HTTP Methods

What is HTTP ?

HTTP stands for Hypertext Transfer Protocol. It is a protocol used for transferring data over the web, specifically between a client (usually a web browser) and a server. HTTP is the foundation of data communication on the World Wide Web.

What are the HTTP Methods ?

GET
POST
PUT
HEAD
DELETE
PATCH
OPTIONS

1. GET

Purpose: The GET method is used to request data from a specified resource on the server. It is the most common HTTP method, primarily used for fetching resources like web pages, images, or data from APIs.
Key Characteristics: GET requests are safe (they don’t modify data) and idempotent (repeated requests will always return the same result). It is used to retrieve information without making any changes to the server.

2. POST

Purpose: The POST method sends data to the server to create or update a resource. It is commonly used when submitting forms or uploading files.
Key Characteristics: POST requests are not safe (they may change data on the server), and they are not idempotent (repeating the request could create or modify resources multiple times). It’s typically used for sending data that will be processed or stored.

3. PUT

Purpose: The PUT method is used to update or replace an existing resource on the server. If the resource doesn’t exist, it can create a new one.
Key Characteristics: PUT is idempotent, meaning that making the same request multiple times will result in the same state. It replaces the entire resource, unlike PATCH, which only updates parts of it.

4. DELETE

Purpose: The DELETE method is used to remove a specified resource from the server.
Key Characteristics: DELETE requests are idempotent, meaning if you delete a resource and then delete it again, the result is the same (the resource remains absent). It’s used when you need to remove data from the server, like deleting a file or database record.

5. HEAD

Purpose: The HEAD method is similar to GET but retrieves only the headers of a resource, without the body. It’s often used to check metadata or verify if a resource exists without downloading it.
Key Characteristics: Like GET, HEAD requests are safe and idempotent. It’s useful for checking the status of a resource, like checking for file existence or size without downloading the content.

6. OPTIONS

Purpose: The OPTIONS method is used to query a server about which HTTP methods it supports for a specific resource. It is commonly used in CORS (Cross-Origin Resource Sharing) scenarios to determine the allowed operations before making a request.
Key Characteristics: OPTIONS requests are safe and idempotent, and they provide information about the server’s capabilities without modifying any resources.

7. PATCH

Purpose: The PATCH method is used to apply partial updates to a resource, unlike PUT, which replaces the entire resource. It’s used when only specific fields or attributes need to be modified.
Key Characteristics: PATCH requests are not idempotent (by default), as sending the same patch multiple times may yield different results. It is used for partial modifications of a resource without needing to send the entire data.

8. TRACE

Purpose: The TRACE method is used for diagnostic purposes. It allows the client to see the path that the request takes to reach the server, including all intermediate proxy servers. The server responds by sending back the exact request it received, which helps with debugging and tracing how the request is being handled by proxies or intermediaries.
Key Characteristics: The TRACE method is safe (it doesn’t modify any data), but it is not idempotent (it may vary based on the proxies or intermediaries along the request path). It’s primarily used for diagnostic or troubleshooting purposes to track the request’s journey through the network.

Note: In practice, the TRACE method is rarely used in production environments due to security concerns, as it can potentially expose sensitive information and headers. Many web servers disable it to mitigate certain types of attacks like cross-site tracing (XST).