将PHP对象序列化为JSON [英] Serializing PHP object to JSON
问题描述
因此，当我偶然发现新的 php.net 上，以获取有关将PHP对象序列化为JSON的信息. ://www.php.net/manual/zh/class.jsonserializable.php> JsonSerializable接口.不过，它只是 PHP> = 5.4 ，而且我正在5.3.x环境中运行.
如何实现这种功能 PHP< 5.4 ?
我还没有在JSON上做很多工作，但是我正在尝试在应用程序中支持API层，并将数据对象(否则会发送到视图)转储到JSON将是完美的.
如果我尝试直接序列化该对象，它将返回一个空的JSON字符串；这是因为我假设json_encode()不知道如何处理该对象.我应该递归地将对象简化为数组，然后对那个进行编码吗?
示例
$data = new Mf_Data();
$data->foo->bar['hello'] = 'world';
echo json_encode($data) 产生一个空对象:
{}
var_dump($data) ，但是，按预期方式工作:
object(Mf_Data)#1 (5) {
["_values":"Mf_Data":private]=>
array(0) {
}
["_children":"Mf_Data":private]=>
array(1) {
[0]=>
array(1) {
["foo"]=>
object(Mf_Data)#2 (5) {
["_values":"Mf_Data":private]=>
array(0) {
}
["_children":"Mf_Data":private]=>
array(1) {
[0]=>
array(1) {
["bar"]=>
object(Mf_Data)#3 (5) {
["_values":"Mf_Data":private]=>
array(1) {
[0]=>
array(1) {
["hello"]=>
string(5) "world"
}
}
["_children":"Mf_Data":private]=>
array(0) {
}
["_parent":"Mf_Data":private]=>
*RECURSION*
["_key":"Mf_Data":private]=>
string(3) "bar"
["_index":"Mf_Data":private]=>
int(0)
}
}
}
["_parent":"Mf_Data":private]=>
*RECURSION*
["_key":"Mf_Data":private]=>
string(3) "foo"
["_index":"Mf_Data":private]=>
int(0)
}
}
}
["_parent":"Mf_Data":private]=>
NULL
["_key":"Mf_Data":private]=>
NULL
["_index":"Mf_Data":private]=>
int(0)
}
附录
1)
这是我为Mf_Data类设计的toArray()函数:
public function toArray()
{
$array = (array) $this;
array_walk_recursive($array, function (&$property) {
if ($property instanceof Mf_Data) {
$property = $property->toArray();
}
});
return $array;
}
但是，由于Mf_Data对象还具有对其父对象(包含 )的引用，因此递归操作将失败.但是，当我删除_parent引用时，它的工作原理就像一个咒语.
2)
仅此而已，转换我所使用的复杂树节点对象的最后一个功能是:
// class name - Mf_Data
// exlcuded properties - $_parent, $_index
public function toArray()
{
$array = get_object_vars($this);
unset($array['_parent'], $array['_index']);
array_walk_recursive($array, function (&$property) {
if (is_object($property) && method_exists($property, 'toArray')) {
$property = $property->toArray();
}
});
return $array;
}
3)
我再次跟进，对实现进行了更清晰的介绍.使用接口进行instanceof检查似乎比method_exists()更干净(但是method_exists()进行跨域继承/实现).
使用unset()似乎也有些混乱，并且似乎应该将逻辑重构为另一种方法.但是，该实现确实复制了属性数组(由于array_diff_key )，因此需要考虑一些事情.
interface ToMapInterface
{
function toMap();
function getToMapProperties();
}
class Node implements ToMapInterface
{
private $index;
private $parent;
private $values = array();
public function toMap()
{
$array = $this->getToMapProperties();
array_walk_recursive($array, function (&$value) {
if ($value instanceof ToMapInterface) {
$value = $value->toMap();
}
});
return $array;
}
public function getToMapProperties()
{
return array_diff_key(get_object_vars($this), array_flip(array(
'index', 'parent'
)));
}
}
编辑:当前是2016年9月24日，PHP 5.4已于2012-03-01发布，支持已终止 2015-09-01.不过，这个答案似乎获得了好评.如果您仍在使用PHP< 5.4，您正在制造安全风险并破坏您的项目.如果您没有令人信服的理由停留在< 5.4，或者甚至已经使用版本> = 5.4，请不要使用此答案，而只需使用PHP> = 5.4(或者，您可以使用最新版本的PHP> = 5.4).一个)并实现 JsonSerializable接口
您将定义一个函数，例如名为getJsonData();的函数，该函数将返回一个数组，stdClass对象或具有可见参数的其他对象，然后返回私有/受保护的参数，然后执行json_encode($data->getJsonData());.本质上，从5.4开始实现该功能，但要手动调用它.
