# Learning Node.JS Programming markdown=yes http://codecondo.com/7-minimal-node-js-web-frameworks/ Learning Style Guide * * * * * * * * * * * * * * * * * * * ## Hello World at Command Prompt Open up a text file and enter: // Call the console.log function. console.log("Hello World"); Save file as hello-console.js and then at the command prompt, execute: `node hello-console.js` Obviously, that produces: `Hello World` ## Hello World HTTP Server Add the following code to a file called: `hello-server.js` --- // Load the http module to create an http server. var http = require('http'); // Configure our HTTP server to respond with Hello World to all requests. var server = http.createServer(function (request, response) { response.writeHead(200, {"Content-Type": "text/plain"}); response.end("Hello World\n"); }); // Listen on port 8080, IP defaults to 127.0.0.1 server.listen(8080); // Put a friendly message on the terminal console.log("Server running at http://127.0.0.1:8080/"); --- Execute the code with: `node hello-server.js` The following message will be displayed to the console: `Server running at http://127.0.0.1:8080/` Point the browser to the domain/sub domain of the server with the port included. Example: If running the server and the browser on the same machine, use: `http://localhost:8080` If the above server code is running, then the following will be displayed in the browser: `Hello World` To stop this server app, hit `Ctrl-C` at the command prompt. ## Counter Add the following code to `counter.js` --- var http = require('http'); var userCount = 0; http.createServer(function (request, response) { console.log('New connection'); userCount++; response.writeHead(200, {'Content-Type': 'text/plain'}); response.write('Hello!\n'); response.write('We have had '+userCount+' visits!\n'); response.end(); }).listen(8080); console.log('Server started'); --- Execute the code with: `node counter.js` The message displayed to the console will say: `Server started` When accessing the server at port 8080 in the browser, the following will be displayed to the browser: `Hello!` `We have had 1 visits!` Back at the server, the console display will say: `New connection` `New connection` A refresh on the browser will cause the following message to be sent by the counter.js app: `Hello!` `We have had 3 visits!` The counter increments by two. Explanation from the [article](http://www.theprojectspot.com/tutorial-post/Node-js-for-beginners-part-1-hello-world/2) : q. Note: You might see the counter going up by two for each request, this is because your browser is requesting the favicon from the server (http://localhost:8080/favicon.ico). br. br. You should also see that Node.js is logging each request it receives to the console. br. br. The main thing we're doing here is setting a 'userCount' variable and incrementing on each request. We're then writing the 'userCount' in the response text. q.. ## Hello World Module Create the file `main.js` with the following code: var hello = require('./hello'); hello.world(); In the same directory, create another file called `hello.js` with the following code: exports.world = function() { console.log('Hello World'); } Execute at the command prompt: `node main.js` The console will display the following: `Hello World` ## Parse Log File ## Using Forever Running a Node.js app as daemon. q. The purpose of Forever is to keep a child process (such as your node.js web server) running continuously and automatically restart it when it exits unexpectedly. q.. I made a change to my Ghost blog installation config file. I killed the Ghost index.js process. When I did, it automatically restarted and loaded the new config settings. `$ npm install forever` `$ forever start /home/nodejs/counter.js` ### Forever commands usage: forever [start | stop | stopall | list] [options] SCRIPT [script options] options: start start SCRIPT as a daemon stop stop the daemon SCRIPT stopall stop all running forever scripts list list all running forever scripts ### Nginx Server Block `$ cd /etc/nginx/sites-available` `$ vim nodejs.yoursite.com` The server block file: server { listen 80; server_name nodejs.yoursite.com; location / { proxy_pass http://nodejs.yoursite.com:8080; } } `$ service restart nginx` In browser, access: http://nodejs.yoursite.com Each refresh will update the counter. Should see something like this: Hello! We have had 18 visits! ## Express Framework `npm install express` q. When you install a module, it will put it in a node_modules folder inside your application directory. You can now require it like any built-in module. q.. file: `static-file-server.js` code: var express = require('express'), app = express(); app.use(express.static(__dirname + '/public')); app.listen(8081); execute: `node static-file-server.js` ## NPM
There are thousands of modules available that solve almost all typical problems that you're likely to encounter. Remember to check npm before re-inventing the wheel. It's not unheard of for a typical Node.js application to have dozens of dependencies. In the previous example we manually installed Express. If you have a lot of dependencies, that's not going to be a very good way to install them. That's why npm makes use of a package.json file.
package.json { "name" : "MyStaticServer", "version" : "0.0.1", "dependencies" : { "express" : "3.3.x" } }
A package.json file contains an overview of your application. There are a lot of available fields, but this is pretty much the minimum. The dependencies section describes the name and version of the modules you'd like to install. In this case I'll accept any version of Express 3.3. You can list as many dependencies as you want in this section. Now instead of installing each dependency separately, we can run a single command and install all of them. `$ npm install` When you run this command npm will look in the current folder for a package.json file. If it finds one, it will install every dependency listed.
## Blogging Test Apps - Wheat is a blogging engine that reads a git repo full of markdown articles and presents them as a website. - A Simple Blog with CouchDB, Bogart, and Node.js ## Bogart Web Framework ## Frameworks * * ## Template Engines Handlebars is one popular template engine. Dust.js ## http GET and POST requests #nodejs - #programming - #javascript - #howto