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Showing posts from January, 2012

CAPTCHA - A Revolution

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CAPTCHA = Completely Automated Public Turing test to tell Computers and Humans Apart What is a CAPTCHA? A System built by Luis von Ahn, Manuel Blum, Nicholas J. Hopper, and John Langford of CMU to make sure that user who is active at the other end is a Human and not a bot. This was initially done to prevent bots entering yahoo chat rooms and redirecting the users to someother sites. CAPTCHA - Reverse Turing Test : Yups, CAPTCHA is a reverse turing test because it reverses the role of computers and human. Computer is a device designed to perform what human want it to. But in the case of CAPTCHA it is reversed. It is completely automated, so computer challenges you to perform some action to identify that you are a human. Initially [even now] CAPTCHA was an distorted image with some characters in it which would make lives of bots harder to detect them but which wouldn't affect human though Next generation of CAPTCHA carried a audio link with the distorted image beside to

Nodejs Modules and Export Explained

Enjoyed a week playing around with nodejs :) Lets share Simple Node Server [http://localhost:6666]: var http = require('http'); var server = http.createServer(function (req, res) {            // Do Whatever you want               res.writeHead(200, {'Content-Type':'text/plain'});               res.end('Running');          }).listen(6666, function () {                    console.log('Node Runs on port 6666'); }); How to install a node_module? NPM is a powerful package manager for node which you can use to install node modules Ex: npm install redis The above command installs redis module in ./node_modules/redis directory How to use a module? Use require() method Ex: require('redis') How will node resolve the modules? Consider /home/xxx/sample  |___ index.js  |___ node_modules           |____ redis                      |____lib/                         ...           |____ my_module