Teleconference Horror

In the spring of 2020, with very little warning, every school in the United States shut down due to the ongoing global pandemic. Classrooms had to move to virtual meeting software like Zoom, which was never intended to be used as the primary means of educating grade schoolers. The teachers did wonderfully with such little notice, and most kids finished out the year with at least a little more knowledge than they started. This story takes place years before then, when online schooling was seen as an optional add-on and not a necessary backup plan in case of plague.

TelEdu provided their take on such a thing in the form of a free third-party add-on for Moodle, a popular e-learning platform. Moodle provides space for teachers to upload recordings and handouts; TelEdu takes it one step further by adding a "virtual classroom" complete with a virtual whiteboard. The catch? You have to pay a subscription fee to use the free module, otherwise it's nonfunctional.

Initech decided they were on a tight schedule to implement a virtual classroom feature for their corporate training, so they went ahead and bought the service without testing it. They then scheduled a demonstration to the client, still without testing it. The client's 10-man team all joined to test out the functionality, and it wasn't long before the phone started ringing off the hook with complaints: slowness, 504 errors, blank pages, the whole nine yards.

That's where Paul comes in to our story. Paul was tasked with finding what had gone wrong and completing the integration. The most common complaint was that Moodle was being slow, but upon testing it himself, Paul found that only the TelEdu module pages were slow, not the rest of the install. So far so good. The code was open-source, so he went digging through to find out what in view.php was taking so long:

$getplan = telEdu_get_plan();$paymentinfo = telEdu_get_payment_info();$getclassdetail = telEdu_get_class($telEduclass->class_id);$pricelist = telEdu_get_price_list($telEduclass->class_id);

Four calls to get info about the class, three of them to do with payment. Not a great start, but not necessarily terrible, either. So, how was the info fetched?

function telEdu_get_plan() { $data['task'] = TELEDU_TASK_GET_PLAN; $result = telEdu_get_curl_info($data); return $result;}

"They couldn't possibly ... could they?" Paul wondered aloud.

function telEdu_get_payment_info() { $data['task'] = TELEDU_TASK_GET_PAYMENT_INFO; $result = telEdu_get_curl_info($data); return $result;}

Just to make sure, Paul next checked what telEdu_get_curl_info actually did:

function telEdu_get_curl_info($data) { global $CFG; require_once($CFG->libdir . '/filelib.php'); $key = $CFG->mod_telEdu_apikey; $baseurl = $CFG->mod_telEdu_baseurl; $urlfirstpart = $baseurl . "/" . $data['task'] . "?apikey=" . $key; if (($data['task'] == TELEDU_TASK_GET_PAYMENT_INFO) || ($data['task'] == TELEDU_TASK_GET_PLAN)) { $location = $baseurl; } else { $location = telEdu_post_url($urlfirstpart, $data); } $postdata = ''; if ($data['task'] == TELEDU_TASK_GET_PAYMENT_INFO) { $postdata = 'task=getPaymentInfo&apikey=' . $key; } else if ($data['task'] == TELEDU_TASK_GET_PLAN) { $postdata = 'task=getplan&apikey=' . $key; } $options = array( 'CURLOPT_RETURNTRANSFER' => true, 'CURLOPT_SSL_VERIFYHOST' => false, 'CURLOPT_SSL_VERIFYPEER' => false, ); $curl = new curl(); $result = $curl->post($location, $postdata, $options); $finalresult = json_decode($result, true); return $finalresult;}

A remote call to another API using, of all things, a shell call out to cURL, which queried URLs from the command line. Then it waited for the result, which was clocking in at anywhere between 1 and 30 seconds ... each call. The result wasn't used anywhere, either. It seemed to be just a precaution in case somewhere down the line they wanted these things.

After another half a day of digging through the rest of the codebase, Paul gave up. Sales told the client that "Due to the high number of users, we need more time to make a small server calibration."

The calibration? Replacing TelEdu with BigBlueButton. Problem solved.

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