json.md

description	Serialize and deserialize FHIR resources as JSON.
icon	brackets-curly

JSON Serialization

serializeToJson() turns a FHIR model object into a JSON string. deserializeFromJson() reads JSON back into a typed model object. The round-trip below builds a PatientResource, serializes it, and deserializes it back.

FHIR model classes use promoted public properties, so you set values through the constructor's named arguments or by assigning the public property. There are no setX() setters.

<?php

use Ardenexal\FHIRTools\Component\Models\R4B\Resource\PatientResource;
use Ardenexal\FHIRTools\Component\Models\R4B\DataType\HumanName;

$patient = new PatientResource(
    id: 'example-123',
    active: true,
    name: [new HumanName(family: 'Doe', given: ['John'])],
);

// Serialize to JSON
$json = $serializer->serializeToJson($patient);
// {"resourceType":"Patient","id":"example-123","active":true,"name":[{"family":"Doe","given":["John"]}]}

// Deserialize JSON back to a model object
$restored = $serializer->deserializeFromJson($json, PatientResource::class);
echo $restored->id;              // "example-123" (a plain string)
echo $restored->name[0]->family; // "Doe"

serializeToJson(object $fhirObject, array $context = []): string and deserializeFromJson(string $jsonData, string $targetClass, array $context = []): object both accept an optional Symfony serializer context array — see Context & Options for validation modes and unknown-element policies.

{% hint style="info" %} Primitive typing on round-trip: simple resource fields such as id stay plain PHP scalars, but typed primitive fields (e.g. HumanName::$family, $given[]) come back as ...\Primitive\StringPrimitive objects after deserialization. These implement Stringable, so echo and string interpolation work directly — but a strict comparison needs a cast: (string) $restored->name[0]->family === 'Doe'. {% endhint %}

Auto-detecting format and resource type

deserialize(string $data, ?string $targetClass = null, array $context = []) sniffs JSON vs XML from the payload and resolves the target class from the resourceType (JSON) or root element (XML), so you can omit the target class:

<?php

$resource = $serializer->deserialize($json);          // format + class auto-detected
$resource = $serializer->deserialize($json, PatientResource::class); // explicit class

Class resolution delegates to the type resolver, so it applies meta.profile and the IG type registry when available (see IG-Aware Serialization).

Error handling

All serialize/deserialize failures are wrapped in FHIRSerializationException (which extends the component base FHIRToolsException). The underlying decode/denormalize error is preserved as the previous exception.

<?php

use Ardenexal\FHIRTools\Component\Serialization\Exception\FHIRSerializationException;

try {
    $patient = $serializer->deserializeFromJson($maybeInvalidJson, PatientResource::class);
} catch (FHIRSerializationException $e) {
    // Inspect $e->getPrevious() for the underlying cause.
    error_log('FHIR deserialization failed: ' . $e->getMessage());
}

FHIRSerializationException also exposes getElementPath(), getDetailedMessage(), and (when debug info was enabled) getDebugInfo() / hasDebugInfo().