JSON Data - Validate Properties in PHP

Question

I'm trying to validate a simple schema against large JSON data. I only need to find if the properties I'm using in my PHP code are present in the JSON data. I've looked at several libraries but they seem overkill since they even validate the data type and I only need the presence of properties.

For example: PHP variables I use: name, age, gender JSON Data:

{
  "Location": "10.2.00",
  "Name": "Foo",
  "Age": "30",
  "Race": "NA",
  "Gender": "Male"
}

So there could be extra data in JSON.

How can I check for the presence of JSON variables in my PHP code or another JSON schema?

Don't Panic · Accepted Answer · 2017-02-17 18:36:17Z

1

If you just need to verify that the keys from your simple schema are present, you can use array_diff_key.

Define your simple schema (keep in mind that the keys are case sensitive.)

$simple_schema = ['Name', 'Age', 'Gender'];

Decode your large JSON data (be sure to use the second argument of json_decode to get an array for comparison.)

$json = json_decode($large_json_data, true);

Then get the difference using array_diff_key.

$missing_keys = array_diff_key(array_flip($simple_schema), $json);

The array_flip converts the values of your simple schema to keys for the comparison.

if $missing_keys is empty, then all the keys in your schema were present in the large JSON data.

edited Feb 17, 2017 at 18:36

answered Feb 17, 2017 at 18:31

Don't Panic

41.9k11 gold badges70 silver badges87 bronze badges

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

2 Comments

user3704920 Over a year ago

@Don't Panic this is a gorgeous solution. The only down-side I see is the case sensitivity. Anyway to make insensitive?

Don't Panic Over a year ago

It's possible to do it case-insensitively, but I don't think it would be possible with array_diff_key. You'd probably need to loop and convert both keys to a common case. If you knew that all the keys in the large data would be in a certain case, you could convert your simple schema keys to that case beforehand.

AbraCadaver · Accepted Answer · 2017-02-17 21:25:23Z

1

So with the addition of the case-insensitivity:

$props = array('name', 'age', 'gender');
$array = array_map('strtolower', array_keys(json_decode($json, true)));

if(empty(array_diff($props, $array))) {
    echo "All properties exist";
}

Use an array of lowercase property names
Get the keys from the JSON and map to strtolower()
Check if the difference is empty() meaning all properties exist

answered Feb 17, 2017 at 21:25

AbraCadaver

79.2k7 gold badges75 silver badges91 bronze badges

Collectives™ on Stack Overflow

JSON Data - Validate Properties in PHP

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related