Multer Azure

This is a multer storage engine for Azure's blob storage.

Installation

npm install --save multer-azure

Usage

var express = require('express')
var multer = require('multer')
var multerAzure = require('multer-azure')

var app = express()

var upload = multer({ 
  storage: multerAzure({
    connectionString: '[Azure Storage Connection String]', //Connection String for azure storage account, this one is prefered if you specified, fallback to account and key if not.
    account: '[Azure Storage Account]', //The name of the Azure storage account
    key: '[Azure Storage Account Key]', //A key listed under Access keys in the storage account pane
    container: '[Blob Container Name]'  //Any container name, it will be created if it doesn't exist
    blobPathResolver: function(req, file, callback){
      var blobPath = yourMagicLogic(req, file); //Calculate blobPath in your own way.
      callback(null, blobPath);
    }
  })
})

app.post('/', upload.any(), function (req, res, next) {
  console.log(req.files)
  res.status(200).send('Uploaded: ' + req.files)
})

File Information

multer-azure will return the following information in each file in the req.files parameter:

Key	Description
fieldname	The field name/key sent in the post request with the image.
originalname	The full original name of the file.
encoding	The file encoding.
mimetype	The MIME type of the file.
filename	The file name in the azure storage.
container	The azure storage container where the file upload to.
blobPath	The full blobName (or we call it blobPath).
url	The full url of the file just got uploaded.

File Naming

Files in an Azure container have to have a unique name. multer-azure allows you to customize the blobPath.

Simply provide a blobPathResolver, the same way as what you do with multer.diskStorage.

    blobPathResolver: function(req, file, callback){
      var blobPath = yourMagicLogic(req, file);//Calculate blobPath in your own way.
      callback(null, blobPath);
    }

If you don't provide a blobPathResolver, a default file name is generated:

Date.now() + encodeURIComponent(new Buffer([FILENAME]).toString('base64')) + extension.

This results in a url safe filename that looks like "1480994807566-Qmx1ZVBUQ0xvZ29MQVJHRTIwMTYuanBn.jpg", which is most likely overkill.

Azure Requirements

The connectionString will be prefered if you pass it, otherwise please provide account and key.

The account is just the name of your storage account that you've created in Azure. For information on how to do this, check out this tutorial.

The key for the key field can be obtained under the Access keys section in the storage account pane in Azure.

The container name can be anything you choose, as long as it's unique to the storage account and as long as it fits Azure's naming restrictions. If the container does not exist the storage engine will create it.