Caching tools

pip-webui2-cache module contains cache behavior
DEMO is HERE

Usage

To start using cache you should:

Step 1

Include module into your application module. PipCacheModule.forRoot(config?: PipCacheModuleConfig).
Config has this optional properties:

• enableLogs - turn on/off logs to console
• prefix - custom prefix for IndexedDB database name

Step 2

Provide model(s) description through InjectionToken PIP_CACHE_MODEL with enabled flag multi.
Structure of PipCacheModel:

class PipCacheModel {
    name: string;
    options: {
        maxAge: number;
        key?: string;
    };
    interceptors: {
        item?: PipCacheInterceptorItemSettings;
        collection?: PipCacheInterceptorCollectionSettings;
    };
}

class PipCacheInterceptorOptions {
    maxAge?: number;
}

class PipCacheInterceptorSettings {
    match: RegExp;
    options?: PipCacheInterceptorOptions;
}

class PipCacheInterceptorItemSettings extends PipCacheInterceptorSettings {
    getKey: (groups: any) => any;
}

class PipCacheInterceptorCollectionSettings extends PipCacheInterceptorSettings {
    responseModify?: {
        responseToItems: (resp: any) => any[];
        itemsToResponse: (items: any[]) => any;
    };
    extractPagination?: (params: HttpParams) => [PipCachePaginationParams, HttpParams];
}

Description:

• name - name of model. Module will use this name with prefix as database name;
• options:
  • maxAge - how long item will remain in cache;
  • key - custom key field different from id which is default
• interceptors - how cache will intercept requests:
  • item - how cache will intercept request for single item:
    • match - regular expression to catch single item request. It HAVE TO contain named group like /items\/(?<id>[^ $\/]*)/ to get key from request;
    • options - custom options to overwrite model options;
    • getKey - function to retrieve key from groups received by matching regular expression of url.
  • collection - how cache will intercept request for collection of items:
    • match - regular expression to catch single item request. It HAVE TO contain named group like /items\/(?<id>[^ $\/]*)/ to get key from request;
    • options - custom options to overwrite model options;
    • responseModify - functions to modify response if items returned in some property of response, not array;
    • extractPagination - extract pagination params from request params. Make sure to delete this params in request params and return them

Example:

export getPhotosKey(groups: any) { return groups && groups.length > 1 && groups[1]; }
export function extractPhotosPagination(params: HttpParams): [PipCachePaginationParams, HttpParams] {
  const res = new PipCachePaginationParams();
  if (params) {
    if (params.has('p') && params.has('l')) {
      res.limit = parseInt(params.get('l'), 10);
      res.offset = (parseInt(params.get('p'), 10) - 1) * res.limit;
      params = params.delete('p');
      params = params.delete('l');
    }
  }
  return [res, params];
}
// ...
{
  provide: PIP_CACHE_MODEL,
  useValue: {
    name: 'photos',
    options: {
      maxAge: 1000 * 60 * 2, // 2 minutes
      key: 'id' // key 'id'
    },
    interceptors: {
      item: {
        match: new RegExp('photos/([^\/]+)

), // Catch all requests and look for id
        getKey: getPhotosKey  // return 'id' from RexExp match
      },
      collection: {
        match: new RegExp('photos'), // Catch all requests and look for 'photos' in request
        extractPagination: extractPhotosPagination // Custom params extractor
      }
    }
  } as PipCacheModel,
  multi: true
}

NB! All interceptors will be checked until some of them will match. If there's no interceptors found - cache won't apply. Interceptors order is important, item should be always before collection, because it has more detailed url to match.