Overview of HTTP Methods

The following article outlines the methods of Http. Any activity is done over the web, be it web browsing or online shopping, which is basically an exchange of data between the end device and the web-server. We expect a secure connection between our device and the web server hosting the site that protects the integrity and confidentiality of the data being exchanged. HTTP (Hypertext Transfer Protocol) is the universally agreed-upon format of transmitting data over a network that governs how data is exchanged between the user devices and website servers and what actions are taken by the web servers and browsers for each ‘command’. HTTPS is an advanced and more secure upgrade to HTTP.

Example

• Browsing Amazon.

As we start typing the word “Amazon” in the address bar or search bar, note here that the browser has automatically suggested the target web address as “https://www.amazon.in/“.

As we click enter and the website is loaded, we also see the icon of a lock right before the web address indicating a secure connection following HTTPS protocols. Any data transferred through HTTPS connection is encrypted before transmitting with Secure Sockets Layer (SSL) and Transport Layer Security (TLS) methods.

All this together ensure the following three layers of security

• Encryption – All data that is exchanged is encrypted.
• Data Integrity – No data can be corrupted or modified during transit.
• Authentication – Ensures that users are connected with the intended websites.

HTTP Methods (also called verbs)

While browsing, the end-user (browser action) sends requests to the web-server and the server sends the correlated response. HTTP defines a set of request methods to indicate the chosen action to be performed. Any user can use any method and the server can be designed to support any combination of methods.

There are 9 pre-defined methods used with HTTP and HTTPS.

1. Get

The GET method is used to retrieve information (“entity”) from the webserver using a specified Request-URI (Uniform Resource Identifier). Requests using GET must only retrieve data and have no other effect on the data.

A conditional GET method requests that the entity be transferred only under the circumstances described by the conditional header field(s), intended to reduce avoidable network usage. Similarly, partial GET requests that only part of the entity be transferred.

2. Head

The HEAD method is identical to GET except that the server transfers the status line and the header section only, without the response body. This is useful for retrieving meta-information written in response headers, without having to transmit the entire content.

This method is often used for testing hypertext links for validity, accessibility, and recent modification, or simply checking what a GET request will return before actually passing a request.

3. Post

This request is used to transmit important structured data to the server, for example, customer data, file uploads, etc. using HTML forms to create or update a resource. It requests the origin server to accept the ‘entity’ enclosed within the request body as a new subordinate of the resource identified by the Request-URI.

A simple example is a “Contact” form on a website. When you fill out the inputs in a form and hit “Send”, that data is embedded in the request body and sent to the server in a format like JSON, XML, or any of other formats.

4. Options

Though not as widely used as the other HTTP methods request should return data describing what other methods the server supports at the given URL without indicating a resource action or requesting a resource retrieval. This can be used to check the functionality of a web server by requesting ‘*’ , which indicates that the request does not apply to a particular resource.

5. Put

Similar to POST, it replaces all the current representations of the target resource with the uploaded content. The PUT method requests that the included entity be stored under the specified Request-URI. If the Request-URI refers to an already existing resource, the entity should be considered as a modified version of the existing one on the server.

Calling the same PUT request multiple times always produces the same result, while calling a POST request repeatedly may create the same resource multiple times.

6. Delete

This method is used to delete the resource at the specified URL. The end-client cannot be assured that the action has been carried out, even if the status code returned from the web server specifies that the action has been finished successfully. However, the server is not expected to indicate success except, when the response is given, it erases the resource or moves it to an isolated location.

7. Trace

This method allows the client to see what is being received at the server end of the request chain and to use that data for testing so that the client can see what changes (if any) have been made by intermediary servers. The final recipient of the request replicates the message received back to the client as the entity-body of the response.

8. Connect

This transforms the request connection to a transparent TCP/IP tunnel, typically to enable SSL-encrypted data exchange (HTTPS) through an unencrypted HTTP proxy. This is called HTTP Tunneling. The request creates a tunnel to the server indicated by the target resource.

9. Patch

This method applies partial modifications to a resource. It provides an entity having a list of changes to be applied to the resource in the form of a PATCH document that uses structures such as XML or JSON or others.

The PATCH method is faster and less resource-consuming than the put method when making partial changes to the specified resource.

Conclusion – HTTP Methods

HTTP requests are the underlying framework that allows users to interact with websites through browsers. This framework is also used in mobile applications that make use of APIs which inherently include combinations of these Request Methods / Verbs for easier development and testing, and ensure smooth and simplified user experience.

This has been a guide to HTTP Methods. Here we discuss their overview and different methods of HTTP in detail. You may also have a look at the following articles to learn more –

1. HTTP Cookies
2. HTTP Caching
3. PHP Filters
4. Graphs in R

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