calckey/src/common/remote/activitypub/resolver.ts

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2018-03-31 10:55:00 +00:00
import RemoteUserObject from '../../../models/remote-user-object';
import { IObject } from './type';
const request = require('request-promise-native');
type IResult = {
resolver: Resolver;
object: IObject;
};
async function resolveUnrequestedOne(this: Resolver, value) {
if (typeof value !== 'string') {
return { resolver: this, object: value };
}
const resolver = new Resolver(this.requesting);
resolver.requesting.add(value);
const object = await request({
url: value,
headers: {
Accept: 'application/activity+json, application/ld+json'
},
json: true
});
if (object === null || (
Array.isArray(object['@context']) ?
!object['@context'].includes('https://www.w3.org/ns/activitystreams') :
object['@context'] !== 'https://www.w3.org/ns/activitystreams'
)) {
throw new Error;
}
return { resolver, object };
}
async function resolveCollection(this: Resolver, value) {
if (Array.isArray(value)) {
return value;
}
const resolved = typeof value === 'string' ?
await resolveUnrequestedOne.call(this, value) :
value;
switch (resolved.type) {
case 'Collection':
return resolved.items;
case 'OrderedCollection':
return resolved.orderedItems;
default:
return [resolved];
}
}
export default class Resolver {
requesting: Set<string>;
constructor(iterable?: Iterable<string>) {
this.requesting = new Set(iterable);
}
async resolve(value): Promise<Promise<IResult>[]> {
const collection = await resolveCollection.call(this, value);
return collection
.filter(element => !this.requesting.has(element))
.map(resolveUnrequestedOne.bind(this));
}
resolveOne(value) {
if (this.requesting.has(value)) {
throw new Error;
}
return resolveUnrequestedOne.call(this, value);
}
async resolveRemoteUserObjects(value) {
const collection = await resolveCollection.call(this, value);
return collection.filter(element => !this.requesting.has(element)).map(element => {
if (typeof element === 'string') {
const object = RemoteUserObject.findOne({ uri: element });
if (object !== null) {
return object;
}
}
return resolveUnrequestedOne.call(this, element);
});
}
}