The Serializer Component
Warning: You are browsing the documentation for Symfony 3.x, which is no longer maintained.
Read the updated version of this page for Symfony 7.1 (the current stable version).
The Serializer component is meant to be used to turn objects into a specific format (XML, JSON, YAML, ...) and the other way around.
In order to do so, the Serializer component follows the following simple schema.
As you can see in the picture above, an array is used as an intermediary between objects and serialized contents. This way, encoders will only deal with turning specific formats into arrays and vice versa. The same way, Normalizers will deal with turning specific objects into arrays and vice versa.
Serialization is a complex topic. This component may not cover all your use cases out of the box, but it can be useful for developing tools to serialize and deserialize your objects.
Installation
1
$ composer require symfony/serializer:^3.4
Note
If you install this component outside of a Symfony application, you must
require the vendor/autoload.php
file in your code to enable the class
autoloading mechanism provided by Composer. Read
this article for more details.
To use the ObjectNormalizer
, the PropertyAccess component
must also be installed.
Usage
See also
This article explains the philosophy of the Serializer and gets you familiar with the concepts of normalizers and encoders. The code examples assume that you use the Serializer as an independent component. If you are using the Serializer in a Symfony application, read How to Use the Serializer after you finish this article.
Using the Serializer component is really simple. You just need to set up the Serializer specifying which encoders and normalizer are going to be available:
1 2 3 4 5 6 7 8 9
use Symfony\Component\Serializer\Encoder\JsonEncoder;
use Symfony\Component\Serializer\Encoder\XmlEncoder;
use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
use Symfony\Component\Serializer\Serializer;
$encoders = [new XmlEncoder(), new JsonEncoder()];
$normalizers = [new ObjectNormalizer()];
$serializer = new Serializer($normalizers, $encoders);
The preferred normalizer is the
ObjectNormalizer,
but other normalizers are available. All the examples shown below use
the ObjectNormalizer
.
Serializing an Object
For the sake of this example, assume the following class already exists in your project:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
namespace App\Model;
class Person
{
private $age;
private $name;
private $sportsperson;
private $createdAt;
// Getters
public function getName()
{
return $this->name;
}
public function getAge()
{
return $this->age;
}
public function getCreatedAt()
{
return $this->createdAt;
}
// Issers
public function isSportsperson()
{
return $this->sportsperson;
}
// Setters
public function setName($name)
{
$this->name = $name;
}
public function setAge($age)
{
$this->age = $age;
}
public function setSportsperson($sportsperson)
{
$this->sportsperson = $sportsperson;
}
public function setCreatedAt($createdAt)
{
$this->createdAt = $createdAt;
}
}
Now, if you want to serialize this object into JSON, you only need to use the Serializer service created before:
1 2 3 4 5 6 7 8 9 10
$person = new App\Model\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
The first parameter of the serialize() is the object to be serialized and the second is used to choose the proper encoder, in this case JsonEncoder.
Deserializing an Object
You'll now learn how to do the exact opposite. This time, the information
of the Person
class would be encoded in XML format:
1 2 3 4 5 6 7 8 9 10 11
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');
In this case, deserialize() needs three parameters:
- The information to be decoded
- The name of the class this information will be decoded to
- The encoder used to convert that information into an array
3.3
Support for the allow_extra_attributes
key in the context was introduced
in Symfony 3.3.
By default, additional attributes that are not mapped to the denormalized object
will be ignored by the Serializer component. If you prefer to throw an exception
when this happens, set the allow_extra_attributes
context option to
false
and provide an object that implements ClassMetadataFactoryInterface
when constructing the normalizer:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
$data = <<<EOF
<person>
<name>foo</name>
<age>99</age>
<city>Paris</city>
</person>
EOF;
// this will throw a Symfony\Component\Serializer\Exception\ExtraAttributesException
// because "city" is not an attribute of the Person class
$classMetadataFactory = new ClassMetadataFactory(new AnnotationLoader(new AnnotationReader()));
$normalizer = new ObjectNormalizer($classMetadataFactory);
$serializer = new Serializer([$normalizer]);
$person = $serializer->deserialize($data, 'App\Model\Person', 'xml', [
'allow_extra_attributes' => false,
]);
Deserializing in an Existing Object
The serializer can also be used to update an existing object:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
// ...
