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SymfonyLive
Paris 2017
The Serializer
Component
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I am Grégoire Pineau
DevOps @blackfireio / @sensiolabs
@symfony Core Contributor
Github / Twitter : @lyrixx
Hello!
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Serialization ?
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“
Serialization is the process of translating data
structures or object state into a format that can
be stored and reconstructed later in the same or
another computer environment.
Adapted from
en.wikipedia.org/wiki/Serialization
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When?
◉ To store data in a DB (RDBMS, Redis, Elasticsearch)
◉ To send / receive data via an API
◉ To send / receive data via messaging system (AMQP)
◉ To detect changes in time-varying data
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Why?
◉ PHP serialize / unserialize functions are powerful but:
○ Not interoperable
○ Not configurable
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Different formats
◉ Binary:
○ Faster
○ Smaller
○ Ex: protobuf, Apache Thrift, …
◉ Textual
○ Human readable / editable
○ Ex: CSV, JSON, XML, YAML, ... 7
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symfony/serializer
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History
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Before symfony 2.7
◉ JMSSerializer:
○ Had more features
○ Had a better integration with others libs
○ Was more used
◉ Symfony Serializer
○ Was not really used
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History
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Symfony 2.7 & next
◉ Tons of new features
◉ … and keeps counting
◉ Better integration with others lib
◉ Simpler than JMSSerializer (?)
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Architecture
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And Decoders
Encoders
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Encoders
◉ CsvEncoder
◉ JsonEncoder
◉ XmlEncoder
◉ YamlEncoder
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Encoder usage
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Decoder usage
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And denormalizers
Normalizers
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Normalizers
AbstractNormalizer, AbstractObjectNormalizer, ArrayDenormalizer,
ContextAwareDenormalizerInterface,
ContextAwareNormalizerInterface, CustomNormalizer,
DataUriNormalizer, DateTimeNormalizer, DenormalizableInterface,
DenormalizerAwareInterface, DenormalizerAwareTrait,
DenormalizerInterface, GetSetMethodNormalizer,
JsonSerializableNormalizer, NormalizableInterface,
NormalizerAwareInterface, NormalizerAwareTrait, NormalizerInterface,
ObjectNormalizer, PropertyNormalizer, SerializerAwareNormalizer
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Object Normalizers
GetSetMethodNormalizer Uses getters and setters
PropertyNormalizer Uses Reflection
CustomNormalizer Uses $object->normalize();
ObjectNormalizer Uses PropertyAccess Component
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Extra Normalizer
DateTimeNormalizer Turns DateTime into string
DataUriNormalizer Turns SplFileInfo into data:uri
ArrayDenormalizer Denormalizes arrays of objects
JsonSerializableNormalizer Turns JsonSerializable into a string
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Normalizer usage
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Denormalizer usage
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And deserializer
Serializer
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Serializer
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Serializer Usage
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Deserializer Usage
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symfony/symfony-demo
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https://github.com/symfony/symfony-demo
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Enable the serializer
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Let’s build an API
on top of
symfony/demo
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Create a Controller
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Try it
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Configuration
Groups
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Groups
◉ Choose what property is (de) serialized
◉ Could be used:
○ For read / write access
○ For security (public, connected user, admin user)
○ For API versioning
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Groups
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Tips
Use the following format for your Groups:
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GET /posts post_list_read
GET /posts/12 post_read
PUT /posts/12 post_write
GET /posts/12/details post_details_read
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Groups
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Context
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Configuration
MaxDepth
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MaxDepth
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Configuration
NameConverter
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NameConverter
Tweak the name of a property:
◉ By default, it uses the property name (CamelCase)
◉ Automatically convert to snake_case
◉ Rename / Alias some property
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Try it again
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Add more data ...
… to the representation
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Custom Object
Normalizer
◉ Allow to tweak at PHP level the normalization
◉ Be able to add or remove some data:
○ Canonical URL
○ “Computed” data: the number of post’s comment
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PostNormalizer
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PostNormalizer
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Custom Object
Normalizer
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Try it again
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Circular Reference
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Circular Reference
◉ Example: “Post” has a one-to-many relation
“Comment”. A “Comment” has a property
“Post”.
◉ By default the serializer will throw an
exception because of the circular reference
◉ But you can implement a Circular Reference
Handler
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Circular Reference
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Circular Reference
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Circular Reference
SF 3.3
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Circular Reference
< SF 3.2
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Deserialization
Aka: How to use user data
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Create a Controller
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Create a Controller
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ConstraintViolation
ListNormalizer
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Send invalid data
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Send valid data
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Deserialization
Into an Object
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Into an Object
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Deserialization
With some relations
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Post Object
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Enable the property
info component
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Try it!
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Solution
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You need to create a TagDenormalizer to handle
the situation: search the tag in DB:
◉ If exists, uses it
◉ If not, create it
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Deserialization
Of array
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The controller
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Summary
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Summary
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◉ Use Groups
◉ Create a normalizer for each serialized entity
○ Service tag: ‘serializer.normalizer’
◉ Create a circular reference handler
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Any questions ?
@lyrixx
Thanks!
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