admob-ssv/src/keydict/provider.ts

Tool for validate AdMob rewarded ads signatures SSV

import type { KeyObject } from 'node:crypto'
import type KeyDictCache from './cache/cache'
import MemoryCache from './cache/memory'
import Fetcher from './fetcher'
import type KeyFetcher from './fetcher/fetcher'

export interface KeyProviderOptions {
  cache?: KeyDictCache
  fetcher?: KeyFetcher
}

export interface KeyProviderInterface {
  get(keyId: number): Promise<KeyObject>
}

export default class KeyProvider implements KeyProviderInterface {
  private cache: KeyDictCache
  private fetcher: KeyFetcher

  constructor(options: KeyProviderOptions = {}) {
    this.cache = options.cache || new MemoryCache()
    this.fetcher = options.fetcher || new Fetcher()
  }

  async get(keyId: number): Promise<KeyObject> {
    if (!(await this.cache.has(keyId))) {
      const keys = await this.fetcher.fetch()
      for (const rawKey of keys) {
        await this.cache.save(rawKey)
      }
    }

    return await this.cache.get(keyId)
  }
}