Web Technology Experts Notes

Sunday, 13 October 2019

How to create http server in NodeJS?

Question: How to create a New server in nodejs?


var http = require("http");
http.createServer(function(request, response) {    
response.writeHead(200, {'Content-Type': 'text/html'});    
response.write("<html>");
response.write("<head>");
response.write("<title>Hello World Page</title>");
response.write("</head>");
response.write("<body>");
response.write("Hello World!");
response.write("</body>");
response.write("</html>");
    response.end();
}).listen(8081);

Question: How to Execute above response in browser?
http://127.0.0.1:8081/
You should be already installed WampServer/Xampp Server.

Question: How to install httpdispatcher?

npm install httpdispatcher

Question: Give an example of http GET Request?


dispatcher.onGet("/contactus", function(req, res) {
    res.writeHead(200, {'Content-Type': 'text/html'});
    res.end('<h3>
Contact US Page</h3>
');
});

Question: Give an example of http POST Request?


dispatcher.onPOST("/contactus", function(req, res) {
    res.writeHead(200, {'Content-Type': 'text/plain'});
    res.end('<h3>
Received POST Data</h3>
');
});

Question: Give an full example of httpdispatcher which have multiple pages?


var dispatcher = require('httpdispatcher'); 
function handleRequest(request, response) {
    try {
        //log the request on console
        console.log(request.url);
        //Disptach
        dispatcher.dispatch(request, response);
    } catch (err) {
        console.log(err);
    }
}
dispatcher.setStatic('resources');

//A sample GET request    
dispatcher.onGet("/contactus", function(req, res) {
    res.writeHead(200, {'Content-Type': 'text/html'});
    res.end('<h3>
Contact US Page</h3>
');
});

dispatcher.onGet("/aboutus", function(req, res) {
    res.writeHead(200, {'Content-Type': 'text/html'});
    res.end('<h3>
About US Page</h3>
');
});


var http = require('http');
var server = http.createServer(handleRequest);
//Lets start our server
server.listen(8081, function() {
    //Callback triggered when server is successfully listening. Hurray!
    console.log("Server listening on: http://localhost:%s", 8081);
});

Saturday, 12 October 2019

How to install and Connect to MySQL in NodeJS?

Hope you have already installed nodeJS, If not Please install first.
https://nodejs.org/en/download/

Question: How to install new package in nodejs?

npm install packagename

Question: How to install MySQL?

npm install mysql

Question: How to update MySQL?

npm update mysql

Question: How to include MySQL?

var mysql = require("mysql");

Question: How to connect to MySQL in nodeJS?

var mysql = require("mysql");
var con = mysql.createConnection({
    host: "localhost",
    user: "root",
    password: "",
    database: "mydb"
});
con.connect(function(err) {
    if (err) {
        console.log('Error connecting to database');
        return;
    }
    console.log('Connection established Successfully');
});

Question: How to connect to MySQL in single string in nodeJS?

var mysql = require("mysql");
var con = mysql.createConnection('mysql://arun:arun@localhost/database'); 
con.connect(function(err) {
    if (err) {
        console.log('Error connecting to database');
        return;
    }
    console.log('Connection established Successfully');
});

Question: How to get records from MySQL database in node.js?

var mysql = require("mysql");
var con = mysql.createConnection({
    host: "localhost",
    user: "root",
    password: "",
    database: "enterprisedev2"
});

con.query('SELECT * FROM admin_members where id<=10 ', function(err, rows) {
    for (var i = 0; i < rows.length; i++) {
        console.log(rows[i]);
    }
});

Question: How to insert record in database?

var mysql = require("mysql");
var con = mysql.createConnection('mysql://arun:arun@localhost/mydb');
var post = {
    'userID': "1",
    'userName': 'username',    
    'device': 'web',
    'stream_time': "0",
    'user_display_name': "arun kumar gupta",
    'user_photo': "hello"
};
con.query('INSERT INTO messages set ?', post, function(err, result) {
    if (err) {
        console.log(err.message);
    } else {
        console.log('record added in db');
    }
});

Question: How to print the query while inserting record?

var mysql = require("mysql");
var con = mysql.createConnection('mysql://arun:arun@localhost/mydb');
var post = {
    'userID': "1",
    'userName': 'username',    
    'device': 'web',
    'stream_time': "0",
    'user_display_name': "arun kumar gupta",
    'user_photo': "hello"
};
var mysqlProfiler = con.query('INSERT INTO messages set ?', post, function(err, result) {});
console.log(mysqlProfiler.sql);

Question: Given another way to insert data in MySQL Database?

var mysql = require("mysql");
var con = mysql.createConnection('mysql://arun:arun@localhost/enterprisedev2');

/* data insert in db */
var postData = {
    userID: "1",
    userName: "arunkg",
    userRole: "1",
    text: 'kkkkkkkkkkkkkkkk',
    status: "1",
    vid: '21'
};

var mysqlProfiler = con.query('INSERT INTO `messages` (`userID`, `userName`, `userRole`,`text`,`status`,`vid`) VALUES (' + [postData.userID, mysql.escape(postData.userName), postData.userRole, mysql.escape(postData.text), postData.status, postData.vid] + ')', function(err, result) {
    if (err) {
        //console.log(err.message);
    } else {
        console.log('record added in db');
    }
});

Sunday, 13 October 2019

How to create http server in NodeJS?

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Saturday, 12 October 2019

How to install and Connect to MySQL in NodeJS?

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