Related
I'm trying to JSON encode some objects in PHP, but I'm facing a problem: I want to encode data which is kept by a class private members.
I found this piece of code to encode this object by calling an encode function like:
public function encodeJSON()
{
foreach ($this as $key => $value)
{
$json->$key = $value;
}
return json_encode($json);
}
However, this only works if the object I want to encode does not contain other objects inside, which is the case. How can I do to encode not only the "outer" object, but encode as well any members that are objects too?
The best method to serialize an object with private properties is to implement the \JsonSerializable interface and then implement your own JsonSerialize method to return the data you require to be serialized.
<?php
class Item implements \JsonSerializable
{
private $var;
private $var1;
private $var2;
public function __construct()
{
// ...
}
public function jsonSerialize()
{
$vars = get_object_vars($this);
return $vars;
}
}
json_encode will now serialize your object correctly.
If you're using php 5.4 you can use the JsonSerializable interface: http://www.php.net/manual/en/class.jsonserializable.php
You just implement a jsonSerialize method in your class which returns whatever you want to be encoded.
Then when you pass your object into json_encode, it'll encode the result of jsonSerialize.
Anyway. You need create public method in your class to return all their fields json encoded
public function getJSONEncode() {
return json_encode(get_object_vars($this));
}
I think #Petah's got the best approach, but that way you lose properties that are array or object. So I added a function wich do that recursively:
function json_encode_private($object) {
function extract_props($object) {
$public = [];
$reflection = new ReflectionClass(get_class($object));
foreach ($reflection->getProperties() as $property) {
$property->setAccessible(true);
$value = $property->getValue($object);
$name = $property->getName();
if(is_array($value)) {
$public[$name] = [];
foreach ($value as $item) {
if (is_object($item)) {
$itemArray = extract_props($item);
$public[$name][] = $itemArray;
} else {
$public[$name][] = $item;
}
}
} else if(is_object($value)) {
$public[$name] = extract_props($value);
} else $public[$name] = $value;
}
return $public;
}
return json_encode(extract_props($object));
}
EDIT: Added is_object() check inside the array loop to avoid a get_class() exception in the next extract_props() call when the array elements are not objects, like strings or numbers.
I think this may be a great case for the Usage of Traits
using the below guist I implemented jsonSerializable interface in multiple points of my app while keeping the code manageable
https://gist.github.com/zburgermeiszter/7dc5e65b06bb34a325a0363726fd8e14
trait JsonSerializeTrait
{
function jsonSerialize()
{
$reflect = new \ReflectionClass($this);
$props = $reflect->getProperties(\ReflectionProperty::IS_STATIC | \ReflectionProperty::IS_PUBLIC | \ReflectionProperty::IS_PROTECTED | \ReflectionProperty::IS_PRIVATE);
$propsIterator = function() use ($props) {
foreach ($props as $prop) {
yield $prop->getName() => $this->{$prop->getName()};
}
};
return iterator_to_array($propsIterator());
}
}
then you just have to do
class YourClass implements JsonSerializable
{
use JsonSerializeTrait;
... normal encapsulated code...
}
public function jsonSerialize()
{
$objectArray = [];
foreach($this as $key => $value) {
$objectArray[$key] = $value;
}
return json_encode($objectArray);
}
I personally think this is a way of doing it. It is similar to Petah's, except It keeps in line with encapsulation well, because the array is populated from the object.
Put this function in either your object or as a trait to be used by your object. To each their own though.
This would print a JSON with all of the properties (public, private and protected) of class foo:
$reflection = new ReflectionClass('Foo');
$properties = $reflection->getdefaultProperties();
echo json_encode($properties);
It would work from any context.
You can only encode an object's private members from within the class. As a side note though, does the json_enocde function not work for you? http://php.net/manual/en/function.json-encode.php
Using reflection you can json_encode private properties, although its not considered best practice:
function json_encode_private($object) {
$public = [];
$reflection = new ReflectionClass($object);
foreach ($reflection->getProperties() as $property) {
$property->setAccessible(true);
$public[$property->getName()] = $property->getValue($object);
}
return json_encode($public);
}
E.g.
class Foo {
public $a = 1;
public $b = 2;
}
class Bar {
private $c = 3;
private $d = 4;
}
var_dump(json_encode(new Foo()));
var_dump(json_encode_private(new Bar()));
Outputs:
string(13) "{"a":1,"b":2}"
string(13) "{"c":3,"d":4}"
http://codepad.viper-7.com/nCcKYW
I'm trying to JSON encode some objects in PHP, but I'm facing a problem: I want to encode data which is kept by a class private members.
