Passing POST Parameters always equals 0

Question

I have the simple aspect of sending the POST request as:

As can be seen, in the PHP server code I have the createGroup action with, the line $groupName = $_REQUEST['group_name'];, that should accept the group_name parameter in the POST request.

However, looking at the log/or the result of the request, the variable $groupName is always 0.

I have other actions in the server index that use this exact same $_REQUEST logic and never have issues passing parameters through a POST request.

How can I get this to work?

case "createGroup":

        // Getting user Id of person created, and checking if not null
        if ($userId = authenticateUser($db, $username, $password, $gcmregid))
        {

            //echo "passed1";
            $groupName = $_REQUEST['group_name'];

            echo "user_sync_id is: " + $userId + ", ";

            echo "groupName is: " + $groupName + ", ";

            if($stmt1 = $db -> prepare("select 
                                            count(*) as num_present
                                        from users_groups a
                                        inner join groups b
                                            on a.group_sync_id = b.group_sync_id
                                        where user_sync_id = ?
                                          and b.group_name = ?
                                        limit 1;"))
            {
                $stmt1->bind_param("ss", $userId, $groupName);
                $stmt1->execute();
                $stmt1->bind_result($present);
                //$num_affected = mysqli_affected_rows($db);
                $stmt1->close();

                //echo "value of present is: "+ $present;

                if($present < 1)
                {
                    if($stmt2 = $db->prepare("insert into groups(group_sync_id, group_name, created_at, group_channel_id)
                                            SELECT 
                                            CASE 
                                            WHEN MAX(group_sync_id) is null
                                            THEN 0
                                            ELSE MAX(group_sync_id)
                                            END + 1
                                            , ?
                                            ,NOW()
                                            ,concat(SUBSTRING(MD5(NOW()),1,7) , cast(ceil(rand()*1000000) as char))
                                            FROM groups;"))
                    {
                        $stmt2->bind_param("s", $groupName);
                        $stmt2->execute();
                        $stmt2->close();

                        if($stmt3 = $db-> prepare("SELECT group_sync_id, group_channel_id
                                                   from groups 
                                                   where group_sync_id = 
                                                   (SELECT 
                                                       max(group_sync_id) as group_sync_id 
                                                   FROM groups 
                                                   WHERE group_name = ?);"))
                        {
                            $stmt3->bind_param("s", $groupName);
                            $stmt3->execute();                          
                            $stmt3->bind_result($getNewGroupId, $group_channel_id);
                            $stmt3->fetch();
                            $stmt3->close();

                            //echo $getNewGroupId;

                            if($stmt4 = $db -> prepare("insert into users_groups(user_group_sync_id, group_sync_id, user_sync_id, status, create_dt)
                                                        SELECT
                                                        CASE
                                                        WHEN max(user_group_sync_id) is null
                                                        THEN 0
                                                        ELSE max(user_group_sync_id)
                                                        END + 1
                                                        , ?
                                                        , ?
                                                        , 1
                                                        , NOW()
                                                        from users_groups;"))
                            {
                                $stmt4->bind_param("ss", $getNewGroupId, $userId);
                                $stmt4->execute();                          
                                $stmt4->close();

                                $newUsersGroup = "SELECT MAX(user_group_sync_id) as user_group_sync_id from users_groups;";

                                if($result5 = $db->query($newUsersGroup))
                                {
                                    //echo "passed7";
                                    $row2 = $result5->fetch_assoc();

                                    $getNewUserGroupId = $row2['user_group_sync_id'];

                                    $out = json_encode(array('group_sync_id' => $getNewGroupId, 'user_group_sync_id' => $getNewUserGroupId, 'group_channel_id' => $group_channel_id ));

                                }
                                else 
                                {
                                    $out = FAILED;
                                }                       

                            }
                            else
                            {
                                $out = FAILED;
                            }   

                        }
                        else
                        {
                            $out = FAILED;
                        }

                    }
                    else
                    {

                    }
                }
                else
                {
                    $out = FAILED;
                }           

            }
            else
            {
                $out = FAILED;
            }
        }
        else
        {
            $out = FAILED;
        }       

    break;

Answer 1

+ is an arithmetic operator not a string operator. . is the concatenation operator for php

echo "groupName is: " . $groupName . ", ";