The process object is globally available to every node module. It contains functionalities which allow us to interact with current process in the system.
The Process object also provides information about the runtime environment. In addition, standard input/output (I/O) occurs through process, we can also gracefully terminate a Node application and we can even signal when the Node event loop (We will discuss this) has finished a cycle.
This is also useful for building command line applications as we can capture all user parameters passed to the program which it has been invoked from the terminal.
The user provided parameters are available in the process.argv variable.
Let us create a small terminal program that passes a message to the module. Create a file called greeting.js
console.log("Total Arguments: ", process.argv.length);
Modules are reusable functionality. They can be a function, a class, an object or even just simple variables.
To import a module we use the require() function in node. Require function is globally available.
NOTE: New version of Node.js supports ES6 notation of import and export statements.
Let’s see some of the features of modules in the examples below. In global.js file:
var path = require("path");console.log(`Full path: ${__filename} and filename is ${path.basename(__filename)}`);
The output of the above code, once you run the command: node global in your terminal, would be:
Let me know what is not clear as I tried to be as elaborate as possible. May be I will add some diagrams to this. Thanks.
import and export are the new es6 features. You can either use it enabling the experimental flag as documented here Node.js v11.10.0 Documentation
Or you can also write your entire node code with bab...
Event Emitters play a very important role in the Node.js ecosystem.
The EventEmitter is a module that facilitates communication/interaction between objects in Node. EventEmitter is at the core of Node asynchronous event-driven architecture. Many of Node’s built-in modules inherit from EventEmitter including prominent frameworks like Express.js.
The concept is quite simple: emitter objects emit named events that cause previously registered listeners to be called. So, an emitter object basically has two main features:
It’s kind of like a pub/sub or observer design pattern (though not exactly).
If you were to publish your blog online, anyone would be able to add, edit and delete articles or delete comments.
Rails provides a very simple HTTP authentication system that will work nicely in this situation.
In the ArticlesController we need to have a way to block access to the various actions if the person is not authenticated. Here we can use the Rails http_basic_authenticate_withmethod, which allows access to the requested action if that method allows it.
To use the authentication system, we specify it at the top of our ArticlesController in app/controllers/articles_controller.rb. In our case, we want the user to be authenticated on every action except index and show, so we write that:
class ArticlesController < ApplicationControllerhttp_basic_authenticate_with name: "dhh", password: "secret", except: [:index, :show]
Before this step, any user of the app could edit any part of the database. This might be okay for very small internal apps or demos, but any real application needs to control permissions for its data. In Meteor, the best way to do this is by declaring methods. Instead of the client code directly calling insert, update, and remove, it will instead call methods that will check if the user is authorized to complete the action and then make any changes to the database on the client's behalf.
Every newly created Meteor project has the insecure package added by default. This is the package that allows us to edit the database from the client. It's useful when prototyping, but now we are taking off the training wheels. To remove this package, go to your app directory and run:
9.1 Remove insecure package:
meteor remove insecure
In this lesson, you’ll learn:
Web developers create documents that can be viewed on the internet, also known as web pages. These documents are usually written in a combination of computer languages called HTML (HyperText Markup Language) and CSS (Cascading Style Sheets).
HTML is used to write the actual document—mainly, th...
Can I use my Android to do my HTML and CSS because I have no laptop.
For linking the HTML page to CSS where there is css/style.css is that the file name?