@amag-ch/sap_cap_common_objectstore/lib/clients/S3Client.js

NodeJS library to communicate with an objectstore

const { 
    S3Client: NativeClient, 
    ListObjectsV2Command,
    HeadObjectCommand,
    GetObjectCommand,
    PutObjectCommand,
    DeleteObjectCommand 
} = require('@aws-sdk/client-s3')
const Client = require('./Client')
const { ObjectStoreError, ObjectStoreCommunicationError } = require('../errors')

module.exports = class S3Client extends Client {

    #client
    #bucket
    #host

    constructor(credentials) {
        super(credentials)

        const { region, access_key_id: accessKeyId, secret_access_key: secretAccessKey, bucket, host } = credentials

        this.#client = new NativeClient({
            region,
            credentials: {
                accessKeyId,
                secretAccessKey
            }
        })
        
        this.#bucket = bucket
        this.#host = host
    }

    /**
     * List all files in store.
     * 
     * @returns {Promise<[{filename: string, modifiedAt: Date, contentLength: integer}]>}
     */
    list = async () => {
        const objects = await this.#send(new ListObjectsV2Command())

        return (objects?.Contents ?? []).map(({ Key, LastModified, Size }) => ({
            filename: Key, 
            modifiedAt: LastModified, 
            contentLength: Size
        }))
    }

    /**
     * Read metadata from file.
     * 
     * @param {string} filename
     * @returns {Promise<{modifiedAt: Date, contentLength: integer}>}
     */
    head = async (filename) => {
        if (!filename) throw new Error('filename not provided')

        const object = await this.#send(new HeadObjectCommand({ Key: filename }))

        return {
            modifiedAt: object.LastModified,
            contentLength: object.ContentLength
        }
    }

    /**
     * Read file.
     * 
     * @param {string} filename
     * @returns {Promise<ReadableStream>}
     */
    get = async (filename) => {
        if (!filename) throw new Error('filename not provided')

        const object = await this.#send(new GetObjectCommand({ Key: filename }))

        return object.Body
    }

    /**
     * Put new file to store.
     *
     * @param {string} filename
     * @param {string|Readable|Blob|ReadableStream<any>|Uint8Array|Buffer} content
     * @param {{contentType?: string}} options
     * @returns {Promise<void>}
     */
    put = async (filename, content, { contentType }={}) => {
        if (!filename) throw new Error('filename not provided')
        if (!content) throw new Error('content not provided')

        await this.#send(new PutObjectCommand({
            Key: filename,
            Body: content,
            ContentType: contentType
        }))
    }

    /**
     * Delete file in store.
     * 
     * @param {string} filename
     * @returns {Promise<void>}
     */
    delete = async (filename) => {
        if (!filename) throw new Error('filename not provided')

        await this.#send(new DeleteObjectCommand({ Key: filename }))
    }

    #send = async (command = {}) => {
        command.input ??= {}
        command.input.Bucket = this.#bucket

        try {

            return await this.#client.send(command)

        } catch (err) {
            if (err.code === 'ECONNRESET')
                throw new ObjectStoreCommunicationError(`Cannot connect to S3 service: ${this.#host}`)

            throw new ObjectStoreError(err.message, { cause: err })
        }
    }
}