I found this piece of code to encode this object by calling an encode function like:
public function encodeJSON()
{
foreach ($this as $key => $value)
{
$json->$key = $value;
}
return json_encode($json);
}
However, this only works if the object I want to encode does not contain other objects inside, which is the case. How can I do to encode not only the "outer" object, but encode as well any members that are objects too?
The best method to serialize an object with private properties is to implement the \JsonSerializable interface and then implement your own JsonSerialize method to return the data you require to be serialized.
<?php
class Item implements \JsonSerializable
{
private $var;
private $var1;
private $var2;
public function __construct()
{
// ...
}
public function jsonSerialize()
{
$vars = get_object_vars($this);
return $vars;
}
}
json_encode will now serialize your object correctly.
If you're using php 5.4 you can use the JsonSerializable interface: http://www.php.net/manual/en/class.jsonserializable.php
You just implement a jsonSerialize method in your class which returns whatever you want to be encoded.
Then when you pass your object into json_encode, it'll encode the result of jsonSerialize.
Anyway. You need create public method in your class to return all their fields json encoded
public function getJSONEncode() {
return json_encode(get_object_vars($this));
}
I think #Petah's got the best approach, but that way you lose properties that are array or object. So I added a function wich do that recursively:
function json_encode_private($object) {
function extract_props($object) {
$public = [];
$reflection = new ReflectionClass(get_class($object));
foreach ($reflection->getProperties() as $property) {
$property->setAccessible(true);
$value = $property->getValue($object);
$name = $property->getName();
if(is_array($value)) {
$public[$name] = [];
foreach ($value as $item) {
if (is_object($item)) {
$itemArray = extract_props($item);
$public[$name][] = $itemArray;
} else {
$public[$name][] = $item;
}
}
} else if(is_object($value)) {
$public[$name] = extract_props($value);
} else $public[$name] = $value;
}
return $public;
}
return json_encode(extract_props($object));
}
EDIT: Added is_object() check inside the array loop to avoid a get_class() exception in the next extract_props() call when the array elements are not objects, like strings or numbers.
I think this may be a great case for the Usage of Traits
using the below guist I implemented jsonSerializable interface in multiple points of my app while keeping the code manageable
https://gist.github.com/zburgermeiszter/7dc5e65b06bb34a325a0363726fd8e14
trait JsonSerializeTrait
{
function jsonSerialize()
{
$reflect = new \ReflectionClass($this);
$props = $reflect->getProperties(\ReflectionProperty::IS_STATIC | \ReflectionProperty::IS_PUBLIC | \ReflectionProperty::IS_PROTECTED | \ReflectionProperty::IS_PRIVATE);
$propsIterator = function() use ($props) {
foreach ($props as $prop) {
yield $prop->getName() => $this->{$prop->getName()};
}
};
return iterator_to_array($propsIterator());
}
}
then you just have to do
class YourClass implements JsonSerializable
{
use JsonSerializeTrait;
... normal encapsulated code...
}
public function jsonSerialize()
{
$objectArray = [];
foreach($this as $key => $value) {
$objectArray[$key] = $value;
}
return json_encode($objectArray);
}
I personally think this is a way of doing it. It is similar to Petah's, except It keeps in line with encapsulation well, because the array is populated from the object.
Put this function in either your object or as a trait to be used by your object. To each their own though.
This would print a JSON with all of the properties (public, private and protected) of class foo:
$reflection = new ReflectionClass('Foo');
$properties = $reflection->getdefaultProperties();
echo json_encode($properties);
It would work from any context.
You can only encode an object's private members from within the class. As a side note though, does the json_enocde function not work for you? http://php.net/manual/en/function.json-encode.php
Using reflection you can json_encode private properties, although its not considered best practice:
function json_encode_private($object) {
$public = [];
$reflection = new ReflectionClass($object);
foreach ($reflection->getProperties() as $property) {
$property->setAccessible(true);
$public[$property->getName()] = $property->getValue($object);
}
return json_encode($public);
}
E.g.
class Foo {
public $a = 1;
public $b = 2;
}
class Bar {
private $c = 3;
private $d = 4;
}
var_dump(json_encode(new Foo()));
var_dump(json_encode_private(new Bar()));
Outputs:
string(13) "{"a":1,"b":2}"
string(13) "{"c":3,"d":4}"
http://codepad.viper-7.com/nCcKYW
I've been fooling with ArrayAccess and PHP's magic (__get, __set) for awhile now, and I'm stuck.
I'm trying to implement a class in which some properties, which are arrays, are read only. They will be set initially by the constructor, but should not be modifiable thereafter.
