How handling error of JSON decode by try and catch

Question

I am unable to handle JSON decode errors. Here is my code:

try {
    $jsonData = file_get_contents($filePath) . ']';
    $jsonObj  = json_decode($jsonData, true);
}
catch (Exception $e) {
    echo '{"result":"FALSE","message":"Caught exception: ' . $e->getMessage() . ' ~' . $filePath . '"}';
}

I am a new PHP programmer. Sorry, if something is wrong.

See here: stackoverflow.com/questions/12265830/…

Gaurav Dave
– Gaurav Dave

2015-07-23 05:51:23 +00:00
Commented Jul 23, 2015 at 5:51 — Gaurav Dave
– Gaurav Dave, Commented Jul 23, 2015 at 5:51

user3567805 · Accepted Answer · 2015-07-23 05:47:38Z

37

Another way to handle json decode error:-

if ($jsonObj === null && json_last_error() !== JSON_ERROR_NONE) {
   echo "json data is incorrect";
}

answered Jul 23, 2015 at 5:47

user3567805

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1 Comment

Jurakin Over a year ago

I had to remove $jsonObj === null.

V. Bozz · Accepted Answer · 2021-10-01 15:48:48Z

36

Since PHP 7.3 one can use the JSON_THROW_ON_ERROR constant.

try {
    $jsonObj = json_decode($jsonData, $associative=true, $depth=512, JSON_THROW_ON_ERROR);
} catch (Exception $e) {
    // handle exception
}

More: https://www.php.net/manual/de/function.json-decode.php#refsect1-function.json-decode-changelog

edited Oct 1, 2021 at 15:48

V. Bozz

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answered Mar 18, 2020 at 16:53

sergej

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Comments

b00t · Accepted Answer · 2017-07-24 19:51:58Z

11

May be you can try, validating json_decode

try {
  $jsonData = file_get_contents($filePath) . ']';
  $jsonObj  = json_decode($jsonData, true);

  if (is_null($jsonObj)) {
    throw ('Error');
  }
} catch (Exception $e) {
  echo '{"result":"FALSE","message":"Caught exception: ' . 
    $e->getMessage() . ' ~' . $filePath . '"}';
}

Read this too

edited Jul 24, 2017 at 19:51

b00t

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answered Jul 23, 2015 at 5:47

Dimag Kharab

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5 Comments

reformed Over a year ago

Why call is_null() when you can just check if $jsonObj === null?

Milen Gardev Over a year ago

There is no difference between comparing is_null() and === null. I would say its just a preference. Check this one stackoverflow.com/questions/8228837/is-nullx-vs-x-null-in-php for more information.

James Over a year ago

@MilenGardev the answer you linked to does not state "there is no difference". It in fact lists the differences, and thus which one to chose depends on the scenario. If you do not need a callback then there's no sense in not using the more performant === null than the function which has additional overhead.

Lulceltech Over a year ago

@James I would challenge you to benchmark the 2 cases side by side over 1000 iterations. The performance difference is so negligible that it almost won't even be measurable with microtime. Even in an environment that needs to be highly optimized, this wouldn't even make my list.

James Over a year ago

"If you do not need XYZ then there's no sense in not using the more performant"

Verkade89 · Accepted Answer · 2015-07-23 05:46:27Z

5

json_decode returns null when a error occurs, like no valid json or exceeded depth size. So basically you just check with if whether the jsondata you obtained is null or not. If it is, use json_last_error to see what went wrong, if not then continue with the script.

$json_data = json_decode($source, true);

if($json_data == null){
  echo json_last_error() . "<br>";
  echo $source; // good to check what the source was, to see where it went wrong
}else{
  //continue with script
}

Something like that should work.

answered Jul 23, 2015 at 5:46

Verkade89

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1 Comment

Vladimir Ch Over a year ago

nope, when i exec json_decode on bad content, other code is useless, php return "Exception" and nothing i can do !

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