$person = new Person();
$person->setName('bar');
$person->setAge(99);
$person->setSportsperson(true);
$data = <<<EOF
<person>
<name>foo</name>
<age>69</age>
</person>
EOF;
$serializer->deserialize($data, Person::class, 'xml', ['object_to_populate' => $person]);
// $person = App\Model\Person(name: 'foo', age: '69', sportsperson: true)
This is a common need when working with an ORM.
Attributes Groups
Sometimes, you want to serialize different sets of attributes from your entities. Groups are a handy way to achieve this need.
Assume you have the following plain-old-PHP object:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
namespace Acme;
class MyObj
{
public $foo;
private $bar;
public function getBar()
{
return $this->bar;
}
public function setBar($bar)
{
return $this->bar = $bar;
}
}
The definition of serialization can be specified using annotations, XML or YAML. The ClassMetadataFactory that will be used by the normalizer must be aware of the format to use.
The following code shows how to initialize the ClassMetadataFactory for each format:
Annotations in PHP files:
1 2 3 4 5
use Doctrine\Common\Annotations\AnnotationReader; use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactory; use Symfony\Component\Serializer\Mapping\Loader\AnnotationLoader; $classMetadataFactory = new ClassMetadataFactory(new AnnotationLoader(new AnnotationReader()));
YAML files:
1 2 3 4
use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactory; use Symfony\Component\Serializer\Mapping\Loader\YamlFileLoader; $classMetadataFactory = new ClassMetadataFactory(new YamlFileLoader('/path/to/your/definition.yml'));
XML files:
1 2 3 4
use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactory; use Symfony\Component\Serializer\Mapping\Loader\XmlFileLoader; $classMetadataFactory = new ClassMetadataFactory(new XmlFileLoader('/path/to/your/definition.xml'));
Then, create your groups definition:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
namespace Acme;
use Symfony\Component\Serializer\Annotation\Groups;
class MyObj
{
/**
* @Groups({"group1", "group2"})
*/
public $foo;
/**
* @Groups("group3")
*/
public function getBar() // is* methods are also supported
{
return $this->bar;
}
// ...
}
1 2 3 4 5 6
Acme\MyObj:
attributes:
foo:
groups: ['group1', 'group2']
bar:
groups: ['group3']
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
<?xml version="1.0" ?>
<serializer xmlns="http://symfony.com/schema/dic/serializer-mapping"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://symfony.com/schema/dic/serializer-mapping
https://symfony.com/schema/dic/serializer-mapping/serializer-mapping-1.0.xsd"
>
<class name="Acme\MyObj">
<attribute name="foo">
<group>group1</group>
<group>group2</group>
</attribute>
<attribute name="bar">
<group>group3</group>
</attribute>
</class>
</serializer>
You are now able to serialize only attributes in the groups you want:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
use Symfony\Component\Serializer\Serializer;
$obj = new MyObj();
$obj->foo = 'foo';
$obj->setBar('bar');
$normalizer = new ObjectNormalizer($classMetadataFactory);
$serializer = new Serializer([$normalizer]);
$data = $serializer->normalize($obj, null, ['groups' => ['group1']]);
// $data = ['foo' => 'foo'];
$obj2 = $serializer->denormalize(
['foo' => 'foo', 'bar' => 'bar'],
'MyObj',
null,
['groups' => ['group1', 'group3']]
);
// $obj2 = MyObj(foo: 'foo', bar: 'bar')
Note
In order to use the annotation loader, you should have installed the
doctrine/annotations
and doctrine/cache
packages with Composer.
Tip
Annotation classes aren't loaded automatically, so you must load them using a class loader like this:
1 2 3 4 5 6 7 8 9
use Composer\Autoload\ClassLoader;
use Doctrine\Common\Annotations\AnnotationRegistry;
/** @var ClassLoader $loader */
$loader = require __DIR__.'/../vendor/autoload.php';
AnnotationRegistry::registerLoader([$loader, 'loadClass']);
return $loader;
Selecting Specific Attributes
It is also possible to serialize only a set of specific attributes:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
use Symfony\Component\Serializer\Serializer;
class User
{
public $familyName;
public $givenName;
public $company;
}
class Company
{
public $name;
public $address;
}
$company = new Company();
$company->name = 'Les-Tilleuls.coop';
$company->address = 'Lille, France';
$user = new User();
$user->familyName = 'Dunglas';
$user->givenName = 'Kévin';
$user->company = $company;
$serializer = new Serializer([new ObjectNormalizer()]);
$data = $serializer->normalize($user, null, ['attributes' => ['familyName', 'company' => ['name']]]);
// $data = ['familyName' => 'Dunglas', 'company' => ['name' => 'Les-Tilleuls.coop']];
Only attributes that are not ignored (see below) are available. If some serialization groups are set, only attributes allowed by those groups can be used.
