This module sets the context for what we will study in this specialization by first providing a historical perspective on computing and web applications. Next we provide an overview of how the Internet works, and then we discuss how web applications have evolved over the past few decades. After that we’ll discuss some of the elements of modern software practice, including the typical tools that software engineers now use and the agile development practices they follow. The notion of software design patterns will introduced, and the n-tier architecture design pattern, fundamental to modern web application design, is then presented. Will also discuss a few current topics related to web application development. Finally, we will show you how to set up the software development environment you will use throughout the remainder of the courses in this.

In this module you will learn about web application frameworks. We will start by talking about the evolution of software and programming languages, and then talk about software application frameworks. The fundamental trade-off we will consider is programmer productivity versus program efficiency. Next you will learn about web application frameworks, as well as the model-view-controller design pattern that is the backbone for many of these frameworks. We will also consider how these frameworks support the agile programming principles associated with modern software practice. This will include a discussion of distributed version control systems and you will learn how to use the popular Git system. We will also demonstrate how to use Git with a Ruby on Rails application. We will use Git to submit all of the programming applications in this specialization.

A successful web application provides information t o users that is (1) useful, and also (2) easy to access and understand. This information is often collected from users, as well as from other information sources, and must be stored in a manner that allows it to be manipulated by the web application. The typical app roach is to store this data in a relational database. In this module you will learn some basic concepts associated with modeling the data in a web application, including h ow to specify the relationships between various data entities. We will also investigate ho w to hook a web application up to a back- end data store, along with good design techniques t hat will make it easier to use the data in your web applications by maintaining consistency th roughout the entire web stack.

Middleware is an abstraction layer that hides details about hardware devices and other lower-level software services from an application. Middleware services implement common low-level functions, such as communication with the operating system, application servers, database servers, etc., so that application developers do not need to concern themselves with these details, and can instead focus on the application functionality they are trying to provide. In a web application, these services generally make use of the HTTP protocol, and in a web application framework, the MVC design pattern can be thought of as being implemented over the middleware.