Cara menggunakan php serialize generator

• Installation
• Usage
• Serializing an Object
• Deserializing an Object
  • Deserializing in an Existing Object
• Attributes Groups
• Selecting Specific Attributes
• Ignoring Attributes
  • Option 1: Using @Ignore Annotation
  • Option 2: Using the Context
• Converting Property Names when Serializing and Deserializing
  • CamelCase to snake_case
  • Configure name conversion using metadata
• Serializing Boolean Attributes
• Using Callbacks to Serialize Properties with Object Instances
• Normalizers
  • Built-in Normalizers
• Encoders
  • Built-in Encoders
  • The JsonEncoder
  • The CsvEncoder
  • The XmlEncoder
  • The YamlEncoder
• Context Builders
• Skipping null Values
• Collecting Type Errors While Denormalizing
• Handling Circular References
• Handling Serialization Depth
• Handling Arrays
• Handling Constructor Arguments
• Recursive Denormalization and Type Safety
• Serializing Interfaces and Abstract Classes
• Learn more

The Serializer Component

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 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

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.

To use the Serializer component, set up the Serializer specifying which encoders and normalizer are going to be available:

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:

Now, if you want to serialize this object into JSON, you only need to use the Serializer service created before:

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:

In this case, deserialize() needs three parameters:

1. The information to be decoded
2. The name of the class this information will be decoded to
3. The encoder used to convert that information into an array

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 AbstractNormalizer::ALLOW_EXTRA_ATTRIBUTES context option to false and provide an object that implements ClassMetadataFactoryInterface when constructing the normalizer:

Deserializing in an Existing Object

The serializer can also be used to update an existing object:

This is a common need when working with an ORM.

The AbstractNormalizer::OBJECT_TO_POPULATE is only used for the top level object. If that object is the root of a tree structure, all child elements that exist in the normalized data will be re-created with new instances.

When the AbstractObjectNormalizer::DEEP_OBJECT_TO_POPULATE option is set to true, existing children of the root OBJECT_TO_POPULATE are updated from the normalized data, instead of the denormalizer re-creating them. Note that DEEP_OBJECT_TO_POPULATE only works for single child objects, but not for arrays of objects. Those will still be replaced when present in the normalized data.

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:

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:

• YAML files:

• XML files:

Then, create your groups definition:

• Attributes
• YAML
• XML

You are now able to serialize only attributes in the groups you want:

Selecting Specific Attributes

It is also possible to serialize only a set of specific attributes:

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

All attributes are included by default when serializing objects. There are two options to ignore some of those attributes.

Option 2: Using the Context

Pass an array with the names of the attributes to ignore using the AbstractNormalizer::IGNORED_ATTRIBUTES key in the context of the serializer method:

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:

And in the serialized form, all attributes must be prefixed by org_ like the following:

A custom name converter can handle such cases:

The custom name converter can be used by passing it as second parameter of any class extending AbstractNormalizer, including GetSetMethodNormalizer and PropertyNormalizer:

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:

Configure name conversion using metadata

When using this component inside a Symfony application and the class metadata factory is enabled as explained in the Attributes Groups section, this is already set up and you only need to provide the configuration. Otherwise:

Now configure your name conversion mapping. Consider an application that defines a Person entity with a firstName property:

• Attributes
• YAML
• XML

This custom mapping is used to convert property names when serializing and deserializing objects:

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, get, and can.

6.1

The support of canners (methods prefixed by can) was introduced in Symfony 6.1.

Normalizers

Normalizers turn objects into arrays and vice versa. They implement NormalizerInterface for normalizing (object to array) and DenormalizerInterface for denormalizing (array to object).

Normalizers are enabled in the serializer passing them as its first argument:

Built-in Normalizers

The Serializer component provides several built-in normalizers:

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, canners, 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, can, add or remove 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 in Symfony applications with the Serializer component enabled.

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).

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) by using PHP reflection. It supports calling the constructor during the denormalization process.

Objects are normalized to a map of property names to property values.

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.

This normalizer works with classes that implement FormInterface.

It will get errors from the form and normalize them into a normalized array.

This normalizer converts objects that implement AbstractUid into strings. The default normalization format for objects that implement Uuid is the RFC 4122 format (example: d9e7a184-5d5b-11ea-a62a-3499710062d0). The default normalization format for objects that implement Ulid is the Base 32 format (example: 01E439TP9XJZ9RPFH3T1PYBCR8). You can change the string format by setting the serializer context option UidNormalizer::NORMALIZATION_FORMAT_KEY to UidNormalizer::NORMALIZATION_FORMAT_BASE_58, UidNormalizer::NORMALIZATION_FORMAT_BASE_32 or UidNormalizer::NORMALIZATION_FORMAT_RFC_4122.

Also it can denormalize uuid or ulid strings to Uuid or Ulid. The format does not matter.

Certain normalizers are enabled by default when using the Serializer component in a Symfony application, additional ones can be enabled by tagging them with serializer.normalizer.