As for groups, attributes can be selected during both the serialization and deserialization process.
Ignoring Attributes
Note
Using attribute groups instead of the setIgnoredAttributes() method is considered best practice.
As an option, there's a way to ignore attributes from the origin object. To remove those attributes use the setIgnoredAttributes() method on the normalizer definition:
1 2 3 4 5 6 7 8 9 10
use Symfony\Component\Serializer\Encoder\JsonEncoder;
use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
use Symfony\Component\Serializer\Serializer;
$normalizer = new ObjectNormalizer();
$normalizer->setIgnoredAttributes(['age']);
$encoder = new JsonEncoder();
$serializer = new Serializer([$normalizer], [$encoder]);
$serializer->serialize($person, 'json'); // Output: {"name":"foo","sportsperson":false}
Converting Property Names when Serializing and Deserializing
Sometimes serialized attributes must be named differently than properties or getter/setter methods of PHP classes.
The Serializer Component provides a handy way to translate or map PHP field names to serialized names: The Name Converter System.
Given you have the following object:
1 2 3 4 5
class Company
{
public $name;
public $address;
}
And in the serialized form, all attributes must be prefixed by org_
like
the following:
1
{"org_name": "Acme Inc.", "org_address": "123 Main Street, Big City"}
A custom name converter can handle such cases:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
use Symfony\Component\Serializer\NameConverter\NameConverterInterface;
class OrgPrefixNameConverter implements NameConverterInterface
{
public function normalize($propertyName)
{
return 'org_'.$propertyName;
}
public function denormalize($propertyName)
{
// removes 'org_' prefix
return 'org_' === substr($propertyName, 0, 4) ? substr($propertyName, 4) : $propertyName;
}
}
The custom name converter can be used by passing it as second parameter of any class extending AbstractNormalizer, including GetSetMethodNormalizer and PropertyNormalizer:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
use Symfony\Component\Serializer\Encoder\JsonEncoder;
use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
use Symfony\Component\Serializer\Serializer;
$nameConverter = new OrgPrefixNameConverter();
$normalizer = new ObjectNormalizer(null, $nameConverter);
$serializer = new Serializer([$normalizer], [new JsonEncoder()]);
$company = new Company();
$company->name = 'Acme Inc.';
$company->address = '123 Main Street, Big City';
$json = $serializer->serialize($company, 'json');
// {"org_name": "Acme Inc.", "org_address": "123 Main Street, Big City"}
$companyCopy = $serializer->deserialize($json, Company::class, 'json');
// Same data as $company
CamelCase to snake_case
In many formats, it's common to use underscores to separate words (also known as snake_case). However, in Symfony applications is common to use CamelCase to name properties (even though the PSR-1 standard doesn't recommend any specific case for property names).
Symfony provides a built-in name converter designed to transform between snake_case and CamelCased styles during serialization and deserialization processes:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
use Symfony\Component\Serializer\NameConverter\CamelCaseToSnakeCaseNameConverter;
use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
$normalizer = new ObjectNormalizer(null, new CamelCaseToSnakeCaseNameConverter());
class Person
{
private $firstName;
public function __construct($firstName)
{
$this->firstName = $firstName;
}
public function getFirstName()
{
return $this->firstName;
}
}
$kevin = new Person('Kévin');
$normalizer->normalize($kevin);
// ['first_name' => 'Kévin'];
$anne = $normalizer->denormalize(['first_name' => 'Anne'], 'Person');
// Person object with firstName: 'Anne'
Serializing Boolean Attributes
If you are using isser methods (methods prefixed by is
, like
App\Model\Person::isSportsperson()
), the Serializer component will
automatically detect and use it to serialize related attributes.
