sent, hence the undefined index error as there was nothing sent:

if (isset($_POST['published'])) {
	$published = 1;
} else {
	$published = 0;
}

That example would handle the published field

btw, have a read up on the use of prepared statements:

http://php.net/manual/en/mysqli.quickstart.prepared-statements.php

They are far superior to any “real_escape_string” functions

2 Likes
6

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