CakePHP 2 requestAction breaks my JSON encoding to Swift... invisibly - php

Question

I've got CakePHP 2 outputting JSON, and I've got Swift 2 code in the Xcode iPhone emulator loading that JSON data.
In my Controller, here's the code that generates the JSON:
public function iosDemoIndex() {
$studentDataIn = $this->Student->getStudentsByUserId(298, 'rASC');
$studentDataOut = [];
foreach ($studentDataIn as $student) {
//$currentIep = $this->Iep->requestAction('/ieps/getCurrentIep/' . $student['Student']['id']);
$goals = $this->Goal->find('all', array('conditions' => array('Goal.student_id =' => $student['Student']['id'])));
$goalHolder = array();
foreach ($goals as $goal) {
array_push($goalHolder, $goal['Goal']['goal_title']);
}
array_push($studentDataOut, array('studentName' => $student['Student']['l_name']. ", " . $student['Student']['f_name'], 'studentGoals' => $goalHolder));
}
$this->set(array(
'students' => $studentDataOut,
'_serialize' => array('students')
));
}
Which works fine. My Swift code succesfully loads the students array via the JSON into an array of structs. But if I simply un-comment line 5 (which grabs data that I ultimately hope to use to restrict the find in line 6), Xcode gives me:
Error with Json: Error Domain=NSCocoaErrorDomain Code=3840 "Invalid value around character 2." UserInfo={NSDebugDescription=Invalid value around character 2.}
Line 5 shouldn't alter the JSON document in any way. And when I look at the JSON itself, it looks the same regardless of whether the line's commented out.
So, any ideas what an unrelated, ought-to-be invisible requestAction could be doing that's breaking my JSON... in a way that I can't see when I look at it? Thanks.

Answer 1

For posterity (future-me):
It was a login issue. The reason the JSON looked identical in my browser was that I had an active user session in the browser at the time. Without that session, (for instance when the iOS emulator tried to load the JSON page) the CakePHP was returning a redirect to login. Viable solutions include replicating the requestAction code in the JSON-generating controller (though that's not very DRY), or establishing proper login handling on the Swift side of things.