The ObjectNormalizer
also takes care of methods starting with has
, add
and remove
.
Using Callbacks to Serialize Properties with Object Instances
When serializing, you can set a callback to format a specific object property:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
use App\Model\Person;
use Symfony\Component\Serializer\Encoder\JsonEncoder;
use Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer;
use Symfony\Component\Serializer\Serializer;
$encoder = new JsonEncoder();
$normalizer = new GetSetMethodNormalizer();
$callback = function ($dateTime) {
return $dateTime instanceof \DateTime
? $dateTime->format(\DateTime::ISO8601)
: '';
};
$normalizer->setCallbacks(['createdAt' => $callback]);
$serializer = new Serializer([$normalizer], [$encoder]);
$person = new Person();
$person->setName('cordoval');
$person->setAge(34);
$person->setCreatedAt(new \DateTime('now'));
$serializer->serialize($person, 'json');
// Output: {"name":"cordoval", "age": 34, "createdAt": "2014-03-22T09:43:12-0500"}
Normalizers
There are several types of normalizers available:
- ObjectNormalizer
-
This normalizer leverages the PropertyAccess Component to read and write in the object. It means that it can access to properties directly and through getters, setters, hassers, issers, adders and removers. It supports calling the constructor during the denormalization process.
Objects are normalized to a map of property names and values (names are generated by removing the
get
,set
,has
,is
,add
orremove
prefix from the method name and transforming the first letter to lowercase; e.g.getFirstName()
->firstName
).The
ObjectNormalizer
is the most powerful normalizer. It is configured by default when using the Symfony Standard Edition with the serializer enabled. - GetSetMethodNormalizer
-
This normalizer reads the content of the class by calling the "getters" (public methods starting with "get"). It will denormalize data by calling the constructor and the "setters" (public methods starting with "set").
Objects are normalized to a map of property names and values (names are generated by removing the
get
prefix from the method name and transforming the first letter to lowercase; e.g.getFirstName()
->firstName
). - PropertyNormalizer
-
This normalizer directly reads and writes public properties as well as private and protected properties (from both the class and all of its parent classes). It supports calling the constructor during the denormalization process.
Objects are normalized to a map of property names to property values.
3.4
The ability to handle parent classes for
PropertyNormalizer
was introduced in Symfony 3.4. - JsonSerializableNormalizer
-
This normalizer works with classes that implement JsonSerializable.
It will call the JsonSerializable::jsonSerialize() method and then further normalize the result. This means that nested JsonSerializable classes will also be normalized.
This normalizer is particularly helpful when you want to gradually migrate from an existing codebase using simple json_encode to the Symfony Serializer by allowing you to mix which normalizers are used for which classes.
Unlike with json_encode circular references can be handled.
- DateTimeNormalizer
-
This normalizer converts DateTimeInterface objects (e.g. DateTime and DateTimeImmutable) into strings. By default, it uses the RFC3339 format.
3.2
Support for specifying datetime format during denormalization was introduced in the
DateTimeNormalizer
in Symfony 3.2. - DataUriNormalizer
-
This normalizer converts SplFileInfo objects into a data URI
string (
data:...
) such that files can be embedded into serialized data. - DateIntervalNormalizer
-
This normalizer converts DateInterval objects into strings. By default, it uses the
P%yY%mM%dDT%hH%iM%sS
format.3.4
The
DateIntervalNormalizer
normalizer was introduced in Symfony 3.4.
Encoders
The Serializer component supports many formats out of the box:
- JsonEncoder
- This class encodes and decodes data in JSON.
- XmlEncoder
- This class encodes and decodes data in XML.
- YamlEncoder
- This encoder encodes and decodes data in YAML. This encoder requires the Yaml Component.
- CsvEncoder
- This encoder encodes and decodes data in CSV.
All these encoders are enabled by default when using the Symfony Standard Edition with the serializer enabled.
