AJAX call error 500 (Internal Server Error) - php

Question

I have a page that, upon loading, fills 3 drop down menus for uses to select from. On my localhost, this works fine, but on my live server I get the error in Developer Tools "POST (my site's name) 500 (Internal Server Error) jquery.js:8630.
Here is the jquery:
$(function() {
//after load, populate lists
Update_List_ProcedureAreas_Schedule();
Update_List_Patients_Cancel();
Update_List_Cancel_Reasons();
});
Here's one of the functions, but the other two are nearly identical, but all 3 fail. I send to a generic functions php file the function that I want to run, and if there are any parameters with the function as well. Maybe be a bit weird, but it helps me organize my code:
function Update_List_Patients_Cancel() {
$.ajax({
url: 'php/functions.php',
type: 'POST',
dataType: 'json',
cache: false,
data: {Function_ID: 'pull_patient_list_cancel'},
success: function(data){
var dropDown = document.getElementById("selectedpatient_cancel");
dropDown.options.length=0;
dropDown[dropDown.length] = new Option('', '')
for (i = 0; i < data.length; i++) {
dropDown[dropDown.length] = new Option(data[i].Patient_Name, data[i].Patient_UID)
}
},
error: function() {
}
});
}
Here is the PHP in 'php/functions.php' which takes the Function_ID and then uses a switch to verify the input and then call the function with any appropriate variables:
<?php
session_start();
//Make sure a funciton was sent
if(isset($_POST['Function_ID']) == true) {$tempFunction = $_POST['Function_ID'];}
else {echo "No fuction selected";}
//switch to functions
switch($tempFunction) {
case 'pull_patient_list_cancel':
pull_patient_list_cancel();
break;
}
//Pull patient list for cancel drop down
function pull_patient_list_cancel() {
require $_SESSION['db_connect']; //code to connect to the database, which is successful, btw
$returnArray = array();
$sql = "
SELECT Patient_UID, Patient_Name
FROM tbl_patients
WHERE Active = 1
";
if($result = $conn->query($sql)) {
$conn->close();
foreach($result->fetch_all(MYSQLI_ASSOC) as $row) {
$returnArray[] = $row;
}
echo json_encode($returnArray);
} else {
$conn->close();
echo "Failed - pull patient lists cancel";
}
}
It looks like for some reason, I'm not able to execute in the foreach loop. I've put in bogus echos to see where the function stops running, and it won't output any echo within the for each loop or after it, but it will up until that loop starts. I've check the response log in Development Tools and see the bogus echos coming through until the foreach loop, and then nothing.
Any ideas?
------------Solution-----------------
The problem was that I had mysqlnd installed on my localhost xampp setup, but it did not install on my digitalocean lampp server that I set up today. So that made the fetch_all(MYSQLI) not work. However, I could stick with the mysql installation and use fetch_assoc() and it worked fine.
But, I ended up installing mysqlnd on my digitalocean droplet by using:
apt-get install php5-mysqlnd
and then restarting the server with
service apache2 restart
and now all of my fetch_all(MYSQLI) functions work. Thanks everyone for your help.

Answer 1

You cannot close the connection before you fetch the results for the foreach. Move the connection close after the loop.
Better still, remove both connection close statements, and put a single one after the else block.
if($result = $conn->query($sql)) {
foreach($result->fetch_all(MYSQLI_ASSOC) as $row) {
$returnArray[] = $row;
}
echo json_encode($returnArray);
} else {
echo "Failed - pull patient lists cancel";
}
$conn->close();

Answer 2

There is syntax error on your PHP function page....
You cannot use isset like this
change your code from
if(isset($_POST['Function_ID']) == true) //which is wrong
To
if(isset($_POST['Function_ID']) && $_POST['Function_ID'])==true)
// this is the right way
Connection should be closed after all the program has executed and
else{}
$conn->close();