Using __get magic by reference, I can access array elements arbitrarily deep in the properties, and I was thinking I can throw exceptions when those properties are targeted via __set.
The problem is though, when I'm accessing the value of an array element, PHP is calling __get to return that part of the array by reference, and I have no knowledge of whether or not its a read or write action.
(The worst part is I knew this going in, but have been fooling with ArrayAccess as a possible workaround solution, given the properties were instances of an implemented object)
Simple example:
class Test{
public function &__get($key){
echo "[READ:{$key}]\n";
}
public function __set($key, $value){
echo "[WRITE:{$key}={$value}]\n";
}
}
$test = new Test;
$test->foo;
$test->foo = 'bar';
$test->foo['bar'];
$test->foo['bar'] = 'zip';
And the output:
[READ:foo]
[WRITE:foo=bar]
[READ:foo]
[READ:foo] // here's the problem
Realistically, I only need the value foo (as per my example) anyways, but I need to know it's a write action, not read.
I've already half accepted that this cannot be achieved, but I'm still hopeful. Does anyone have any idea how what I'm looking to accomplish can be done?
I was considering some possible workarounds with ArrayAccess, but so far as I can tell, I'll end up back at this spot, given I'm going to use the property notation that invokes __get.
Update: Another fun day with ArrayAccess.
(This is a different issue, but I suppose it works in. Posting just for kicks.)
class Mf_Params implements ArrayAccess{
private $_key = null;
private $_parent = null;
private $_data = array();
private $_temp = array();
public function __construct(Array $data = array(), $key = null, self $parent = null){
$this->_parent = $parent;
$this->_key = $key;
foreach($data as $key => $value){
$this->_data[$key] = is_array($value)
? new self($value, $key, $this)
: $value;
}
}
public function toArray(){
$array = array();
foreach($this->_data as $key => $value){
$array[$key] = $value instanceof self
? $value->toArray()
: $value;
}
return $array;
}
public function offsetGet($offset){
if(isset($this->_data[$offset])){
return $this->_data[$offset];
}
// if offset not exist return temp instance
return $this->_temp[$offset] = new self(array(), $offset, $this);
}
public function offsetSet($offset, $value){
$child = $this;
// copy temp instances to data after array reference chain
while(!is_null($parent = $child->_parent) && $parent->_temp[$child->_key] === $child){
$parent->_data[$child->_key] = $parent->_temp[$child->_key];
$child = $parent;
}
// drop temp
foreach($child->_temp as &$temp){
unset($temp);
}
if(is_null($offset)){
$this->_data[] = is_array($value)
? new self($value, null, $this)
: $value;
}else{
$this->_data[$offset] = is_array($value)
? new self($value, $offset, $this)
: $value;
}
}
public function offsetExists($offset){
return isset($this->_data[$offset]);
}
public function offsetUnset($offset){
unset($this->_data[$offset]);
}
}
You need to use a second class, implementing ArrayAccess, to use instead of your arrays. Then you will be able to control what is added to the array with the offsetSet() method:
class ReadOnlyArray implements ArrayAccess {
private $container = array();
public function __construct(array $array) {
$this->container = $array;
}
public function offsetSet($offset, $value) {
throw new Exception('Read-only');
}
public function offsetExists($offset) {
return isset($this->container[$offset]);
}
public function offsetUnset($offset) {
unset($this->container[$offset]);
}
public function offsetGet($offset) {
if (! array_key_exists($offset, $this->container)) {
throw new Exception('Undefined offset');
}
return $this->container[$offset];
}
}
You can then initialize your ReadOnlyArray with your original array:
$readOnlyArray = new ReadOnlyArray(array('foo', 'bar'));
You could not return by ref, which would solve the problem of changability, but would not allow changing of some values that are allowed to be changed.
Alternatively you need to wrap every returned array in ArrayAccess, too - and forbid write access there.
Is it possible to decode a json string to an object other than stdClass?
Not automatically. But you can do it the old fashioned route.
$data = json_decode($json, true);
$class = new Whatever();
foreach ($data as $key => $value) $class->{$key} = $value;
Or alternatively, you could make that more automatic:
class Whatever {
public function set($data) {
foreach ($data AS $key => $value) $this->{$key} = $value;
}
}
$class = new Whatever();
$class->set($data);
Edit: getting a little fancier:
class JSONObject {
public function __construct($json = false) {
if ($json) $this->set(json_decode($json, true));
}
public function set($data) {
foreach ($data AS $key => $value) {
if (is_array($value)) {
$sub = new JSONObject;
$sub->set($value);
$value = $sub;
}
$this->{$key} = $value;
}
}
}
// These next steps aren't necessary. I'm just prepping test data.