Here is an example of how to enable the built-in GetSetMethodNormalizer, a faster alternative to the ObjectNormalizer:

• YAML
• XML
• PHP

Encoders

Encoders turn arrays into formats and vice versa. They implement EncoderInterface for encoding (array to format) and DecoderInterface for decoding (format to array).

You can add new encoders to a Serializer instance by using its second constructor argument:

Built-in Encoders

The Serializer component provides several built-in encoders:

All these encoders are enabled by default when using the Serializer component in a Symfony application.

The JsonEncoder

The JsonEncoder encodes to and decodes from JSON strings, based on the PHP json_encode and json_decode functions. It can be useful to modify how these functions operate in certain instances by providing options such as JSON_PRESERVE_ZERO_FRACTION. You can use the serialization context to pass in these options using the key json_encode_options or json_decode_options respectively:

The CsvEncoder

The CsvEncoder encodes to and decodes from CSV.

The CsvEncoder Context Options

The encode() method defines a third optional parameter called context which defines the configuration options for the CsvEncoder an associative array:

These are the options available:

The XmlEncoder

This encoder transforms arrays into XML and vice versa.

For example, take an object normalized as following:

The XmlEncoder will encode this object like that:

The special # key can be used to define the data of a node:

Furthermore, keys beginning with @ will be considered attributes, and the key #comment can be used for encoding XML comments:

You can pass the context key as_collection in order to have the results always as a collection.

Tip

XML comments are ignored by default when decoding contents, but this behavior can be changed with the optional context key XmlEncoder::DECODER_IGNORED_NODE_TYPES.

Data with #comment keys are encoded to XML comments by default. This can be changed with the optional $encoderIgnoredNodeTypes argument of the XmlEncoder class constructor.

The XmlEncoder Context Options

The encode() method defines a third optional parameter called context which defines the configuration options for the XmlEncoder an associative array:

These are the options available:

Example with custom context:

The YamlEncoder

This encoder requires the Yaml Component and transforms from and to Yaml.

The YamlEncoder Context Options

The encode() method, like other encoder, uses context to set configuration options for the YamlEncoder an associative array:

These are the options available:

Context Builders

Instead of passing plain PHP arrays to the serialization context, you can use "context builders" to define the context using a fluent interface:

6.1

Context builders were introduced in Symfony 6.1.

Skipping null Values

By default, the Serializer will preserve properties containing a null value. You can change this behavior by setting the AbstractObjectNormalizer::SKIP_NULL_VALUES context option to true:

Collecting Type Errors While Denormalizing

When denormalizing a payload to an object with typed properties, you'll get an exception if the payload contains properties that don't have the same type as the object.

In those situations, use the COLLECT_DENORMALIZATION_ERRORS option to collect all exceptions at once, and to get the object partially denormalized:

Handling Circular References

Circular references are common when dealing with entity relations:

To avoid infinite loops, GetSetMethodNormalizer or ObjectNormalizer throw a CircularReferenceException when such a case is encountered:

The key circular_reference_limit in the default context sets the number of times it will serialize the same object before considering it a circular reference. The 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:

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:

The serializer can be configured to set a maximum depth for a given property. Here, we set it to 2 for the $child property:

• Attributes
• YAML
• XML

The metadata loader corresponding to the chosen format must be configured in order to use this feature. It is done automatically when using the Serializer component in a Symfony application. When using the standalone component, refer to the groups documentation to learn how to do that.

The check is only done if the AbstractObjectNormalizer::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:

Instead of throwing an exception, a custom callable can be executed when the maximum depth is reached. This is especially useful when serializing entities having unique identifiers:

Handling Arrays

The Serializer component is capable of handling arrays of objects as well. Serializing arrays works just like serializing a single object:

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:

Handling Constructor Arguments

If the class constructor defines arguments, as usually happens with Value Objects, the serializer won't be able to create the object if some arguments are missing. In those cases, use the default_constructor_arguments context option:

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 this component in a Symfony application, 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:

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.

Serializing Interfaces and Abstract Classes

When dealing with objects that are fairly similar or share properties, you may use interfaces or abstract classes. The Serializer component allows you to serialize and deserialize these objects using a "discriminator class mapping".

The discriminator is the field (in the serialized string) used to differentiate between the possible objects. In practice, when using the Serializer component, pass a ClassDiscriminatorResolverInterface implementation to the ObjectNormalizer.

The Serializer component provides an implementation of ClassDiscriminatorResolverInterface called ClassDiscriminatorFromClassMetadata which uses the class metadata factory and a mapping configuration to serialize and deserialize objects of the correct class.

When using this component inside a Symfony application and the class metadata factory is enabled as explained in the Attributes Groups section, this is already set up and you only need to provide the configuration. Otherwise:

Now configure your discriminator class mapping. Consider an application that defines an abstract CodeRepository class extended by GitHubCodeRepository and BitBucketCodeRepository classes:

• Attributes
• YAML
• XML

Once configured, the serializer uses the mapping to pick the correct class:

Learn more

• How to Use the Serializer

See also

Normalizers for the Symfony Serializer Component supporting popular web API formats (JSON-LD, GraphQL, OpenAPI, HAL, JSON:API) are available as part of the API Platform project.

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).