ap-lib/context

The Context library provides a lightweight context storage system for managing and retrieving shared data across different parts of an application. It supports dynamic storage, object retrieval, and type enforcement.

dev-main 2025-04-02 00:48 UTC

Requires

• php: ^8.3

Requires (Dev)

• phpunit/phpunit: 10.5.*

MIT

• Anton Panfilov

README

The Context library provides a lightweight context storage system for managing and retrieving shared data across different parts of an application. It supports dynamic storage, object retrieval, and type enforcement.

Installation

composer require ap-lib/normalizer

Features

• Store and retrieve arbitrary values using string keys.
• Store objects and retrieve them with type enforcement.
• Prevent accidental overwrites with an optional replace flag.
• Retrieve stored values by name or class.
• Exception handling for invalid operations.

Requirements

• PHP 8.3 or higher

Getting started

Storing and Retrieving a Single Object

If you store an object without a name, its class name is automatically used as the key:

use AP\Context\Context;

class User {
    public function __construct(public int $id, public string $email) {}
}

$context = new Context();

$user = new User(12, "[e-mail]");

// Store the object using its class name
$context->set($user);

// Retrieve the object by class name
$retrievedUser = $context->get(User::class);
var_dump($retrievedUser === $user); // true

// Retrieve with type enforcement
$retrievedUser = $context->getObject(User::class);
var_dump($retrievedUser === $user); // true

Storing and Retrieving Multiple Similar Objects

You can store multiple objects of the same class using custom names:

$context = new Context();

$user = new User(12, "[e-mail]");
$realUser = new User(1, "[e-mail]");

$context->set($user);                     // Stored with class name
$context->set($realUser, "realUser");      // Stored with custom name

// Retrieve the default user
$retrievedUser = $context->get(User::class);
var_dump($retrievedUser === $user); // true

// Retrieve with type enforcement
$retrievedUser = $context->getObject(User::class);
var_dump($retrievedUser === $user); // true

// Retrieve the real user by custom name
$retrievedRealUser = $context->get("realUser");
var_dump($retrievedRealUser === $realUser); // true

// Retrieve the real user with type enforcement
$retrievedRealUser = $context->getObject(User::class, "realUser");
var_dump($retrievedRealUser === $realUser); // true

Storing and Retrieving Custom Data

You can store and retrieve non-object values, such as arrays, strings, or numbers, using a custom name:

$context = new Context();

$userData = ["id" => 12, "email" => "[e-mail]"];

// Store the array with a custom name
$context->set($userData, "user");

// Retrieve the stored array
$retrievedData = $context->get("user");
var_dump($retrievedData === $userData); // true

Working with References

Working with Array References

When retrieving an array by reference, modifications to the retrieved array will affect the stored array.

$context = new Context();

$name = "original";
$original = ["foo" => "boo"];

$context->set($original, $name);

// Get a reference to the stored array
$ref = &$context->get($name);
$ref["foo"] = "changed";

// The original stored array is now modified
var_dump($context->get($name)); 
// Output: ["foo" => "changed"]

Fully Replacing an Array via Reference:

$name = "original";
$original = ["foo" => "boo"];

$context->set($original, $name);

// Get a reference to the stored array
$ref = &$context->get($name);
$ref = ["hello" => "world"];

// The original stored array is now modified
var_dump($context->get($name)); 
// Output: ["hello" => "world"]

Working with Object References

hen retrieving an object, modifications to its properties affect the stored object.

$context = new Context();

$user = new User(1, "[e-mail]");

$context->set($user);

// Get a reference to the stored object
$ref = $context->getObject(User::class);
$ref->id = 2;

// The original stored object is now modified
var_dump($context->getObject(User::class)); 
// Output: User { id: 2, email: "[e-mail]" }

Error Handling

Type Enforcement Errors

If you try to retrieve an object with getObject(), but the stored data does not match the expected class, an exception is thrown:

$context = new Context();

// Store an array using the class name
$context->set(["id" => 12, "email" => "[e-mail]"], User::class);

// This will throw an UnexpectedValueException because the stored data is not a User object
$context->getObject(User::class);

Handling Missing

If you try to retrieve an object that has not been stored, an exception is thrown:

$context = new Context();

// This will throw an UnexpectedValueException because no User object exists
$context->getObject(User::class);

// This will throw an UnexpectedValueException because "randomName" does not exist too
$context->get("randomName");