Codelybrary: Back-end (server.js) using Node.js-Express.js

var express = require('express');

var morgan = require('morgan');

var path = require('path');

var Pool= require('pg').Pool;

var crypto=require('crypto');

var bodyParser=require('body-parser');

var session = require('express-session');

var app = express();

app.use(morgan('combined'));

app.use(bodyParser.json());

app.use(session(

{ resave:true,

saveUninitialized:false,

rolling:true,

secret: 'someRandomSecretValue',

cookie: { maxAge: 1000 * 60 * 15}//session expires automatically in 15 mins

}

));

var config={

user:'internetadvancedsolutions',

database:'internetadvancedsolutions',

host:'db.imad.hasura-app.io',

port:'5432',

password:process.env.DB_PASSWORD

};

var pool= new Pool(config);

app.get('/ui/:fileName', function (req, res) {

res.sendFile(path.join(__dirname, 'ui', req.params.fileName));

});

app.get('/', function (req, res) {

res.sendFile(path.join(__dirname, 'ui', 'index.html'));

});

var counter=0;

app.get('/counter',function(req,res){

counter=counter+1;

res.send("Total visits "+counter.toString());

});

//defining our hash function

function hash(input,salt){

salt='random';

var hashed=crypto.pbkdf2Sync(input,salt,10000,512,'sha512');

// return ["pbkdf2", "10000", salt, hashed.toString('hex')].join('$');

return(hashed.toString('hex'));

}

function createArticle(data,idd){

//var article1=data.topic;

//var ids =idd;

// var htmlarticle=`<a href="/aa/archive/${ids}" class="fontcolor1">${article1}</a>`;

var htmlarticle=`

<a href="/aa/archive/36" class="fontcolor1">How to make a text blink in webpage</a><br>

<a href="/aa/archive/23" class="fontcolor1">WAMP stack</a><br>

<a href="/aa/archive/29" class="fontcolor1">How to program a microcontroller</a><br>

<a href="/aa/archive/26" class="fontcolor1">Front-end development</a><br>

<a href="/aa/archive/25" class="fontcolor1">google charts</a><br>

<a href="/aa/archive/20" class="fontcolor1">Coding Tips</a><br>

<a href="/aa/archive/19" class="fontcolor1">cyber means?</a><br>

<a href="/aa/archive/21" class="fontcolor1">javaScript</a><br>

<a href="/aa/archive/16" class="fontcolor1">java is language to program computers</a><br>

return htmlarticle;

}

function createTemplate(data1,data2){

var title=data1.title;

var heading=data1.heading;

var username= data2;

// var content=data.content;

var htmltemplate=`

<!doctype html>

<html>

<head>

<title>${title}</title>

</head>

<body>

<td><h2 id="h1" class="center text-big bold">Internet Advanced Solutions (IAS)</h2>

<h3 id ="h3" class ="center text-medium bold">${heading}</h3></td></tr>

</table>

<hr>

</pre>

</div>

Learning by Sharing

</div>

<p></p>

Knowledge increases by giving...teaching is the best way of learning !

</div>

<hr>

<a class="hyperlinks1" href="/lo/logout" align="right">Logout</a><br>

<hr>

<p id="user" class="fontcolor1">Dear ${username} Welcome to IAS forum !, please post your article below</p>

<p class="fontcolor1">Article Heading :<textarea id="topic" cols="100" rows="1" maxlength="100" autofocus required></textarea></p>

<table>

<tr>

</td><td rowspan="2"><div id="h1" class="blink_me"> PUBLISHED ARTICLES<br>Go to these articles and ask questions/answer to questions/leave your remarks...<br>that's how we learn!</div><br><div id="content"></div><br></td>

</tr>

</table>

</pre>

</div>

document.getElementById("t").innerHTML=Date();

var button=document.getElementById("submit");

var para=document.getElementById("p1");

button.onclick=function()

{

var request = new XMLHttpRequest();

request.onreadystatechange=function()

{

if(request.readyState===XMLHttpRequest.DONE)

{

if(request.status===200)

{

para.innerHTML="Your article posted successfuly !... Will be publised soon... after approval ";

}

else

{

para.innerHTML="Oops ! submission failed ";

