Using json_encode on objects in PHP (regardless of scope)

Question

I'm trying to output lists of objects as json and would like to know if there's a way to make objects usable to json_encode? The code I've got looks something like

$related = $user->getRelatedUsers();
echo json_encode($related);

Right now, I'm just iterating through the array of users and individually exporting them into arrays for json_encode to turn into usable json for me. I've already tried making the objects iterable, but json_encode just seems to skip them anyway.

edit: here's the var_dump();

php > var_dump($a);
object(RedBean_OODBBean)#14 (2) {
  ["properties":"RedBean_OODBBean":private]=>
  array(11) {
    ["id"]=>
    string(5) "17972"
    ["pk_UniversalID"]=>
    string(5) "18830"
    ["UniversalIdentity"]=>
    string(1) "1"
    ["UniversalUserName"]=>
    string(9) "showforce"
    ["UniversalPassword"]=>
    string(32) ""
    ["UniversalDomain"]=>
    string(1) "0"
    ["UniversalCrunchBase"]=>
    string(1) "0"
    ["isApproved"]=>
    string(1) "0"
    ["accountHash"]=>
    string(32) ""
    ["CurrentEvent"]=>
    string(4) "1204"
    ["userType"]=>
    string(7) "company"
  }
  ["__info":"RedBean_OODBBean":private]=>
  array(4) {
    ["type"]=>
    string(4) "user"
    ["sys"]=>
    array(1) {
      ["idfield"]=>
      string(2) "id"
    }
    ["tainted"]=>
    bool(false)
    ["model"]=>
    object(Model_User)#16 (1) {
      ["bean":protected]=>
      *RECURSION*
    }
  }
}

and here's what json_encode gives me:

php > echo json_encode($a);
{}

I ended up with just this:

    function json_encode_objs($item){   
        if(!is_array($item) && !is_object($item)){   
            return json_encode($item);   
        }else{   
            $pieces = array();   
            foreach($item as $k=>$v){   
                $pieces[] = "\"$k\":".json_encode_objs($v);   
            }   
            return '{'.implode(',',$pieces).'}';   
        }   
    }   

It takes arrays full of those objects or just single instances and turns them into json - I use it instead of json_encode. I'm sure there are places I could make it better, but I was hoping that json_encode would be able to detect when to iterate through an object based on its exposed interfaces.

Hamza

What is the output of var_dump($related) and echo json_encode($related)? – Commute

'objects' by definition are not iterable. – Tani

By iterable, I mean that the objects implement the interface IteratorAggregate and that I can iterate over them with a simple foreach. – Hamza

Answer 1

In RedBeanPHP 2.0 there is a mass-export function which turns an entire collection of beans into arrays. This works with the JSON encoder..

json_encode( R::exportAll( $beans ) );

Bioplasm

Also, in RB 2.0, if you cast a bean to a string you'll get the JSON representation. – Bioplasm

Answer 2

All the properties of your object are private. aka... not available outside their class's scope.

Solution for PHP >= 5.4

Use the new JsonSerializable Interface to provide your own json representation to be used by json_encode

class Thing implements JsonSerializable {
    ...
    public function jsonSerialize() {
        return [
            'something' => $this->something,
            'protected_something' => $this->get_protected_something(),
            'private_something' => $this->get_private_something()
        ];
    }
    ...
}

Solution for PHP < 5.4

If you do want to serialize your private and protected object properties, you have to implement a JSON encoding function inside your Class that utilizes json_encode() on a data structure you create for this purpose.

class Thing {
    ...
    public function to_json() {
        return json_encode(array(
            'something' => $this->something,
            'protected_something' => $this->get_protected_something(),
            'private_something' => $this->get_private_something()                
        ));
    }
    ...
}

A more detailed writeup

Tani

json_encode() is just outputting "{}" when I pass it these objects. It's not a matter of having my arrays be defined associative or not, unfortunately. – Hamza

I believe he is talking about the $a->properties array, which looks like it contains the data you're after. Because that is a private variable, it will be ignored by json_encode(), and cause json_encode() to output '{}' as you are describing. – Fenugreek

I was hoping that json_encode() would be able to see exposed methods to define some sort of behavior involving objects without externally accessible properties. It seems that this cannot yet be done, so I wrote up a function to recursively process these lists of objects, instead. – Hamza

You can see another solution at jrgns.net/content/… – Coming

for completeness, as mentioned by @Jrgns, you can return get_object_vars( $this ); to dump all the properties. – Propitiatory

implementing JsonSerializable is an elegant way to do this – Incredible

This should be the accepted answer. Private fields are according to the Encapsulation OOP principle so using JsonSerializable interface is the best way to solve the problem – Delanty

Answer 3

In PHP >= 5.4.0 there is a new interface for serializing objects to JSON : JsonSerializable

Just implement the interface in your object and define a JsonSerializable method which will be called when you use json_encode.

