AWS S3 Storage Adapter for NestJS with Fastify

S3Storage.ts

import { Req } from "@nestjs/common";
import { FastifyRequest } from "fastify";
import { File, StorageEngine } from "fastify-multer/lib/interfaces";
import * as uuid from 'uuid';

export type Info = Partial<
    File & AWS.S3.ManagedUpload.SendData & AWS.S3.Types.PutObjectRequest
>;

export class S3Storage implements StorageEngine {
    private readonly s3: AWS.S3;
    private readonly bucket: string;
    private readonly prefix: string;
    private readonly randomFileName: boolean;
    private readonly acl: string;

    constructor(opts) {
        this.s3 = opts.s3;
        this.bucket = opts.bucket;
        this.prefix = opts.prefix || '';
        this.randomFileName = opts.randomFileName || false;
        this.acl = opts.acl ?? undefined;
    }

    _handleFile(@Req() req: FastifyRequest, file: File, cb: (error: Error|null, info?: Info) => void) {
        let currentSize = 0;
        const extension = file.originalname.split('.').pop().toLowerCase();
        const uid = uuid.v4();
        const params: AWS.S3.Types.PutObjectRequest = {
            Bucket: this.bucket,
            Key: `${this.prefix}${file.path ?? !this.randomFileName ? `${uid}/` : ''}${this.randomFileName ? `${uid}.${extension}` : file.originalname}`,
            Body: file.stream,
            ContentType: file.mimetype,
            ACL: this.acl,
        };
        const upload = this.s3.upload(params);

        upload.on('httpUploadProgress', (e) => {
            if (e.total) {
                currentSize = e.total;
            }
        });

        upload.promise().then((uploadData) => {
            cb(null, {
                size: currentSize,
                ...uploadData,
            })
        }, cb);
    }

    _removeFile(req: FastifyRequest, file: Info, cb: (error: Error|null) => void) {
        this.s3.deleteObject({ Bucket: file.Bucket, Key: file.Key }, cb);
    }
}