import * as request from 'request-promise-native'; import { IObject } from './type'; import config from '../../config'; import { apLogger } from './logger'; export const logger = apLogger.createSubLogger('resolver'); export default class Resolver { private history: Set; private timeout = 10 * 1000; constructor() { this.history = new Set(); } public async resolveCollection(value: any) { const collection = typeof value === 'string' ? await this.resolve(value) : value; switch (collection.type) { case 'Collection': collection.objects = collection.items; break; case 'OrderedCollection': collection.objects = collection.orderedItems; break; default: throw new Error(`unknown collection type: ${collection.type}`); } return collection; } public async resolve(value: any): Promise { if (value == null) { throw new Error('resolvee is null (or undefined)'); } if (typeof value !== 'string') { return value; } if (this.history.has(value)) { throw new Error('cannot resolve already resolved one'); } this.history.add(value); const object = await request({ url: value, proxy: config.proxy, timeout: this.timeout, headers: { 'User-Agent': config.user_agent, Accept: 'application/activity+json, application/ld+json' }, json: true }).catch(e => { throw new Error(`request error: ${e.message}`); }); if (object === null || ( Array.isArray(object['@context']) ? !object['@context'].includes('https://www.w3.org/ns/activitystreams') : object['@context'] !== 'https://www.w3.org/ns/activitystreams' )) { logger.error(`invalid response: ${value}`); throw new Error('invalid response'); } return object; } }