Reading JSON returns empty

Question

I am reading a JSON from a URL, as code below:

$link1 = file_get_contents('http://gwmestampas.com.br/arquivo.json');

$obj = json_decode($link1);
echo $obj->event;
echo $obj["event"];


 foreach($obj as $link){
    $event = $link->event;
    $event2 = $link["event"];
    //$numOrd =  $link->resource->payment->_links->order->title;
    //$tipoPag =  $link->resource->payment->events->type;
    //$numPag =  $link->resource->payment->id;        
}; 

echo $event.'-<br>';
echo $event2.'-<br>';
echo $numOrd.'-<br>';
echo $tipoPag.'-<br>';
echo $numPag.'-<br>';

I tried several ways but always returns empty.

Answer 1

The returned JSON is invalid. It has multiple "loose" objects, one followed by the other:

{"date":"","env":"" ... }{"date":"","env":"", ... } 

Note that after the first object is closed with }, another object with {. This is not a valid JSON.

The correct thing would be for these objects to be inside some other structure, like an array, for example:

[ {"date":"","env":"" ... }, {"date":"","env":"", ... }, ... ]

That would be a valid JSON. In the example above, we have an array: it is delimited by [] and there are commas separating the elements.

Ideally, the URL should return a JSON in the correct format. If you have no control over the URL you are accessing, the only way is to manually manipulate the string.

---

Attention: the code below has been made specifically for the JSON in question. The premise is assumed that JSON always comes like this: objects always start with {"date": and there are no spaces between them. If there is the slightest change in format, it no longer works (so ideally the URL should return a valid JSON).

The idea is to transform this string, which contains objects in sequence, into an array. For this we need to put [ at first, ] at the end and a comma between the objects:

$link1 = file_get_contents('http://gwmestampas.com.br/arquivo.json');
$obj = json_decode('['. preg_replace('/((?<!^)\{"date":)/', ',$1', $link1). ']', true);

Regular expression takes string {"date": (provided it is not at the beginning) and puts a comma before it. I also put the [ and ] and pass on the result to json_decode.

Thus, $obj will have all objects, simply iterate by the same:

foreach ($obj as $link) {
    echo $link['event'];
    if (array_key_exists('payment', $link['resource'])) // nem todo resource tem payment
        echo ', '. $link['resource']['payment']['_links']['order']['title'];
    echo PHP_EOL;
}

From what I’ve seen, resouce may or may not have payment or other fields, but then just go testing if they exist before accessing them.

---

Remembering again that this is a limited solution. If the string changes (for example, it returns an object that does not start with {"date":, or any other change that no longer matches our premises), it no longer works. If you have any property date inside another internal object, the regex will insert a comma where it should not (luckily it does not, which is why it works in this case). Of course, depending on the change, simply change the regex, but using regex to manipulate JSON is not ideal.

The ideal is that the service returns a valid JSON, so you don’t have to keep doing these tricks to fix the string.