Cloudflare Developers•13mo ago

I m having a problem with my KV Cache I

I'm having a problem with my KV Cache. I get this error "this.kv.get is not a function" and I can't figure out why. Here is my implementation

import type { KVNamespace } from '@cloudflare/workers-types'

export type KVCacheInstanceType<T> = InstanceType<typeof KVCache<T>>

export class KVCache<T> {
  private kv: KVNamespace
  constructor(namespace: KVNamespace) {
    this.kv = namespace
  }
  async get(key: string): Promise<T | null> {
    try {
      const value = await this.kv.get(key, 'text')
      return value ? this.parseJson(value) : null
    } catch (error) {
      console.log(error)
      return null
    }
  }

  async set(key: string, value: T, ttl?: number): Promise<void> {
    try {
      const stringValue = this.stringifyJson(value)
      const options = ttl ? { expirationTtl: ttl } : undefined
      await this.kv.put(key, stringValue, options)
    } catch (error) {
      console.log(error)
      return
    }
  }

  async delete(key: string) {
    ...
  }

  private parseJson(value: string): T | null {
    ...
  }

  private stringifyJson(value: T): string {
    ...
  }
}
// Usage
const cache = new KVCache<GooglePublicKeys>(config.namespace)

import type { KVNamespace } from '@cloudflare/workers-types'

export type KVCacheInstanceType<T> = InstanceType<typeof KVCache<T>>

export class KVCache<T> {
  private kv: KVNamespace
  constructor(namespace: KVNamespace) {
    this.kv = namespace
  }
  async get(key: string): Promise<T | null> {
    try {
      const value = await this.kv.get(key, 'text')
      return value ? this.parseJson(value) : null
    } catch (error) {
      console.log(error)
      return null
    }
  }

  async set(key: string, value: T, ttl?: number): Promise<void> {
    try {
      const stringValue = this.stringifyJson(value)
      const options = ttl ? { expirationTtl: ttl } : undefined
      await this.kv.put(key, stringValue, options)
    } catch (error) {
      console.log(error)
      return
    }
  }

  async delete(key: string) {
    ...
  }

  private parseJson(value: string): T | null {
    ...
  }

  private stringifyJson(value: T): string {
    ...
  }
}
// Usage
const cache = new KVCache<GooglePublicKeys>(config.namespace)

I checked my NAMESPACE and when I console(this.kv) it matches what I setup in Cloudflare.

3 Replies

MBrimmer•13mo ago

I figured this out but my Typescript is still wrong I now access my Namespace from the env with the name passed as an environment variable like this

// @ts-ignore
const cache = new KVCache<GooglePublicKeys>(env[env.CLOUDFLARE_KV_NAMESPACE] as KVNamespace)

// @ts-ignore
const cache = new KVCache<GooglePublicKeys>(env[env.CLOUDFLARE_KV_NAMESPACE] as KVNamespace)

I have the env typed with an interface and the Namespace doesn't play well with that approach.

Unknown User•13mo ago

Message Not Public

MBrimmer•13mo ago

Hey @MattD | WorkersKV Sorry, not sure how I missed your response. The issue is CLOUDFLARE_KV_NAMESPACE is a string that tells my application which namespace e.g. development-namespace or production-namespace and is defined at runtime not compile time. Cloudflare provides my namespace as defined by my wrangler config. So this is only a typescript issue now and I solved it like this.

namespace: env[
   env.CLOUDFLARE_KV_NAMESPACE as keyof typeof env
] as unknown as KVNamespace

namespace: env[
   env.CLOUDFLARE_KV_NAMESPACE as keyof typeof env
] as unknown as KVNamespace

Not sure if this is how other people are doing it, but it working for me right now. Thanks for getting back with me!

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I m having a problem with my KV Cache I