Training Guide: Programming in HTML5 with JavaScript and CSS3 Ebook

354 CHAPTER 8 Websites and services

Uninstalling a package

Uninstall a local package by executing the following command from the root folder of the

application.

npm uninstall math_example

To uninstall a global package, execute the following command.

npm uninstall -g math_example

Fast forward to express

Although it is relatively easy to create a Hello module with Node.js, much more work is

necessary if you intend to create a complete web framework. For example, when a request is

received at the server for a resource such as a webpage or a web service, you typically need

to route the request to get the proper resource. You might also want to implement sessions

to hold data between each request. What about authentication? It doesn’t make sense for

you to create this framework when you can install a more streamlined framework. The express

web application framework for node.js is available at http://expressjs.com/. You can install

express by using the previously mentioned npm install command, or you can read the next

section to learn how to install express from a dependency list.

This framework is also referred to as expressjs or simply express. In this book, it will be

referred to as express. The express framework provides a thin layer of features over Node.js,

where performance is maintained.

Starting with express

To begin using express, you must install Node.js first, and then you create a folder for your

web application. In this example, the folder is the following.

C:\node_samples\HelloExpress

Next, you set up a dependency on express, so you need the current version number of

express. Execute the following command to get the version information.

npm info express version

At the time of this writing, the version is 3.0.0. You need this version number when you add

the dependency to the package.json file.

To create the package.json file in the HelloExpress folder, navigate to that folder, execute

the following command, and follow the prompts.

npm init

The following is the completed package.json.

{

"name": "HelloExpress",

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