Saturday 31 March 2012

Creating a Node.js program in Cloud9 IDE


Cloud9 IDE is an online development environment for Javascript and Node.js applications as well as HTML, CSS, PHP, Java, Ruby and 23 other languages. Cloud9 IDE lets you build, debug, and run your Node.js applications within the browser. Set breakpoints, follow the call stack, and analyze your performance. In this post I’ll demonstrate how to build a simple Node.js server app using Cloud9 IDE.
Creating a new project:
Creating a project in Cloud 9 IDE requires an account which is available as a free subscription at http://c9.io/. After successful registration you can create a new project by adding a new project form the dashboard.


After entering the project name you can select the type of project to create
·         Git project: will allow you to run git commands from the console and push your changes to Github
·         Mercurial: will allow you to run hg commands form the console and push your changes to Bitbucket.
·         FTP: will allow you to upload your files directly to an FTP server you have access to.
Select create after choosing a project type. Now, just click Start Editing to get started!
You can right click on the selected project and add a ‘New File’

Creating the node.js server
We’ll create a simple http server with controllers to handle the request and send the response to the clients. Create a new loginController.js file and add the code given below.
exports.process = function handle(response) {
    response.writeHead(200);
    response.end('<html>' +
                    '<head>' +
                        '<meta http-equiv="Content-Type" content="text/html; ' +
                        'charset=UTF-8" />' +
                    '</head>' +
                    '<body>' +
                    '<form action="/login" method="post">' +
                         'Login name:<input type=text value="" name="txtLogin" style="width: 100px"></br>' +
                         'Password  :<input type=password value="" name="txtPassword" style="width: 100px"></br>' +
                         '<input type="submit" value="Login" /> &nbsp; &nbsp; <input type="submit" value="Cancel" />' +
                    '</form>' +
                    '</body>' +
                    '</html>');
The process property is assigned to an object called 'exports'. Such an 'exports' object is available in every module, and it is returned whenever the required function is used to include the module. We can now use this function as given below
var loginController = require('./handlers/loginController');
loginController.process(response);
Similarly you can create the other controllers and then the http server like
var http = require('http');
var homeController = require('./handlers/homeController');
var loginController = require('./handlers/loginController');
var errorController = require('./handlers/errorController');
var port = process.env.PORT;

var requestListener = function(request, response)
{
    switch(request.url)
    {
        case '/':
            homeController.process(response);
            break;
        case '/login':
            loginController.process(response);
            break;
        default:
            errorController.process(response);
            break;
    }
}

var server = http.createServer(requestListener);
server.listen(port);
In the first line, we included the http core module and assign it to a variable called http. Later we use this variable called server by calling http.createServer().
You can also specify which port the server listens to. When Node.js projects run within Cloud 9 IDE, you can retrieve the port information with process.env.PORT. You can run the project by clicking the Debug button. 



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