Knex NodeJS and inserting into the database

Question

I am new to nodejs and was trying to set up an API server, here is my first attempt. I wanted to use mysql instead of mongo db.

My problem is that 'knex('user').insert({email: req.body.email});' doesn't seem to want to save to the database.

var dbConfig = {
  client: 'mysql',
  connection: {
    host     : 'localhost',
    user     : 'root',
    password : '',
    database : 'db_nodeapi'
  }
};
var express = require('express');                       // call express
var bodyParser = require('body-parser');                // call body-parser
var knex = require('knex')(dbConfig);                   // set up database connection
var app = express();                                    // define our app using express
app.use(bodyParser.urlencoded({ extended: true }));     // configure app to use bodyParser() 
app.use(bodyParser.json());                             // this will let us get the data from a POST
var router     = express.Router();                      // get an instance of the express Router
router.use(function(req, res, next) {                   // middle ware for authentication
    console.log(' -Logging- ');
    next();                                             // continue to next route without stopping
});
router.get('/', function(req, res) {                    // listen for a post on root
    res.json({ message: ' -Success- ' });   
});
router.route('/user')                                   // set up user route
    .post(function(req, res) {                          // listen for a post on user
        console.log(' -Post -');                        // report a post
        knex('user').insert({email: req.body.email});   // insert user into user table
        res.json({ success: true, message: 'ok' });     // respond back to request
    });
app.use('/api', router);                                // register routes beginning with /api  
var port = process.env.PORT || 8080;                    // set server port number
app.listen(port);                                       // setup listener
console.log('Magic happens on port ' + port);           // report port number chosen

Problem is I can't get knex to add to the database!

CREATE TABLE IF NOT EXISTS `user` (
`id` int(11) NOT NULL,
  `email` varchar(255) NOT NULL
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=2 ;

Here is the database

Answer 1

The problem in your code is that you are missing the ".then" statement, which causes the actual execution of the code.

   knex('user').insert({email: req.body.email})
      .then( function (result) {
          res.json({ success: true, message: 'ok' });     // respond back to request
       })

That should work. Since knex.js's insert function is a promise, you need to call .then() to actually call it.

Answer 2

Someone has already given a solution. I am here to talk about why adding a then statement can solve this problem.

In fact, then, catch statement are both ok. Please refer to the knex documentation(http://knexjs.org/#Interfaces-then), which mentions:

Coerces the current query builder chain into a promise state.

So select, update, insert, etc. are just the query statement builder, you have to use then or catch to convert it to promise state.

Examples are as follows:

knex('user').insert({email: req.body.email}) //not working
knex('user').insert({email: req.body.email}).then(()=>{}) //working
knex('user').insert({email: req.body.email}).catch(()=>{}) //working

.then(()=>{
    knex('user').insert({email: req.body.email}) //not working
    knex('user').insert({email: req.body.email}).then(()=>{}) //working
    knex('user').insert({email: req.body.email}).catch(()=>{}) //working
    return knex('user').insert({email: req.body.email}) //working
})