Everything about HTTP

Details about HTTP, Port Number, Status Codes, Request Methods, and Headers

What is HTTP?

• HTTP is a hypertext transfer protocol.
• HTTP is basically built on TCP (Transmission Control Protocol). TCP is a lower-level protocol that handles other lower-level important stuff that HTTP does not have to worry about.

Image take from Wikipedia

Status Codes

• 1XX - Information
• 2XX - Success
• 3XX - Redirect
• 4XX - Client Error (like 404 NOT FOUND), Here the client is responsible for the error.
• 5XX - Server Error (like 503 Server Not Available), Here server is responsible for the error.

Port Number

• Like http we also have https, ftp, ssh etc which have some port number assigned to it.
• It is mainly done to distinguish between all these, as when we will search for something then how our computer will know whether to use http or https.

Port Number assigned:-

• http - 80
• https - 443
• ftp - 21, ftp stands for File Transfer Protocol.
• ssh - 22, ssh stands for Secure Server Protocol.

Note:-

- When we will search for https://google.com then by default, the search will be for https://google.com:443

- By all these ports it doesn’t mean that https will not work with the port number 234, it will work but it is not what anyone will advise someone to do.

More about Port Numbers

• Port numbers are not infinite. They are finite and they range from 0 to 65535. That simply means we cannot start any port number great than 65535.
• Port numbers below 1023 are privileged port numbers. They require certain administrative access to be opened.

Request Methods

• GET method is the default request method.
• Mostly we do use GET methods to browse most of the web.
• GET basically means that you are visiting web pages.
• POST means you want to interact or send some data to the server. POST is used to communicate data to the server.
• PUT - Its functionality is the same as that of POST but if we will use PUT rather than POST then our server and client both know that we want to create the resource.
• PATCH means to edit the resource.
• DELETE means to delete a particular resource.

NOTE :-

- GET is the method should not have a body as if it will store some data like username, and password then anyone can access those data via just visiting the site.

- We can do anything we want using GET and POST on the internet under http. These two are the most powerful methods to use.

- Functionality wise POST is the most superior as it can perform as others as well. Because POST contain the Request Payload body which contains the resources.

Request Headers

• HTTP headers are just a way to provide more information to the request.
• For example Content-Type: text/html , this content-type header simply tells which type of content we have.

Full View of the Request Header

:authority: codedamn.com
:method: GET
:path: /
:scheme: https
accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
accept-encoding: gzip, deflate, br
accept-language: en-GB,en-US;q=0.9,en;q=0.8,hi;q=0.7
cookie: _gcl_au=1.1.659405939.1664042912; _ga=GA1.1.1679921718.1664042913; _fbp=fb.1.1664042912877.1560911668; AUTH_TOKEN=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VybmFtZSI6ImR1a2U3ODYiLCJfaWQiOiI2MTFjYTUyYzQxYzRhMTAwMDhlNDg4M2QiLCJuYW1lIjoiTW9oaXQgTWlzaHJhIiwiaWF0IjoxNjY0MDQzODM1LCJleHAiOjE2NjkyMjc4MzV9.uzly7qoYubm5iW-vok9M4c7kKG-Qd3HZ6YPKVKQSy4k; amp_824c80=XqiaBPuVfqgshtUxKQWhWe...1ge1rdkrm.1ge1rdkrm.1.2.3; _clck=1drazbx|1|f59|0; crisp-client%2Fsession%2F3e9d1351-f1a3-4320-986d-a97e915064bd=session_b9678a0f-dd6f-4726-95d0-fbbd9d6f8f9f; _clsk=o2x2c1|1664372093460|10|1|n.clarity.ms/collect; _ga_5Q1YFB1R0F=GS1.1.1664372054.10.1.1664372095.0.0.0; amp_824c80_codedamn.com=XqiaBPuVfqgshtUxKQWhWe.NjExY2E1MmM0MWM0YTEwMDA4ZTQ4ODNk..1ge24s6mj.1ge24teib.26.e.2k
referer: https://www.google.com/
sec-ch-ua: "Google Chrome";v="105", "Not)A;Brand";v="8", "Chromium";v="105"
sec-ch-ua-mobile: ?0
sec-ch-ua-platform: "Windows"
sec-fetch-dest: document
sec-fetch-mode: navigate
sec-fetch-site: cross-site
sec-fetch-user: ?1
upgrade-insecure-requests: 1
user-agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/105.0.0.0 Safari/537.36

Firstly, know that:

• URLs are a type of URI
• URNs are a type of URI
• URCs are a type of URI

and there are many other

URI

• A standard for identifying documents using a short string of numbers, letters, and symbols.
• Defined by https://datatracker.ietf.org/doc/html/rfc3986

Examples:- URLs, URNs, URCs, and many others.

URL

• Contains information about how to fetch a resource from its location.
• Always start with the protocol
• Can be relative

Examples:

• http://example.com/mypage.html
• file:///home/user/file.txt
• tel:1-888-555-5555

URN

• Identifies a resource by a unique and persistent name, but doesn’t necessarily tell you how to locate it on the internet.
• It usually starts with the prefix urn:

Examples:

• urn:isbn:0451450523 to identify a book by its ISBN number.
• urn:uuid:6e8bc430-9c3a-11d9-9669-0800200c9a66 a globally unique identifier

URC

• Points to metadata about a document rather than to the document itself.
• An example of a URC is one that points to the HTML source code of a page
• Examples:- like: view-source:http://example.com/