JSON Property of non-object & Invalid argument supplied for foreach - php

Question

I have a wordpress function that calls an API via Zebra_cURL and then uses json_decode to render the data appropriately. Yet there is erratic behavior and the following two errors are occurring: Trying to get property of non-object in [template file] on line 42 and through lines 50.
The lines in question are below:
//Course display callback function
function display_courses($result) {
$result->body = json_decode(html_entity_decode($result->body));
$title = $result->body[0]->{'Title'};
$term = $result->body[0]->{'Term'};
$meetings = $result->body[0]->{'Meetings'};
$status = $result->body[0]->{'Status'};
$course_number = $result->body[0]->{'OfferingName'};
$clean_course_number = preg_replace('/[^A-Za-z0-9\-]/', '', $course_number);
$credits = $result->body[0]->{'Credits'};
$instructor = $result->body[0]->{'InstructorsFullName'};
$description = $result->body[0]->{'SectionDetails'}[0]->{'Description'};
}
And then later I get an error Invalid argument supplied for foreach() in [template file] on line 64 which is:
//Call callback function
function parse_courses($result) {
$result->body = json_decode(html_entity_decode($result->body));
$course_data = array();
foreach($result->body as $course) {
[code]
}
[more code]
}
What exactly am I doing wrong here to cause these errors?
Here's a link to the full template file. Apologies for the vast code dump but I'm a bit in over my head with this.

Answer 1

You must always verify the output of functions/methods if the result if "as expected"
In your case, you did not check what json_decode() has returned
function parse_courses($result) {
$result = json_decode(html_entity_decode($result->body));
if ((!is_array ($result) && !is_object($result)) ||
(is_array($result) || count($result) == 0) ||
(json_last_error() != JSON_ERROR_NONE)) { // only for PHP >= 5.3.0
// log the error or warning here ...
// $input = $result;
// $output = print_r ($result, TRUE);
// Only for PHP >= 5.3.0
// json_last_error();
// json_last_error_msg();
return -1;
}
$result->body = $result;
$course_data = array();
foreach($result->body as $course) {
[code]
}
[more code]
}