What is HTTP and why it is used?

What is the difference between TCP and HTTP traffic?

You can always tell what kind of traffic it is if you are on a secure network, you usually find a green dot (or green rectangle) next to a website in the URL bar (Chrome, Internet Explorer etc. This tells us what protocol that website is using (usually http or https).

So this makes me wonder what differences and advantages that TCP offers that http does not. Basically they have different roles within a network stack but are both types of data transfers. A TCP connection always represents at one end the sender and at the other end the receiver. This means that every packet sent corresponds with the sending device and thus the data is protected.

HTTP over TCP offers more opportunities as the data transfer is much faster and has in itself the possibility of more complex information exchange, for example file uploads or form/login/data submission.

What type of traffic is HTTP?

I'm a bit confused on the types of HTTP traffic, and how they relate to each other.

When I first learned about HTTP, it was my understanding that the web page I was visiting was being transferred from the server to my browser, and the browser was then displaying it to me. My understanding is that when you type in a URL into your web browser, it performs a HTTP GET request to that URL (which retrieves the web page). If you then navigate to another URL, a HTTP GET request is performed. Does this mean that all HTTP requests are made via GET requests? Are there any other types of HTTP traffic?
There are two major types of HTTP traffic. POST request. GET request is used to fetch data from the server. POST request is used to send data to the server. In most cases, the GET request is used. But when you use POST request, the data will be sent to the server with some headers.

This is a example of a GET request. GET /path/to/page HTTP/1.1 Host: www.8 Accept-Language: en-us,en;q=0.5 Accept-Encoding: gzip, deflate. If-Modified-Since: Wed, 10 Nov 2023 07:13:31 GMT. If-None-Match: "a4e716e1dfd2". Cookie: ga=GA1.1224209823.1429595891
You can see the GET request header in the above example. This is a POST request. POST /path/to/page HTTP/1.

How does HTTP traffic work?

A look into the HTTP protocol

Let's start by talking about HTTP traffic, which is the fundamental building block of our web applications.

HTTP is an application protocol designed to exchange information between two endpoints. Endpoints are basically anything you can communicate with over the internet. For example, your browser and a web server, or two different computers communicating over the internet. This is how we interact with the World Wide Web.

HTTP traffic is made up of two distinct phases. The first phase is the request and the second one is the response. Let's take a closer look at these two phases and learn what they mean.

Request: The initial request from the client to the server. The first thing you should know about HTTP traffic is that it's divided into two phases, which is why we call it a request-response model. The first phase in the request-response model is a request and the second phase is the response.

Every single time your web browser makes a request to a web server, it sends a message to the server with the specific HTTP header along with the URL and the body of the request. The request gets the server's attention and the server sees that it's a request and not something else. The server then checks whether the request is allowed to send the requested content. If the server doesn't send back an appropriate response to the client, the client will simply close the connection without receiving any data from the server. But there are times when the server doesn't get back an appropriate response, for example, if the server is overloaded, or it has a large number of pending requests. In this scenario, the connection will remain open for quite some time, because the client expects a response. Now, the browser will receive a time-out error and it has to retry sending the request again after a few seconds.

When the server receives a request, the next step is to receive the URL and the HTTP header of the request. Then, if the server needs to perform certain actions or provide certain resources for the client, it sends back a response to the client. The response contains an HTTP header which contains the HTTP code of the response, and the HTTP body which includes the content of the response along with the status code and the reason why the server didn't provide a particular response to the client.