| 1 | import crypto from 'node:crypto' |
| 2 | import { Injectable, Logger } from '@nestjs/common' |
| 3 | import { AppException, ResponseCode } from '@yikart/common' |
| 4 | import { ServerRedisService } from '../../common/redis' |
| 5 | import { config } from '../../config' |
| 6 | |
| 7 | @Injectable() |
| 8 | export class ShortLinkService { |
| 9 | private readonly logger = new Logger(ShortLinkService.name) |
| 10 | |
| 11 | constructor( |
| 12 | private readonly redisService: ServerRedisService, |
| 13 | ) {} |
| 14 | |
| 15 | private generateCode(length = 8): string { |
| 16 | const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789' |
| 17 | const randomBytes = crypto.randomBytes(length) |
| 18 | let result = '' |
| 19 | for (let i = 0; i < length; i++) { |
| 20 | result += chars[randomBytes[i] % chars.length] |
| 21 | } |
| 22 | return result |
| 23 | } |
| 24 | |
| 25 | async create(originalUrl: string): Promise<string> { |
| 26 | const code = this.generateCode() |
| 27 | |
| 28 | await this.redisService.saveShortLink(code, originalUrl) |
| 29 | |
| 30 | return `${config.channel.shortLink.baseUrl}${code}` |
| 31 | } |
| 32 | |
| 33 | async getByCode(code: string): Promise<string> { |
| 34 | const originalUrl = await this.redisService.getShortLink(code) |
| 35 | |
| 36 | if (!originalUrl) { |
| 37 | throw new AppException(ResponseCode.ShortLinkNotFound) |
| 38 | } |
| 39 | |
| 40 | return originalUrl |
| 41 | } |
| 42 | } |
| 43 |