3.2
The YamlEncoder
and CsvEncoder
encoders were introduced in Symfony 3.2
Handling Circular References
Circular references are common when dealing with entity relations:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51
class Organization
{
private $name;
private $members;
public function setName($name)
{
$this->name = $name;
}
public function getName()
{
return $this->name;
}
public function setMembers(array $members)
{
$this->members = $members;
}
public function getMembers()
{
return $this->members;
}
}
class Member
{
private $name;
private $organization;
public function setName($name)
{
$this->name = $name;
}
public function getName()
{
return $this->name;
}
public function setOrganization(Organization $organization)
{
$this->organization = $organization;
}
public function getOrganization()
{
return $this->organization;
}
}
To avoid infinite loops, GetSetMethodNormalizer or ObjectNormalizer throw a CircularReferenceException when such a case is encountered:
1 2 3 4 5 6 7 8 9 10
$member = new Member();
$member->setName('Kévin');
$organization = new Organization();
$organization->setName('Les-Tilleuls.coop');
$organization->setMembers([$member]);
$member->setOrganization($organization);
echo $serializer->serialize($organization, 'json'); // Throws a CircularReferenceException
The setCircularReferenceLimit()
method of this normalizer sets the number
of times it will serialize the same object before considering it a circular
reference. Its default value is 1
.
Instead of throwing an exception, circular references can also be handled by custom callables. This is especially useful when serializing entities having unique identifiers:
1 2 3 4 5 6 7 8 9 10
$encoder = new JsonEncoder();
$normalizer = new ObjectNormalizer();
$normalizer->setCircularReferenceHandler(function ($object) {
return $object->getName();
});
$serializer = new Serializer([$normalizer], [$encoder]);
var_dump($serializer->serialize($org, 'json'));
// {"name":"Les-Tilleuls.coop","members":[{"name":"K\u00e9vin", organization: "Les-Tilleuls.coop"}]}
Handling Serialization Depth
The Serializer component is able to detect and limit the serialization depth. It is especially useful when serializing large trees. Assume the following data structure:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
namespace Acme;
class MyObj
{
public $foo;
/**
* @var self
*/
public $child;
}
$level1 = new MyObj();
$level1->foo = 'level1';
$level2 = new MyObj();
$level2->foo = 'level2';
$level1->child = $level2;
$level3 = new MyObj();
$level3->foo = 'level3';
$level2->child = $level3;
The serializer can be configured to set a maximum depth for a given property.
Here, we set it to 2 for the $child
property:
1 2 3 4 5 6 7 8 9 10 11 12 13
namespace Acme;
use Symfony\Component\Serializer\Annotation\MaxDepth;
class MyObj
{
/**
* @MaxDepth(2)
*/
public $child;
// ...
}
1 2 3 4
Acme\MyObj:
attributes:
child:
max_depth: 2
1 2 3 4 5 6 7 8 9 10
<?xml version="1.0" ?>
<serializer xmlns="http://symfony.com/schema/dic/serializer-mapping"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://symfony.com/schema/dic/serializer-mapping
https://symfony.com/schema/dic/serializer-mapping/serializer-mapping-1.0.xsd"
>
<class name="Acme\MyObj">
<attribute name="child" max-depth="2"/>
</class>
</serializer>
The metadata loader corresponding to the chosen format must be configured in order to use this feature. It is done automatically when using the Symfony Standard Edition. When using the standalone component, refer to the groups documentation to learn how to do that.
