⁉️ 𝐌𝐨𝐭𝐢𝐯𝐚𝐭𝐢𝐨𝐧
The Proxy pattern belongs to the structural category and provides a surrogate or placeholder for another object to control access to it. It is also known as a Surrogate.

🌍 𝐑𝐞𝐚𝐥-𝐖𝐨𝐫𝐥𝐝 𝐒𝐜𝐞𝐧𝐚𝐫𝐢𝐨
Imagine we are building a document editor that embeds graphical objects in documents. Creating some graphical objects, like large raster images, is expensive. However, opening a document should be fast, so we want to avoid creating all expensive objects immediately.
These requirements suggest creating expensive objects on demand. So, what should we put in place of the image initially?

🎯 𝑺𝒐𝒍𝒖𝒕𝒊𝒐𝒏 — 𝑷𝒓𝒐𝒙𝒚 𝑷𝒂𝒕𝒕𝒆𝒓𝒏
The solution is to use another object, an image proxy, that acts like the real image. The proxy behaves just like the image and takes care of instantiating it only when needed. The image proxy creates the real image only when the document editor requests it to display it. After creation, the proxy forwards all subsequent requests directly to the real image. Therefore, the proxy keeps a reference to the real image once it’s created.

🧠 𝑾𝒉𝒆𝒏 𝒕𝒐 𝑨𝒑𝒑𝒍𝒚:
𝐑𝐞𝐦𝐨𝐭𝐞 𝐩𝐫𝐨𝐱𝐲: When the real object is located elsewhere (over the network or on a different machine), communicating directly can be complex. A proxy can handle communication instead.
𝐕𝐢𝐫𝐭𝐮𝐚𝐥 𝐩𝐫𝐨𝐱𝐲: When creating an object is expensive, a proxy can delay creation until it’s actually needed (lazy loading). See the real-world example above.
𝐏𝐫𝐨𝐭𝐞𝐜𝐭𝐢𝐨𝐧 𝐩𝐫𝐨𝐱𝐲: Controls access to the original object, enforcing access rights.
𝐒𝐦𝐚𝐫𝐭 𝐫𝐞𝐟𝐞𝐫𝐞𝐧𝐜𝐞: Replaces a simple reference but adds extra behavior each time the object is accessed (e.g., counting references).

💎 𝐑𝐞𝐥𝐚𝐭𝐞𝐝 𝐏𝐚𝐭𝐭𝐞𝐫𝐧𝐬:
𝐀𝐝𝐚𝐩𝐭𝐞𝐫: Provides a different interface for an object, while a proxy provides the same interface as its subject.
𝐃𝐞𝐜𝐨𝐫𝐚𝐭𝐨𝐫: Similar in structure to a proxy but adds responsibilities to an object, whereas a proxy controls access.

📂 𝑪𝒐𝒅𝒆 𝑬𝒙𝒂𝒎𝒑𝒍𝒆:
👉 𝐆𝐢𝐭𝐇𝐮𝐛 - https://github.com/shirin-monzavi/ProxyDesignPatternSample/tree/master

❓ Have you ever used the Proxy Pattern in your projects? Share your experience!