$data = array(
"this" => "that",
"what" => "who",
"how" => "dy",
"multi" => array(
"more" => "stuff"
)
);
$jsonString = json_encode($data);
// Here's the sweetness.
$class = new JSONObject($jsonString);
print_r($class);
We built JsonMapper to map JSON objects onto our own model classes automatically. It works fine with nested/child objects.
It only relies on docblock type information for mapping, which most class properties have anyway:
<?php
$mapper = new JsonMapper();
$contactObject = $mapper->map(
json_decode(file_get_contents('http://example.org/contact.json')),
new Contact()
);
?>
You can do it - it's a kludge but totally possible. We had to do when we started storing things in couchbase.
$stdobj = json_decode($json_encoded_myClassInstance); //JSON to stdClass
$temp = serialize($stdobj); //stdClass to serialized
// Now we reach in and change the class of the serialized object
$temp = preg_replace('#^O:8:"stdClass":#','O:7:"MyClass":',$temp);
// Unserialize and walk away like nothing happend
$myClassInstance = unserialize($temp); // Presto a php Class
In our benchmarks this was way faster than trying to iterate through all the class variables.
Caveat: Won't work for nested objects other than stdClass
Edit: keep in mind the data source, it's strongly recommended that you don't do this withe untrusted data from users without a very carful analysis of the risks.
You could use Johannes Schmitt's Serializer library.
$serializer = JMS\Serializer\SerializerBuilder::create()->build();
$object = $serializer->deserialize($jsonData, 'MyNamespace\MyObject', 'json');
In the latest version of the JMS serializer the syntax is:
$serializer = SerializerBuilder::create()->build();
$object = $serializer->deserialize($jsonData, MyObject::class, 'json');
I'm surprised no one mentioned this, yet.
Use the Symfony Serializer component: https://symfony.com/doc/current/components/serializer.html
Serializing from Object to JSON:
use App\Model\Person;
$person = new Person();
$person->setName('foo');
$person->setAge(99);
$person->setSportsperson(false);
$jsonContent = $serializer->serialize($person, 'json');
// $jsonContent contains {"name":"foo","age":99,"sportsperson":false,"createdAt":null}
echo $jsonContent; // or return it in a Response
Deserializing from JSON to Object: (this example uses XML just to demonstrate the flexibility of formats)
use App\Model\Person;
$data = <<<EOF
<person>
<name>foo</name>
<age>99</age>
<sportsperson>false</sportsperson>
</person>
EOF;
$person = $serializer->deserialize($data, Person::class, 'xml');
You can do it in below way ..
<?php
class CatalogProduct
{
public $product_id;
public $sku;
public $name;
public $set;
public $type;
public $category_ids;
public $website_ids;
function __construct(array $data)
{
foreach($data as $key => $val)
{
if(property_exists(__CLASS__,$key))
{
$this->$key = $val;
}
}
}
}
?>
For more details visit
create-custom-class-in-php-from-json-or-array
You can make a wrapper for your object and make the wrapper look like it is the object itself. And it will work with multilevel objects.
<?php
class Obj
{
public $slave;
public function __get($key) {
return property_exists ( $this->slave , $key ) ? $this->slave->{$key} : null;
}
public function __construct(stdClass $slave)
{
$this->slave = $slave;
}
}
$std = json_decode('{"s3":{"s2":{"s1":777}}}');
$o = new Obj($std);
echo $o->s3->s2->s1; // you will have 777
No, this is not possible as of PHP 5.5.1.
The only thing possible is to have json_decode return associate arrays instead of the StdClass objects.
Use Reflection:
function json_decode_object(string $json, string $class)
{
$reflection = new ReflectionClass($class);
$instance = $reflection->newInstanceWithoutConstructor();
$json = json_decode($json, true);
$properties = $reflection->getProperties();
foreach ($properties as $key => $property) {
$property->setAccessible(true);
$property->setValue($instance, $json[$property->getName()]);
}
return $instance;
}
As Gordon says is not possible. But if you are looking for a way to obtain a string that can be decoded as an instance of a give class you can use serialize and unserialize instead.
class Foo
{
protected $bar = 'Hello World';
function getBar() {
return $this->bar;
}
}
$string = serialize(new Foo);
$foo = unserialize($string);
echo $foo->getBar();
I once created an abstract base class for this purpose. Let's call it JsonConvertible. It should serialize and deserialize the public members. This is possible using Reflection and late static binding.
