# How to exclude a route from caching in nest.js


![image.png](https://cdn.hashnode.com/res/hashnode/image/upload/v1642041251940/W8635Ihhq.png)
I love working with  [Nest.js](nestjs.com), it's such an excellent framework for teams to build a scalable backend server. 
Recently, I've been working on caching all our routes. It worked well for a few days then I noticed I missed an endpoint that can not be cached, which was to generate a coupon code. Imagine two customers ending up with the same coupon code. I immediately started looking at how to ignore a certain route while using global caching in nest.js but to my surprise, there is no pre-built decorator or config to do that. But there are simple ways to achieve that.

Nest.js uses  [CacheInterceptor](https://github.com/nestjs/nest/blob/master/packages/common/cache/interceptors/cache.interceptor.ts)  to intercept our HTTP request and decide whether to cache it or not. We can create our own custom interceptor that `extends` default  [CacheInterceptor](https://github.com/nestjs/nest/blob/master/packages/common/cache/interceptors/cache.interceptor.ts) and add some logic to ignore a route.

A suggested way can be found on  [StackOverflow](https://stackoverflow.com/questions/54471331/how-to-ignore-an-interceptor-for-a-particular-route-in-nestjs) but I did not want to hard code the route paths in my interceptor.

There's another way we can do it by combining our custom CacheInterceptor and a CustomDecorator.

First, we need to create a custom cache interceptor. Note that this is slightly different from the accepted StackOverflow answer.

`my-cache.interceptor.ts`

```ts
import { CacheInterceptor, ExecutionContext } from '@nestjs/common';

export class MyCacheInterceptor extends CacheInterceptor {
  protected isRequestCacheable(context: ExecutionContext): boolean {
    const http = context.switchToHttp();
    const request = http.getRequest();

    const ignoreCaching: boolean = this.reflector.get(
      'ignoreCaching',
      context.getHandler(),
    );

    return !ignoreCaching || request.method === 'GET';
  }
}
```
Here, we're overriding a method on default interceptor `isRequestCacheable` which tells nest.js whether to go ahead and cache it or ignore it. In this method, we are using nest.js Reflector to get the metadata value. If metadata `ignoreCaching` is set to true, we tell nest.js to ignore it otherwise cache it if the request method is `GET`.
We're going to create a custom decorator to set this metadata value.

Let's create a `no-cache.decorator.ts` file somewhere -

```ts
import { SetMetadata } from '@nestjs/common';

export const NoCache = () => SetMetadata('ignoreCaching', true);
```

We're almost done. Now let's test it. Let's use this decorator in our controller
```ts

@Controller('coupon')
export class CouponController {
  constructor(private readonly couponService: CouponService) {}

  @Get('code')
  @NoCache()
  code() {
    return this.couponService.generateCode();
  }

}
```
and, that's all. Now any controller which is decorated with `NoCache` will be ignored from caching. Pretty Neat right?