TypeScript icon, indicating that this package has built-in type declarations

    3.0.0 • Public • Published


    last commit npm version MIT License node packagephobia install size packagephobia publish size

    multer-cloud-storage is a multer custom store engine for Google Cloud Storage service. It is a fork from ARozar's multer-google-storage that uses latest version of Google Cloud's API, allows additional information (like destination and contentType) to be set and reduces module footprint.


    npm install multer-cloud-storage --save


    yarn add multer-cloud-storage



    import * as multer from 'multer';
    import * as express from 'express';
    import MulterGoogleCloudStorage from 'multer-cloud-storage';
    const app = express();
    const uploadHandler = multer({
      storage: new MulterGoogleCloudStorage()
    });'/upload', uploadHandler.any(), (req, res) => {

    ES5 / Common.js imports

    var multer = require("multer");
    var express = require("express");
    var multerGoogleStorage = require("multer-cloud-storage");
    var app = express();
    var uploadHandler = multer({
        storage: multerGoogleStorage.storageEngine()
    });'/upload', uploadHandler.any(), function (req, res) {

    NB: This package is written to work with es5 or higher. If you have an editor or IDE that can understand d.ts (typescript) type definitions you will get additional support from your tooling though you do not need to be using typescript to use this package.

    Google Cloud

    Creating a storage bucket

    For instructions on how to create a storage bucket see the following documentation from Google.

    Obtaining credentials

    For instructions on how to obtain the JSON keyfile as well a projectId (contained in the key file) please refer to the following documentation from Google.


    Default method

    If using the MulterGoogleCloudStorage class without passing in any configuration options then the following environment variables will need to be set:

    1. GCS_BUCKET, the name of the bucket to save to.
    2. GCLOUD_PROJECT, this is your projectId. It can be found in the json credentials that you generated.
    3. GCS_KEYFILE, this is the path to the json key that you generated.

    Explicit method

    The constructor of the MulterGoogleCloudStorage class can be passed an optional configuration object.

    Parameter Name Type Sample Value Default Value Notes
    acl string "publicRead" "private" Accepted values are defined in predefinedAcl options
    autoRetry boolean true true
    bucket string "mybucketname" Takes precedence over GCS_BUCKET
    contentType function (request, file): string
    contentType string "application/pdf" If set, this value will be used in place of file.mimetype
    destination string "my_folder/" "" Despite Google Cloud Storage service stores objects in a flat name space, it is possible to list and filter them in a tree-like structure (more on How Subdirectories Work article)
    email string ""
    filename function (request, file, callback): void
    filename string "my_file.pdf" If defined, this name will be used in place of file.originalname - use with caution, because the object can be easily overwritten (consider to configure Object Versioning and Concurrency Control)
    hideFilename boolean true false If set to true, an UUID v4 will be used as object filename and Content-Type will be undefined
    keyFilename string "./key.json" Takes precedence over GCS_KEYFILE
    maxRetries number 5 3
    projectId string "test-prj-1234" Takes precedence over GCLOUD_PROJECT
    uniformBucketLevelAccess boolean true Signifies whether uniformBucketLevelAccess is enabled on the target bucket. When true, the predefinedAcl parameter is removed from requests as it causes 400 Bad Request responses.

    Custom file naming function

    If you need to customize the naming of files then you are able to provide a function that will be called before uploading the file. The third argument of the function must be a standard node callback so pass any error in the first argument (or null on sucess) and the string name of the file on success.

    getFilename(req, file, cb) {

    Custom content-type function

    If you need to customize the content-type of files then you are able to provide a function that will be called before uploading the file.

    getContentType( req, file ) {
    	return undefined;

    Changes in multer API

    When used with multer-cloud-storage, multer will present additional file information.

    File information

    Each file contains the following information:

    Key Description Origin
    fieldname Field name specified in the form multer
    originalname Name of the file on the user's computer multer
    encoding Encoding type of the file multer
    mimetype Mime type of the file multer
    bucket Bucket name multer-cloud-storage
    destination The pseudo-folder to which the file has been saved multer-cloud-storage
    filename The name of the file on Google Cloud Storage multer-cloud-storage
    path The full path to the uploaded file (basically destination+ filename) multer-cloud-storage
    contentType Content-type defined for stored object multer-cloud-storage
    size Size of the file in bytes multer-cloud-storage
    uri Google Cloud Storage path multer-cloud-storage
    linkUrl Download link for allowed users (may require authentication) multer-cloud-storage
    selfLink The link to the stored object (used for Cloud Storage APIs requests) multer-cloud-storage


    npm i multer-cloud-storage

    DownloadsWeekly Downloads






    Unpacked Size

    40.5 kB

    Total Files


    Last publish


    • alexandre.steinberg