abstract class JsonConvertible {
static function fromJson($json) {
$result = new static();
$objJson = json_decode($json);
$class = new \ReflectionClass($result);
$publicProps = $class->getProperties(\ReflectionProperty::IS_PUBLIC);
foreach ($publicProps as $prop) {
$propName = $prop->name;
if (isset($objJson->$propName) {
$prop->setValue($result, $objJson->$propName);
}
else {
$prop->setValue($result, null);
}
}
return $result;
}
function toJson() {
return json_encode($this);
}
}
class MyClass extends JsonConvertible {
public $name;
public $whatever;
}
$mine = MyClass::fromJson('{"name": "My Name", "whatever": "Whatever"}');
echo $mine->toJson();
Just from memory, so probably not flawless. You will also have to exclude static properties and may give derived classes the chance to make some properties ignored when serialized to/from json. I hope you get the idea, nonetheless.
JSON is a simple protocol to transfer data between various programming languages (and it's also a subset of JavaScript) which supports just certain types: numbers, strings, arrays/lists, objects/dicts. Objects are just key=value maps and Arrays are ordered lists.
So there is no way to express custom objects in a generic way. The solution is defining a structure where your program(s) will know that it's a custom object.
Here's an example:
{ "cls": "MyClass", fields: { "a": 123, "foo": "bar" } }
This could be used to create an instance of MyClass and set the fields a and foo to 123 and "bar".
I went ahead and implemented John Petit's answer, as a function(gist):
function json_decode_to(string $json, string $class = stdClass::class, int $depth = 512, int $options = 0)
{
$stdObj = json_decode($json, false, $depth, $options);
if ($class === stdClass::class) return $stdObj;
$count = strlen($class);
$temp = serialize($stdObj);
$temp = preg_replace("#^O:8:\"stdClass\":#", "O:$count:\"$class\":", $temp);
return unserialize($temp);
}
This worked perfectly for my use case. However Yevgeniy Afanasyev's response seems equally promising to me. It could be possible to have your class have an extra "constructor", like so:
public static function withJson(string $json) {
$instance = new static();
// Do your thing
return $instance;
}
This is also inspired by this answer.
EDIT: I have been using karriereat/json-decoder for some time now, and I have had absolutely no trouble with it. It is lightweight and very easily extensible. Here's an example of a binding I wrote to deserialize JSON into a Carbon/CarbonImmutable object.
All this here inspired me to a generic function:
function loadJSON($Obj, $json)
{
$dcod = json_decode($json);
$prop = get_object_vars ( $dcod );
foreach($prop as $key => $lock)
{
if(property_exists ( $Obj , $key ))
{
if(is_object($dcod->$key))
{
loadJSON($Obj->$key, json_encode($dcod->$key));
}
else
{
$Obj->$key = $dcod->$key;
}
}
}
}
to be called in class declaration:
class Bar{public $bar = " Boss";}
class Bas
{
public $ber ;
public $bas=" Boven";
public function __construct()
{$this->ber = new Bar;}
}
class Baz
{
public $bes ;
public $baz=" Baaz";
public function __construct()
{$this->bes = new Bas;}
}
$Bazjson = '{"bes":{"ber":{"bar":"Baas"}}}';
$Bazobj = new Baz;
loadJSON($Bazobj, $Bazjson);
var_dump($Bazobj);
This worked for me, especially for if you don't have setters or named properties in the target class
function cast($jsonstring, $class)
{
//$class is a string like 'User'
$json= json_decode($jsonstring,true); //array
$reflection = new ReflectionClass($class);
$instance = $reflection->newInstanceWithoutConstructor();
$keys = array_keys($json);
foreach ($keys as $key => $property) {
$instance->{$property} =$json[$property];
}
// print_r($instance);
return $instance;
}
Not directly, but if the class has a constructor with parameter names that match the keys in the JSON object, you can simply decode the JSON into an associative array and pass it to the constructor via the '...' (argument unpacking) operator:
<?php
class MyClass {
public function __construct(
public int $id,
public string $name,
public array $attributes,
){}
}
$json = '{"name":"foo","id":42,"attributes":{"color":"red"}}';
$object = new MyClass(...json_decode($json, true));
print_r($object);
Output:
MyClass Object
(
[id] => 42
[name] => foo
[attributes] => Array
(
[color] => red
)
)
However, in practice, there is often some additional mapping to do, especially sub-objects that need to be recursively decoded too. So usually it is better to have a static fromArray function in each class that pre-processes the json-decoded array before passing the result to the constructor:
class Part {
public function __construct(public float $weight){}
public static function fromArray(array $data): self {
return new self(...$data);
}
}
class System {
public function __construct(
public string $name,
public Part $mainPart,
public array $otherParts,
){}
public static function fromArray(array $data): self {
$data['mainPart'] = Part::fromArray($data['mainPart']);
$data['otherParts'] = array_map(Part::fromArray(...), $data['otherParts']); // php 8.1
return new self(...$data);
}
}
$json = '{"name":"foo","mainPart":{"weight":2},"otherParts":[{"weight":1}, {"weight":0.5}]}';
$object = System::fromArray(json_decode($json, true));
Is there any way to create all instance properties dynamically? For example, I would like to be able to generate all attributes in the constructor and still be able to access them after the class is instantiated like this: $object->property. Note that I want to access the properties separately, and not using an array; here's an example of what I don't want:
class Thing {
public $properties;
function __construct(array $props=array()) {
$this->properties = $props;
}
}
$foo = new Thing(array('bar' => 'baz');
# I don't want to have to do this:
$foo->properties['bar'];
# I want to do this:
//$foo->bar;
To be more specific, when I'm dealing with classes that have a large number of properties, I would like to be able to select all columns in a database (which represent the properties) and create instance properties from them. Each column value should be stored in a separate instance property.
