Notes

Request Response Model

Nov 03, 20243 min read

Note

you see this everywhere but Simple, Classic

  • Client makes a request
  • Server parse the request(tries to give it meaning)
    • Parse means this is where it start and this is where it ends
    • Serialization changing the content(request) to something I can understand
  • Server process the request
  • Server sends a response
  • Client parse the response and consumes it.

What is a request ?

Since the backend and the frontend(client) have to agree what is it. Its not just send one thing and end it there it’s continuous stream of data so you have to understand where the data start and ends. This is parsing.

Also What is the language of the request is is

  • XML
  • JSON
  • binary

Where can I find this model ?

Sort answer is like everywhere

  • Web
  • HTTP
  • DNS
  • SSH
  • ls (list directories)
  • remote procedure call (the abstraction of taking request to execute a function to a remote server)
  • SQL and Database
    • you send query to the database the database process your SQL code and give you the response
  • API REST/SOAP/GraphQl(created by META tries not to be chatty)

What is Anatomy of Request/Response model

A request is defined by both the client and server Request is defined by the protocol(where it start and end) and by the message format(is this XML, JSON or other)

Example

If you send an Image you can send it as one file or you can send it as a bunch of files
If you send it as one if internet is down for one second your whole Image is lost so it’s not resumable
But if you send it in chunk you only have to send the chunk you haven’t send already so you can resume.

What is the downside of this model?

In Notification service this model wouldn’t work why?

  • because the client has to make a request but in notification service the client doesn’t know when the notification comes
  • the only way to make request/response method work is when the client says does the notification arrived? a bunch of time until it gets the response saying the notification is arrived here is it. Since you don’t know if the notification have arrived you are going to get a bunch of empty response and this is very bad design.

Demo

Code time

curl --trace out.txt http://google.com

This command do is make get request to google.com and --trace make it so that we can see everything that it do in the middle of the request and puts it in out.txt

Next pattern Synchronous Vs Asynchronous

Graph View

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