Calling a function in a function with JSON arrays - php

Question

I have a function A which loads the data from db if the user has liked the image. I have another function B which loads the count for the total number of likes for the image. Both these functions return response using JSON.
If I call them individually, everything works fine, but if I call function B in function A, I get no JSON response and nothing happens although firebug does show two JSON arrays being outputted.
What is wrong with the code?
Function A:
public function loadLikes() {
//sql query
try
{
$query = $this->_db->prepare($sql);
$params = array(':imageid' => $imageid, ':author' => $author);
$query->execute($params);
//calling function B
$this->countLikes($imageid);
if ($query->rowCount() > 0) {
while ($row = $query->fetch(PDO::FETCH_ASSOC)) {
if ($row['like'] == '1') {
$response = json_encode(array('like' => true));
echo $response;
return TRUE;
}
elseif ($row['like'] == '2') {
$response = json_encode(array('unlike' => true));
echo $response;
return TRUE;
}
else {
$error = "Invalid";
$response = json_encode(array('like' => false, 'text' => $error));
echo $response;
return FALSE;
}
}
}
else {
$response = json_encode(array('unlike' => true));
echo $response;
return FALSE;
}
}
catch(PDOException $ex)
{
echo json_encode(array('like' => false, 'text' => $ex));
return FALSE;
}
}
Function B:
public function countLikes($i) {
//sql query
try
{
$query = $this->_db->prepare($sql);
$params = array(':imageid' => $i);
$query->execute($params);
if ($query->rowCount() > 0) {
$count = $query->fetchColumn();
$response = json_encode(array('count' => $count));
echo $response;
return TRUE;
}
}
catch(PDOException $ex)
{
return FALSE;
}
}
jQuery:
$.ajax({
type: "POST",
url: url,
data: postData,
dataType: "json",
success: function(data){
$(".count-like").show(600).text(data.count);
if(data.like) {
$("a#alike").attr('class', 'starred');
}
else if (data.unlike) {
$("a#alike").attr('class', 'unlike');
}
else {
alert(data.text);
}
}
});

Answer 1

If you invoke both functions, then each will output a JSON array. This will result in a HTTP response with following content:
{"like":1}{"count":2}
Both arrays would be valid separately. But if concatenated like this, it's no longer valid JSON.
Instead of outputting the json serialization with echo you should collect it in a temporary variable, merge the two arrays, and then output the combined array with a single:
echo json_encode(array_merge($countArray, $likeArray));
Example adaptions of your code
Function B should become:
public function countLikes($i) {
//sql query
try
{
$query = $this->_db->prepare($sql);
$params = array(':imageid' => $i);
$query->execute($params);
if ($query->rowCount() > 0) {
$count = $query->fetchColumn();
/* JUST RETURN HERE */
return (array('count' => $count));
}
}
catch(PDOException $ex)
{
/* INSTEAD OF FALSE use an empty array,
which is interpreted as false in boolean context*/
return array();
}
}
Then when you call the function:
//calling function B
$countArray = $this->countLikes($imageid);
This will always be an array. Which you then can use in the output code:
$response = json_encode(array('like' => true) + $countArray);
(It's still inadvisable to have an echo right there. But too much code, too little context to propose a nicer rewrite. And if it works, ..)