PHP Notice: Trying to get property of non object error

Question

I am trying to get data from a webpage which shows most of the time just the value 0 but it sometimes changes to something like this.

{"deals":[{"symbol":"SymbolTest","type":"TestCall","amount":"0.00","duration":"30","durationUnit":"m","date":"2017.07.12 7:55:10 PM"}]}

But this text is only shown there instead of 0 for approx. 1-2 seconds.

So I created a script which checks the webpage constantly if the value changed from 0 to something else. And if another text is shown i will get a notification via IFTTT on my phone with the important data I need. (Theoretically) Thats where I am stuck. I think I got everything correctly but I just can not find my mistake.

This is my current code:

function sendNotification($url, $fields) {
  //url-ify the data for the POST
  $fields_string = '';
  foreach($fields as $key=>$value) { $fields_string .= $key.'='.$value.'&'; 
}
  rtrim($fields_string, '&');

  //open connection
  $ch = curl_init();

  //set the url, number of POST vars, POST data
  curl_setopt($ch,CURLOPT_URL, $url);
  curl_setopt($ch,CURLOPT_POST, count($fields));
  curl_setopt($ch,CURLOPT_POSTFIELDS, $fields_string);

  //execute post
  $result = curl_exec($ch);

  //close connection
  curl_close($ch);
}

$url = 'http://example.com:54321/?request=deals&token=example';
$notifyUrl = 'https://maker.ifttt.com/trigger/dealreceived/with/key/examplekey';

while (true) {
  $content = file_get_contents($url);

  if ($content != '0') {
    echo 'No 0 found -IFTTT request sent';

    $data = json_decode($content);
    $notificationData = [];

    foreach ($data->deals as $deal) {
      $notificationData = [
        'value1' => $deal->symbol,
        'value2' => $deal->type,
        'value3' => $deal->duration
      ];

      sendNotification($notifyUrl, $notificationData);
    }

  }
}

The error I am getting is the following:

PHP Notice:  Trying to get property of non-object in /home/example.cloudwaysapps.com/example/public_html/watch.php on line 36                       

PHP Warning:  Invalid argument supplied for foreach() in /home/example.cloudwaysapps.com/example/public_html/watch.php on line 36

This is line 36:

foreach ($data->deals as $deal) {

Any advice is appreciated. I am stuck unfortunately..

Yes try to var_dump the whole $data and see what results you get — T30, Jul 13 '17 at 15:38
Possible duplicate of [Notice: Trying to get property of non-object error](https://stackoverflow.com/questions/22636826/notice-trying-to-get-property-of-non-object-error) — Jonnix, Jul 13 '17 at 15:38
If I understand correctly I could do it like this foreach($data[0]->deals as &deal){ — Salexes, Jul 13 '17 at 16:11

score 0 · Answer 1 · answered Jul 13 '17 at 16:11

0

There are some places where you can fail here: file_get_content - you should check if it return false - maybe you fail to get the content at all. json_decode - may return false if the syntax is bad, you should check it and if it is false you can check json_last_error to see what the error is.

answered Jul 13 '17 at 16:11

Danny Yeshurun

407
6
10

Thanks will try that now! – Salexes Jul 13 '17 at 16:14

PHP Notice: Trying to get property of non object error

1 Answers1