Express js – Upload images to Azure Blob Storage

Last updated on November 21, 2022

const express = require('express')
const app = express()
const port = 6000
const bodyParser = require('body-parser');
const multer = require('multer')
const inMemoryStorage = multer.memoryStorage();
const singleFileUpload = multer({ storage: inMemoryStorage });
const azureStorage = require('azure-storage');
const getStream = require('into-stream');

// parse application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({ extended: false }));

// parse application/json
app.use(bodyParser.json());

const azureStorageConfig = {
    accountName: "",
    accountKey: "",
    blobURL: "",
    containerName: ""
};

uploadFileToBlob = async (directoryPath, file) => {

    return new Promise((resolve, reject) => {

        const blobName = getBlobName(file.originalname);
        const stream = getStream(file.buffer);
        const streamLength = file.buffer.length;

        const blobService = azureStorage.createBlobService(azureStorageConfig.accountName, azureStorageConfig.accountKey); 
        blobService.createBlockBlobFromStream(azureStorageConfig.containerName, `${directoryPath}/${blobName}`, stream, streamLength, err => {
            if (err) {
                reject(err);
            } else {
                resolve({ filename: blobName, 
                    originalname: file.originalname, 
                    size: streamLength, 
                    path: `${azureStorageConfig.containerName}/${directoryPath}/${blobName}`,
                    url: `${azureStorageConfig.blobURL}${azureStorageConfig.containerName}/${directoryPath}/${blobName}` });
            }
        });

    });

};

const getBlobName = originalName => {
    const identifier = Math.random().toString().replace(/0\./, ''); // remove "0." from start of string
    return `${identifier}-${originalName}`;
};

const imageUpload = async(req, res, next) => {
    try {
        const image = await uploadFileToBlob('images', req.file); // images is a directory in the Azure container
        return res.json(image);
    } catch (error) {
        next(error);
    }
}

app.post('/upload/image', singleFileUpload.single('image'), imageUpload)


app.listen(port, () => console.log(`Example app listening on port ${port}!`))