Retrieving JSON response from local database - json

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
});
});
});