Sort of. There are magic methods that allow you to hook your own code up to implement class behavior at runtime:
class foo {
public function __get($name) {
return('dynamic!');
}
public function __set($name, $value) {
$this->internalData[$name] = $value;
}
}
That's an example for dynamic getter and setter methods, it allows you to execute behavior whenever an object property is accessed. For example
print(new foo()->someProperty);
would print, in this case, "dynamic!" and you could also assign a value to an arbitrarily named property in which case the __set() method is silently invoked. The __call($name, $params) method does the same for object method calls. Very useful in special cases. But most of the time, you'll get by with:
class foo {
public function __construct() {
foreach(getSomeDataArray() as $k => $value)
$this->{$k} = $value;
}
}
...because mostly, all you need is to dump the content of an array into correspondingly named class fields once, or at least at very explicit points in the execution path. So, unless you really need dynamic behavior, use that last example to fill your objects with data.
This is called overloading
http://php.net/manual/en/language.oop5.overloading.php
It depends exactly what you want. Can you modify the class dynamically? Not really. But can you create object properties dynamically, as in one particular instance of that class? Yes.
class Test
{
public function __construct($x)
{
$this->{$x} = "dynamic";
}
}
$a = new Test("bar");
print $a->bar;
Outputs:
dynamic
So an object property named "bar" was created dynamically in the constructor.
Yes, you can.
class test
{
public function __construct()
{
$arr = array
(
'column1',
'column2',
'column3'
);
foreach ($arr as $key => $value)
{
$this->$value = '';
}
}
public function __set($key, $value)
{
$this->$key = $value;
}
public function __get($value)
{
return 'This is __get magic '.$value;
}
}
$test = new test;
// Results from our constructor test.
var_dump($test);
// Using __set
$test->new = 'variable';
var_dump($test);
// Using __get
print $test->hello;
Output
object(test)#1 (3) {
["column1"]=>
string(0) ""
["column2"]=>
string(0) ""
["column3"]=>
string(0) ""
}
object(test)#1 (4) {
["column1"]=>
string(0) ""
["column2"]=>
string(0) ""
["column3"]=>
string(0) ""
["new"]=>
string(8) "variable"
}
This is __get magic hello
This code will set dynamic properties in the constructor which can then be accessed with $this->column. It's also good practice to use the __get and __set magic methods to deal with properties that are not defined within the class. More information them can be found here.
http://www.tuxradar.com/practicalphp/6/14/2
http://www.tuxradar.com/practicalphp/6/14/3
You can use an instance variable to act as a holder for arbitrary values and then use the __get magic method to retrieve them as regular properties:
class My_Class
{
private $_properties = array();
public function __construct(Array $hash)
{
$this->_properties = $hash;
}
public function __get($name)
{
if (array_key_exists($name, $this->_properties)) {
return $this->_properties[$name];
}
return null;
}
}
Why is every example so complicated?
<?php namespace example;
error_reporting(E_ALL | E_STRICT);
class Foo
{
// class completely empty
}
$testcase = new Foo();
$testcase->example = 'Dynamic property';
echo $testcase->example;
Here is simple function to populate object members without making class members public.
It also leaves constructor for your own usage, creating new instance of object without invoking constructor! So, your domain object doesn't depend on database!
/**
* Create new instance of a specified class and populate it with given data.
*
* #param string $className
* #param array $data e.g. array(columnName => value, ..)
* #param array $mappings Map column name to class field name, e.g. array(columnName => fieldName)
* #return object Populated instance of $className
*/
function createEntity($className, array $data, $mappings = array())
{
$reflClass = new ReflectionClass($className);
// Creates a new instance of a given class, without invoking the constructor.