}

var topic1=document.getElementById("topic").value;

var topic = topic1.trim();

var user_post1=document.getElementById("user_post").value;

var user_post = user_post1.trim();

var username_post= "${username}";

console.log(topic);

console.log(user_post);

console.log(username_post);

request.open('POST','/pa/post',true);

request.setRequestHeader('Content-Type', 'application/json');

//request.send(JSON.stringify({user_post:user_post, topic:topic}));

request.send(JSON.stringify({user_post:user_post, topic:topic, username_post:username_post}));

para.innerHTML="Posting.............";

};

window.onload= function()

{

var request1= new XMLHttpRequest();

request1.onreadystatechange=function()

{

if(request1.readyState==4 && request1.status==200 )

{

var allarticles =request1.responseText;

var div=document.getElementById("content");

div.innerHTML=allarticles+'<br>';

}

};

request1.open('GET',"/ga/publish",true);

request1.send(null);

};

</script>

</body>

</html>

return htmltemplate;

}

function createTemplate1(data1){

var title1=data1.title;

var heading1=data1.subject;

var content1=data1.duration;

var content2=data1.start_date;

var content3=data1.content;

var price=data1.fees;

var htmltemplate1=`

<!doctype html>

<html>

<head>

<title>${title1}</title>

</head>

<body>

<table>

<tr>

<td>

<td><h2 id="h1" class="center text-big bold" align="center">Internet Advanced Solutions (IAS)</h2><h3 id ="h3" class ="center text-medium bold"> ${heading1}</h3></td>

</tr>

</table>

<hr>

| <a class ="hyperlinks" href="/">Home</a> | <a class ="hyperlinks" href="/db/6">IAS Code Library</a><hr>

</pre>

</div>

Learning by Sharing

</div>

<tr><td>Course & Duration : </td><td>

${content1}

</td></tr>

<tr><td>Start Date : </td><td>

${content2.toDateString()}

</td></tr>

${price}

</td></tr>

</table>

</div>

<div>

<hr>

${content3}

<hr>

</div>

<tr><td>My IT skills</td></tr>

<tr><th>Languages </th><th>Frameworks </th><th>Front-end </th><th>Back-end </th></tr>

<tr><td>C/C++</td><td>Android Studio</td><td>HTML</td><td>Node.js</td></tr>

<tr><td>Swift</td><td>Xcode 8</td><td>CSS</td><td>Express.js</td></tr>

<tr><td>java</td><td>Eclipse IDE</td><td>javaScript</td><td>PHP</td></tr>

<tr><td>Python</td><td>Linux</td><td>Angular JS</td><td>SQL</td></tr>

<tr><td>Sketch</td><td>Arduino IDE</td><td>Bootstrap</td><td>JSP</td></tr>

<tr><td>Embedded C</td><td>XAMPP</td><td>Ajax</td><td>Servlets</td></tr>

</table>

</pre>

</div>

</body>

</html>

return htmltemplate1;

}

function createPost(data1,data2,data3,data4,data5){

var title1='IAS Forum';

var heading1=data3;

var content1=data1;

var poster=data2;

var commenter = data4;

var post_id = data5;

var htmltemplatePost=`

<!doctype html>

<html>

<head>

<title>${title1}</title>

</head>

<body>

<table>

<tr>

<td>

<td><h2 id="h1" class="center text-big bold" align="center">Internet Advanced Solutions (IAS)</h2><h3 id ="h3" class ="center text-medium bold">Article: ${heading1}</h3></h6></td>

</tr>

</table>

<hr>

| <a class ="hyperlinks" href="/">Home</a> | <a class ="hyperlinks" href="/db/6">IAS Code Library</a> | <a class="hyperlinks" href="/lo/logout" align="right">Logout</a><hr>

</pre>

</div>

Learning by Sharing

</div>

<h2>This article is contributed by <span id="blue">${poster}</apan></h2>

<h4>

${content1}

</h4>

</div>

<hr>

<p>Dear ${commenter} add your comments/remarks/queries to this article here</p>

<table>

<tr>

</tr>

</table>

<button id="submit" >Submit</button>

<h3>Message Board</h3>

<hr>

<tr><td>My IT skills</td></tr>

<tr><th>Languages </th><th>Frameworks </th><th>Front-end </th><th>Back-end </th></tr>

