The Request/Response Cycle

Before you can build a web scraper, you must take a second and think about how the internet works. At its core, the internet is a network of computers connected together, discoverable through Domain Lookup System (DNS) servers. When you want to visit a website, your browser sends the website URL to a DNS server, the URL is translated into an IP address, and your browser then sends a request to the machine at that IP address. The machine, called a web server, receives and inspects the request, and makes a decision on what to send back to your browser. Your browser then parses the information sent by the server and displays content on your screen depending on the format of the data. The web server and browser are able to communicate because of the adherence to a global set of rules called the HTTP. In this chapter, you will learn some of the key points...