$entity = unserialize(sprintf('O:%d:"%s":0:{}', strlen($className), $className));
foreach ($data as $column => $value)
{
// translate column name to an entity field name
$field = isset($mappings[$column]) ? $mappings[$column] : $column;
if ($reflClass->hasProperty($field))
{
$reflProp = $reflClass->getProperty($field);
$reflProp->setAccessible(true);
$reflProp->setValue($entity, $value);
}
}
return $entity;
}
/******** And here is example ********/
/**
* Your domain class without any database specific code!
*/
class Employee
{
// Class members are not accessible for outside world
protected $id;
protected $name;
protected $email;
// Constructor will not be called by createEntity, it yours!
public function __construct($name, $email)
{
$this->name = $name;
$this->emai = $email;
}
public function getId()
{
return $this->id;
}
public function getName()
{
return $this->name;
}
public function getEmail()
{
return $this->email;
}
}
$row = array('employee_id' => '1', 'name' => 'John Galt', 'email' => 'john.galt#whoisjohngalt.com');
$mappings = array('employee_id' => 'id'); // Employee has id field, so we add translation for it
$john = createEntity('Employee', $row, $mappings);
print $john->getName(); // John Galt
print $john->getEmail(); // john.galt#whoisjohngalt.com
//...
P.S. Retrieving data from object is similar, e.g. use $reflProp->setValue($entity, $value);
P.P.S. This function is heavily inspired by Doctrine2 ORM which is awesome!
class DataStore // Automatically extends stdClass
{
public function __construct($Data) // $Data can be array or stdClass
{
foreach($Data AS $key => $value)
{
$this->$key = $value;
}
}
}
$arr = array('year_start' => 1995, 'year_end' => 2003);
$ds = new DataStore($arr);
$gap = $ds->year_end - $ds->year_start;
echo "Year gap = " . $gap; // Outputs 8
You can:
$variable = 'foo';
$this->$variable = 'bar';
Would set the attribute foo of the object it's called on to bar.
You can also use functions:
$this->{strtolower('FOO')} = 'bar';
This would also set foo (not FOO) to bar.
Extend stdClass.
class MyClass extends stdClass
{
public function __construct()
{
$this->prop=1;
}
}
I hope this is what you need.
This is really complicated way to handle this kind of rapid development. I like answers and magic methods but in my opinion it is better to use code generators like CodeSmith.
I have made template that connect to database, read all columns and their data types and generate whole class accordingly.
This way I have error free (no typos) readable code. And if your database model changes run generator again... it works for me.
If you really really must do it, the best way is to overload an ArrayObject, that allows to maintain iteration support (foreach) that will still loop through all your properties.
I note that you said "without using an array", and I just want to assure you that that while technically an array is being used in the background, you NEVER HAVE TO SEE IT. You access all properties via ->properyname or foreach ($class in $name => $value).
Here is a sample I was working on yesterday, note this is also STRONGLY TYPED. So properties that are marked "integer" will throw an error if you try and supply a "string".
You can remove that of course.
There is also an AddProperty() member function, although it is not demonstrated in the example. That will allow you to add properties later.
Sample usage:
$Action = new StronglyTypedDynamicObject("Action",
new StrongProperty("Player", "ActionPlayer"), // ActionPlayer
new StrongProperty("pos", "integer"),
new StrongProperty("type", "integer"),
new StrongProperty("amount", "double"),
new StrongProperty("toCall", "double"));
$ActionPlayer = new StronglyTypedDynamicObject("ActionPlayer",
new StrongProperty("Seat", "integer"),
new StrongProperty("BankRoll", "double"),
new StrongProperty("Name", "string"));
$ActionPlayer->Seat = 1;
$ActionPlayer->Name = "Doctor Phil";
$Action->pos = 2;
$Action->type = 1;
$Action->amount = 7.0;
$Action->Player = $ActionPlayer;
$newAction = $Action->factory();
$newAction->pos = 4;
print_r($Action);
print_r($newAction);
class StrongProperty {
var $value;
var $type;
function __construct($name, $type) {
$this->name = $name;
$this->type = $type;
}
}
class StronglyTypedDynamicObject extends ModifiedStrictArrayObject {
static $basic_types = array(
"boolean",
"integer",
"double",
"string",
"array",
"object",
"resource",
);
var $properties = array(
"__objectName" => "string"
);