<tr><td>C/C++</td><td>Android Studio</td><td>HTML</td><td>Node.js</td></tr>

<tr><td>Swift</td><td>Xcode 8</td><td>CSS</td><td>Express.js</td></tr>

<tr><td>java</td><td>Eclipse IDE</td><td>javaScript</td><td>PHP</td></tr>

<tr><td>Python</td><td>Linux</td><td>Angular JS</td><td>SQL</td></tr>

<tr><td>Sketch</td><td>Arduino IDE</td><td>Bootstrap</td><td>JSP</td></tr>

<tr><td>Embedded C</td><td>XAMPP</td><td>Ajax</td><td>Servlets</td></tr>

</table>

</pre>

</div>

var button=document.getElementById("submit");

var para2=document.getElementById("c");

button.onclick=function(){

var request = new XMLHttpRequest();

request.onreadystatechange=function()

{

if(request.readyState===XMLHttpRequest.DONE)

{

if(request.status===200)

{

var user_comment = document.getElementById("user_comments");

para2.innerHTML ='<span id="blue">'+ " ${commenter}"+'</span>'+'<br>' + user_comment.value;

}

else

{

para2.innerHTML="Oops ! submission failed ";

}

var user_comment1 = document.getElementById("user_comments").value;

var user_comment = user_comment1.trim();

var commenter_name= "${commenter}";

var post_id_ = ${post_id};

console.log(user_comment);

console.log(commenter_name);

console.log(post_id_);

request.open('POST','/com/submit-comments',true);

request.setRequestHeader('Content-Type', 'application/json');

request.send(JSON.stringify({user_comment:user_comment, commenter_name:commenter_name, post_id_:post_id_}));

para2.innerHTML="submitting your comments.............thanks" +" ${commenter}";

};

window.onload= function()

{

var request1= new XMLHttpRequest();

request1.onreadystatechange=function()

{

if(request1.readyState==4 && request1.status==200 )

{

var allarticles =JSON.parse(request1.responseText);

var commentsList='<hr>';

for(i=allarticles.length-1;i>=0;i--)

{

commentsList += '<p id ="blue">'+ allarticles[i].user_name +'<br>'+ '<span id ="black">' + allarticles[i].user_comment+'</span>'+'</p>';

}

var para3=document.getElementById("d");

para3.innerHTML=commentsList;

// para3.innerHTML=allarticles;

}

};

var post_id_ = ${post_id};

request1.open('POST',"/co/get-comments",true);

request1.setRequestHeader('Content-Type', 'application/json');

request1.send(JSON.stringify({ post_id_:post_id_}));

};

</script>

</body>

</html>

return htmltemplatePost;

}

//function to create a new user

app.post('/rg/create-user',function(req,res){

var usern1=req.body.username;

var usern= usern1.trim();

console.log(usern);

var passw=req.body.password;

console.log(passw);

var salt=crypto.randomBytes(128).toString('hex');

var dbString=hash(passw,salt);

console.log(dbString);

pool.query('INSERT INTO "users" (username, password) VALUES ($1, $2)',[usern,dbString] ,function (err, result) {

if (err) {

res.status(500).send(err.toString());

} else {

res.send('User successfully created: ' + usern);

}

});

app.post('/lg/login', function (req, res) {

var username = req.body.username;

var password = req.body.password;

console.log(username);

console.log(password);

pool.query('SELECT * FROM "users" WHERE username = $1', [username], function (err, result) {

if (err) {

res.status(500).send(err.toString());

} else {

if (result.rows.length === 0) {

res.status(403).send('username/password is invalid');

} else {

// Match the password

console.log("username inputed ="+username);

var dbString = result.rows[0].password;

console.log("stored hashed password ="+dbString);

//var salt = dbString.split('$')[2];

var salt ='random';

var hashedPassword = hash(password, salt);

console.log(" hashed password ="+hashedPassword);

if (hashedPassword === dbString) {

// Set the session

//req.session.auth = {userId: result.rows[0].id};

req.session.auth = {userId: result.rows[0].username};

// set cookie with a session id

// internally, on the server side, it maps the session id to an //object

//{ auth: {userId }}

res.send('credentials correct!');

}

else {

res.status(403).send('username/password is invalid');

}

});

app.get('/:articleName',function(req,res){

if (req.session && req.session.auth && req.session.auth.userId ) {

// Load the user object

pool.query('SELECT * FROM "article" WHERE id= $1', [req.params.articleName], function(err,result){

if (err) {

res.status(500).send(err.toString());

} else {

var username = req.session.auth.userId;

console.log("session in username is" + username);

var articleData=result.rows[0];

