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Request format

HTTP 2.0 and beyond

We will use HTTP1.1 in this course but know that there are versions more recent like HTTP2 and HTTP3 that bring improvements in performance and security.

Notably HTTP2 introduces

And there is also HTTP/3 which uses QUIC (above UDP and no longer TCP) as a transport protocol, offering additional improvements in terms of latency and security.

Request types

You may have noticed the GET in the previous request.

Basically it’s to say that we want to make a GET type request.
Implied there are other types of requests :

These are the main types of requests but there are others, for the complete list you can take a tour here Hypertext Transfer Protocol

⚠️ In practice it often happens that POST is used, instead of PATCH,
to update data already present on the server side ... 🤢

Let’s experiment

In Python 🐍 you suspect there is everything you need!!

import requests

We will use

the site http://httpbin.org which provides a relatively useful test server.
and the python/httpbin-client folder of the course

Return codes

When we make a request to a server via http/https, the latter returns us first a return code. These codes are standardized (non-exhaustive list) :

And so the first thing to do when you make a request to a server is to check that the return code is 200 because otherwise there’s no point in continuing!

The notion of API

Application Programming Interface

Allows to define how a consumer program will be able to exploit the functionalities given by a provider program

In the particular domain of the Web, the API is actually defined from a URL. Indeed, access to the resource is done by making a GET request (or POST, depending on the case) on a particular URL.

Image from Jérémy Mésière, Architecte Middleware chez Manutan

Image from Jérémy Mésière, Architecte Middleware chez Manutan

REST API

Representational State Transfer

Set of principles governing Web application architecture.

  • HTTP Methods:

    Operations are performed using HTTP methods: GET (read), POST (create), PUT/PATCH (update), DELETE (delete). Example: A GET request to a blog API to retrieve a specific article.

  • Resources:

    In REST, all data or states are considered as “resources”. Each resource is uniquely identified by a URI (Uniform Resource Identifier). Example: /articles/123 can represent the resource for the article with ID 123.

  • Stateless:

    Each REST API request must contain all the necessary information to be understood by the server. No session state is maintained on the server. Advantages: Simplifies server design and improves scalability.

  • Resource representation:

    Resources can be represented in different formats, JSON and XML being the most common. The choice of format is often indicated in the HTTP Content-Type header of the request.

The importance of HTTP headers

HTTP headers are parameters sent in HTTP requests and responses that provide essential information about the HTTP transaction.

Notably this will allow us to manage authentication 🔐 when we want to access protected APIs, the data format, the API version

Some classic headers:

Intro to networking
Data Encoding
Intro to networking
Epilogue