So the solution for PHP >= 5.4.0 should look something like this:

class JsonObject implements JsonSerializable
{
    // properties

    // function called when encoded with json_encode
    public function jsonSerialize()
    {
        return get_object_vars($this);
    }
}

Ioab

To echo the JSON array, return json_encode($result) where $result = get_object_vars($this); – Gangrene

This should be the accepted answer - automatically works with any class as get_object_vars will iterate all the properties. – Defile

I'm not sure what has changed in PHP or my code, but no matter what I do lately get_object_vars($this) disregards the scope of $this and refuses to introspect on the private members of object. When all members are private, I get an empty array result. I'm using PHP 5.6.31. Is there some requirement for getting get_object_vars($this) to recognize scope? – Rajiv

I don't think anything changed for get_object_vars. It was always only returning properties which were accessible. Thus when calling from within an object you'll get all privates and from outside you don't. See php.net/get_object_vars#example-6296 – Nisus

Answer 4

Following code worked for me:

public function jsonSerialize()
{
    return get_object_vars($this);
}

Grouper

Emh. Maybe it's json.encode(get_object_vars($this))? – Shrunk

Answer 5

I didn't see this mentioned yet, but beans have a built-in method called getProperties().

So, to use it:

// What bean do we want to get?
$type = 'book';
$id = 13;

// Load the bean
$post = R::load($type,$id);

// Get the properties
$props = $post->getProperties();

// Print the JSON-encoded value
print json_encode($props);

This outputs:

{
    "id": "13",
    "title": "Oliver Twist",
    "author": "Charles Dickens"
}

Now take it a step further. If we have an array of beans...

// An array of beans (just an example)
$series = array($post,$post,$post);

...then we could do the following:

• Loop through the array with a foreach loop.

• Replace each element (a bean) with an array of the bean's properties.

So this...

foreach ($series as &$val) {
  $val = $val->getProperties();
}

print json_encode($series);

...outputs this:

[
    {
        "id": "13",
        "title": "Oliver Twist",
        "author": "Charles Dickens"
    },
    {
        "id": "13",
        "title": "Oliver Twist",
        "author": "Charles Dickens"
    },
    {
        "id": "13",
        "title": "Oliver Twist",
        "author": "Charles Dickens"
    }
]

Hope this helps!

Whispering

Answer 6

I usually include a small function in my objects which allows me to dump to array or json or xml. Something like:

public function exportObj($method = 'a')
{
     if($method == 'j')
     {
         return json_encode(get_object_vars($this));
     }
     else
     {
         return get_object_vars($this);
     }
}

either way, get_object_vars() is probably useful to you.

Dispensation

I can just use json_encode($thing->export()); to give me the json I want, but that doesn't work as well when I've got arrays of them. – Hamza

Then you can convert the array of objects into an array of arrays with something like for each($objArray as $key => $obj){$arrArray[$key] = $obj->export());} json_encode($arrArray); or you could do an array_map with get_object_vars(). – Dispensation

Answer 7

$products=R::findAll('products');
$string = rtrim(implode(',', $products), ',');
echo $string;

Groundhog

Answer 8

Here is my way:

function xml2array($xml_data)
{
    $xml_to_array = [];

    if(isset($xml_data))
    {
        if(is_iterable($xml_data))
        {
            foreach($xml_data as $key => $value)
            {
                if(is_object($value))
                {
                    if(empty((array)$value))
                    {
                        $value = (string)$value;
                    }
                    else
                    {
                        $value = (array)$value;
                    }
                    $value = xml2array($value);
                }
                $xml_to_array[$key] = $value;
            }
        }
        else
        {
            $xml_to_array = $xml_data;
        }
    }

    return $xml_to_array;
}

Anamorphic

Answer 9

for an array of objects, I used something like this, while following the custom method for php < 5.4:

$jsArray=array();

//transaction is an array of the class transaction
//which implements the method to_json

foreach($transactions as $tran)
{
    $jsArray[]=$tran->to_json();
}

echo json_encode($jsArray);

Gyrostatics