Pushing Related Resources Using HTTP/2
HTTP/2 allows a server to pre-emptively send (or "push") responses (along with corresponding "promised" requests) to a client in association with a previous client-initiated request. This can be useful when the server knows the client will need to have those responses available in order to fully process the response to the original request.
API Platform leverages this capability by pushing relations of a resource to clients.
Note: We strongly recommend using Vulcain instead of this feature. Vulcain is faster, cleaner, more flexible, and is supported out of the box in the API Platform distribution.
<?php
// api/src/Entity/Book.php
namespace App\Entity;
use ApiPlatform\Metadata\ApiProperty;
use ApiPlatform\Metadata\ApiResource;
#[ApiResource]
class Book
{
#[ApiProperty(push: true)]
public Author $author;
// ...
}
By setting the push
attribute to true
on a property holding a relation, API Platform will automatically add a valid Link
HTTP header with the preload
relation.
According to the Preload W3C Candidate Recommendation, web servers and proxy servers can read this header, fetch the related resource and send it to the client using Server Push.
With the Caddy web server (the server shipped as part of the distribution), you must add the push
directive to your Caddyfile
to be able to use this feature.
NGINX, Apache, Cloudflare, Fastly and Akamai honor this header.
Using this feature maximises HTTP cache hits for your API resources. For best performance, this feature should be used in conjunction with the built-in HTTP cache invalidation system (based on Varnish).
What' new?

Sep 15,16 2022: new edition of our conference dedicated to API Platform and its ecosystem!
The Distribution: Create Powerful APIs with Ease
Core
- General Design Considerations
- GraphQL Support
- Enabling GraphQL
- Changing Location of the GraphQL Endpoint
- GraphiQL
- GraphQL Playground
- Modifying or Disabling the Default IDE
- Request with application/graphql Content-Type
- Operations
- Queries
- Mutations
- Subscriptions
- Workflow of the Resolvers
- Events
- Filters
- Pagination
- Security
- Serialization Groups
- Exception and Error
- Name Conversion
- Custom Types
- Modify the Extracted Types
- Changing the Serialization Context Dynamically
- Export the Schema in SDL
- Handling File Upload
- Change Default Descriptions
- State Providers
- Filters
- Doctrine ORM and MongoDB ODM Filters
- Elasticsearch Filters
- Serializer Filters
- Creating Custom Filters
- ApiFilter Attribute
- The Serialization Process
- Overall Process
- Available Serializers
- The Serialization Context, Groups and Relations
- Using Serialization Groups
- Using Serialization Groups per Operation
- Embedding Relations
- Property Normalization Context
- Calculated Field
- Changing the Serialization Context Dynamically
- Changing the Serialization Context on a Per-item Basis
- Name Conversion
- Decorating a Serializer and Adding Extra Data
- Entity Identifier Case
- Embedding the JSON-LD Context
- Collection Relation
- Validation
- Validating Submitted Data
- Using Validation Groups
- Using Validation Groups on Operations
- Dynamic Validation Groups
- Sequential Validation Groups
- Validating Delete Operations
- Error Levels and Payload Serialization
- Validation on Collection Relations
- Open Vocabulary Generated from Validation Metadata
- Specification Property Restrictions
- Collecting Denormalization Errors
- Overriding Default Order
- OpenAPI Specification Support (formerly Swagger)
- Using the OpenAPI Command
- Overriding the OpenAPI Specification
- Using the OpenAPI and Swagger Contexts
- Disabling an Operation From OpenAPI Documentation
- Changing the Name of a Definition
- Changing Operations in the OpenAPI Documentation
- Disabling Swagger UI or ReDoc
- Changing the Location of Swagger UI
- Using a custom Asset Package in Swagger UI
- Overriding the UI Template
- Compatibility Layer with Amazon API Gateway
- OAuth
- Info Object
- Pushing Related Resources Using HTTP/2
- Using External Vocabularies
- URL Generation Strategy
- NelmioApiDocBundle Integration
- Bootstraping the core library
Schema Generator
- Configuration
- Customizing PHP Namespaces
- Forcing a Field Type (Range)
- Forcing a Field Cardinality
- Changing the Default Cardinality
- Adding a Custom Attribute or Modifying a Generated Attribute
- Forcing (or Enabling) a Class Parent
- Forcing a Class to be Abstract
- Define API Platform Operations
- Forcing a Nullable Property
- Forcing a Unique Property
- Making a Property Read-Only
- Making a Property Write-Only
- Forcing an Embeddable Class to be Embedded
- Skipping Accessor Method Generation
- Using Fluent Mutator Methods
- Disabling the id Generator
- Generating UUIDs
- User-submitted UUIDs
- Generating Custom IDs
- Disabling Usage of Doctrine Collections
- Changing the Field Visibility
- Generating Assert\Type Attributes
- Forcing Doctrine Inheritance Mapping Attribute
- Interfaces and Doctrine Resolve Target Entity Listener
- Custom Schemas
- All Types, Resolve Types and Exclude
- Checking GoodRelation Compatibility
- Author PHPDoc
- PHP File Header
- Disabling Generators and Creating Custom Ones
- Full Configuration Reference