function __construct($objectName /*, [ new StrongProperty("name", "string"), [ new StrongProperty("name", "string"), [ ... ]]] */) {
$this->__objectName = $objectName;
$args = func_get_args();
array_shift($args);
foreach ($args as $arg) {
if ($arg instanceof StrongProperty) {
$this->AddProperty($arg->name, $arg->type);
} else {
throw new Exception("Invalid Argument");
}
}
}
function factory() {
$new = clone $this;
foreach ($new as $key => $value) {
if ($key != "__objectName") {
unset($new[$key]);
}
}
// $new->__objectName = $this->__objectName;
return $new;
}
function AddProperty($name, $type) {
$this->properties[$name] = $type;
return;
if (in_array($short_type, self::$basic_types)) {
$this->properties[$name] = $type;
} else {
throw new Exception("Invalid Type: $type");
}
}
public function __set($name, $value) {
self::sdprintf("%s(%s)\n", __FUNCTION__, $name);
$this->check($name, $value);
$this->offsetSet($name, $value);
}
public function __get($name) {
self::sdprintf("%s(%s)\n", __FUNCTION__, $name);
$this->check($name);
return $this->offsetGet($name);
}
protected function check($name, $value = "r4nd0m") {
if (!array_key_exists($name, $this->properties)) {
throw new Exception("Attempt to access non-existent property '$name'");
}
$value__objectName = "";
if ($value != "r4nd0m") {
if ($value instanceof StronglyTypedDynamicObject) {
$value__objectName = $value->__objectName;
}
if (gettype($value) != $this->properties[$name] && $value__objectName != $this->properties[$name]) {
throw new Exception("Attempt to set {$name} ({$this->properties[$name]}) with type " . gettype($value) . ".$value__objectName");
}
}
}
}
class ModifiedStrictArrayObject extends ArrayObject {
static $debugLevel = 0;
/* Some example properties */
static public function StaticDebug($message) {
if (static::$debugLevel > 1) {
fprintf(STDERR, "%s\n", trim($message));
}
}
static public function sdprintf() {
$args = func_get_args();
$string = call_user_func_array("sprintf", $args);
self::StaticDebug("D " . trim($string));
}
protected function check($name) {
if (!array_key_exists($name, $this->properties)) {
throw new Exception("Attempt to access non-existent property '$name'");
}
}
//static public function sget($name, $default = NULL) {
/******/ public function get ($name, $default = NULL) {
self::sdprintf("%s(%s)\n", __FUNCTION__, $name);
$this->check($name);
if (array_key_exists($name, $this->storage)) {
return $this->storage[$name];
}
return $default;
}
public function offsetGet($name) {
self::sdprintf("%s(%s)\n", __FUNCTION__, implode(",", func_get_args()));
$this->check($name);
return call_user_func_array(array(parent, __FUNCTION__), func_get_args());
}
public function offsetSet($name, $value) {
self::sdprintf("%s(%s)\n", __FUNCTION__, implode(",", func_get_args()));
$this->check($name);
return call_user_func_array(array(parent, __FUNCTION__), func_get_args());
}
public function offsetExists($name) {
self::sdprintf("%s(%s)\n", __FUNCTION__, implode(",", func_get_args()));
$this->check($name);
return call_user_func_array(array(parent, __FUNCTION__), func_get_args());
}
public function offsetUnset($name) {
self::sdprintf("%s(%s)\n", __FUNCTION__, implode(",", func_get_args()));
$this->check($name);
return call_user_func_array(array(parent, __FUNCTION__), func_get_args());
}
public function __toString() {
self::sdprintf("%s(%s)\n", __FUNCTION__, $name);
foreach ($this as $key => $value) {
$output .= "$key: $value\n";
}
return $output;
}
function __construct($array = false, $flags = 0, $iterator_class = "ArrayIterator") {
self::sdprintf("%s(%s)\n", __FUNCTION__, implode(",", func_get_args()));
parent::setFlags(parent::ARRAY_AS_PROPS);
}
}
After reading #Udo 's answer. I've come up with the following pattern, that doesn't bloat a class instance with what-ever items that is in your constructor array argument but still let you type less and easily add new properties to the class.
class DBModelConfig
{
public $host;
public $username;
public $password;
public $db;
public $port = '3306';
public $charset = 'utf8';
public $collation = 'utf8_unicode_ci';
public function __construct($config)
{
foreach ($config as $key => $value) {
if (property_exists($this, $key)) {
$this->{$key} = $value;
}
}
}
}
Then you can pass arrays like:
[
'host' => 'localhost',
'driver' => 'mysql',
'username' => 'myuser',
'password' => '1234',
'charset' => 'utf8',
'collation' => 'utf8_unicode_ci',
'db' => 'key not used in receiving class'
]