HTTP Methods
HTTP methods indicate the action that the client wishes to perform on the web server resource.
Common HTTP methods are:
| HTTP Method | Description |
| GET | The client requests a resource on the web server. |
| POST | The client submits data to a resource on the web server. |
| PUT | The client replaces a resource on the web server. |
| DELETE | The client deletes a resource on the web server. |
HTTP Request Body
HTTP requests can optionally include a request body. A request body is often included when using the HTTP POST and PUT methods to transmit data.
POST /users HTTP/1.1
Host: example.com
{
"key1":"value1",
"key2":"value2",
"array1":["value3","value4"]
}
PUT /users/1 HTTP/1.1
Host: example.com
Content-type: text/json
{"key1":"value1"}
HTTP Response Body
Following the HTTP response headers is the HTTP response body. This is the main content of the HTTP response.
This can contain images, video, HTML documents and other media types.
HTTP/1.1 200 OK
Date: Fri, 17 Feb 2023 15:00:00 GMT+2
Server: Apache/2.2.14 (Linux)
Content-Length: 84
Content-Type: text/html
<html>
<head><title>Test</title></head>
<body>Test HTML page.</body>
</html>
Have you ever noticed the lock icon
beside the URL in your web browser?
This means the secure version of HTTP is being used.
HTTP is a core operational protocol
of the world wide web.
It is what enables your web browser to
communicate with a web server that hosts a website.
HTTP is the communication protocol
you use whenever you browse the web.
HTTP stands for Hypertext Transfer Protocol
is a protocol used for transferring
web resources such as HTML documents,
images, styles, and other files.
HTTP is a request response-based protocol.
A web browser or client sends
an HTTP request to a server,
and the web server sends
the HTTP response back to the browser.
Next, let's start exploring
the makeup of an HTTP request.
An HTTP request consists of a method,
path, version, and headers.
The HTTP method describes
the type of action that the client was to perform.
The primary or the most commonly used HTTP methods
are GET,
POST, PUT and DELETE.
The GET method is used to
retrieve information from the given server.
The POST request is used to send data to the server.
The PUT method updates
whatever currently exists on the website with
something else and
the DELETE method removes the resource.
The path is the representation of
where the resource is stored on the web server.
For example, if you requested
an image at https://example.com/index.html,
the path would be /index.html.
There are multiple versions of the HTTP protocol.
I won't explore these right now,
but I want you to be aware that Version
1.1 and 2.0 are the most used.
Finally, there are the headers.
Headers contain additional information
about the request,
and the client that is making the request.
For certain requests methods,
the requests will also contain a body
of content that the client is sending.
Now, let's cover some details
about the makeup of an HTTP response.
HTTP responses follow a format
similar to the request format.
Following the header, the response
will optionally contain
a message body consisting of
the response contents such as the HTML document,
the image file, and so forth.
HTTP status codes indicate if
the HTTP requests successfully completed.
The core values are in the range of a
100-599 and grouped by purpose.
The status message is
a text representation of the status code.
During your web browsing,
have you ever encountered pages that display
404 error not found or 500 errors?
The server is not responding?
These are HTTP status codes.
I want to briefly explain to you
the status codes and their grouping.
There are five groups of status codes.
They're grouped by the first digit of the error number.
Informational is grouped from 100-199.
Successful responses are grouped from 200-299.
Redirection messages are from 300-399.
Client error responses ranged from
400-499 and server error responses are from 500- 599.
Information responses are
provisional responses sent by the server.
These responses are interim before the actual response.
The most common inflammation response is 100 Continue,
which indicates that the web client should continue to
request or ignore the response
if the request is already finished.
Successful responses indicate that
the request was successfully processed by the web server,
with the most common success response
being 200 Ok. You're
receiving these responses every day when you
receive content successfully from a website.
The meaning of Ok depends on the HTTP method.
If the method is GET,
it means that the resource is found and is
included in the body of the HTTP response.
If it's POST, it means that
the resource was successfully
transmitted to the web server.
If it's PUT, the resource was
successfully transmitted to the web server.
Finally, if the method is DELETE,
it means the resource was deleted.
Redirection responses indicate to the web client
that the requested resource
has been moved to a different path.
The most common response codes used are
301 Moved Permanently and 302 was Found.
The difference between the redirection messages 301 and
302 is that 302 indicates a temporary redirection.
The resource has been temporarily moved.
When web browsers receive these responses,
they will automatically submit
the request for the resource at the new path.
Client error responses indicate
that the requests contained
bad syntax or content
and cannot be processed by the webserver.
The most common codes used are,
400 is used where the web browser or
client submitted bad data to the web server.
401 is used to indicate that the user
must log into an account
before the request can be processed.
403 is used to indicate the request was valid,
but that the webserver is refusing to process it.
This is often used to indicate that a user does not have
sufficient permissions to execute
an action in a web application.
404 is used to indicate that
the requested resource was not found on the web server.
Server error responses indicate that a failure
occurred on the webserver while
trying to process the request.
The most common code used is 500 Internal Server Error,
which is a generic error status
indicating that the server fail to process the request.
Now, have you ever bought something
online and needed to enter your credit card information?
You wouldn't want someone else to get
this information from the HTTP request.
This is where HTTPS is involved.
HTTPS is the secure version of HTTP.
It is used for secure communication between two computers
so that nobody else can see
the information being sent and received.
It does this by using something called encryption.
We won't cover encryption right now.
Like an HTTP,
the requests and responses still behave
in the same way and have the same content.
The big difference is before the content is sent,
it is turned into a secret code.
Only the other computer can turn
the secret code back into its original content.
If someone else was to look at the code,
it wouldn't be understandable.
You use HTTPS every day.
This is the lock icon you see
beside the URL in your web browser.
Before I finish,
Firstly, it is a protocol
used by web clients and web servers.
It works to transfer web resources such as
HTML files and as
the foundation of any data exchanges on the web.
Also, remember that by using HTTPS,
we send the information securely.
Requests are sent by the client,
usually a web browser,
and the server replies with responses which may be
the return of an image or an HTML page.
HTTP requests have a syntax that includes method,
path, versions, and headers.
HTTP responses follow a similar format to the request.
HTTP status codes indicate whether
the HTTP requests successfully completed.
The status code is a three-digit number that
corresponds with groups representing
different types of results.
Now you know how the HTTP protocol request
and the response cycle works.
You know about its methods and the elements that
make up an HTTP request.