The check is only done if the enable_max_depth
key of the serializer context
is set to true
. In the following example, the third level is not serialized
because it is deeper than the configured maximum depth of 2:
1 2 3 4 5 6 7 8 9 10 11 12
$result = $serializer->normalize($level1, null, ['enable_max_depth' => true]);
/*
$result = [
'foo' => 'level1',
'child' => [
'foo' => 'level2',
'child' => [
'child' => null,
],
],
];
*/
Handling Arrays
The Serializer component is capable of handling arrays of objects as well. Serializing arrays works just like serializing a single object:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
use Acme\Person;
$person1 = new Person();
$person1->setName('foo');
$person1->setAge(99);
$person1->setSportsman(false);
$person2 = new Person();
$person2->setName('bar');
$person2->setAge(33);
$person2->setSportsman(true);
$persons = [$person1, $person2];
$data = $serializer->serialize($persons, 'json');
// $data contains [{"name":"foo","age":99,"sportsman":false},{"name":"bar","age":33,"sportsman":true}]
If you want to deserialize such a structure, you need to add the
ArrayDenormalizer
to the set of normalizers. By appending []
to the type parameter of the
deserialize() method,
you indicate that you're expecting an array instead of a single object:
1 2 3 4 5 6 7 8 9 10 11 12
use Symfony\Component\Serializer\Encoder\JsonEncoder;
use Symfony\Component\Serializer\Normalizer\ArrayDenormalizer;
use Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer;
use Symfony\Component\Serializer\Serializer;
$serializer = new Serializer(
[new GetSetMethodNormalizer(), new ArrayDenormalizer()],
[new JsonEncoder()]
);
$data = ...; // The serialized data from the previous example
$persons = $serializer->deserialize($data, 'Acme\Person[]', 'json');
The XmlEncoder
This encoder transforms arrays into XML and vice versa. For example, take an object normalized as following:
1
['foo' => [1, 2], 'bar' => true];
The XmlEncoder
encodes this object as follows:
1 2 3 4 5 6
<?xml version="1.0"?>
<response>
<foo>1</foo>
<foo>2</foo>
<bar>1</bar>
</response>
The array keys beginning with @
are considered XML attributes:
1 2 3 4 5 6 7
['foo' => ['@bar' => 'value']];
// is encoded as follows:
// <?xml version="1.0"?>
// <response>
// <foo bar="value"/>
// </response>
Use the special #
key to define the data of a node:
1 2 3 4 5 6 7
['foo' => ['@bar' => 'value', '#' => 'baz']];
// is encoded as follows:
// <?xml version="1.0"?>
// <response>
// <foo bar="value">baz</foo>
// </response>
Context
The encode()
method defines a third optional parameter called context
which defines the configuration options for the XmlEncoder an associative array:
1
$xmlEncoder->encode($array, 'xml', $context);
These are the options available:
xml_format_output
- If set to true, formats the generated XML with line breaks and indentation.
xml_version
-
Sets the XML version attribute (default:
1.1
). xml_encoding
-
Sets the XML encoding attribute (default:
utf-8
). xml_standalone
-
Adds standalone attribute in the generated XML (default:
true
). xml_root_node_name
-
Sets the root node name (default:
response
). remove_empty_tags
- If set to true, removes all empty tags in the generated XML.
Recursive Denormalization and Type Safety
The Serializer Component can use the PropertyInfo Component to denormalize complex types (objects). The type of the class' property will be guessed using the provided extractor and used to recursively denormalize the inner data.
When using the Symfony Standard Edition, all normalizers are automatically configured to use the registered extractors.
When using the component standalone, an implementation of PropertyTypeExtractorInterface,
(usually an instance of PropertyInfoExtractor) must be passed as the 4th
parameter of the ObjectNormalizer
:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
namespace Acme;
use Symfony\Component\PropertyInfo\Extractor\ReflectionExtractor;
use Symfony\Component\Serializer\Normalizer\DateTimeNormalizer;
use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
use Symfony\Component\Serializer\Serializer;
class ObjectOuter
{
private $inner;
private $date;
public function getInner()
{
return $this->inner;
}
public function setInner(ObjectInner $inner)
{
$this->inner = $inner;
}
public function setDate(\DateTimeInterface $date)
{
$this->date = $date;
}
public function getDate()
{
return $this->date;
}
}
class ObjectInner
{
public $foo;
public $bar;
}
$normalizer = new ObjectNormalizer(null, null, null, new ReflectionExtractor());
$serializer = new Serializer([new DateTimeNormalizer(), $normalizer]);
$obj = $serializer->denormalize(
['inner' => ['foo' => 'foo', 'bar' => 'bar'], 'date' => '1988/01/21'],
'Acme\ObjectOuter'
);
dump($obj->getInner()->foo); // 'foo'
dump($obj->getInner()->bar); // 'bar'
dump($obj->getDate()->format('Y-m-d')); // '1988-01-21'
When a PropertyTypeExtractor
is available, the normalizer will also check that the data to denormalize
matches the type of the property (even for primitive types). For instance, if a string
is provided, but
the type of the property is int
, an UnexpectedValueException
will be thrown. The type enforcement of the properties can be disabled by setting
the serializer context option ObjectNormalizer::DISABLE_TYPE_ENFORCEMENT
to true
.
Learn more
See also
A popular alternative to the Symfony Serializer Component is the third-party library, JMS serializer (versions before `v1.12.0` were released under the Apache license, so incompatible with GPLv2 projects).