Web Application for Docker

Docker is a open source toll designed to make it easier to create, deploy, and run applications by using containers. Containers allow a developer to package up an application with all of the parts it needs, such as libraries and other dependencies, and ship it all out as one package . All that is needed for programs distributed through Docker is inside the image and does not intersect with the primary system and other containers.

In a way, Docker is a bit like a virtual machine. But unlike a virtual machine, rather than creating a whole virtual operating system, Docker allows applications to use the same Linux kernel as the system that they’re running on and only requires applications be shipped with things.

Docker is a tool that is designed to benefit both developers and system administrators, making it a part of many DevOps (developers + operations) toolchains.

Developing a Web Application for Docker:

The Common Gateway Interface, or CGI, is a set of standards that define how information is exchanged between the web server and a custom script.

To understand the concept of CGI, let us see what happens when we click a hyper link to browse a particular web page or URL.

• Your browser contacts the HTTP web server and demands for the URL, i.e., filename.
• Web Server parses the URL and looks for the filename. If it finds that file then sends it back to the browser, otherwise sends an error message indicating that you requested a wrong file.
• Web browser takes response from web server and displays either the received file or error message.

To Run any program as CGI the following steps to be followed:

• The program file should be in cgi-bin directory

var/www/cgi-bin

• Make file as executable file. An executable file is a type of computer file that runs a program when it is opened. This means it executes code or a series of instructions contained in the file.

chmod +x <file_name>

• Use of hashbang (#!) indicates that the webpage uses client-side rendering to deliver the right content. A large number of sites use hashbang as they have some useful features which make them great for client-side applications.
• Mention the type of content to be displayed on the client browser.

httpd is the Apache HyperText Transfer Protocol (HTTP) server program. It is designed to be run as a standalone daemon process. When used like this it will create a pool of child processes or threads to handle requests.

The subprocess module is a powerful part of the Python standard library that lets you run external programs and inspect their outputs easily.

JAVA SCRIPT

JavaScript is a text-based programming language used both on the client-side and server-side that allows you to make web pages interactive. Where HTML and CSS are languages that give structure and style to web pages, JavaScript gives web pages interactive elements that engage a user.

JavaScript is used in both Back End and Front End Development. JavaScript is used across the web development stack. JS is a simple and easy to learn programming language as compared to other languages such as C++, Ruby, and Python. It is a high-level, interpreted language that can easily be embedded with languages like HTML.

Uses of JavaScript :

JavaScript is one of the most used languages in the market these days. Below graph shows a graphical representation of a company for all languages. JavaScript stands second in the lineup. It is mainly used in building websites and web applications.

• Web Development : Web development is the work involved in developing a Web site for the Internet or an intranet. Web development can range from developing a simple single static page of plain text to complex web applications, electronic businesses, and social network services. JavaScript adds interactivity to your website. This happens in games, in the behavior of responses when buttons are pressed or with data entry on forms; with dynamic styling; with animation, etc.
• Web Application : A web application is application software that runs on a web server, unlike computer-based software programs that are run locally on the operating system of the device. Web applications are accessed by the user through a web browser with an active network connection. As JavaScript is a client-side programming language which helps web developer to do Web Application Development and make dynamic and interactive web pages by implementing custom client-side scripts. Developers can also use cross-platform runtime engines like Node.js to write server-side code in JavaScript.

JavaScript is an open source and cross-platform language and therefore mostly used for creating network-centric applications. Nowadays it has become an inseparable part of the core technologies of the internet. JavaScript is used in web technologies to make web pages interactive. Along with HTML and CSS, JavaScript is widely used in web servers and databases.

Examples of scripted Behavior :

• Loading new webpage content without reloading the page, via Ajax or a Web socket. For example, user of social media can send and receive messages without leaving the current page.
• Web page animations, such as fading objects in and out, resizing, and moving them.
• Playing browser games.
• Controlling the playback of streaming media.
• Generating pop-ups.
• validating input values of a web form before the data is sent to a web server.
• Logging data about the user’s behavior then sending it to a server. The website owner can use this data for analytics , Ad Tracking , and personalization .

Thank you!!