HTTP: Request Methods

What is HTTP?

The Hypertext Transfer Protocol (HTTP) is designed to enable communications between clients and servers.

HTTP works as a request-response protocol between a client and server.

Example: A client (browser) sends an HTTP request to the server; then the server returns a response to the client. The response contains status information about the request and may also contain the requested content.

HTTP Methods

  • GET
  • POST
  • PUT
  • HEAD
  • DELETE
  • PATCH
  • OPTIONS

The two most common HTTP methods are: GET and POST.

The GET Method

GET is used to request data from a specified resource.

GET is one of the most common HTTP methods.

Note that the query string (name/value pairs) is sent in the URL of a GET request:

/test/demo_form.php?name1=value1&name2=value2

Some other notes on GET requests:

  • GET requests can be cached
  • GET requests remain in the browser history
  • GET requests can be bookmarked
  • GET requests should never be used when dealing with sensitive data
  • GET requests have length restrictions
  • GET requests are only used to request data (not modify)

The POST Method

POST is used to send data to a server to create/update a resource.

The data sent to the server with POST is stored in the request body of the HTTP request:

POST /test/demo_form.php HTTP/1.1
Host: w3schools.com
name1=value1&name2=value2

POST is one of the most common HTTP methods.

Some other notes on POST requests:

  • POST requests are never cached
  • POST requests do not remain in the browser history
  • POST requests cannot be bookmarked
  • POST requests have no restrictions on data length

The PUT Method

PUT is used to send data to a server to create/update a resource.

The difference between POST and PUT is that PUT requests are idempotent. That is, calling the same PUT request multiple times will always produce the same result. In contrast, calling a POST request repeatedly have side effects of creating the same resource multiple times.

The HEAD Method

HEAD is almost identical to GET, but without the response body.

In other words, if GET /users returns a list of users, then HEAD /users will make the same request but will not return the list of users.

HEAD requests are useful for checking what a GET request will return before actually making a GET request - like before downloading a large file or response body.

The DELETE Method

The DELETE method deletes the specified resource.

The OPTIONS Method

The OPTIONS method describes the communication options for the target resource.

Compare GET vs. POST

The following table compares the two HTTP methods: GET and POST.

  GET POST
BACK button/Reload Harmless Data will be re-submitted (the browser should alert the user that the data are about to be re-submitted)
Bookmarked Can be bookmarked Cannot be bookmarked
Cached Can be cached Not cached
Encoding type application/x-www-form-urlencoded application/x-www-form-urlencoded or multipart/form-data. Use multipart encoding for binary data
History Parameters remain in browser history Parameters are not saved in browser history
Restrictions on data length Yes, when sending data, the GET method adds the data to the URL; and the length of a URL is limited (maximum URL length is 2048 characters) No restrictions
Restrictions on data type Only ASCII characters allowed No restrictions. Binary data is also allowed
Security GET is less secure compared to POST because data sent is part of the URL

Never use GET when sending passwords or other sensitive information!		 POST is a little safer than GET because the parameters are not stored in browser history or in web server logs
Visibility Data is visible to everyone in the URL Data is not displayed in the URL

Comments

Post a Comment

Popular posts from this blog

REST API

Image
What is a REST API? REST or RESTful API design (Representational State Transfer) is designed to take advantage of existing protocols. While REST can be used over nearly any protocol, it usually takes advantage of HTTP when used for Web APIs. This means that developers do not need to install libraries or additional software in order to take advantage of a REST API design. REST API Design was defined by Dr. Roy Fielding in his 2000 doctorate dissertation. It is notable for its incredible layer of flexibility. Since data is not tied to methods and resources, REST has the ability to handle multiple types of calls, return different data formats and even change structurally with the correct implementation of hypermedia. This freedom and flexibility inherent in REST API design allow you to build an API that meets your needs while also meeting the needs of very diverse customers. Unlike SOAP , REST is not constraine...
Read more

Quantum Computing

Image
Quantum Computers perform calculations based on the probability of an object's state before it is measured - instead of just 1s or 0s - which means they have the potential to process exponentially more data compared to classical computers.
Read more

XML v/s JSON

Image
Both JSON and XML can be used to receive data from a web server. JSON is used to store information in an organized, and easy-to-access manner. Its full form is JavaScript Object Notation. It offers a human-readable collection of data which can be accessed logically. XML is a markup language which is designed to store data. It's popularly used or transfer of data. It is case sensitive. XML offers you to define markup elements and generate customized markup language. The basic unit in the XML is known as an element. Extension of XML file is .xml KEY DIFFERENCE JSON object has a type whereas XML data is typeless. JSON does not provide namespace support while XML provides namespaces support. JSON has no display capabilities whereas XML offers the capability to display data. JSON is less secured whereas XML is more secure compared to JSON. JSON supports only UTF-8 encoding whereas XML supports various encoding formats. JSON Code vs XML Code Let's see a sample JSON Code { ...
Read more