// res.send(createTemplate(articleData));

res.send(createTemplate(articleData,username));

// res.send(result.rows[0].username);

}

});

} else {

res.status(400).send('You are not logged in....Please go to Login page and sign-in');

}

});

app.get('/db/:n', function(req,res){pool.query("SELECT * FROM course WHERE id=$1", [req.params.n], function(err,result)

{

if(err)

{

res.status(500).send(err.toString());

}

else

{

if(result.rows.length===0)

{

res.status(404).send('Could not access database');

}

else

{

var ta=result.rows[0];

res.send(createTemplate1(ta));

}

});

app.post('/pa/post',function(req,res){

var text=req.body.user_post;

var topic=req.body.topic;

var posters_name= req.body.username_post;

console.log(text);

console.log(topic);

console.log(posters_name);

pool.query('INSERT INTO "posts" (user_post,topic,posters_name) VALUES ($1,$2,$3)',[text,topic,posters_name],function (err, result) {

if (err) {

res.status(500).send(err.toString());

} else {

res.send("posted");

}

});

app.get('/ga/publish', function(req,res){

pool.query('SELECT topic FROM "posts" ', function (err, result)

{

if (err) {

res.status(500).send(err.toString());

}

else

{

// console.log(result.rows.length);

var ar = result.rows[1];

var n =1;

res.send(createArticle(ar,n));

for(var i=result.rows.length; i>=0;i--)

{

var ar = result.rows[i];

var id = i;

res.send(createArticle(ar,id));

}

});

app.get('/aa/archive/:ids', function(req,res){

if (req.session && req.session.auth && req.session.auth.userId )

{

var match_id= req.params.ids;

pool.query('SELECT * FROM "posts" WHERE id=$1',[match_id], function (err, result) {

if (err) {

res.status(500).send(err.toString());

}else{

// var ida = req.params.ids;

//var art = result.rows[ida].user_post;

//var art = JSON.stringify(result.rows[0].user_post);

var art = result.rows[0].user_post;

//var user= result.rows[ida].posters_name;

var user= result.rows[0].posters_name;

//var topic=result.rows[ida].topic;

var topic=result.rows[0].topic;

var commenter = req.session.auth.userId;

//var post_id = result.rows[ida].id;

var post_id = result.rows[0].id;

res.send(createPost(art,user,topic,commenter,post_id));

}

});

}

else {

res.status(400).send('You are not logged in....Please go to Login page and sign-in');

}

});

var lout= `

<!doctype html>

<html>

<head>

<title>Thanks for Visiting</title>

</head>

<body>

<td><h2 id="h1" class="center text-big bold">Internet Advanced Solutions (IAS)</h2>

<h3 id ="h3" class ="center text-medium bold"><pre>Logged out! Thanks for visiting</pre></h3></td></tr>

</table>

<hr>

<a class ="hyperlinks" href="/">Back to Home</a> <a class ="hyperlinks" href="/db/9" align="center">Login again</a><hr>

</pre>

</div>

Learning by Sharing

</div>

<p></p>

Knowledge increases by giving...teaching is the best way of learning !

</div>

<hr>

</body>

</html>

app.get('/lo/logout', function (req, res) {

delete req.session.auth;

res.send(lout);

});

app.post('/com/submit-comments',function(req,res){

var comment=req.body.user_comment;

var commenter=req.body.commenter_name;

var post_id= req.body.post_id_;

console.log(comment);

console.log(commenter);

console.log(post_id);

pool.query('INSERT INTO "comments" (user_comment,user_name,post_id) VALUES ($1,$2,$3)',[comment,commenter,post_id],function (err, result) {

if (err) {

res.status(500).send(err.toString());

} else {

res.send("posted");

}

});

app.post('/co/get-comments', function (req, res) {

// make a select request

// return a response with the results

// pool.query('SELECT * FROM comments', function (err, result) {

var post_id= req.body.post_id_;

//var post_id =25;

console.log(post_id);

pool.query("select * from comments where post_id = $1",[post_id], function (err, result) {

if (err) {

res.status(500).send(err.toString());

} else {

res.send(JSON.stringify(result.rows));

}

});

var port = 8080;

app.listen(8080, function () {

console.log(`IAS app listening on port ${port}!`);

});

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Tuesday, September 5, 2017

Back-end (server.js) using Node.js-Express.js

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