I am using express/node to create a back-end api for authentication/authorization and using mongodb to store the data.
I'm using express-validator to validate the input req. I want to validate whether a username already exists or not - the library recommends i should use an async function to do this.
Although it returns the data with the correct error message in postman, my server crashes with the message.
Error: Can't set headers after they are sent.
Server.js
app.use(validator({
customValidators: {
isUsernameAvailable: function(username) {
return new Promise(function(resolve, reject) {
User.findOne({'username': username}, function(err, results) {
if(err) {
return resolve(err);
}
reject(results);
});
});
}
}
}));
auth.route.js
var express = require('express');
var router = express.Router();
var controller = require('../controllers/auth.controller');
var middleware = require('../middleware/auth.middleware');
router.post('/login', controller.login);
router.post('/register', middleware.register, controller.register);
module.exports = router;
auth.middleware.js
module.exports.register = function(req, res, next)
{
req.checkBody({
'username': {
notEmpty: true,
errorMessage: 'Username is required'
},
'email': {
notEmpty: true,
isEmail: {
errorMessage: 'Invalid Email Address'
},
errorMessage: 'Email is required'
},
'password': {
notEmpty: true,
errorMessage: 'Password is required'
},
'password_confirmation': {
notEmpty: true,
errorMessage: 'Password Confirmation is required'
}
});
req.assert('password_confirmation', 'Passwords do not match').equals(req.body.password);
req.check('username', 'This username is already taken').isUsernameAvailable();
var errors = req.validationErrors(true);
if(errors) {
return res.json({
success: false,
errors: errors
});
}
req.asyncValidationErrors().catch(function(errors) {
if(errors) {
return res.json({
success:false,
errors: errors
});
};
});
next();
}
