parse JSON data with different structures - arrays

Question

I have a problem with accessing a certain property(hlink) in JSON code. This is because the structure of the JSON output is not always the same ,and as a result I get following error: "Cannot use object of type stdClass as array in...". Can someone help me to solve this problem?
JSON output 1 (Array)
Array (
[0] => stdClass Object (
[hlink] => http://www.rock-zottegem.be/
[main] => true
[mediatype] => webresource )
[1] => stdClass Object (
[copyright] => Rock Zottegem
[creationdate] => 20/03/2013 14:35:57
[filename] => b014933c-fdfd-4d93-939b-ac7adf3a20a3.jpg
[filetype] => jpeg
[hlink] => http://media.uitdatabank.be/20130320/b014933c-fdfd-4d93-939b-ac7adf3a20a3.jpg
)
JSON output 2
stdClass Object (
[copyright] => Beschrijving niet beschikbaar
[creationdate] => 24/04/2013 19:22:47
[filename] => Cinematek_F14281_1.jpg
[filetype] => jpeg
[hlink] => http://media.uitdatabank.be/20130424/Cinematek_F14281_1.jpg
[main] => true
[mediatype] => photo
)
And this is my code:
try {
if (!empty($img[1]->hlink)){
echo "<img src=" . $img[1]->hlink . "?maxheight=300></img>";
}
}
catch (Exception $e){
$e->getMessage();
}

Answer 1

Assuming this is PHP, and you know that the JSON always contains either an object or an array of objects, the problem boils down to detecting which you've received.
Try something like:
if (is_array($img)) {
$hlink = $img[0]->hlink;
} else {
$hlink = $img->hlink;
}

Answer 2

This isn't directly answering your question, but it should give you the means to investigate the problems you are having.
Code Sample
var obj1 = [ new Date(), new Date() ];
var obj2 = new Date();
obj3 = "bad";
function whatIsIt(obj) {
if (Array.isArray(obj)) {
console.log("obj has " + obj.length + " elements");
} else if (obj instanceof Date) {
console.log(obj.getTime());
} else {
console.warn("unexpected object of type " + typeof obj);
}
}
// Use objects
whatIsIt(obj1);
whatIsIt(obj2);
whatIsIt(obj3);
// Serialize objects as strings
var obj1JSON = JSON.stringify(obj1);
// Notice how the Date object gets stringified to a string
// which no longer parses back to a Date object.
// This is because the Date object can be fully represented as a sting.
var obj2JSON = JSON.stringify(obj2);
var obj3JSON = JSON.stringify(obj3);
// Parse strings back, possibly into JS objects
whatIsIt(JSON.parse(obj1JSON));
// This one became a string above and stays one
// unless you construct a new Date from the string.
whatIsIt(JSON.parse(obj2JSON));
whatIsIt(JSON.parse(obj3JSON));
Output
obj has 2 elements JsonExample:6
1369955261466 JsonExample:8
unexpected object of type string JsonExample:10
obj has 2 elements JsonExample:6
unexpected object of type string JsonExample:10
unexpected object of type string JsonExample:10
undefined