Master the Proxy Pattern with a Fun Story and Go Example

Hello, I’m NiuNiu, sharing my friend XiaoYang’s new work: an illustrated guide to the Proxy Pattern.

The proxy pattern provides a proxy object for a class of objects, allowing the proxy to perform operations on behalf of the original object. Why add a proxy layer instead of using the original object directly? The following story illustrates typical usage scenarios.

Analysis: Because Daxiong fears being beaten by Panghu, he asks Doraemon to apologize on his behalf. Here, Daxiong is the client object , Panghu is the target object , and Doraemon acts as the proxy . This typical proxy mediates communication while protecting the client.

The advantage of the proxy pattern is that it effectively isolates the client and target objects, protecting the client. Variants include protection proxy, virtual proxy, and cache proxy; their implementations are similar, with the proxy handling operations for the original object.

Analysis: While acting as a mediator, Doraemon extends functionality to handle Panghu, demonstrating that a proxy can add extra features to the client, adhering to the open‑closed principle (open for extension, closed for modification).

Common usage scenarios include the ES6 Proxy object, which intercepts operations before they reach the target, and virtual proxies for image lazy‑loading, separating image creation from loading to avoid unnecessary performance costs.

Below is a Golang implementation of the proxy pattern:

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