How to validate json string in PHP like JSON_VALID in mysql? [duplicate]

Question

I would like to validate json string before inserting it into mysql database so that JSON_VALID constraint is not violated. Using json_decode like

json_decode($string, true, 512, JSON_THROW_ON_ERROR);

is not enough because

json_decode('["\u001f?\b\u0000\u0000\u0000\u0000\u0000\u0002\u0003KL)NKLI\u0003\u0000z,?o\u0007\u0000\u0000\u0000"]', true, 512, JSON_THROW_ON_ERROR);

throws no error but

select JSON_VALID('["\u001f?\b\u0000\u0000\u0000\u0000\u0000\u0002\u0003KL)NKLI\u0003\u0000z,?o\u0007\u0000\u0000\u0000"]') as result;

returns false. How can I achieve my goal?

jsonlint.com says it's valid.

Barmar
– Barmar

2022-07-31 00:31:55 +00:00
Commented Jul 31, 2022 at 0:31 — Barmar
– Barmar, Commented Jul 31, 2022 at 0:31

Barmar · Accepted Answer · 2022-07-31 02:00:09Z

1

The JSON is valid, that's why the PHP version doesn't throw an error. But in SQL you need to escape all the backslashes to make them literal, so they'll be seen by the JSON parser. This is why MySQL mistakenly claimed it's not valid.

> select JSON_VALID('["\\u001f?\\b\\u0000\\u0000\\u0000\\u0000\\u0000\\u0002\\u0003KL)NKLI\\u0003\\u0000z,?o\\u0007\\u0000\\u0000\\u0000"]') as result; 
+--------+
| result |
+--------+
|      1 |
+--------+

edited Jul 31, 2022 at 2:00

answered Jul 31, 2022 at 0:36

Barmar

789k57 gold badges554 silver badges669 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Murad Ali Over a year ago

He want to validate it using PHP.

adbeno Over a year ago

Ok, so the problem was escaping.

Barmar Over a year ago

@MuradAli The PHP is fine. I'm just showing why he got a different result in MySQL.

Murad Ali · Accepted Answer · 2022-07-31 01:45:23Z

0

The string you calling a json string is a unicode. But you want to validate your json string using PHP so here is the code.

function json_validator($data=NULL) {

  if (!empty($data)) {

                @json_decode($data);
                return (json_last_error() === JSON_ERROR_NONE);
        }
        return false;
}

$jsonString = '["\u001f?\b\u0000\u0000\u0000\u0000\u0000\u0002\u0003KL)NKLI\u0003\u0000z,?o\u0007\u0000\u0000\u0000"]';

echo (json_validator($jsonString) ? "JSON is Valid" : "JSON is Not Valid");

Source

Well this return true, but the string is an escaped unicode in a json style. 😂

Updated Method 2

$jsonString = '["\u001f?\b\u0000\u0000\u0000\u0000\u0000\u0002\u0003KL)NKLI\u0003\u0000z,?o\u0007\u0000\u0000\u0000"]';
try {
    json_decode($jsonString, true, 512, JSON_THROW_ON_ERROR);
} catch (\Exception $e) {
    // echo $e->getMessage();
    echo "Invalid JSON";
}

edited Jul 31, 2022 at 1:45

answered Jul 31, 2022 at 0:40

Murad Ali

5982 silver badges16 bronze badges

2 Comments

Barmar Over a year ago

Doesn't the JSON_THROW_ON_ERROR flag serve the same purpose?

Murad Ali Over a year ago

Yeah, we can use that I just add the second method.

Collectives™ on Stack Overflow

How to validate json string in PHP like JSON_VALID in mysql? [duplicate]

2 Answers 2

3 Comments

2 Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

2 Comments

Linked

Related