Generating Code from PHP Attributes

Attributes supply structured metadata that a code generator can inspect using Reflection.

The examples below begin with the core behavior, then move to an application-oriented use.

How Generating Code from PHP Attributes Works

Attributes supply structured metadata that a code generator can inspect using Reflection.

Example 1: Basic Usage

This example uses a small input to make the main behavior visible.

<?php

#[Attribute] class EntityName { public function __construct(public string $name) {} }
#[EntityName("users")] class UserRecord {}
$attribute = (new ReflectionClass(UserRecord::class))->getAttributes(EntityName::class)[0]->newInstance();
echo $attribute->name;

Output:

users

Attributes supply structured metadata that a code generator can inspect using Reflection.

Example 2: A Different Input

A different set of values shows the same operation in another situation.

<?php

#[Attribute(Attribute::TARGET_PROPERTY)] class Column { public function __construct(public string $name) {} }
class Entry { #[Column("entry_id")] public int $id; }
$attributes = (new ReflectionProperty(Entry::class, "id"))->getAttributes(Column::class);
echo $attributes[0]->newInstance()->name;

Output:

entry_id

Reflect only trusted classes and escape or validate generated identifiers before emitting source code or SQL.

Practical Example: Applying the Feature

This example shows an application-style use of the feature, with its surrounding setup visible.

<?php

#[Attribute(Attribute::TARGET_CLASS)] class Table { public function __construct(public string $name) {} }
#[Table("orders")] class OrderRecord {}
$attributes = (new ReflectionClass(OrderRecord::class))->getAttributes(Table::class);
$tableName = $attributes[0]->newInstance()->name;
echo "SELECT * FROM " . $tableName; // Only use trusted class metadata for generated SQL identifiers.

Output:

SELECT * FROM orders

The code is shown for learning. Adjust the class names, inputs and error handling to suit your application.

Important Behavior and Edge Cases

• Reflect only trusted classes and escape or validate generated identifiers before emitting source code or SQL.
• Attributes supply structured metadata that a code generator can inspect using Reflection.
• Observe differences in empty inputs, invalid states and optional extension availability where relevant.

Comparison With Related Approaches

Common Beginner Mistakes

Key Takeaways

• Attributes supply structured metadata that a code generator can inspect using Reflection.
• Reflect only trusted classes and escape or validate generated identifiers before emitting source code or SQL.
• Use the example that matches the values, runtime version and dependencies in your application.

Generating Code from PHP Attributes is useful when its behavior matches the data structure and lifecycle of your PHP application. Choose it with a clear understanding of its preconditions and returned values.