Node/Express

Node is a runtime environment for running JavaScript.

HTTP is a protocol (a set of rules) that talks about sending HTML (and now other kinds of data) back and forth across the network.

Node & the Network

We can use node to run javascript in response to a newtork request.

Node & Express

Specifically, we'll use a web framework called Express in order to create a dynamic web server that interacts with a database.

By the end of this unit, we'll have designed a 3-tier application similar to this.

File Server vs. Application Server

We'll be dealing with 2 kinds of server for doing HTTP:

1. File Server - depending on a request to the computer, sends back a specific file on the filesystem.

   • Simple logic - if file exists, send back. Else, send back an error.
   • Don't have to write it ourselves (has already been written before) - See here if you want to know how one might be written in node:https://developer.mozilla.org/en-US/docs/Learn/Server-side/Node_server_without_framework

1. Application Server

   • dynamically responds to requests and serves back HTML (or other) based on the request
   • Uses express.js framework to handle shuttling requests to our js code.
   • the js code we write inside the express files is the logic that determines what gets sent back in the response.