Design Patterns in PHP 8: Proxy
Tags: webdev, programming, php, oop
Published: 2023-09-02 09:53:29

Hello, fellow developers!🧑🏼‍💻

Today, we're diving into another fascinating design pattern: the Proxy Pattern. This pattern is particularly useful for controlling access to objects, lazy initialization, and logging, among other things. Let's explore how to implement this pattern in PHP 8.

## Why Use the Proxy Pattern?
The Proxy pattern serves as a placeholder for another object to control access to it. This is useful in various scenarios, such as:
- **Access Control**: Restricting unauthorized operations.
- **Lazy Initialization**: Deferring the creation and initialization of expensive objects until they are needed.
- **Logging and Monitoring**: Keeping track of operations performed on an object.

## Basic Implementation
Before diving into a real-world example, let's look at a basic implementation of the Proxy pattern.

```php
interface ImageInterface {
    public function display(): void;
}

class RealImage implements ImageInterface {
    private string $filename;

    public function __construct(string $filename) {
        $this->filename = $filename;
        $this->loadImage();
    }

    private function loadImage(): void {
        echo "Loading image: $this->filename\n";
    }

    public function display(): void {
        echo "Displaying image: $this->filename\n";
    }
}

class ProxyImage implements ImageInterface {
    private ?RealImage $realImage = null;
    private string $filename;

    public function __construct(string $filename) {
        $this->filename = $filename;
    }

    public function display(): void {
        if ($this->realImage === null) {
            $this->realImage = new RealImage($this->filename);
        }
        $this->realImage->display();
    }
}
```

In this example, `ProxyImage` serves as a proxy for `RealImage`. It controls access to `RealImage`, loading it only when it's needed.

## Real-world Example
Imagine you're building an e-commerce platform where you need to display product images. Loading all high-resolution images at once can be resource-intensive. Here, the Proxy pattern can help.

```php
// Usage
$productImage = new ProxyImage("high_res_product_image.jpg");

// Image will be loaded and displayed only when needed
$productImage->display();
```

## Advantages and Disadvantages

### Pros
- **Efficiency**: It can lead to a more efficient use of system resources.
- **Security**: It can add an extra layer of protection around the real object.

### Cons
- **Complexity**: It introduces an additional layer, which can complicate the system.

## Conclusion
The Proxy pattern is a powerful design pattern that offers various advantages, from resource management to access control. Its implementation in PHP 8 is straightforward, and it can significantly improve your application's performance and security.

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-----

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