tethys.backend/app/Library/Oai/TokenWorkerSerice.ts

96 lines
2.9 KiB
TypeScript

import ResumptionToken from './ResumptionToken.js';
import { createClient, RedisClientType } from 'redis';
import InternalServerErrorException from '#app/exceptions/InternalServerException';
import { sprintf } from 'sprintf-js';
import dayjs from 'dayjs';
import TokenWorkerContract from './TokenWorkerContract.js';
export default class TokenWorkerService implements TokenWorkerContract {
protected filePrefix = 'rs_';
protected fileExtension = 'txt';
private cache: RedisClientType;
public ttl: number;
private url: string;
private connected = false;
constructor(ttl: number) {
this.ttl = ttl; // time to live
this.url = process.env.REDIS_URL || 'redis://127.0.0.1:6379';
}
public async connect() {
this.cache = createClient({ url: this.url });
this.cache.on('error', (err) => {
this.connected = false;
console.log('[Redis] Redis Client Error: ', err);
});
this.cache.on('connect', () => {
this.connected = true;
});
await this.cache.connect();
}
public get isConnected(): boolean {
return this.connected;
}
public async has(key: string): Promise<boolean> {
const result = await this.cache.get(key);
return result !== undefined && result !== null;
}
public async set(token: ResumptionToken): Promise<string> {
const uniqueName = await this.generateUniqueName();
const serialToken = JSON.stringify(token);
await this.cache.setEx(uniqueName, this.ttl, serialToken);
return uniqueName;
}
private async generateUniqueName(): Promise<string> {
let fc = 0;
const uniqueId = dayjs().unix().toString();
let uniqueName: string;
let cacheKeyExists: boolean;
do {
// format values
// %s - String
// %d - Signed decimal number (negative, zero or positive)
// [0-9] (Specifies the minimum width held of to the variable value)
uniqueName = sprintf('%s%05d', uniqueId, fc++);
cacheKeyExists = await this.has(uniqueName);
} while (cacheKeyExists);
return uniqueName;
}
public async get(key: string): Promise<ResumptionToken | null> {
if (!this.cache) {
throw new InternalServerErrorException('Dataset is not available for OAI export!');
}
const result = await this.cache.get(key);
return result ? this.parseToken(result) : null;
}
private parseToken(result: string): ResumptionToken {
const rToken: ResumptionToken = new ResumptionToken();
const parsed = JSON.parse(result);
Object.assign(rToken, parsed);
return rToken;
}
public del(key: string) {
this.cache.del(key);
}
public flush() {
this.cache.flushAll();
}
public async close() {
await this.cache.disconnect();
this.connected = false;
}
}