Session Member and Other member IDs are not being sent to my MySQL query. Private Messaging System

Question

For context I am new to jQuery, PHP, and MySQL. So apologies if this is an easy fix.

I am building a simple private messaging system based off my initial code for a public forum (which is much simpler). Going off what I have learned so far in the short span of time, I am almost done with the hard part (retrieving specific chat private data). But I am getting a undefined variable error that I can not seem to resolve.

Notice: Undefined variable: sessionmember in C:\\xampp\\htdocs\\StEndas\\handlers\\ajax_privatemessager.php on line 28

Notice: Undefined variable: othermember in C:\\xampp\\htdocs\\StEndas\\handlers\\ajax_privatemessager.php on line 28

Notice: Undefined variable: sessionmember in C:\\xampp\\htdocs\\StEndas\\handlers\\ajax_privatemessager.php on line 29

Notice: Undefined variable: othermember in C:\\xampp\\htdocs\\StEndas\\handlers\\ajax_privatemessager.php on line 29

No convo between you two yet.

Mock Up (pagemail.php)

This particular section of the mockup is contained within a while loop that prints the records of every member other than the user currently in session. All printed conversation windows are hidden with the a bootstrap pilltab menu (toggle-data).

    <div id="member_ID_<?php echo $row['member_ID'];?>" class="tab-pane fade">
                          <header class="clearfix">
                            <h4>Your conversation with <b><?php echo $row['member_name'];?></b>.</h4>
                          </header>
                          <div class="chat">
                            <div class="privatemessager-chathistory scrollfeed">

                            </div> <!-- end forum-chathistory -->
                            <form action="#" method="post">

                              <fieldset>
                                <textarea placeholder="Type message.." id="privatemessager-message" name="privatemessager-message" class="message-box" required></textarea>
                                <input type="text" id="privatemessager-sessionmember" name="privatemessager-sessionmember" value="<?php echo $_SESSION['member_ID'];?>"/>
                                <input type="text" id="privatemessager-othermember" name="privatemessager-othermember" value="<?php echo $row['member_ID'];?>"/>
                                <input type="hidden">
                              </fieldset>

                            </form>
                          </div> <!-- end chat -->
     </div>

jQuery Code (also in pagemail.php for now)

The sending message section of the code has not been modified yet for this new purpose, please ignore that bit.

           <script>

                        $(document).ready(function(){
                          loadChat();
                        });

                        $('#privatemessager-message').keyup(function(e){
                           var privatemessage = $(this).val();
                           // alert(e); // Displays the value of the keyboard button.
                          if(e.which == 13){ // 13 is the keyboard value of the 'Enter' key. "IF (USER HITS ENTER)"
                             $.post('handlers/ajax_privatemessager.php?action=sendPrivateMessage&privatemessager-message='+privatemessage, function(response){
                                 loadChat();
                                 $('#privatemessager-message').val('');
                             });
                          }

                        });

              /* THIS IS THE SECTION NEEDING ATTENTION */

                        function loadChat(){
                          $.post('handlers/ajax_privatemessager.php?action=getPrivatemessage', function(response){
                                $('.privatemessager-chathistory').html(response);
                          });
                        }

                        setInterval(function(){
                            loadChat();
                        }, 1000); // Every 1 second the method 'loadchat' is activated.

          </script>

PHP Code (ajax_privatemessager.php)

The sending message section of the code has not been modified yet for this new purpose, please ignore that bit.

**<?php
    session_start();
    include "db_Connect.php";


    if(isset($_REQUEST['action'])){
      switch($_REQUEST['action']){

        case "sendPrivateMessage":

        $privatemessage = $_GET["privatemessager-message"];
        $sessionmember = $_GET["privatemessager-sessionmember"];
        $othermember = $_GET["privatemessager-othermember"];

        $privatemessage = addslashes($privatemessage);

           $sql = "INSERT INTO tbl_forum (message, member_ID) VALUES ('$privatemessage', '$new_member_ID' )";
           $result = $mysqli->query($sql) or die(mysqli_error($mysqli));

           echo 1;

        break;


      /* THIS IS THE SECTION NEEDING ATTENTION */

        case "getPrivatemessage":

               $sql = "SELECT privatemessage_message, privatemessage_time_created, privatemessage_sent_by, privatemessage_sent_to
                       FROM  tbl_privatemessages
                       WHERE (privatemessage_sent_by = '$sessionmember' AND privatemessage_sent_to = '$othermember')
                       OR (privatemessage_sent_to = '$sessionmember' AND privatemessage_sent_by = '$othermember')
                       ORDER BY privatemessage_time_created ASC";
               $result = $mysqli->query($sql) or die(mysqli_error($mysqli));

               if ($result->num_rows > 0) {
                 // output data of each row
                 while($row = $result->fetch_assoc()) {
                   ?>
                          <div class="chat-message clearfix">

                                    <div class="chat-message-content clearfix">
                                        <span class="chat-time"><?php echo $row['privatemessage_time_created'];?></span>
                                        <h5><?php echo $row['privatemessage_sent_by'];?></h5>
                                        <p class="chat-message"><?php echo $row['privatemessage_message'];?></p>
                                    </div> <!-- end chat-message-content -->

                          </div> <!-- end chat-message -->
                                <hr>

                   <?php
                 }
               } else {
                 echo "</br></br>";
                 echo "No convo between you two yet.";
               }

        break;
      }
    }

    ?>**

Any and all advice will be taken with much gratitude. Thank you in advance for taking your time to read this.

Answer 1

Your problem appears to be that in the case "getPrivatemessage" code you are attempting to use your $sessionmember etc. variables, however you have not actually set them, since the code to set their values ie

$privatemessage = $_GET["privatemessager-message"];
$sessionmember = $_GET["privatemessager-sessionmember"];
$othermember = $_GET["privatemessager-othermember"];

only exists in the "sendPrivateMessage" branch of the switch statement. You need to either copy that code into the "getPrivatemessage" branch or perhaps move it to between

if(isset($_REQUEST['action'])){

and

switch($_REQUEST['action']){