Can we say node.js is a web server?

Question

I found that I am confusing between web framework and web server.

Apache is a web server.

Tornado is a web server written in Python.

Answer 1

How I feel your pain !

Like many, I found it hard to get to the essence of Node.js because most people only write/talk about the part of Node that they find useful - and the part they find interesting is usually a secondary benefit of Node rather than its primary purpose. I must say that I think it's mad for people to say that Node is just a JavaScript runtime. Node's use of JavaScript - and its selection of the V8 runtime - are simply means to an end, the best tools for the problem that Node's developers wanted to solve.

Node's primary purpose was to make the management of user events in a web app more efficient. So Node is overwhelmingly used on the back end of a web app. Event management demands that something is listening at the server machine for these user events. So a http server must be set up to route each event to its appropriate handler script. Node provides a framework for quickly setting up a server to listen on a dedicated port for user requests. Node uses JavaScript for event handling because JavaScript has callback functions: this allows one task to be suspended until the result of a dependent task is returned. Not many other languages have this feature and those that do may not have an interpreter as effficient as Google's V8 runtime. Most web developers know JavaScript so there's no additional language learning with Node. What's more, having callback functions allows the putting of all user tasks on a single thread without having explicit blocking applied to tasks demanding access to the database or file system. And this is what leads to the superior executional efficiency of Node under heavy concurrent use - the primary purpose for its development.

To help Node users quickly write back end code, Node's developers also organized both a built-in JS library for routine tasks (e.g. matters related to HTTP requests, string (de)coding, streams etc) and the NPM (Node Package Manager) repositary: this is an open source, user-maintained set of script packages for various standard and custom functions. All Node projects allow importation of NPM packages into a project via the established npm install command.

User requests handled via Node will be things needed by the web app like authentication, database querying, content management (Strapi CMS), etc. All these will be sent to the Node port. (Where analysis of data got from a database is takes a lot of CPU time, this type of process is best put on a separate thread so it doesn't slow simpler user requests.) Other types of user request, e.g. to load another webpage, download CSS/JS/image files, etc, will continue to be sent by the browser to the default port(s) on the server machine where the web server program (Apache, NGinx, etc) will handle them.

So, in practice, Node is principally a framework for rapid server-creation and event-handling but one that replaces only some of the functions of the web server program.

Other non-backend uses of Node simply exploit one or other of its features, e.g. the V8 engine. For example, the frontend build tools Grunt and Gulp use Node.js to process a build script that can be coded to convert SASS to CSS, minify CSS/JS files, optimize image size/loading, etc. But this sort of work is really just by-product use of Node, not its principal use which is for making efficient backend processes for web applications.