Express, Nodejs use Multer for different Services

Question

I am using express server and multer for upload file on different services (local, azure, cloudinary, amazon s3 etc). For that i am using different module of multer multer-azure, multer-cloudinary etc.

I need this configuration will be applied to user wise and that information comes from the database. So i need a extra call to fetch data from database before multer come in action.

I am able to call database query but when i am trying to call multer function, req parameter coming blank. Here is what i am doing.

var multerUtility = require('./upload/multer.utility');
let multer = new multerUtility().getActiveMulterService();
router.post('/', getMetadataConfiguration, multer, (req, res, next) => {
  console.log('========== req ==========', req.file); // It is coming blank
  console.log('========== req ==========', req.body); // It is coming blank
});

Here is first middleware function, which fetch data from database to verifiy which service will use to upload file.

function getMetadataConfiguration(res, req, next) {
  var conn = new jsforce.Connection({
    loginUrl : config.org_url,
  });
  var records = [];
  conn.login(username, password, function(err, userInfo) {
    if (err) {
      return console.error(err);
    }
    conn.query("query", (err, result) => {
      if(err) {
        res.status(500).send(err);
      }
      console.log('=========== result=========', result);
      req.serviceConfig = result.records[0];
      next();
    });
  });
}

And here is my MulterUtility Class to handle configuration: upload/multer.utility.js

class MulterUtility {
  constructor() {
  }

  getActiveMulterService(req, res, next) {
    var multerConfiguration;
    if(req.serviceConfig.service == 'azure') {
      multerConfiguration = multer({
        storage: multerAzure({
          connectionString: config.azure.connectionString,
          account: config.azure.account,
          key: config.azure.key,
          container: config.azure.container
        })
      }).single('image');
    } else if(req.serviceConfig.service == 'cloudinary') {
      multerConfiguration = multer({
        storage: cloudinaryStorage({
          cloudinary: cloudinary,
          folder: config.storageFolder
          // allowedFormats: ['jpg', 'png', 'jpeg']
        })
      }).single('image');
    } else if(req.serviceConfig.service === 'amazon') {
      multerConfiguration = multer({
        storage: multerS3({
          s3: s3,
          bucket: 'mycontainer',
          acl: 'public-read',
          contentType: multerS3.AUTO_CONTENT_TYPE,
          metadata: function (req, file, cb) {
            cb(null, {fieldName: file.fieldname});
          },
          key: function (req, file, cb) {
            cb(null, Date.now().toString() + '-' + file.originalname)
          }
        })
      }).single('image');
    } else if(req.serviceConfig.service === 'local') {
      multerConfiguration = multer({
        storage: multer.memoryStorage()
      }).single('image');
    }
    return multerConfiguration;
  }
}

module.exports = MulterUtility;

After executing multer, i am not recieving a req.file or req.body params what multer sets after uploading file. For now you can consider the 'local' file upload as mentioned in last condition.

stdob-- stdob-- · Accepted Answer · 2018-09-04T12:15:43

The problem is that you call the method getActiveMulterService once before the router. But you need to call it for each post. Try something like this:

var multerUtility = require('./upload/multer.utility');
let multers = new multerUtility();
router.post('/', 
    getMetadataConfiguration, 
    (req, res, next) => multers.getActiveMulterService(req, res, next)(req, res, next), 
    (req, res, next) => {
      console.log('========== req ==========', req.file); // It is coming blank
      console.log('========== req ==========', req.body); // It is coming blank
    });

And in this function you have arguments in the wrong order:

getMetadataConfiguration(res, req, next)
// ==>
getMetadataConfiguration(req, res, next)

Express, Nodejs use Multer for different Services

2 Answers