Retrieving JSON response from local database

Question

I am trying to print JSON response in my local browser of the data from my local system

---

I have my code::

var express=require('express');
var fs=require('fs');
var http=require('http');
var crypto=require('crypto');
var mysql=require('mysql');
var async=require('async');

var app=express();

var connection=mysql.createConnection({
  host: 'localhost',
  user: 'root',
  database: 'ImagePostingDB'
});

connection.connect();
app.set('port',process.env.PORT||7002); 
app.use('/Details',express.static(__dirname+'/public/images')); 
app.use(express.bodyParser());



app.get('/DescriptionSortedPrice/',function(request,response){
  var name_of_restaurants;
  async.series( [
    // Get the first table contents
    function ( callback ) {
      connection.query('SELECT * FROM ImagePostingtable ORDER BY Sl_no', function(err, rows, fields)
      {
        console.log('Connection result error '+err);
        name_of_restaurants = rows;
        callback();
      });

    }
   // Send the response
   ], function ( error, results ) {
    response.json({
      'restaurants' : name_of_restaurants
    });
  });
});



http.createServer(app).listen(app.get('port'),function(){
  console.log('Express server listening on port'+app.get('port'));
});

---

When i tried with postman:: i have no JSON response::

---

• How to resolve this ?

or

• how to find my root cause of the problem

---

{Edit}

var express=require('express');
var fs=require('fs');
var http=require('http');
var crypto=require('crypto');
var mysql=require('mysql');
var async=require('async');

var app=express();

var connection=mysql.createConnection({
    host: 'localhost',
    user: 'root',
    database: 'ImagePostingDB'
});

connection.connect(function(err) { if ( !err ) { console.log("Connected to MySQL"); } else if ( err ) { console.log(err); } });
app.set('port',process.env.PORT||7002); 
app.use('/Details',express.static(__dirname+'/public/images')); 
app.use(express.bodyParser());





app.get('/DescriptionSortedPrice/',function(request,response){
  connection.query('SELECT * FROM ImagePostingtable ORDER BY Sl_no', function(err, rows, fields) {
    if (err) {
      return response.send(500, err.message);
    }

    response.json({
      'restaurants' : rows
    });
  });
});






http.createServer(app).listen(app.get('port'),function(){
        console.log('Express server listening on port'+app.get('port'));

});

---

I have a Snapshot in my command prompt like this::

Answer 1

First: can you confirm that the server doesn't crash when you launch the request? A response code of 0 usually means that the connection was cut (or that no response was sent at all).

async.series is supposed to be used to call multiple asynchronous functions in series: there's no need to use it if you only call one function.

The callbacks in async.series follow Node.js's callback style, which means they take an error (or null) as a first parameter, and then the results of the function. But you don't send it any arguments: callback(). However, your code still works because you use a local variable name_of_restaurants that you overwrite in your asynchronous function. Be careful because that's not how you are supposed to use this pattern. Here is a more elegant solution:

app.get('/DescriptionSortedPrice/',function(request,response){
  connection.query('SELECT * FROM ImagePostingtable ORDER BY Sl_no', function(err, rows, fields) {
    if (err) {
      console.log('Encountered an error:', err.message);
      return response.send(500, err.message);
    }

    console.log('Found results:', rows);
    response.json({
      'restaurants' : rows
    });
  });
});