类似的事情会起作用，因为从类内部调用get_object_vars()可以访问私有/受保护的变量:
function getJsonData(){
$var = get_object_vars($this);
foreach ($var as &$value) {
if (is_object($value) && method_exists($value,'getJsonData')) {
$value = $value->getJsonData();
}
}
return $var;
}
So I was wandering around php.net for information about serializing PHP objects to JSON, when I stumbled across the new JsonSerializable Interface. It's only PHP >= 5.4 though, and I'm running in a 5.3.x environment.
How is this sort of functionality achieved PHP < 5.4?
I've not worked much with JSON yet, but I'm trying to support an API layer in an application, and dumping the data object (that would otherwise be sent to the view) into JSON would be perfect.
If I attempt to serialize the object directly, it returns an empty JSON string; which is because I assume json_encode() doesn't know what the heck to do with the object. Should I recursively reduce the object into an array, and then encode that?
Example
$data = new Mf_Data();
$data->foo->bar['hello'] = 'world';
echo json_encode($data) produces an empty object:
{}
var_dump($data) however, works as expected:
object(Mf_Data)#1 (5) {
["_values":"Mf_Data":private]=>
array(0) {
}
["_children":"Mf_Data":private]=>
array(1) {
[0]=>
array(1) {
["foo"]=>
object(Mf_Data)#2 (5) {
["_values":"Mf_Data":private]=>
array(0) {
}
["_children":"Mf_Data":private]=>
array(1) {
[0]=>
array(1) {
["bar"]=>
object(Mf_Data)#3 (5) {
["_values":"Mf_Data":private]=>
array(1) {
[0]=>
array(1) {
["hello"]=>
string(5) "world"
}
}
["_children":"Mf_Data":private]=>
array(0) {
}
["_parent":"Mf_Data":private]=>
*RECURSION*
["_key":"Mf_Data":private]=>
string(3) "bar"
["_index":"Mf_Data":private]=>
int(0)
}
}
}
["_parent":"Mf_Data":private]=>
*RECURSION*
["_key":"Mf_Data":private]=>
string(3) "foo"
["_index":"Mf_Data":private]=>
int(0)
}
}
}
["_parent":"Mf_Data":private]=>
NULL
["_key":"Mf_Data":private]=>
NULL
["_index":"Mf_Data":private]=>
int(0)
}
Addendum
1)
So this is the toArray() function I've devised for the Mf_Data class:
public function toArray()
{
$array = (array) $this;
array_walk_recursive($array, function (&$property) {
if ($property instanceof Mf_Data) {
$property = $property->toArray();
}
});
return $array;
}
However since the Mf_Data objects also have a reference to their parent (containing) object, this fails with recursion. Works like a charm though when I remove the _parent reference.
2)
Just to follow up, the final function to transform a complex tree-node object I went with was:
// class name - Mf_Data
// exlcuded properties - $_parent, $_index
public function toArray()
{
$array = get_object_vars($this);
unset($array['_parent'], $array['_index']);
array_walk_recursive($array, function (&$property) {
if (is_object($property) && method_exists($property, 'toArray')) {
$property = $property->toArray();
}
});
return $array;
}
3)
I'm following up again, with a bit cleaner of an implementation. Using interfaces for an instanceof check seems much cleaner than method_exists() (however method_exists() does cross-cut inheritance/implementation).
Using unset() seemed a bit messy too, and it seems that logic should be refactored into another method. However, this implementation does copy the property array (due to array_diff_key), so something to consider.
interface ToMapInterface
{
function toMap();
function getToMapProperties();
}
class Node implements ToMapInterface
{
private $index;
private $parent;
private $values = array();
public function toMap()
{
$array = $this->getToMapProperties();
array_walk_recursive($array, function (&$value) {
if ($value instanceof ToMapInterface) {
$value = $value->toMap();
}
});
return $array;
}
public function getToMapProperties()
{
return array_diff_key(get_object_vars($this), array_flip(array(
'index', 'parent'
)));
}
}
edit: it's currently 2016-09-24, and PHP 5.4 has been released 2012-03-01, and support has ended 2015-09-01. Still, this answer seems to gain upvotes. If you're still using PHP < 5.4, your are creating a security risk and endagering your project. If you have no compelling reasons to stay at <5.4, or even already use version >= 5.4, do not use this answer, and just use PHP>= 5.4 (or, you know, a recent one) and implement the JsonSerializable interface
You would define a function, for instance named getJsonData();, which would return either an array, stdClass object, or some other object with visible parameters rather then private/protected ones, and do a json_encode($data->getJsonData());. In essence, implement the function from 5.4, but call it by hand.
Something like this would work, as get_object_vars() is called from inside the class, having access to private/protected variables:
function getJsonData(){
$var = get_object_vars($this);
foreach ($var as &$value) {
if (is_object($value) && method_exists($value,'getJsonData')) {
$value = $value->getJsonData();
}
}
return $var;
}
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