docs: English JsonRpcBundle docs, REST and MCP Bundle sections, package cards
en/articles/from-tg/series/php-can-do/readonly.md
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# readonly + accessors
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*Stable DTOs and Value Objects without boilerplate*
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- **Added in:** readonly β PHP 8.1, accessors β PHP 8.4
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- **What it gives you:** the ability to create objects whose data can't be changed by accident, plus a new syntax for controlling access to properties via get / set without separate methods.
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## What it's about
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`readonly` makes a property immutable after initialization β the value can be set only once (usually in the constructor).
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`accessors` let you add control over reading and writing properties without classic getters and setters β right in the class body.
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Together they make a perfect combination for DTOs, VOs and configuration classes: the data is immutable and access is controlled.
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## The classic approach
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```php
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class Product {
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private string $name;
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private float $price;
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public function __construct(string $name, float $price)
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{
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$this->name = $name;
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$this->price = $price;
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}
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public function getPrice(): float {
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return $this->price;
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}
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public function setPrice(float $price): void {
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if ($price < 0) {
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throw new InvalidArgumentException('Price must be positive');
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}
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$this->price = $price;
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}
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}
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```
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It works, but most of this code exists only to provide basic encapsulation.
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## Now the same β the modern way
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```php
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class Product {
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public readonly string $name;
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private float $price {
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get => $this->price;
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set => $this->price = max(0, $value);
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}
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public function __construct(string $name, float $price)
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{
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$this->name = $name;
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$this->price = $price;
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}
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}
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```
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`readonly` guarantees the name is immutable, and the `accessors` automatically check the price on write.
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## One more example β a Value Object
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```php
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class Coordinates {
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public readonly float $lat {
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get => round($this->lat, 6);
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}
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public readonly float $lng {
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get => round($this->lng, 6);
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}
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public function __construct(float $lat, float $lng)
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{
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$this->lat = $lat;
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$this->lng = $lng;
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}
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}
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```
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No changes after creation, only controlled access on read.
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## Where it really helps
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- `DTO`: API requests and responses;
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- `Value Object`: Money, Price, GeoPoint, Range;
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- `Immutable configurations`: service parameters, constant states.
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## Conclusion
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> readonly and accessors are a step towards real record classes in PHP.
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> They let you write clean, predictable structures without a ton of boilerplate.
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Today every DTO of mine is readonly.
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β [Previous: Enums](/articles/from-tg/series/php-can-do/enums) Β· [Whole series](/articles/from-tg/series/php-can-do) Β· [Next: Attributes β](/articles/from-tg/series/php-can-do/attributes)
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---
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*First published in Ukrainian in the Telegram channel [βCreated to dieβ](https://t.me/php_while_true/95) on November 30, 2025.*