smartjimp/ts/smartjimp.classes.smartjimp.ts

import * as plugins from './smartjimp.plugins.js';

export interface IDimensions {
  width?: number;
  height?: number;
}

export class SmartJimp {
  public levelCache = new plugins.levelcache.LevelCache({
    cacheId: 'mastercache',
    maxMemoryStorageInMB: 100,
    maxDiskStorageInMB: 5000, 
  });

  /**
   * get a key that is unique for a wanted asset variation
   */
  private getCacheKey(
    sourceTypeArg: 'streamfile' | 'smartfile',
    sourceIdArg: string,
    wantedDimensionsArg?: IDimensions
  ) {
    return `${sourceTypeArg}_${sourceIdArg}_${
      wantedDimensionsArg
        ? `${wantedDimensionsArg.width || 'auto' }x${wantedDimensionsArg.height || 'auto'}`
        : 'original'
    }`;
  }

  private async computeAssetVariation(assetBuffer: Buffer, wantedDimensions?: IDimensions) {
    if (!wantedDimensions) {
      return assetBuffer;
    }
    let sharpImage = plugins.sharp(assetBuffer);
    sharpImage = sharpImage.resize(wantedDimensions.width, wantedDimensions.height);
    const result = await sharpImage.resize(wantedDimensions.width, wantedDimensions.height).avif().toBuffer();
    return result;
  }

  public async getFromSmartfile(
    smartfileArg: plugins.smartfile.SmartFile,
    wantedDimensionsArg?: IDimensions
  ) {
    const cacheKey = this.getCacheKey('smartfile', await smartfileArg.getHash(), wantedDimensionsArg);
    const existingCacheEntry = await this.levelCache.retrieveCacheEntryByKey(cacheKey);
    if (existingCacheEntry) {
      return existingCacheEntry.contents;
    } else {
      const computedAssetBuffer = await this.computeAssetVariation(smartfileArg.contentBuffer, wantedDimensionsArg);
      this.levelCache.storeCacheEntryByKey(cacheKey, new plugins.levelcache.CacheEntry({
        contents: computedAssetBuffer,
        ttl: 600000
      }));
      return computedAssetBuffer;
    }
  }

  public async createAvifImageFromBuffer(bufferArg: Buffer) {
    const sharpImage = plugins.sharp(bufferArg);
    const result = await sharpImage.avif().toBuffer();
    return result;
  }

}