Nodejs: returning result on async result

Question

I\'m trying to code an RESTfull API in nodejs which is basically around a controller/modele schema and I meet some problems about the async nature of nodejs:

Station.js:

Answer 1

You should use a callback in this case (take a look at promises as well)

your controller will look like this:

'use strict';

var url = require('url');

var Stations = require('./StationsService');

module.exports.stationsGet = function stationsGet(req, res, next){

    Stations.stationsGet(req.swagger.params['arg'], function(err, result) {
        if(typeof result !== 'undefined') {
            res.setHeader('Content-Type', 'application/json');
            res.end(JSON.stringify(result || {}, null, 2));
        }
        else
            res.end();
    });
};

And the model you made must accept a callback as a last parameter, and you return err and the result like follows:

'use strict';
exports.stationsGet = function(param, cb){
    var data_output = {};

    var sql = 'SELECT * FROM foo WHERE args = ${foo}';

    db.execute(sql, {foo: param}, db.queryResult.any, function(result){
       cb(null, result); // first parameter is the error and the second is the result, this is pretty standard in node
    });
}

I hope this helps you