What happens when you make an HTTP request?

Thoughts about an additional resource.

We’ll have to clarify what a “server” is…

https://developer.mozilla.org/en-US/docs/Learn/Getting_started_with_the_web/How_the_Web_works

Assuming Browser with well-formed Uniform Resource Identifier/URL.
A Domain Name is a human-readable address but it is not the actual address of the resource.
The URL is an alias that acts as a pointer to the true Internet Protocol address and location of the requested resource.
- Has the browser recently visited this address and already determined the IP?
- If not, it will as the operating system if another program has (there’s a host file where they are saved).
- If it has the IP address already – then great.
- If not, it will ask the Internet Service Provider.
  - This means that other people may have already requested this and it’s saving all of those connections (scary!)
- If it has the IP address already – then great.
- If not, then it will ask the global authority DNS (look into these details). It will know how to find it (But is the most work)
  - that will come back and the ISP will get a taste(for other users), and the OS(for other programs), and the browser etc. those things will all keep that info for next time
With the IP address in hand, the browser can properly make its HTTP request
- That will go to the ISP
- A range of other intermediate computers along the routing
The web server will note the request (this is a computer)
- This has a program that will run (“The web server”) / dedicated to serving the files that are requested
  - The physical computer is often called a “server” / but it’s just a computer. The program is the server.
  - Clarify that… (apache / nginx) (we can build a simple one) (check curl) (create one with PHP)
- It’s waiting for requests.
- It has a bunch of rules
The HTML could be a file sitting on the file system of that computer
- Or / it could be being created on the fly – based on a set of data/request – or other things – and it will create an HTML file from that
The browser will receive that HTML file
It will read the HTML file and create a tree-like structure called the Document Object Model.
- It might be complete
- but it’s likely to reference separate images, CSS, JS – and all other sorts of files
  - It will start building the website
  - and then – will start requesting the other files
  - WHEN does the final paint happen? (look at these details)
- At this point, the website is all loaded – and it will just exist
  - But it’s also likely to have lots of scripts that are waiting to see if there will be any input
  - At that point, the user can interact with the program in whatever way it’s designed to work
  - Clicking a regular link might load a new page just like we’ve described above.
  - Clicking a button or adding some text to an input might create new pieces of HTML and insert it into the DOM and update the page

Introduction