const path = require('path');
//const http = require('http');
const express = require('express');
const app = express();
const staticPath = path.join(__dirname, "/public");
var bodyParser = require('body-parser')
const cassandra = require('cassandra-driver');
const client = new cassandra.Client({
contactPoints: ['127.0.0.1:9042'],
localDataCenter: 'datacenter1',
keyspace: 'glink'
});
//var server = http.createServer(app);
let id = 1; /* Ideally should initialize id to be nextFromDB or write to file and read */
const port = 63342; // Port that the server listens on */
app.use( bodyParser.json() );
app.use(bodyParser.urlencoded({
extended: true
}));
app.use(express.static(staticPath));
const GLINK_SIZE = 6;
function getRandomGLink() {
let glink = "";
glink = newString(GLINK_SIZE);
//console.log(glink);
validateLink(glink);
return glink;
}
function validateLink(glink) {
let qry = "SELECT id FROM data WHERE glink = ? allow filtering";
client.execute(qry, [glink], {}, (err, result) => {
if(err) {
console.log(err.message);
glink = null;
}
if (result.rows.length === 0) {
console.log("Done");
} else {
console.log(glink);
glink = getRandomGLink();
}
});
return glink;
}
function newString(n) {
let str = "";
let symbols = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
for (let i = 0; i < n; i ++) {
str += symbols.charAt(Math.floor(Math.random() * 52));
}
return str;
}
function nextId() {
let next = id;
id = id + 1;
return next;
}
function filter(path) {
if (path.match(new RegExp("^/[a-zA-Z]+/*$"))) {
if (path.charAt(0) === '/') {
path = path.substring(1);
}
if (path.charAt(path.length - 1) === '/' && path.length > 1) {
path = path.substring(0, path.length - 1);
}
return path;
} else {
console.log("failed check. path is " + path);
return null;
}
}
app.get('/', (request, response) => {
response.render("index.html");
})
app.get('/node_modules/', (request, response) => {
response.sendFile(path.join(staticPath, "/error.html"));
})
app.get('/public/', (request, response) => {
response.sendFile(path.join(staticPath, "/error.html"));
})
const query = "INSERT INTO data (id, url, glink) VALUES (?, ?, ?)";
app.post('/add', function(req, res) {
let input_url = req.body.url;
let input_glink = req.body.glink;
console.log("Received query " + input_url + " and " + input_glink);
let currID = nextId();
if (input_glink === "") {
input_glink = getRandomGLink();
client.execute(query, [currID, input_url, input_glink], {prepare: true}, function(err,result) {
if (err) {
res.send("
" + err.message + "
");
} else {
res.send("
New entry has been added with url = " + req.body.url + " and glink = " + input_glink + "
");
}
});
} else {
let selectQuery = "SELECT id FROM data where glink = ? allow filtering";
client.execute(selectQuery, [input_glink],{} ,function(err, result) {
if (result.rows.length === 0) {
client.execute(query, [currID, input_url, input_glink], {prepare: true}, function(err,result) {
if (err) {
res.send("
{err.message}
");
} else {
res.send("" +
"
" +
"New entry has been added with url = " + req.body.url + " and glink = " /*+ req.body.glink*/ + "" +
"
" +
"" +
"
" +
"" +
"
" +
"" +
"");
}
});
} else {
res.send("
This glink has already been registered. Please try a different glink
");
}
});
}
})
/* Redirect requests to corresponding entry in database */
app.get('/*', (request, response) => {
let req_path = request.path;
req_path = filter(req_path);
console.log("Path is " +req_path);
if (req_path == null) {
response.sendFile(path.join(staticPath, "/error.html"));
return;
}
let selQry = "select url from data where glink = ? allow filtering";
client.execute(selQry, [req_path], {}, function(err, result) {
if (result.rows.length === 0) {
console.log("Failed");
response.sendFile(path.join(staticPath, "/error.html"));
} else {
let page = result.rows[0]["url"];
console.log(page);
response.writeHead(301, {Location: page});
response.end();
}
})
})
app.listen(port, function(){
console.log("server listening on port 63342");
})
/** Validate url and glink on client side as well */
/** Put the glink in a span or label and make it copyable */